Following optimisations of the SVE register handling we no longer load the SVE state from a saved copy of the FPSIMD registers, we convert directly in registers or from one saved state to another. Remove the function so we don't need to update it during further refactoring.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 2 -- arch/arm64/kernel/entry-fpsimd.S | 16 ---------------- 2 files changed, 18 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 9a62884183e5..e0e30567b80f 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -69,8 +69,6 @@ extern void sve_save_state(void *state, u32 *pfpsr); extern void sve_load_state(void const *state, u32 const *pfpsr, unsigned long vq_minus_1); extern void sve_flush_live(unsigned long vq_minus_1); -extern void sve_load_from_fpsimd_state(struct user_fpsimd_state const *state, - unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); extern void sve_set_vq(unsigned long vq_minus_1);

diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 196e921f61de..afbf7dc47e1d 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -66,22 +66,6 @@ SYM_FUNC_START(sve_set_vq) ret SYM_FUNC_END(sve_set_vq)

-/* - * Load SVE state from FPSIMD state. - * - * x0 = pointer to struct fpsimd_state - * x1 = VQ - 1 - * - * Each SVE vector will be loaded with the first 128-bits taken from FPSIMD - * and the rest zeroed. All the other SVE registers will be zeroed. - */ -SYM_FUNC_START(sve_load_from_fpsimd_state) - sve_load_vq x1, x2, x3 - fpsimd_restore x0, 8 - sve_flush_p_ffr - ret -SYM_FUNC_END(sve_load_from_fpsimd_state) - /* * Zero all SVE registers but the first 128-bits of each vector *

SME introduces streaming SVE mode in which FFR is not present and the instructions for accessing it UNDEF. In preparation for handling this update the low level SVE state access functions to take a flag specifying if FFR should be handled. When saving the register state we store a zero for FFR to guard against uninitialized data being read. No behaviour change should be introduced by this patch.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 6 +++--- arch/arm64/include/asm/fpsimdmacros.h | 20 ++++++++++++++------ arch/arm64/kernel/entry-fpsimd.S | 17 +++++++++++------ arch/arm64/kernel/fpsimd.c | 10 ++++++---- arch/arm64/kvm/hyp/fpsimd.S | 6 ++++-- 5 files changed, 38 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 917ecc301d1d..7f8a44a9a5e6 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -65,10 +65,10 @@ static inline void *sve_pffr(struct thread_struct *thread) return (char *)thread->sve_state + sve_ffr_offset(thread->sve_vl); }

-extern void sve_save_state(void *state, u32 *pfpsr); +extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr); extern void sve_load_state(void const *state, u32 const *pfpsr, - unsigned long vq_minus_1); -extern void sve_flush_live(unsigned long vq_minus_1); + int restore_ffr, unsigned long vq_minus_1); +extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); extern void sve_set_vq(unsigned long vq_minus_1);

diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index 00a2c0b69c2b..84d8cb7b07fa 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -217,28 +217,36 @@ .macro sve_flush_z _for n, 0, 31, _sve_flush_z \n .endm -.macro sve_flush_p_ffr +.macro sve_flush_p _for n, 0, 15, _sve_pfalse \n +.endm +.macro sve_flush_ffr _sve_wrffr 0 .endm

-.macro sve_save nxbase, xpfpsr, nxtmp +.macro sve_save nxbase, xpfpsr, save_ffr, nxtmp _for n, 0, 31, _sve_str_v \n, \nxbase, \n - 34 _for n, 0, 15, _sve_str_p \n, \nxbase, \n - 16 + cbz \save_ffr, 921f _sve_rdffr 0 _sve_str_p 0, \nxbase _sve_ldr_p 0, \nxbase, -16 - + b 922f +921: + str xzr, [x\nxbase, #0] // Zero out FFR +922: mrs x\nxtmp, fpsr str w\nxtmp, [\xpfpsr] mrs x\nxtmp, fpcr str w\nxtmp, [\xpfpsr, #4] .endm

-.macro __sve_load nxbase, xpfpsr, nxtmp +.macro __sve_load nxbase, xpfpsr, restore_ffr, nxtmp _for n, 0, 31, _sve_ldr_v \n, \nxbase, \n - 34 + cbz \restore_ffr, 921f _sve_ldr_p 0, \nxbase _sve_wrffr 0 +921: _for n, 0, 15, _sve_ldr_p \n, \nxbase, \n - 16

ldr w\nxtmp, [\xpfpsr] @@ -247,7 +255,7 @@ msr fpcr, x\nxtmp .endm

-.macro sve_load nxbase, xpfpsr, xvqminus1, nxtmp, xtmp2 +.macro sve_load nxbase, xpfpsr, restore_ffr, xvqminus1, nxtmp, xtmp2 sve_load_vq \xvqminus1, x\nxtmp, \xtmp2 - __sve_load \nxbase, \xpfpsr, \nxtmp + __sve_load \nxbase, \xpfpsr, \restore_ffr, \nxtmp .endm diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index afbf7dc47e1d..13c27465bfa8 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -38,9 +38,10 @@ SYM_FUNC_END(fpsimd_load_state) * * x0 - pointer to buffer for state * x1 - pointer to storage for FPSR + * x2 - Save FFR if non-zero */ SYM_FUNC_START(sve_save_state) - sve_save 0, x1, 2 + sve_save 0, x1, x2, 3 ret SYM_FUNC_END(sve_save_state)

@@ -49,10 +50,11 @@ SYM_FUNC_END(sve_save_state) * * x0 - pointer to buffer for state * x1 - pointer to storage for FPSR - * x2 - VQ-1 + * x2 - Restore FFR if non-zero + * x3 - VQ-1 */ SYM_FUNC_START(sve_load_state) - sve_load 0, x1, x2, 3, x4 + sve_load 0, x1, x2, x3, 4, x5 ret SYM_FUNC_END(sve_load_state)

@@ -72,12 +74,15 @@ SYM_FUNC_END(sve_set_vq) * VQ must already be configured by caller, any further updates of VQ * will need to ensure that the register state remains valid. * - * x0 = VQ - 1 + * x0 = include FFR? + * x1 = VQ - 1 */ SYM_FUNC_START(sve_flush_live) - cbz x0, 1f // A VQ-1 of 0 is 128 bits so no extra Z state + cbz x1, 1f // A VQ-1 of 0 is 128 bits so no extra Z state sve_flush_z -1: sve_flush_p_ffr +1: cbz x0, 2f + sve_flush_p +2: sve_flush_ffr ret SYM_FUNC_END(sve_flush_live)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 0f6df1ece618..3d5d243c3f1c 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -289,7 +289,7 @@ static void task_fpsimd_load(void)

if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) sve_load_state(sve_pffr(&current->thread), - &current->thread.uw.fpsimd_state.fpsr, + &current->thread.uw.fpsimd_state.fpsr, true, sve_vq_from_vl(current->thread.sve_vl) - 1); else fpsimd_load_state(&current->thread.uw.fpsimd_state); @@ -325,7 +325,7 @@ static void fpsimd_save(void)

sve_save_state((char *)last->sve_state + sve_ffr_offset(last->sve_vl), - &last->st->fpsr); + &last->st->fpsr, true); } else { fpsimd_save_state(last->st); } @@ -962,7 +962,7 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) unsigned long vq_minus_one = sve_vq_from_vl(current->thread.sve_vl) - 1; sve_set_vq(vq_minus_one); - sve_flush_live(vq_minus_one); + sve_flush_live(true, vq_minus_one); fpsimd_bind_task_to_cpu(); } else { fpsimd_to_sve(current); @@ -1356,7 +1356,8 @@ void __efi_fpsimd_begin(void) __this_cpu_write(efi_sve_state_used, true);

sve_save_state(sve_state + sve_ffr_offset(sve_max_vl), - &this_cpu_ptr(&efi_fpsimd_state)->fpsr); + &this_cpu_ptr(&efi_fpsimd_state)->fpsr, + true); } else { fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state)); } @@ -1382,6 +1383,7 @@ void __efi_fpsimd_end(void)

sve_load_state(sve_state + sve_ffr_offset(sve_max_vl), &this_cpu_ptr(&efi_fpsimd_state)->fpsr, + true, sve_vq_from_vl(sve_get_vl()) - 1);

__this_cpu_write(efi_sve_state_used, false); diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S index 3c635929771a..1bb3b04b84e6 100644 --- a/arch/arm64/kvm/hyp/fpsimd.S +++ b/arch/arm64/kvm/hyp/fpsimd.S @@ -21,11 +21,13 @@ SYM_FUNC_START(__fpsimd_restore_state) SYM_FUNC_END(__fpsimd_restore_state)

SYM_FUNC_START(__sve_restore_state) - __sve_load 0, x1, 2 + mov x2, #1 + __sve_load 0, x1, x2, 3 ret SYM_FUNC_END(__sve_restore_state)

SYM_FUNC_START(__sve_save_state) - sve_save 0, x1, 2 + mov x2, #1 + sve_save 0, x1, x2, 3 ret SYM_FUNC_END(__sve_save_state)

In a system with SME there are parallel vector length controls for SVE and SME vectors which function in much the same way so it is desirable to share the code for handling them as much as possible. In order to prepare for doing this add a layer of accessor functions for the various VL related operations on tasks.

Since almost all current interactions are actually via task->thread rather than directly with the thread_info the accessors use that. Accessors are provided for both generic and SVE specific usage, the generic accessors should be used for cases where register state is being manipulated since the registers are shared between streaming and regular SVE so we know that when SME support is implemented we will always have to be in the appropriate mode already and hence can generalise now.

Since we are using task_struct and we don't want to cause widespread inclusion of sched.h the acessors are all out of line, it is hoped that none of the uses are in a sufficiently critical path for this to be an issue. Those that are most likely to present an issue are in the same translation unit so hopefully the compiler may be able to inline anyway.

This is purely adding the layer of abstraction, additional work will be needed to support tasks using SME.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 2 +- arch/arm64/include/asm/processor.h | 10 ++++++ arch/arm64/kernel/fpsimd.c | 55 +++++++++++++++++++++--------- arch/arm64/kernel/ptrace.c | 4 +-- arch/arm64/kernel/signal.c | 6 ++-- 5 files changed, 54 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 7f8a44a9a5e6..d164e2f35837 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -62,7 +62,7 @@ static inline size_t sve_ffr_offset(int vl)

static inline void *sve_pffr(struct thread_struct *thread) { - return (char *)thread->sve_state + sve_ffr_offset(thread->sve_vl); + return (char *)thread->sve_state + sve_ffr_offset(thread_get_sve_vl(thread)); }

extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr); diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index ee2bdc1b9f5b..adb6a46a1fae 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -164,6 +164,16 @@ struct thread_struct { u64 sctlr_user; };

+static inline unsigned int thread_get_sve_vl(struct thread_struct *thread) +{ + return thread->sve_vl; +} + +unsigned int task_get_sve_vl(const struct task_struct *task); +void task_set_sve_vl(struct task_struct *task, unsigned long vl); +unsigned int task_get_sve_vl_onexec(const struct task_struct *task); +void task_set_sve_vl_onexec(struct task_struct *task, unsigned long vl); + #define SCTLR_USER_MASK \ (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | SCTLR_ELx_ENDA | SCTLR_ELx_ENDB | \ SCTLR_EL1_TCF0_MASK) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 25aa6f2386a1..f7eb54e9a8b8 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -228,6 +228,26 @@ static void sve_free(struct task_struct *task) __sve_free(task); }

+unsigned int task_get_sve_vl(const struct task_struct *task) +{ + return task->thread.sve_vl; +} + +void task_set_sve_vl(struct task_struct *task, unsigned long vl) +{ + task->thread.sve_vl = vl; +} + +unsigned int task_get_sve_vl_onexec(const struct task_struct *task) +{ + return task->thread.sve_vl_onexec; +} + +void task_set_sve_vl_onexec(struct task_struct *task, unsigned long vl) +{ + task->thread.sve_vl_onexec = vl; +} + /* * TIF_SVE controls whether a task can use SVE without trapping while * in userspace, and also the way a task's FPSIMD/SVE state is stored @@ -290,7 +310,7 @@ static void task_fpsimd_load(void) if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) sve_load_state(sve_pffr(&current->thread), &current->thread.uw.fpsimd_state.fpsr, true, - sve_vq_from_vl(current->thread.sve_vl) - 1); + sve_vq_from_vl(task_get_sve_vl(current)) - 1); else fpsimd_load_state(&current->thread.uw.fpsimd_state); } @@ -458,7 +478,7 @@ static void fpsimd_to_sve(struct task_struct *task) if (!system_supports_sve()) return;

- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task)); __fpsimd_to_sve(sst, fst, vq); }

@@ -484,7 +504,7 @@ static void sve_to_fpsimd(struct task_struct *task) if (!system_supports_sve()) return;

- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task)); for (i = 0; i < SVE_NUM_ZREGS; ++i) { p = (__uint128_t const *)ZREG(sst, vq, i); fst->vregs[i] = arm64_le128_to_cpu(*p); @@ -499,7 +519,7 @@ static void sve_to_fpsimd(struct task_struct *task) */ static size_t sve_state_size(struct task_struct const *task) { - return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task->thread.sve_vl)); + return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task_get_sve_vl(task))); }

/* @@ -574,7 +594,7 @@ void sve_sync_from_fpsimd_zeropad(struct task_struct *task) if (!test_tsk_thread_flag(task, TIF_SVE)) return;

- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task));

memset(sst, 0, SVE_SIG_REGS_SIZE(vq)); __fpsimd_to_sve(sst, fst, vq); @@ -602,16 +622,16 @@ int sve_set_vector_length(struct task_struct *task,

if (flags & (PR_SVE_VL_INHERIT | PR_SVE_SET_VL_ONEXEC)) - task->thread.sve_vl_onexec = vl; + task_set_sve_vl_onexec(task, vl); else /* Reset VL to system default on next exec: */ - task->thread.sve_vl_onexec = 0; + task_set_sve_vl_onexec(task, 0);

/* Only actually set the VL if not deferred: */ if (flags & PR_SVE_SET_VL_ONEXEC) goto out;

- if (vl == task->thread.sve_vl) + if (vl == task_get_sve_vl(task)) goto out;

/* @@ -638,7 +658,7 @@ int sve_set_vector_length(struct task_struct *task, */ sve_free(task);

- task->thread.sve_vl = vl; + task_set_sve_vl(task, vl);

out: update_tsk_thread_flag(task, TIF_SVE_VL_INHERIT, @@ -658,9 +678,9 @@ static int sve_prctl_status(unsigned long flags) int ret;

if (flags & PR_SVE_SET_VL_ONEXEC) - ret = current->thread.sve_vl_onexec; + ret = task_get_sve_vl_onexec(current); else - ret = current->thread.sve_vl; + ret = task_get_sve_vl(current);

if (test_thread_flag(TIF_SVE_VL_INHERIT)) ret |= PR_SVE_VL_INHERIT; @@ -960,7 +980,7 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) */ if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { unsigned long vq_minus_one = - sve_vq_from_vl(current->thread.sve_vl) - 1; + sve_vq_from_vl(task_get_sve_vl(current)) - 1; sve_set_vq(vq_minus_one); sve_flush_live(true, vq_minus_one); fpsimd_bind_task_to_cpu(); @@ -1060,8 +1080,9 @@ void fpsimd_flush_thread(void) * If a bug causes this to go wrong, we make some noise and * try to fudge thread.sve_vl to a safe value here. */ - vl = current->thread.sve_vl_onexec ? - current->thread.sve_vl_onexec : get_sve_default_vl(); + vl = task_get_sve_vl_onexec(current); + if (!vl) + vl = get_sve_default_vl();

if (WARN_ON(!sve_vl_valid(vl))) vl = SVE_VL_MIN; @@ -1070,14 +1091,14 @@ void fpsimd_flush_thread(void) if (WARN_ON(supported_vl != vl)) vl = supported_vl;

- current->thread.sve_vl = vl; + task_set_sve_vl(current, vl);

/* * If the task is not set to inherit, ensure that the vector * length will be reset by a subsequent exec: */ if (!test_thread_flag(TIF_SVE_VL_INHERIT)) - current->thread.sve_vl_onexec = 0; + task_set_sve_vl_onexec(current, 0); }

put_cpu_fpsimd_context(); @@ -1122,7 +1143,7 @@ static void fpsimd_bind_task_to_cpu(void) WARN_ON(!system_supports_fpsimd()); last->st = &current->thread.uw.fpsimd_state; last->sve_state = current->thread.sve_state; - last->sve_vl = current->thread.sve_vl; + last->sve_vl = task_get_sve_vl(current); current->thread.fpsimd_cpu = smp_processor_id();

if (system_supports_sve()) { diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index e26196a33cf4..95ff03a1b077 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -725,7 +725,7 @@ static void sve_init_header_from_task(struct user_sve_header *header, if (test_tsk_thread_flag(target, TIF_SVE_VL_INHERIT)) header->flags |= SVE_PT_VL_INHERIT;

- header->vl = target->thread.sve_vl; + header->vl = task_get_sve_vl(target); vq = sve_vq_from_vl(header->vl);

header->max_vl = sve_max_vl; @@ -820,7 +820,7 @@ static int sve_set(struct task_struct *target, goto out;

/* Actual VL set may be less than the user asked for: */ - vq = sve_vq_from_vl(target->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(target));

/* Registers: FPSIMD-only case */

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index c287b9407f28..aa1d9d7918da 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -227,7 +227,7 @@ static int preserve_sve_context(struct sve_context __user *ctx) { int err = 0; u16 reserved[ARRAY_SIZE(ctx->__reserved)]; - unsigned int vl = current->thread.sve_vl; + unsigned int vl = task_get_sve_vl(current); unsigned int vq = 0;

if (test_thread_flag(TIF_SVE)) @@ -266,7 +266,7 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user) if (__copy_from_user(&sve, user->sve, sizeof(sve))) return -EFAULT;

- if (sve.vl != current->thread.sve_vl) + if (sve.vl != task_get_sve_vl(current)) return -EINVAL;

if (sve.head.size <= sizeof(*user->sve)) { @@ -597,7 +597,7 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, int vl = sve_max_vl;

if (!add_all) - vl = current->thread.sve_vl; + vl = task_get_sve_vl(current);

vq = sve_vq_from_vl(vl); }

Currently when restoring the SVE state we supply the SVE vector length as an argument to sve_load_state() and the underlying macros. This becomes inconvenient with the addition of SME since we may need to restore any combination of SVE and SME vector lengths, and we already separately restore the vector length in the KVM code. We don't need to know the vector length during the actual register load since the SME load instructions can index into the data array for us.

Refactor the interface so we explicitly set the vector length separately to restoring the SVE registers in preparation for adding SME support, no functional change should be involved.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 2 +- arch/arm64/include/asm/fpsimdmacros.h | 7 +------ arch/arm64/kernel/entry-fpsimd.S | 3 +-- arch/arm64/kernel/fpsimd.c | 13 +++++++------ arch/arm64/kvm/hyp/fpsimd.S | 2 +- 5 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 5a1f79a4a500..1d0b5fa253a0 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -67,7 +67,7 @@ static inline void *sve_pffr(struct thread_struct *thread)

extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr); extern void sve_load_state(void const *state, u32 const *pfpsr, - int restore_ffr, unsigned long vq_minus_1); + int restore_ffr); extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); extern void sve_set_vq(unsigned long vq_minus_1); diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index 84d8cb7b07fa..b22538a6137e 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -241,7 +241,7 @@ str w\nxtmp, [\xpfpsr, #4] .endm

-.macro __sve_load nxbase, xpfpsr, restore_ffr, nxtmp +.macro sve_load nxbase, xpfpsr, restore_ffr, nxtmp _for n, 0, 31, _sve_ldr_v \n, \nxbase, \n - 34 cbz \restore_ffr, 921f _sve_ldr_p 0, \nxbase @@ -254,8 +254,3 @@ ldr w\nxtmp, [\xpfpsr, #4] msr fpcr, x\nxtmp .endm - -.macro sve_load nxbase, xpfpsr, restore_ffr, xvqminus1, nxtmp, xtmp2 - sve_load_vq \xvqminus1, x\nxtmp, \xtmp2 - __sve_load \nxbase, \xpfpsr, \restore_ffr, \nxtmp -.endm diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 13c27465bfa8..2339d370bfe1 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -51,10 +51,9 @@ SYM_FUNC_END(sve_save_state) * x0 - pointer to buffer for state * x1 - pointer to storage for FPSR * x2 - Restore FFR if non-zero - * x3 - VQ-1 */ SYM_FUNC_START(sve_load_state) - sve_load 0, x1, x2, x3, 4, x5 + sve_load 0, x1, x2, 4 ret SYM_FUNC_END(sve_load_state)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 9248c9efe5fd..e75dd20a40cf 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -318,12 +318,13 @@ static void task_fpsimd_load(void) WARN_ON(!system_supports_fpsimd()); WARN_ON(!have_cpu_fpsimd_context());

- if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) + if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) { + sve_set_vq(sve_vq_from_vl(task_get_sve_vl(current)) - 1); sve_load_state(sve_pffr(&current->thread), - &current->thread.uw.fpsimd_state.fpsr, true, - sve_vq_from_vl(task_get_sve_vl(current)) - 1); - else + &current->thread.uw.fpsimd_state.fpsr, true); + } else { fpsimd_load_state(&current->thread.uw.fpsimd_state); + } }

/* @@ -1423,10 +1424,10 @@ void __efi_fpsimd_end(void) likely(__this_cpu_read(efi_sve_state_used))) { char const *sve_state = this_cpu_ptr(efi_sve_state);

+ sve_set_vq(sve_vq_from_vl(sve_get_vl()) - 1); sve_load_state(sve_state + sve_ffr_offset(sve_max_vl()), &this_cpu_ptr(&efi_fpsimd_state)->fpsr, - true, - sve_vq_from_vl(sve_get_vl()) - 1); + true);

__this_cpu_write(efi_sve_state_used, false); } else { diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S index 1bb3b04b84e6..e950875e31ce 100644 --- a/arch/arm64/kvm/hyp/fpsimd.S +++ b/arch/arm64/kvm/hyp/fpsimd.S @@ -22,7 +22,7 @@ SYM_FUNC_END(__fpsimd_restore_state)

SYM_FUNC_START(__sve_restore_state) mov x2, #1 - __sve_load 0, x1, x2, 3 + sve_load 0, x1, x2, 3 ret SYM_FUNC_END(__sve_restore_state)

The vector length configuration for SME is very similar to that for SVE so in order to allow reuse refactor the SVE configuration so that it takes the vector type from the struct ctl_table. Since there's no dedicated space for this we repurpose the extra1 field to store the vector type, this is otherwise unused for integer sysctls.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/kernel/fpsimd.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 3474122f9207..53462636b5cf 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -15,6 +15,7 @@ #include <linux/compiler.h> #include <linux/cpu.h> #include <linux/cpu_pm.h> +#include <linux/ctype.h> #include <linux/kernel.h> #include <linux/linkage.h> #include <linux/irqflags.h> @@ -155,11 +156,6 @@ static int get_default_vl(enum vec_type type) return READ_ONCE(vl_config[type].__default_vl); }

-static int get_sve_default_vl(void) -{ - return get_default_vl(ARM64_VEC_SVE); -} - #ifdef CONFIG_ARM64_SVE

static void set_default_vl(enum vec_type type, int val) @@ -172,6 +168,11 @@ static void set_sve_default_vl(int val) set_default_vl(ARM64_VEC_SVE, val); }

+static int get_sve_default_vl(void) +{ + return get_default_vl(ARM64_VEC_SVE); +} + static void __percpu *efi_sve_state;

#else /* ! CONFIG_ARM64_SVE */ @@ -406,17 +407,21 @@ static unsigned int find_supported_vector_length(enum vec_type type,

#if defined(CONFIG_ARM64_SVE) && defined(CONFIG_SYSCTL)

-static int sve_proc_do_default_vl(struct ctl_table *table, int write, +static int vec_proc_do_default_vl(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { - struct vl_info *info = &vl_info[ARM64_VEC_SVE]; + struct vl_info *info = table->extra1; + enum vec_type type = info->type; int ret; - int vl = get_sve_default_vl(); + int vl = get_default_vl(type); struct ctl_table tmp_table = { .data = &vl, .maxlen = sizeof(vl), };

+ if (!info) + return -EINVAL; + ret = proc_dointvec(&tmp_table, write, buffer, lenp, ppos); if (ret || !write) return ret; @@ -428,7 +433,7 @@ static int sve_proc_do_default_vl(struct ctl_table *table, int write, if (!sve_vl_valid(vl)) return -EINVAL;

- set_sve_default_vl(find_supported_vector_length(ARM64_VEC_SVE, vl)); + set_default_vl(type, find_supported_vector_length(type, vl)); return 0; }

@@ -436,7 +441,8 @@ static struct ctl_table sve_default_vl_table[] = { { .procname = "sve_default_vector_length", .mode = 0644, - .proc_handler = sve_proc_do_default_vl, + .proc_handler = vec_proc_do_default_vl, + .extra1 = &vl_info[ARM64_VEC_SVE], }, { } }; @@ -1107,7 +1113,7 @@ static void fpsimd_flush_thread_vl(enum vec_type type) vl = get_default_vl(type);

if (WARN_ON(!sve_vl_valid(vl))) - vl = SVE_VL_MIN; + vl = vl_info[type].min_vl;

supported_vl = find_supported_vector_length(type, vl); if (WARN_ON(supported_vl != vl))

SME introduces a new mode called streaming mode in which the SVE registers have a different vector length. Since the ptrace interface for this is based on the existing SVE interface prepare for supporting this by moving the regset specific configuration into struct and passing that around, allowing these tests to be reused for streaming mode. As we will also have to verify the interoperation of the SVE and streaming SVE regsets don't just iterate over an array.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/sve-ptrace.c | 219 ++++++++++++------ 1 file changed, 142 insertions(+), 77 deletions(-)

diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c index c4417bc48d4f..af798b9d232c 100644 --- a/tools/testing/selftests/arm64/fp/sve-ptrace.c +++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c @@ -21,16 +21,37 @@

#include "../../kselftest.h"

-#define VL_TESTS (((SVE_VQ_MAX - SVE_VQ_MIN) + 1) * 3) -#define FPSIMD_TESTS 5 - -#define EXPECTED_TESTS (VL_TESTS + FPSIMD_TESTS) +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

/* <linux/elf.h> and <sys/auxv.h> don't like each other, so: */ #ifndef NT_ARM_SVE #define NT_ARM_SVE 0x405 #endif

+struct vec_type { + const char *name; + unsigned long hwcap_type; + unsigned long hwcap; + int regset; + int prctl_set; +}; + +static const struct vec_type vec_types[] = { + { + .name = "SVE", + .hwcap_type = AT_HWCAP, + .hwcap = HWCAP_SVE, + .regset = NT_ARM_SVE, + .prctl_set = PR_SVE_SET_VL, + }, +}; + +#define VL_TESTS (((SVE_VQ_MAX - SVE_VQ_MIN) + 1) * 3) +#define FLAG_TESTS 2 +#define FPSIMD_TESTS 3 + +#define EXPECTED_TESTS ((VL_TESTS + FLAG_TESTS + FPSIMD_TESTS) * ARRAY_SIZE(vec_types)) + static void fill_buf(char *buf, size_t size) { int i; @@ -59,7 +80,8 @@ static int get_fpsimd(pid_t pid, struct user_fpsimd_state *fpsimd) return ptrace(PTRACE_GETREGSET, pid, NT_PRFPREG, &iov); }

-static struct user_sve_header *get_sve(pid_t pid, void **buf, size_t *size) +static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type, + void **buf, size_t *size) { struct user_sve_header *sve; void *p; @@ -80,7 +102,7 @@ static struct user_sve_header *get_sve(pid_t pid, void **buf, size_t *size)

iov.iov_base = *buf; iov.iov_len = sz; - if (ptrace(PTRACE_GETREGSET, pid, NT_ARM_SVE, &iov)) + if (ptrace(PTRACE_GETREGSET, pid, type->regset, &iov)) goto error;

sve = *buf; @@ -96,17 +118,18 @@ static struct user_sve_header *get_sve(pid_t pid, void **buf, size_t *size) return NULL; }

-static int set_sve(pid_t pid, const struct user_sve_header *sve) +static int set_sve(pid_t pid, const struct vec_type *type, + const struct user_sve_header *sve) { struct iovec iov;

iov.iov_base = (void *)sve; iov.iov_len = sve->size; - return ptrace(PTRACE_SETREGSET, pid, NT_ARM_SVE, &iov); + return ptrace(PTRACE_SETREGSET, pid, type->regset, &iov); }

/* Validate setting and getting the inherit flag */ -static void ptrace_set_get_inherit(pid_t child) +static void ptrace_set_get_inherit(pid_t child, const struct vec_type *type) { struct user_sve_header sve; struct user_sve_header *new_sve = NULL; @@ -118,9 +141,10 @@ static void ptrace_set_get_inherit(pid_t child) sve.size = sizeof(sve); sve.vl = sve_vl_from_vq(SVE_VQ_MIN); sve.flags = SVE_PT_VL_INHERIT; - ret = set_sve(child, &sve); + ret = set_sve(child, type, &sve); if (ret != 0) { - ksft_test_result_fail("Failed to set SVE_PT_VL_INHERIT\n"); + ksft_test_result_fail("Failed to set %s SVE_PT_VL_INHERIT\n", + type->name); return; }

@@ -128,35 +152,39 @@ static void ptrace_set_get_inherit(pid_t child) * Read back the new register state and verify that we have * set the flags we expected. */ - if (!get_sve(child, (void **)&new_sve, &new_sve_size)) { - ksft_test_result_fail("Failed to read SVE flags\n"); + if (!get_sve(child, type, (void **)&new_sve, &new_sve_size)) { + ksft_test_result_fail("Failed to read %s SVE flags\n", + type->name); return; }

ksft_test_result(new_sve->flags & SVE_PT_VL_INHERIT, - "SVE_PT_VL_INHERIT set\n"); + "%s SVE_PT_VL_INHERIT set\n", type->name);

/* Now clear */ sve.flags &= ~SVE_PT_VL_INHERIT; - ret = set_sve(child, &sve); + ret = set_sve(child, type, &sve); if (ret != 0) { - ksft_test_result_fail("Failed to clear SVE_PT_VL_INHERIT\n"); + ksft_test_result_fail("Failed to clear %s SVE_PT_VL_INHERIT\n", + type->name); return; }

- if (!get_sve(child, (void **)&new_sve, &new_sve_size)) { - ksft_test_result_fail("Failed to read SVE flags\n"); + if (!get_sve(child, type, (void **)&new_sve, &new_sve_size)) { + ksft_test_result_fail("Failed to read %s SVE flags\n", + type->name); return; }

ksft_test_result(!(new_sve->flags & SVE_PT_VL_INHERIT), - "SVE_PT_VL_INHERIT cleared\n"); + "%s SVE_PT_VL_INHERIT cleared\n", type->name);

free(new_sve); }

/* Validate attempting to set the specfied VL via ptrace */ -static void ptrace_set_get_vl(pid_t child, unsigned int vl, bool *supported) +static void ptrace_set_get_vl(pid_t child, const struct vec_type *type, + unsigned int vl, bool *supported) { struct user_sve_header sve; struct user_sve_header *new_sve = NULL; @@ -166,10 +194,10 @@ static void ptrace_set_get_vl(pid_t child, unsigned int vl, bool *supported) *supported = false;

/* Check if the VL is supported in this process */ - prctl_vl = prctl(PR_SVE_SET_VL, vl); + prctl_vl = prctl(type->prctl_set, vl); if (prctl_vl == -1) - ksft_exit_fail_msg("prctl(PR_SVE_SET_VL) failed: %s (%d)\n", - strerror(errno), errno); + ksft_exit_fail_msg("prctl(PR_%s_SET_VL) failed: %s (%d)\n", + type->name, strerror(errno), errno);

/* If the VL is not supported then a supported VL will be returned */ *supported = (prctl_vl == vl); @@ -178,9 +206,10 @@ static void ptrace_set_get_vl(pid_t child, unsigned int vl, bool *supported) memset(&sve, 0, sizeof(sve)); sve.size = sizeof(sve); sve.vl = vl; - ret = set_sve(child, &sve); + ret = set_sve(child, type, &sve); if (ret != 0) { - ksft_test_result_fail("Failed to set VL %u\n", vl); + ksft_test_result_fail("Failed to set %s VL %u\n", + type->name, vl); return; }

@@ -188,12 +217,14 @@ static void ptrace_set_get_vl(pid_t child, unsigned int vl, bool *supported) * Read back the new register state and verify that we have the * same VL that we got from prctl() on ourselves. */ - if (!get_sve(child, (void **)&new_sve, &new_sve_size)) { - ksft_test_result_fail("Failed to read VL %u\n", vl); + if (!get_sve(child, type, (void **)&new_sve, &new_sve_size)) { + ksft_test_result_fail("Failed to read %s VL %u\n", + type->name, vl); return; }

- ksft_test_result(new_sve->vl = prctl_vl, "Set VL %u\n", vl); + ksft_test_result(new_sve->vl = prctl_vl, "Set %s VL %u\n", + type->name, vl);

free(new_sve); } @@ -209,7 +240,7 @@ static void check_u32(unsigned int vl, const char *reg, }

/* Access the FPSIMD registers via the SVE regset */ -static void ptrace_sve_fpsimd(pid_t child) +static void ptrace_sve_fpsimd(pid_t child, const struct vec_type *type) { void *svebuf = NULL; size_t svebufsz = 0; @@ -219,17 +250,18 @@ static void ptrace_sve_fpsimd(pid_t child) unsigned char *p;

/* New process should start with FPSIMD registers only */ - sve = get_sve(child, &svebuf, &svebufsz); + sve = get_sve(child, type, &svebuf, &svebufsz); if (!sve) { - ksft_test_result_fail("get_sve: %s\n", strerror(errno)); + ksft_test_result_fail("get_sve(%s): %s\n", + type->name, strerror(errno));

return; } else { - ksft_test_result_pass("get_sve(FPSIMD)\n"); + ksft_test_result_pass("get_sve(%s FPSIMD)\n", type->name); }

ksft_test_result((sve->flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD, - "Set FPSIMD registers\n"); + "Set FPSIMD registers via %s\n", type->name); if ((sve->flags & SVE_PT_REGS_MASK) != SVE_PT_REGS_FPSIMD) goto out;

@@ -243,9 +275,9 @@ static void ptrace_sve_fpsimd(pid_t child) p[j] = j; }

- if (set_sve(child, sve)) { - ksft_test_result_fail("set_sve(FPSIMD): %s\n", - strerror(errno)); + if (set_sve(child, type, sve)) { + ksft_test_result_fail("set_sve(%s FPSIMD): %s\n", + type->name, strerror(errno));

goto out; } @@ -257,16 +289,20 @@ static void ptrace_sve_fpsimd(pid_t child) goto out; } if (memcmp(fpsimd, &new_fpsimd, sizeof(*fpsimd)) == 0) - ksft_test_result_pass("get_fpsimd() gave same state\n"); + ksft_test_result_pass("%s get_fpsimd() gave same state\n", + type->name); else - ksft_test_result_fail("get_fpsimd() gave different state\n"); + ksft_test_result_fail("%s get_fpsimd() gave different state\n", + type->name);

out: free(svebuf); }

/* Validate attempting to set SVE data and read SVE data */ -static void ptrace_set_sve_get_sve_data(pid_t child, unsigned int vl) +static void ptrace_set_sve_get_sve_data(pid_t child, + const struct vec_type *type, + unsigned int vl) { void *write_buf; void *read_buf = NULL; @@ -281,8 +317,8 @@ static void ptrace_set_sve_get_sve_data(pid_t child, unsigned int vl) data_size = SVE_PT_SVE_OFFSET + SVE_PT_SVE_SIZE(vq, SVE_PT_REGS_SVE); write_buf = malloc(data_size); if (!write_buf) { - ksft_test_result_fail("Error allocating %d byte buffer for VL %u\n", - data_size, vl); + ksft_test_result_fail("Error allocating %d byte buffer for %s VL %u\n", + data_size, type->name, vl); return; } write_sve = write_buf; @@ -306,23 +342,26 @@ static void ptrace_set_sve_get_sve_data(pid_t child, unsigned int vl)

/* TODO: Generate a valid FFR pattern */

- ret = set_sve(child, write_sve); + ret = set_sve(child, type, write_sve); if (ret != 0) { - ksft_test_result_fail("Failed to set VL %u data\n", vl); + ksft_test_result_fail("Failed to set %s VL %u data\n", + type->name, vl); goto out; }

/* Read the data back */ - if (!get_sve(child, (void **)&read_buf, &read_sve_size)) { - ksft_test_result_fail("Failed to read VL %u data\n", vl); + if (!get_sve(child, type, (void **)&read_buf, &read_sve_size)) { + ksft_test_result_fail("Failed to read %s VL %u data\n", + type->name, vl); goto out; } read_sve = read_buf;

/* We might read more data if there's extensions we don't know */ if (read_sve->size < write_sve->size) { - ksft_test_result_fail("Wrote %d bytes, only read %d\n", - write_sve->size, read_sve->size); + ksft_test_result_fail("%s wrote %d bytes, only read %d\n", + type->name, write_sve->size, + read_sve->size); goto out_read; }

@@ -349,7 +388,8 @@ static void ptrace_set_sve_get_sve_data(pid_t child, unsigned int vl) check_u32(vl, "FPCR", write_buf + SVE_PT_SVE_FPCR_OFFSET(vq), read_buf + SVE_PT_SVE_FPCR_OFFSET(vq), &errors);

- ksft_test_result(errors == 0, "Set and get SVE data for VL %u\n", vl); + ksft_test_result(errors == 0, "Set and get %s data for VL %u\n", + type->name, vl);

out_read: free(read_buf); @@ -358,7 +398,9 @@ static void ptrace_set_sve_get_sve_data(pid_t child, unsigned int vl) }

/* Validate attempting to set SVE data and read SVE data */ -static void ptrace_set_sve_get_fpsimd_data(pid_t child, unsigned int vl) +static void ptrace_set_sve_get_fpsimd_data(pid_t child, + const struct vec_type *type, + unsigned int vl) { void *write_buf; struct user_sve_header *write_sve; @@ -376,8 +418,8 @@ static void ptrace_set_sve_get_fpsimd_data(pid_t child, unsigned int vl) data_size = SVE_PT_SVE_OFFSET + SVE_PT_SVE_SIZE(vq, SVE_PT_REGS_SVE); write_buf = malloc(data_size); if (!write_buf) { - ksft_test_result_fail("Error allocating %d byte buffer for VL %u\n", - data_size, vl); + ksft_test_result_fail("Error allocating %d byte buffer for %s VL %u\n", + data_size, type->name, vl); return; } write_sve = write_buf; @@ -395,16 +437,17 @@ static void ptrace_set_sve_get_fpsimd_data(pid_t child, unsigned int vl) fill_buf(write_buf + SVE_PT_SVE_FPSR_OFFSET(vq), SVE_PT_SVE_FPSR_SIZE); fill_buf(write_buf + SVE_PT_SVE_FPCR_OFFSET(vq), SVE_PT_SVE_FPCR_SIZE);

- ret = set_sve(child, write_sve); + ret = set_sve(child, type, write_sve); if (ret != 0) { - ksft_test_result_fail("Failed to set VL %u data\n", vl); + ksft_test_result_fail("Failed to set %s VL %u data\n", + type->name, vl); goto out; }

/* Read the data back */ if (get_fpsimd(child, &fpsimd_state)) { - ksft_test_result_fail("Failed to read VL %u FPSIMD data\n", - vl); + ksft_test_result_fail("Failed to read %s VL %u FPSIMD data\n", + type->name, vl); goto out; }

@@ -419,7 +462,8 @@ static void ptrace_set_sve_get_fpsimd_data(pid_t child, unsigned int vl) sizeof(tmp));

if (tmp != fpsimd_state.vregs[i]) { - printf("# Mismatch in FPSIMD for VL %u Z%d\n", vl, i); + printf("# Mismatch in FPSIMD for %s VL %u Z%d\n", + type->name, vl, i); errors++; } } @@ -429,8 +473,8 @@ static void ptrace_set_sve_get_fpsimd_data(pid_t child, unsigned int vl) check_u32(vl, "FPCR", write_buf + SVE_PT_SVE_FPCR_OFFSET(vq), &fpsimd_state.fpcr, &errors);

- ksft_test_result(errors == 0, "Set and get FPSIMD data for VL %u\n", - vl); + ksft_test_result(errors == 0, "Set and get FPSIMD data for %s VL %u\n", + type->name, vl);

out: free(write_buf); @@ -440,7 +484,7 @@ static int do_parent(pid_t child) { int ret = EXIT_FAILURE; pid_t pid; - int status; + int status, i; siginfo_t si; unsigned int vq, vl; bool vl_supported; @@ -499,26 +543,47 @@ static int do_parent(pid_t child) } }

- /* FPSIMD via SVE regset */ - ptrace_sve_fpsimd(child); - - /* prctl() flags */ - ptrace_set_get_inherit(child); - - /* Step through every possible VQ */ - for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; vq++) { - vl = sve_vl_from_vq(vq); + for (i = 0; i < ARRAY_SIZE(vec_types); i++) { + /* FPSIMD via SVE regset */ + if (getauxval(vec_types[i].hwcap_type) & vec_types[i].hwcap) { + ptrace_sve_fpsimd(child, &vec_types[i]); + } else { + ksft_test_result_skip("%s FPSIMD get via SVE\n", + vec_types[i].name); + ksft_test_result_skip("%s FPSIMD set via SVE\n", + vec_types[i].name); + ksft_test_result_skip("%s set read via FPSIMD\n", + vec_types[i].name); + }

- /* First, try to set this vector length */ - ptrace_set_get_vl(child, vl, &vl_supported); + /* prctl() flags */ + ptrace_set_get_inherit(child, &vec_types[i]); + + /* Step through every possible VQ */ + for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; vq++) { + vl = sve_vl_from_vq(vq); + + /* First, try to set this vector length */ + if (getauxval(vec_types[i].hwcap_type) & + vec_types[i].hwcap) { + ptrace_set_get_vl(child, &vec_types[i], vl, + &vl_supported); + } else { + ksft_test_result_skip("%s get/set VL %d\n", + vec_types[i].name, vl); + vl_supported = false; + }

- /* If the VL is supported validate data set/get */ - if (vl_supported) { - ptrace_set_sve_get_sve_data(child, vl); - ptrace_set_sve_get_fpsimd_data(child, vl); - } else { - ksft_test_result_skip("set SVE get SVE for VL %d\n", vl); - ksft_test_result_skip("set SVE get FPSIMD for VL %d\n", vl); + /* If the VL is supported validate data set/get */ + if (vl_supported) { + ptrace_set_sve_get_sve_data(child, &vec_types[i], vl); + ptrace_set_sve_get_fpsimd_data(child, &vec_types[i], vl); + } else { + ksft_test_result_skip("%s set SVE get SVE for VL %d\n", + vec_types[i].name, vl); + ksft_test_result_skip("%s set SVE get FPSIMD for VL %d\n", + vec_types[i].name, vl); + } } }

Allow test programs to determine their thread ID.

Signed-off-by: Mark Brown broonie@kernel.org Cc: Willy Tarreau w@1wt.eu --- tools/include/nolibc/nolibc.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)

diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h index 3430667b0d24..fea8aace0119 100644 --- a/tools/include/nolibc/nolibc.h +++ b/tools/include/nolibc/nolibc.h @@ -1555,6 +1555,12 @@ pid_t sys_getpid(void) return my_syscall0(__NR_getpid); }

+static __attribute__((unused)) +pid_t sys_gettid(void) +{ + return my_syscall0(__NR_gettid); +} + static __attribute__((unused)) int sys_gettimeofday(struct timeval *tv, struct timezone *tz) { @@ -2013,6 +2019,18 @@ pid_t getpid(void) return ret; }

+static __attribute__((unused)) +pid_t gettid(void) +{ + pid_t ret = sys_gettid(); + + if (ret < 0) { + SET_ERRNO(-ret); + ret = -1; + } + return ret; +} + static __attribute__((unused)) int gettimeofday(struct timeval *tv, struct timezone *tz) {

Provide ABI documentation for SME similar to that for SVE. Due to the very large overlap around streaming SVE mode in both implementation and interfaces documentation for streaming mode SVE is added to the SVE document rather than the SME one.

Signed-off-by: Mark Brown broonie@kernel.org --- Documentation/arm64/index.rst | 1 + Documentation/arm64/sme.rst | 428 ++++++++++++++++++++++++++++++++++ Documentation/arm64/sve.rst | 69 +++++- 3 files changed, 488 insertions(+), 10 deletions(-) create mode 100644 Documentation/arm64/sme.rst

diff --git a/Documentation/arm64/index.rst b/Documentation/arm64/index.rst index 4f840bac083e..ae21f8118830 100644 --- a/Documentation/arm64/index.rst +++ b/Documentation/arm64/index.rst @@ -21,6 +21,7 @@ ARM64 Architecture perf pointer-authentication silicon-errata + sme sve tagged-address-abi tagged-pointers diff --git a/Documentation/arm64/sme.rst b/Documentation/arm64/sme.rst new file mode 100644 index 000000000000..5a4294aca6dc --- /dev/null +++ b/Documentation/arm64/sme.rst @@ -0,0 +1,428 @@ +=================================================== +Scalable Matrix Extension support for AArch64 Linux +=================================================== + +This document outlines briefly the interface provided to userspace by Linux in +order to support use of the ARM Scalable Matrix Extension (SME). + +This is an outline of the most important features and issues only and not +intended to be exhaustive. It should be read in conjunction with the SVE +documentation in sve.rst which provides details on the Streaming SVE mode +included in SME. + +This document does not aim to describe the SME architecture or programmer's +model. To aid understanding, a minimal description of relevant programmer's +model features for SME is included in Appendix A. + + +1. General +----------- + +* PSTATE.SM and PSTATE.ZA, the streaming mode vector length, the ZA + register state and TPIDR2_EL0 are tracked per thread. + +* The presence of SVE is reported to userspace via HWCAP2_SME in the aux vector + AT_HWCAP2 entry. Presence of this flag implies the presence of the SME + instructions and registers, and the Linux-specific system interfaces + described in this document. SME is reported in /proc/cpuinfo as "sme". + +* Support for the execution of SME instructions in userspace can also be + detected by reading the CPU ID register ID_AA64PFR1_EL1 using an MRS + instruction, and checking that the value of the SME field is nonzero. [3] + + It does not guarantee the presence of the system interfaces described in the + following sections: software that needs to verify that those interfaces are + present must check for HWCAP2_SME instead. + +* There are a number of optional SME features, presence of these is reported + through AT_HWCAP2 through: + + HWCAP2_SME_I16I64 + HWCAP2_SME_F64F64 + HWCAP2_SME_I8I32 + HWCAP2_SME_F16F32 + HWCAP2_SME_B16F32 + HWCAP2_SME_F32F32 + + This list may be extended over time as the SME architecture evolves. + + These extensions are also reported via the CPU ID register ID_AA64SMFR0_EL1, + which userspace can read using an MRS instruction. See elf_hwcaps.txt and + cpu-feature-registers.txt for details. + +* Debuggers should restrict themselves to interacting with the target via the + NT_ARM_SVE, NT_ARM_SSVE and NT_ARM_ZA regsets. The recommended way + of detecting support for these regsets is to connect to a target process + first and then attempt a + + ptrace(PTRACE_GETREGSET, pid, NT_ARM_<regset>, &iov). + +* Whenever ZA register values are exchanged in memory between userspace and + the kernel, the register value is encoded in memory as a series of horizontal + vectors from 0 to VL/8-1 stored in the same endianness invariant format as is + used for SVE vectors. + +* On thread creation TPIDR2_EL0 is set to 0. + +2. Vector lengths +------------------ + +SME defines a second vector length similar to the SVE vector length which is +controls the size of the streaming mode SVE vectors and the ZA matrix array. +The ZA matrix is square with each side having as many bytes as a SVE vector. + + +3. Sharing of streaming and non-streaming mode SVE state +--------------------------------------------------------- + +It is implementation defined which if any parts of the SVE state are shared +between streaming and non-streaming modes. When switching between modes +via software interfaces such as ptrace if no register content is provided as +part of switching no state will be assumed to be shared and everything will +be zeroed. + + +4. System call behaviour +------------------------- + +* On syscall PSTATE.ZA is preserved, if PSTATE.ZA==1 then the contents of the + ZA matrix are preserved. + +* On syscall PSTATE.SM will be cleared and the SVE registers will be handled + as normal. + +* Neither the SVE registers nor ZA are used to pass arguments to or receive + results from any syscall. + +* On creation fork() or clone() the newly created process will have PSTATE.SM + and PSTATE.ZA cleared. + +* All other SME state of a thread, including the currently configured vector + length, the state of the PR_SME_VL_INHERIT flag, and the deferred vector + length (if any), is preserved across all syscalls, subject to the specific + exceptions for execve() described in section 6. + + +5. Signal handling +------------------- + +* A new signal frame record za_context encodes the ZA register contents on + signal delivery. [1] + +* The signal frame record for ZA always contains basic metadata, in particular + the thread's vector length (in za_context.vl). + +* The ZA matrix may or may not be included in the record, depending on + the value of PSTATE.ZA. The registers are present if and only if: + za_context.head.size >= ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(za_context.vl)) + in which case PSTATE.ZA == 1. + +* If matrix data is present, the remainder of the record has a vl-dependent + size and layout. Macros ZA_SIG_* are defined [1] to facilitate access to + them. + +* The matrix is stored as a series of horizontal vectors in the same format as + is used for SVE vectors. + +* If the ZA context is too big to fit in sigcontext.__reserved[], then extra + space is allocated on the stack, an extra_context record is written in + __reserved[] referencing this space. za_context is then written in the + extra space. Refer to [1] for further details about this mechanism. + + +5. Signal return +----------------- + +When returning from a signal handler: + +* If there is no za_context record in the signal frame, or if the record is + present but contains no register data as desribed in the previous section, + then ZA is disabled. + +* If za_context is present in the signal frame and contains matrix data then + PSTATE.ZA is set to 1 and ZA is populated with the specified data. + +* The vector length cannot be changed via signal return. If za_context.vl in + the signal frame does not match the current vector length, the signal return + attempt is treated as illegal, resulting in a forced SIGSEGV. + + +6. prctl extensions +-------------------- + +Some new prctl() calls are added to allow programs to manage the SME vector +length: + +prctl(PR_SME_SET_VL, unsigned long arg) + + Sets the vector length of the calling thread and related flags, where + arg == vl | flags. Other threads of the calling process are unaffected. + + vl is the desired vector length, where sve_vl_valid(vl) must be true. + + flags: + + PR_SME_VL_INHERIT + + Inherit the current vector length across execve(). Otherwise, the + vector length is reset to the system default at execve(). (See + Section 9.) + + PR_SME_SET_VL_ONEXEC + + Defer the requested vector length change until the next execve() + performed by this thread. + + The effect is equivalent to implicit exceution of the following + call immediately after the next execve() (if any) by the thread: + + prctl(PR_SME_SET_VL, arg & ~PR_SME_SET_VL_ONEXEC) + + This allows launching of a new program with a different vector + length, while avoiding runtime side effects in the caller. + + Without PR_SME_SET_VL_ONEXEC, the requested change takes effect + immediately. + + + Return value: a nonnegative on success, or a negative value on error: + EINVAL: SME not supported, invalid vector length requested, or + invalid flags. + + + On success: + + * Either the calling thread's vector length or the deferred vector length + to be applied at the next execve() by the thread (dependent on whether + PR_SME_SET_VL_ONEXEC is present in arg), is set to the largest value + supported by the system that is less than or equal to vl. If vl == + SVE_VL_MAX, the value set will be the largest value supported by the + system. + + * Any previously outstanding deferred vector length change in the calling + thread is cancelled. + + * The returned value describes the resulting configuration, encoded as for + PR_SME_GET_VL. The vector length reported in this value is the new + current vector length for this thread if PR_SME_SET_VL_ONEXEC was not + present in arg; otherwise, the reported vector length is the deferred + vector length that will be applied at the next execve() by the calling + thread. + + * Changing the vector length causes all of ZA, P0..P15, FFR and all bits of + Z0..Z31 except for Z0 bits [127:0] .. Z31 bits [127:0] to become + unspecified, including both streaming and non-streaming SVE state. + Calling PR_SME_SET_VL with vl equal to the thread's current vector + length, or calling PR_SME_SET_VL with the PR_SVE_SET_VL_ONEXEC flag, + does not constitute a change to the vector length for this purpose. + + * Changing the vector length causes PSTATE.ZA and PSTATE.SM to be cleared. + Calling PR_SME_SET_VL with vl equal to the thread's current vector + length, or calling PR_SME_SET_VL with the PR_SVE_SET_VL_ONEXEC flag, + does not constitute a change to the vector length for this purpose. + + +prctl(PR_SME_GET_VL) + + Gets the vector length of the calling thread. + + The following flag may be OR-ed into the result: + + PR_SME_VL_INHERIT + + Vector length will be inherited across execve(). + + There is no way to determine whether there is an outstanding deferred + vector length change (which would only normally be the case between a + fork() or vfork() and the corresponding execve() in typical use). + + To extract the vector length from the result, and it with + PR_SME_VL_LEN_MASK. + + Return value: a nonnegative value on success, or a negative value on error: + EINVAL: SME not supported. + + +7. ptrace extensions +--------------------- + +* A new regset NT_ARM_SSVE is defined for access to streaming mode SVE + state via PTRACE_GETREGSET and PTRACE_SETREGSET, this is documented in + sve.rst. + +* A new regset NT_ARM_ZA is defined for ZA state for access to ZA state via + PTRACE_GETREGSET and PTRACE_SETREGSET. + + Refer to [2] for definitions. + +The regset data starts with struct user_za_header, containing: + + size + + Size of the complete regset, in bytes. + This depends on vl and possibly on other things in the future. + + If a call to PTRACE_GETREGSET requests less data than the value of + size, the caller can allocate a larger buffer and retry in order to + read the complete regset. + + max_size + + Maximum size in bytes that the regset can grow to for the target + thread. The regset won't grow bigger than this even if the target + thread changes its vector length etc. + + vl + + Target thread's current streaming vector length, in bytes. + + max_vl + + Maximum possible streaming vector length for the target thread. + + flags + + Zero or more of the following flags, which have the same + meaning and behaviour as the corresponding PR_SET_VL_* flags: + + SME_PT_VL_INHERIT + + SME_PT_VL_ONEXEC (SETREGSET only). + +* The effects of changing the vector length and/or flags are equivalent to + those documented for PR_SME_SET_VL. + + The caller must make a further GETREGSET call if it needs to know what VL is + actually set by SETREGSET, unless is it known in advance that the requested + VL is supported. + +* The size and layout of the payload depends on the header fields. The + SME_PT_ZA_*() macros are provided to facilitate access to the data. + +* In either case, for SETREGSET it is permissible to omit the payload, in which + case the vector length and flags are changed and PSTATE.ZA is set to 0 + (along with any consequences of those changes). If a payload is provided + then PSTATE.ZA will be set to 1. + +* For SETREGSET, if the requested VL is not supported, the effect will be the + same as if the payload were omitted, except that an EIO error is reported. + No attempt is made to translate the payload data to the correct layout + for the vector length actually set. It is up to the caller to translate the + payload layout for the actual VL and retry. + +* The effect of writing a partial, incomplete payload is unspecified. + + +8. ELF coredump extensions +--------------------------- + +* NT_ARM_SSVE notes will be added to each coredump for + each thread of the dumped process. The contents will be equivalent to the + data that would have been read if a PTRACE_GETREGSET of the corresponding + type were executed for each thread when the coredump was generated. + +* A NT_ARM_ZA note will be added to each coredump for each thread of the + dumped process. The contents will be equivalent to the data that would have + been read if a PTRACE_GETREGSET of NT_ARM_ZA were executed for each thread + when the coredump was generated. + + +9. System runtime configuration +-------------------------------- + +* To mitigate the ABI impact of expansion of the signal frame, a policy + mechanism is provided for administrators, distro maintainers and developers + to set the default vector length for userspace processes: + +/proc/sys/abi/sme_default_vector_length + + Writing the text representation of an integer to this file sets the system + default vector length to the specified value, unless the value is greater + than the maximum vector length supported by the system in which case the + default vector length is set to that maximum. + + The result can be determined by reopening the file and reading its + contents. + + At boot, the default vector length is initially set to 32 or the maximum + supported vector length, whichever is smaller and supported. This + determines the initial vector length of the init process (PID 1). + + Reading this file returns the current system default vector length. + +* At every execve() call, the new vector length of the new process is set to + the system default vector length, unless + + * PR_SME_VL_INHERIT (or equivalently SME_PT_VL_INHERIT) is set for the + calling thread, or + + * a deferred vector length change is pending, established via the + PR_SME_SET_VL_ONEXEC flag (or SME_PT_VL_ONEXEC). + +* Modifying the system default vector length does not affect the vector length + of any existing process or thread that does not make an execve() call. + + +Appendix A. SME programmer's model (informative) +================================================= + +This section provides a minimal description of the additions made by SVE to the +ARMv8-A programmer's model that are relevant to this document. + +Note: This section is for information only and not intended to be complete or +to replace any architectural specification. + +A.1. Registers +--------------- + +In A64 state, SME adds the following: + +* A new mode, streaming mode, in which a subset of the normal FPSIMD and SVE + features are available. When supported EL0 software may enter and leave + streaming mode at any time. + + For best system performance it is strongly encourage for software to enable + streaming mode only when it is actively being used. + +* A new vector length controlling the size of ZA and the Z registers when in + streaming mode, separately to the vector length used for SVE when not in + streaming mode. There is no requirement that either the currently selected + vector length or the set of vector lengths supported for the two modes in + a given system have any relationship. The streaming mode vector length + is referred to as SVL. + +* A new ZA matrix register. This is a square matrix of SVLxSVL bits. Most + operations on ZA require that streaming mode be enabled but ZA can be + enabled without streaming mode in order to load, save and retain data. + + For best system performance it is strongly encourage for software to enable + ZA only when it is actively being used. + +* Two new 1 bit fields in PSTATE which may be controlled via the SMSTART and + SMSTOP instructions or by access to the SVCR system register: + + * PSTATE.ZA, if this is 1 then the ZA matrix is accessible and has valid + data while if it is 0 then ZA can not be accessed. When PSTATE.ZA is + changed from 0 to 1 all bits in ZA are cleared. + + * PSTATE.SM, if this is 1 then the PE is in streaming mode. When the value + of PSTATE.SM is changed then it is implementationd defined if the subset + of the floating point register bits valid in both modes may be retained. + Any other bits will be cleared. + + +References +========== + +[1] arch/arm64/include/uapi/asm/sigcontext.h + AArch64 Linux signal ABI definitions + +[2] arch/arm64/include/uapi/asm/ptrace.h + AArch64 Linux ptrace ABI definitions + +[3] Documentation/arm64/cpu-feature-registers.rst + +[4] ARM IHI0055C + http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055c/IHI0055C_beta_aapc... + http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html + Procedure Call Standard for the ARM 64-bit Architecture (AArch64) diff --git a/Documentation/arm64/sve.rst b/Documentation/arm64/sve.rst index 03137154299e..18b2bb1e8843 100644 --- a/Documentation/arm64/sve.rst +++ b/Documentation/arm64/sve.rst @@ -7,7 +7,9 @@ Author: Dave Martin Dave.Martin@arm.com Date: 4 August 2017

This document outlines briefly the interface provided to userspace by Linux in -order to support use of the ARM Scalable Vector Extension (SVE). +order to support use of the ARM Scalable Vector Extension (SVE), including +interactions with Streaming SVE mode added by the Scalable Matrix Extension +(SME).

This is an outline of the most important features and issues only and not intended to be exhaustive. @@ -23,6 +25,9 @@ model features for SVE is included in Appendix A. * SVE registers Z0..Z31, P0..P15 and FFR and the current vector length VL, are tracked per-thread.

+* In streaming mode FFR is not accessible, when these interfaces are used to + access streaming mode FFR is read and written as zero. + * The presence of SVE is reported to userspace via HWCAP_SVE in the aux vector AT_HWCAP entry. Presence of this flag implies the presence of the SVE instructions and registers, and the Linux-specific system interfaces @@ -53,10 +58,19 @@ model features for SVE is included in Appendix A. which userspace can read using an MRS instruction. See elf_hwcaps.txt and cpu-feature-registers.txt for details.

+* On hardware that supports the SME extensions, HWCAP2_SME will also be + reported in the AT_HWCAP2 aux vector entry. Among other things SME adds + streaming mode which provides a subset of the SVE feature set using a + separate SME vector length and the same Z/V registers. See sme.rst + for more details. + * Debuggers should restrict themselves to interacting with the target via the NT_ARM_SVE regset. The recommended way of detecting support for this regset is to connect to a target process first and then attempt a - ptrace(PTRACE_GETREGSET, pid, NT_ARM_SVE, &iov). + ptrace(PTRACE_GETREGSET, pid, NT_ARM_SVE, &iov). Note that when SME is + present and streaming SVE mode is in use the FPSIMD subset of registers + will be read via NT_ARM_SVE and NT_ARM_SVE writes will exit streaming mode + in the target.

* Whenever SVE scalable register values (Zn, Pn, FFR) are exchanged in memory between userspace and the kernel, the register value is encoded in memory in @@ -126,6 +140,11 @@ the SVE instruction set architecture. are only present in fpsimd_context. For convenience, the content of V0..V31 is duplicated between sve_context and fpsimd_context.

+* The record contains a flag field which includes a flag SVE_SIG_FLAG_SM which + if set indicates that the thread is in streaming mode and the vector length + and register data (if present) describe the streaming SVE data and vector + length. + * The signal frame record for SVE always contains basic metadata, in particular the thread's vector length (in sve_context.vl).

@@ -170,6 +189,11 @@ When returning from a signal handler: the signal frame does not match the current vector length, the signal return attempt is treated as illegal, resulting in a forced SIGSEGV.

+* It is permitted to enter or leave streaming mode by setting or clearing + the SVE_SIG_FLAG_SM flag but applications should take care to ensure that + when doing so sve_context.vl and any register data are appropriate for the + vector length in the new mode. +

6. prctl extensions -------------------- @@ -265,8 +289,14 @@ prctl(PR_SVE_GET_VL) 7. ptrace extensions ---------------------

-* A new regset NT_ARM_SVE is defined for use with PTRACE_GETREGSET and - PTRACE_SETREGSET. +* New regsets NT_ARM_SVE and NT_ARM_SSVE are defined for use with + PTRACE_GETREGSET and PTRACE_SETREGSET. NT_ARM_SSVE describes the + streaming mode SVE registers and NT_ARM_SVE describes the + non-streaming mode SVE registers. + + In this description a register set is referred to as being "live" when + the target is in the appropriate streaming or non-streaming mode and is + using data beyond the subset shared with the FPSIMD Vn registers.

Refer to [2] for definitions.

@@ -297,7 +327,7 @@ The regset data starts with struct user_sve_header, containing:

flags

- either + at most one of

SVE_PT_REGS_FPSIMD

@@ -331,6 +361,10 @@ The regset data starts with struct user_sve_header, containing:

SVE_PT_VL_ONEXEC (SETREGSET only).

+ If neither FPSIMD nor SVE flags are provided then no register + payload is available, this is only possible when SME is implemented. + + * The effects of changing the vector length and/or flags are equivalent to those documented for PR_SVE_SET_VL.

@@ -346,6 +380,13 @@ The regset data starts with struct user_sve_header, containing: case only the vector length and flags are changed (along with any consequences of those changes).

+* In systems supporting SME when in streaming mode a GETREGSET for + NT_REG_SVE will return only the user_sve_header with no register data, + similarly a GETREGSET for NT_REG_SSVE will not return any register data + when not in streaming mode. + +* A GETREGSET for NT_ARM_SSVE will never return SVE_PT_REGS_FPSIMD. + * For SETREGSET, if an SVE_PT_REGS_SVE payload is present and the requested VL is not supported, the effect will be the same as if the payload were omitted, except that an EIO error is reported. No @@ -355,17 +396,25 @@ The regset data starts with struct user_sve_header, containing: unspecified. It is up to the caller to translate the payload layout for the actual VL and retry.

+* Where SME is implemented it is not possible to GETREGSET the register + state for normal SVE when in streaming mode, nor the streaming mode + register state when in normal mode, regardless of the implementation defined + behaviour of the hardware for sharing data between the two modes. + +* Any SETREGSET of NT_ARM_SVE will exit streaming mode if the target was in + streaming mode and any SETREGSET of NT_ARM_SSVE will enter streaming mode + if the target was not in streaming mode. + * The effect of writing a partial, incomplete payload is unspecified.

8. ELF coredump extensions ---------------------------

-* A NT_ARM_SVE note will be added to each coredump for each thread of the - dumped process. The contents will be equivalent to the data that would have - been read if a PTRACE_GETREGSET of NT_ARM_SVE were executed for each thread - when the coredump was generated. - +* NT_ARM_SVE and NT_ARM_SSVE notes will be added to each coredump for + each thread of the dumped process. The contents will be equivalent to the + data that would have been read if a PTRACE_GETREGSET of the corresponding + type were executed for each thread when the coredump was generated.

9. System runtime configuration --------------------------------

As with SVE rather than impose ambitious toolchain requirements for SME we manually encode the few instructions which we require in order to perform the work the kernel needs to do. That is currently:

- Vector store and load for the ZA array. - Zeroing of the whole ZA array.

This does not include the SMSTART and SMSTOP instructions which are single instructions and only used from C code, a later patch will define them as inline assembly.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimdmacros.h | 44 +++++++++++++++++++++++++++ 1 file changed, 44 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index b22538a6137e..bc45bb984c49 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -93,6 +93,12 @@ .endif .endm

+.macro _sme_check_wv v + .if (\v) < 12 || (\v) > 15 + .error "Bad vector select register \v." + .endif +.endm + /* SVE instruction encodings for non-SVE-capable assemblers */ /* (pre binutils 2.28, all kernel capable clang versions support SVE) */

@@ -174,6 +180,44 @@ | (\np) .endm

+/* SME instruction encodings for non-SME-capable assemblers */ + +/* + * STR (vector from ZA array): + * STR ZA[\nw, #\offset], [X\nxbase, #\offset, MUL VL] + */ +.macro _sme_str_zav nw, nxbase, offset=0 + _sme_check_wv \nw + _check_general_reg \nxbase + _check_num (\offset), -0x100, 0xff + .inst 0xe1200000 \ + | (((\nw) & 3) << 13) \ + | ((\nxbase) << 5) \ + | ((\offset) & 7) +.endm + +/* + * LDR (vector to ZA array): + * LDR ZA[\nw, #\offset], [X\nxbase, #\offset, MUL VL] + */ +.macro _sme_ldr_zav nw, nxbase, offset=0 + _sme_check_wv \nw + _check_general_reg \nxbase + _check_num (\offset), -0x100, 0xff + .inst 0xe1000000 \ + | (((\nw) & 3) << 13) \ + | ((\nxbase) << 5) \ + | ((\offset) & 7) +.endm + +/* + * Zero the entire ZA array + * ZERO ZA + */ +.macro zero_za + .inst 0xc00800ff +.endm + .macro __for from:req, to:req .if (\from) == (\to) _for__body %\from

This patch introduces basic cpufeature support for discovering the presence of the Scalable Matrix Extension and reporting hwcaps for the detected features.

Signed-off-by: Mark Brown broonie@kernel.org --- Documentation/arm64/elf_hwcaps.rst | 29 ++++++++++++++++++++ arch/arm64/include/asm/cpu.h | 1 + arch/arm64/include/asm/cpufeature.h | 6 +++++ arch/arm64/include/asm/fpsimd.h | 1 + arch/arm64/include/asm/hwcap.h | 7 +++++ arch/arm64/include/uapi/asm/hwcap.h | 7 +++++ arch/arm64/kernel/cpufeature.c | 41 +++++++++++++++++++++++++++++ arch/arm64/kernel/cpuinfo.c | 8 ++++++ arch/arm64/kernel/fpsimd.c | 19 +++++++++++++ arch/arm64/tools/cpucaps | 1 + 10 files changed, 120 insertions(+)

diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst index ec1a5a63c1d0..39680ff764bb 100644 --- a/Documentation/arm64/elf_hwcaps.rst +++ b/Documentation/arm64/elf_hwcaps.rst @@ -247,6 +247,35 @@ HWCAP2_MTE Functionality implied by ID_AA64PFR1_EL1.MTE == 0b0010, as described by Documentation/arm64/memory-tagging-extension.rst.

+HWCAP2_SME + + Functionality implied by ID_AA64PFR1_EL1.SME == 0b0001, as described + by Documentation/arm64/sme.rst. + +HWCAP2_SME_I16I64 + + Functionality implied by ID_AA64SMFR0_EL1.I16I64 == 0b1111. + +HWCAP2_SME_F64F64 + + Functionality implied by ID_AA64SMFR0_EL1.F64F64 == 0b1. + +HWCAP2_SME_I8I32 + + Functionality implied by ID_AA64SMFR0_EL1.I8I32 == 0b1111. + +HWCAP2_SME_F16F32 + + Functionality implied by ID_AA64SMFR0_EL1.F16F32 == 0b1. + +HWCAP2_SME_B16F32 + + Functionality implied by ID_AA64SMFR0_EL1.B16F32 == 0b1. + +HWCAP2_SME_F32F32 + + Functionality implied by ID_AA64SMFR0_EL1.F32F32 == 0b1. + 4. Unused AT_HWCAP bits -----------------------

diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h index 0f6d16faa540..667b66fe1a53 100644 --- a/arch/arm64/include/asm/cpu.h +++ b/arch/arm64/include/asm/cpu.h @@ -57,6 +57,7 @@ struct cpuinfo_arm64 { u64 reg_id_aa64pfr0; u64 reg_id_aa64pfr1; u64 reg_id_aa64zfr0; + u64 reg_id_aa64smfr0;

struct cpuinfo_32bit aarch32;

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index ef6be92b1921..e1b745bf5fbe 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -727,6 +727,12 @@ static __always_inline bool system_supports_sve(void) cpus_have_const_cap(ARM64_SVE); }

+static __always_inline bool system_supports_sme(void) +{ + return IS_ENABLED(CONFIG_ARM64_SME) && + cpus_have_const_cap(ARM64_SME); +} + static __always_inline bool system_supports_cnp(void) { return IS_ENABLED(CONFIG_ARM64_CNP) && diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 577bfcc252d6..e28e09f30ad4 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -74,6 +74,7 @@ extern void sve_set_vq(unsigned long vq_minus_1);

struct arm64_cpu_capabilities; extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused); +extern void sme_kernel_enable(const struct arm64_cpu_capabilities *__unused);

extern u64 read_zcr_features(void);

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index 8c129db8232a..37605f4be103 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -105,6 +105,13 @@ #define KERNEL_HWCAP_RNG __khwcap2_feature(RNG) #define KERNEL_HWCAP_BTI __khwcap2_feature(BTI) #define KERNEL_HWCAP_MTE __khwcap2_feature(MTE) +#define KERNEL_HWCAP_SME __khwcap2_feature(SME) +#define KERNEL_HWCAP_SME_I16I64 __khwcap2_feature(SME_I16I64) +#define KERNEL_HWCAP_SME_F64F64 __khwcap2_feature(SME_F64F64) +#define KERNEL_HWCAP_SME_I8I32 __khwcap2_feature(SME_I8I32) +#define KERNEL_HWCAP_SME_F16F32 __khwcap2_feature(SME_F16F32) +#define KERNEL_HWCAP_SME_B16F32 __khwcap2_feature(SME_B16F32) +#define KERNEL_HWCAP_SME_F32F32 __khwcap2_feature(SME_F32F32)

/* * This yields a mask that user programs can use to figure out what diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index b8f41aa234ee..2d6bbee3c68a 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -75,5 +75,12 @@ #define HWCAP2_RNG (1 << 16) #define HWCAP2_BTI (1 << 17) #define HWCAP2_MTE (1 << 18) +#define HWCAP2_SME (1 << 19) +#define HWCAP2_SME_I16I64 (1 << 20) +#define HWCAP2_SME_F64F64 (1 << 21) +#define HWCAP2_SME_I8I32 (1 << 22) +#define HWCAP2_SME_F16F32 (1 << 23) +#define HWCAP2_SME_B16F32 (1 << 24) +#define HWCAP2_SME_F32F32 (1 << 25)

#endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 405a65d7e618..9d3e87ba5d5a 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -246,6 +246,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { };

static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = { + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SME_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_MPAMFRAC_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_RASFRAC_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_MTE), @@ -278,6 +279,22 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = { ARM64_FTR_END, };

+static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = { + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_I16I64_SHIFT, 4, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F64F64_SHIFT, 1, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_I8I32_SHIFT, 4, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F16F32_SHIFT, 1, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_B16F32_SHIFT, 1, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F32F32_SHIFT, 1, 0), + ARM64_FTR_END, +}; + static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = { ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ECV_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_FGT_SHIFT, 4, 0), @@ -624,6 +641,7 @@ static const struct __ftr_reg_entry { ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1, &id_aa64pfr1_override), ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0), + ARM64_FTR_REG(SYS_ID_AA64SMFR0_EL1, ftr_id_aa64smfr0),

/* Op1 = 0, CRn = 0, CRm = 5 */ ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0), @@ -935,6 +953,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0); init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1); init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0); + init_cpu_ftr_reg(SYS_ID_AA64SMFR0_EL1, info->reg_id_aa64smfr0);

if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) init_32bit_cpu_features(&info->aarch32); @@ -2332,6 +2351,19 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, .min_field_value = 1, }, +#ifdef CONFIG_ARM64_SME + { + .desc = "Scalable Matrix Extension", + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .capability = ARM64_SME, + .sys_reg = SYS_ID_AA64PFR1_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64PFR1_SME_SHIFT, + .min_field_value = ID_AA64PFR1_SME, + .matches = has_cpuid_feature, + .cpu_enable = sme_kernel_enable, + }, +#endif /* CONFIG_ARM64_SME */ {}, };

@@ -2451,6 +2483,15 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { #ifdef CONFIG_ARM64_MTE HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE), #endif /* CONFIG_ARM64_MTE */ +#ifdef CONFIG_ARM64_SME + HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SME_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SME, CAP_HWCAP, KERNEL_HWCAP_SME), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_I16I64_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_I16I64, CAP_HWCAP, KERNEL_HWCAP_SME_I16I64), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F64F64_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_F64F64, CAP_HWCAP, KERNEL_HWCAP_SME_F64F64), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_I8I32_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_I8I32, CAP_HWCAP, KERNEL_HWCAP_SME_I8I32), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F16F32_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_F16F32, CAP_HWCAP, KERNEL_HWCAP_SME_F16F32), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_B16F32_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_B16F32, CAP_HWCAP, KERNEL_HWCAP_SME_B16F32), + HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F32F32_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_F32F32, CAP_HWCAP, KERNEL_HWCAP_SME_F32F32), +#endif /* CONFIG_ARM64_SME */ {}, };

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 87731fea5e41..9830fa0c7647 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -94,6 +94,13 @@ static const char *const hwcap_str[] = { [KERNEL_HWCAP_RNG] = "rng", [KERNEL_HWCAP_BTI] = "bti", [KERNEL_HWCAP_MTE] = "mte", + [KERNEL_HWCAP_SME] = "sme", + [KERNEL_HWCAP_SME_I16I64] = "smei16i64", + [KERNEL_HWCAP_SME_F64F64] = "smef64f64", + [KERNEL_HWCAP_SME_I8I32] = "smei8i32", + [KERNEL_HWCAP_SME_F16F32] = "smef16f32", + [KERNEL_HWCAP_SME_B16F32] = "smeb16f32", + [KERNEL_HWCAP_SME_F32F32] = "smef32f32", };

#ifdef CONFIG_COMPAT @@ -396,6 +403,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1); info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1); info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1); + info->reg_id_aa64smfr0 = read_cpuid(ID_AA64SMFR0_EL1);

if (id_aa64pfr1_mte(info->reg_id_aa64pfr1)) info->reg_gmid = read_cpuid(GMID_EL1); diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 66842aade1ba..5b3b47dfa620 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -986,6 +986,21 @@ void fpsimd_release_task(struct task_struct *dead_task)

#endif /* CONFIG_ARM64_SVE */

+#ifdef CONFIG_ARM64_SME + +void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) +{ + /* Set priority for all PEs to architecturally defined minimum */ + write_sysreg_s(read_sysreg_s(SYS_SMPRI_EL1) & ~SMPRI_EL1_PRIORITY_MASK, + SYS_SMPRI_EL1); + + /* Allow SME in kernel */ + write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_SMEN_EL1EN, CPACR_EL1); + isb(); +} + +#endif /* CONFIG_ARM64_SVE */ + /* * Trapped SVE access * @@ -1528,6 +1543,10 @@ static int __init fpsimd_init(void) if (!cpu_have_named_feature(ASIMD)) pr_notice("Advanced SIMD is not implemented\n");

+ + if (cpu_have_named_feature(SME) && !cpu_have_named_feature(SVE)) + pr_notice("SME is implemented but not SVE\n"); + return sve_sysctl_init(); } core_initcall(fpsimd_init); diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 49305c2e6dfd..a21a82d3cd64 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -39,6 +39,7 @@ HW_DBM KVM_PROTECTED_MODE MISMATCHED_CACHE_TYPE MTE +SME SPECTRE_V2 SPECTRE_V3A SPECTRE_V4

As for SVE provide a sysctl which allows the default SME vector length to be configured.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/kernel/fpsimd.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 2da7c955d275..9c2b3893f14d 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -482,6 +482,30 @@ static int __init sve_sysctl_init(void) static int __init sve_sysctl_init(void) { return 0; } #endif /* ! (CONFIG_ARM64_SVE && CONFIG_SYSCTL) */

+#if defined(CONFIG_ARM64_SME) && defined(CONFIG_SYSCTL) +static struct ctl_table sme_default_vl_table[] = { + { + .procname = "sme_default_vector_length", + .mode = 0644, + .proc_handler = vec_proc_do_default_vl, + .extra1 = &vl_info[ARM64_VEC_SME], + }, + { } +}; + +static int __init sme_sysctl_init(void) +{ + if (system_supports_sme()) + if (!register_sysctl("abi", sme_default_vl_table)) + return -EINVAL; + + return 0; +} + +#else /* ! (CONFIG_ARM64_SME && CONFIG_SYSCTL) */ +static int __init sme_sysctl_init(void) { return 0; } +#endif /* ! (CONFIG_ARM64_SME && CONFIG_SYSCTL) */ + #define ZREG(sve_state, vq, n) ((char *)(sve_state) + \ (SVE_SIG_ZREG_OFFSET(vq, n) - SVE_SIG_REGS_OFFSET))

@@ -1676,6 +1700,9 @@ static int __init fpsimd_init(void) if (cpu_have_named_feature(SME) && !cpu_have_named_feature(SVE)) pr_notice("SME is implemented but not SVE\n");

- return sve_sysctl_init(); + sve_sysctl_init(); + sme_sysctl_init(); + + return 0; } core_initcall(fpsimd_init);

The Scalable Matrix Extension introduces support for a new thread specific data register TPIDR2 intended for use by libc. The kernel must save the value of TPIDR2 on context switch and should ensure that all new threads start off with a default value of 0. Add a field to the thread_struct to store TPIDR2 and context switch it with the other thread specific data.

In case there are future extensions which also use TPIDR2 we introduce system_supports_tpidr2() and use that rather than system_supports_sme() for TPIDR2 handling.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/cpufeature.h | 5 +++++ arch/arm64/include/asm/processor.h | 1 + arch/arm64/kernel/fpsimd.c | 4 ++++ arch/arm64/kernel/process.c | 14 ++++++++++++-- 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 9a183267b341..8d0cff410b40 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -740,6 +740,11 @@ static __always_inline bool system_supports_sme(void) cpus_have_const_cap(ARM64_SME); }

+static __always_inline bool system_supports_tpidr2(void) +{ + return system_supports_sme(); +} + static __always_inline bool system_supports_cnp(void) { return IS_ENABLED(CONFIG_ARM64_CNP) && diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index a62d2f8045bf..51eca2513cb5 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -168,6 +168,7 @@ struct thread_struct { u64 mte_ctrl; #endif u64 sctlr_user; + u64 tpidr2_el0; };

static inline unsigned int thread_get_vl(struct thread_struct *thread, diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 96780b6821b6..a619ce38eddc 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1101,6 +1101,10 @@ void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) /* Allow SME in kernel */ write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_SMEN_EL1EN, CPACR_EL1); isb(); + + /* Allow EL0 to access TPIDR2 */ + write_sysreg(read_sysreg(SCTLR_EL1) | SCTLR_ELx_ENTP2, SCTLR_EL1); + isb(); }

/* diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 40adb8cdbf5a..3f4279ad68bc 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -249,6 +249,8 @@ void show_regs(struct pt_regs *regs) static void tls_thread_flush(void) { write_sysreg(0, tpidr_el0); + if (system_supports_tpidr2()) + write_sysreg_s(0, SYS_TPIDR2_EL0);

if (is_compat_task()) { current->thread.uw.tp_value = 0; @@ -342,6 +344,8 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, * out-of-sync with the saved value. */ *task_user_tls(p) = read_sysreg(tpidr_el0); + if (system_supports_tpidr2()) + p->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0);

if (stack_start) { if (is_compat_thread(task_thread_info(p))) @@ -352,10 +356,12 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,

/* * If a TLS pointer was passed to clone, use it for the new - * thread. + * thread. We also reset TPIDR2 if it's in use. */ - if (clone_flags & CLONE_SETTLS) + if (clone_flags & CLONE_SETTLS) { p->thread.uw.tp_value = tls; + p->thread.tpidr2_el0 = 0; + } } else { /* * A kthread has no context to ERET to, so ensure any buggy @@ -386,6 +392,8 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, void tls_preserve_current_state(void) { *task_user_tls(current) = read_sysreg(tpidr_el0); + if (system_supports_tpidr2() && !is_compat_task()) + current->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0); }

static void tls_thread_switch(struct task_struct *next) @@ -398,6 +406,8 @@ static void tls_thread_switch(struct task_struct *next) write_sysreg(0, tpidrro_el0);

write_sysreg(*task_user_tls(next), tpidr_el0); + if (system_supports_tpidr2()) + write_sysreg_s(next->thread.tpidr2_el0, SYS_TPIDR2_EL0); }

/*

When in streaming mode we need to save and restore the streaming mode SVE register state rather than the regular SVE register state. This uses the streaming mode vector length and omits FFR but is otherwise identical, if TIF_SVE is enabled when we are in streaming mode then streaming mode takes precedence.

This does not handle use of streaming SVE state with KVM, ptrace or signals. This will be updated in further patches.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 23 +++++- arch/arm64/include/asm/fpsimdmacros.h | 11 +++ arch/arm64/include/asm/processor.h | 10 +++ arch/arm64/kernel/entry-fpsimd.S | 9 ++ arch/arm64/kernel/fpsimd.c | 114 +++++++++++++++++++++----- arch/arm64/kvm/fpsimd.c | 3 +- 6 files changed, 147 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 3550317cbb3d..391db07566aa 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -46,11 +46,22 @@ extern void fpsimd_restore_current_state(void); extern void fpsimd_update_current_state(struct user_fpsimd_state const *state);

extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state, - void *sve_state, unsigned int sve_vl); + void *sve_state, unsigned int sve_vl, + unsigned int sme_vl);

extern void fpsimd_flush_task_state(struct task_struct *target); extern void fpsimd_save_and_flush_cpu_state(void);

+static inline bool thread_sm_enabled(struct thread_struct *thread) +{ + return system_supports_sme() && (thread->svcr & SYS_SVCR_EL0_SM_MASK); +} + +static inline bool thread_za_enabled(struct thread_struct *thread) +{ + return system_supports_sme() && (thread->svcr & SYS_SVCR_EL0_ZA_MASK); +} + /* Maximum VL that SVE/SME VL-agnostic software can transparently support */ #define VL_ARCH_MAX 0x100

@@ -62,7 +73,14 @@ static inline size_t sve_ffr_offset(int vl)

static inline void *sve_pffr(struct thread_struct *thread) { - return (char *)thread->sve_state + sve_ffr_offset(thread_get_sve_vl(thread)); + unsigned int vl; + + if (system_supports_sme() && thread_sm_enabled(thread)) + vl = thread_get_sme_vl(thread); + else + vl = thread_get_sve_vl(thread); + + return (char *)thread->sve_state + sve_ffr_offset(vl); }

extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr); @@ -71,6 +89,7 @@ extern void sve_load_state(void const *state, u32 const *pfpsr, extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); extern void sve_set_vq(unsigned long vq_minus_1); +extern void sme_set_vq(unsigned long vq_minus_1);

struct arm64_cpu_capabilities; extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused); diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index bc45bb984c49..c86fc2fc72e9 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -252,6 +252,17 @@ 921: .endm

+/* Update SMCR_EL1.LEN with the new VQ */ +.macro sme_load_vq xvqminus1, xtmp, xtmp2 + mrs_s \xtmp, SYS_SMCR_EL1 + bic \xtmp2, \xtmp, SMCR_ELx_LEN_MASK + orr \xtmp2, \xtmp2, \xvqminus1 + cmp \xtmp2, \xtmp + b.eq 921f + msr_s SYS_SMCR_EL1, \xtmp2 //self-synchronising +921: +.endm + /* Preserve the first 128-bits of Znz and zero the rest. */ .macro _sve_flush_z nz _sve_check_zreg \nz diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 3c235e165725..338cb03811bd 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -183,6 +183,11 @@ static inline unsigned int thread_get_sve_vl(struct thread_struct *thread) return thread_get_vl(thread, ARM64_VEC_SVE); }

+static inline unsigned int thread_get_sme_vl(struct thread_struct *thread) +{ + return thread_get_vl(thread, ARM64_VEC_SME); +} + unsigned int task_get_vl(const struct task_struct *task, enum vec_type type); void task_set_vl(struct task_struct *task, enum vec_type type, unsigned long vl); @@ -196,6 +201,11 @@ static inline unsigned int task_get_sve_vl(const struct task_struct *task) return task_get_vl(task, ARM64_VEC_SVE); }

+static inline unsigned int task_get_sme_vl(const struct task_struct *task) +{ + return task_get_vl(task, ARM64_VEC_SME); +} + static inline void task_set_sve_vl(struct task_struct *task, unsigned long vl) { task_set_vl(task, ARM64_VEC_SVE, vl); diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 2339d370bfe1..55eb45b3faa9 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -86,3 +86,12 @@ SYM_FUNC_START(sve_flush_live) SYM_FUNC_END(sve_flush_live)

#endif /* CONFIG_ARM64_SVE */ + +#ifdef CONFIG_ARM64_SME + +SYM_FUNC_START(sme_set_vq) + sme_load_vq x0, x1, x2 + ret +SYM_FUNC_END(sme_set_vq) + +#endif /* CONFIG_ARM64_SME */ diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index c43bf252482f..07a6990066af 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -118,6 +118,7 @@ struct fpsimd_last_state_struct { struct user_fpsimd_state *st; void *sve_state; unsigned int sve_vl; + unsigned int sme_vl; };

static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state); @@ -296,17 +297,28 @@ void task_set_vl_onexec(struct task_struct *task, enum vec_type type, task->thread.vl_onexec[type] = vl; }

+/* + * TIF_SME controls whether a task can use SME without trapping while + * in userspace, when TIF_SME is set then we must have storage + * alocated in sve_state and za_state to store the contents of both ZA + * and the SVE registers for both streaming and non-streaming modes. + * + * If both SVCR.ZA and SVCR.SM are disabled then at any point we + * may disable TIF_SME and reenable traps. + */ + + /* * TIF_SVE controls whether a task can use SVE without trapping while - * in userspace, and also the way a task's FPSIMD/SVE state is stored - * in thread_struct. + * in userspace, and also (together with TIF_SME) the way a task's + * FPSIMD/SVE state is stored in thread_struct. * * The kernel uses this flag to track whether a user task is actively * using SVE, and therefore whether full SVE register state needs to * be tracked. If not, the cheaper FPSIMD context handling code can * be used instead of the more costly SVE equivalents. * - * * TIF_SVE set: + * * TIF_SVE or SVCR.SM set: * * The task can execute SVE instructions while in userspace without * trapping to the kernel. @@ -314,7 +326,8 @@ void task_set_vl_onexec(struct task_struct *task, enum vec_type type, * When stored, Z0-Z31 (incorporating Vn in bits[127:0] or the * corresponding Zn), P0-P15 and FFR are encoded in in * task->thread.sve_state, formatted appropriately for vector - * length task->thread.sve_vl. + * length task->thread.sve_vl or, if SVCR.SM is set, + * task->thread.sme_vl. * * task->thread.sve_state must point to a valid buffer at least * sve_state_size(task) bytes in size. @@ -352,19 +365,40 @@ void task_set_vl_onexec(struct task_struct *task, enum vec_type type, */ static void task_fpsimd_load(void) { + bool restore_sve_regs = false; + bool restore_ffr; + WARN_ON(!system_supports_fpsimd()); WARN_ON(!have_cpu_fpsimd_context());

- if (IS_ENABLED(CONFIG_ARM64_SME) && test_thread_flag(TIF_SME)) - write_sysreg_s(current->thread.svcr, SYS_SVCR_EL0); - + /* Check if we should restore SVE first */ if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) { sve_set_vq(sve_vq_from_vl(task_get_sve_vl(current)) - 1); + restore_sve_regs = true; + restore_ffr = true; + } + + /* Restore SME, override SVE register configuration if needed */ + if (system_supports_sme()) { + unsigned long sme_vl = task_get_sme_vl(current); + + if (test_thread_flag(TIF_SME)) + sme_set_vq(sve_vq_from_vl(sme_vl) - 1); + + write_sysreg_s(current->thread.svcr, SYS_SVCR_EL0); + + if (thread_sm_enabled(&current->thread)) { + restore_sve_regs = true; + restore_ffr = false; + } + } + + if (restore_sve_regs) sve_load_state(sve_pffr(&current->thread), - &current->thread.uw.fpsimd_state.fpsr, true); - } else { + &current->thread.uw.fpsimd_state.fpsr, + restore_ffr); + else fpsimd_load_state(&current->thread.uw.fpsimd_state); - } }

/* @@ -376,6 +410,9 @@ static void fpsimd_save(void) struct fpsimd_last_state_struct const *last = this_cpu_ptr(&fpsimd_last_state); /* set by fpsimd_bind_task_to_cpu() or fpsimd_bind_state_to_cpu() */ + bool save_sve_regs = false; + bool save_ffr; + unsigned int vl;

WARN_ON(!system_supports_fpsimd()); WARN_ON(!have_cpu_fpsimd_context()); @@ -383,13 +420,37 @@ static void fpsimd_save(void) if (test_thread_flag(TIF_FOREIGN_FPSTATE)) return;

- if (IS_ENABLED(CONFIG_ARM64_SME) && - test_thread_flag(TIF_SME)) + if (test_thread_flag(TIF_SVE)) { + save_sve_regs = true; + save_ffr = true; + vl = last->sve_vl; + } + + if (system_supports_sme()) { current->thread.svcr = read_sysreg_s(SYS_SVCR_EL0);

- if (IS_ENABLED(CONFIG_ARM64_SVE) && - test_thread_flag(TIF_SVE)) { - if (WARN_ON(sve_get_vl() != last->sve_vl)) { + /* Are we still using SME at all? */ + if (!(current->thread.svcr & (SYS_SVCR_EL0_ZA_MASK | + SYS_SVCR_EL0_SM_MASK))) + clear_thread_flag(TIF_SME); + + if (thread_za_enabled(&current->thread)) { + /* ZA state managment is not implemented yet */ + force_signal_inject(SIGKILL, SI_KERNEL, 0, 0); + return; + } + + /* If we are in streaming mode override regular SVE. */ + if (thread_sm_enabled(&current->thread)) { + save_sve_regs = true; + save_ffr = false; + vl = last->sme_vl; + } + } + + if (IS_ENABLED(CONFIG_ARM64_SVE) && save_sve_regs) { + /* Get the configured VL from RDVL, will account for SM */ + if (WARN_ON(sve_get_vl() != vl)) { /* * Can't save the user regs, so current would * re-enter user with corrupt state. @@ -400,8 +461,8 @@ static void fpsimd_save(void) }

sve_save_state((char *)last->sve_state + - sve_ffr_offset(last->sve_vl), - &last->st->fpsr, true); + sve_ffr_offset(vl), + &last->st->fpsr, save_ffr); } else { fpsimd_save_state(last->st); } @@ -609,7 +670,14 @@ static void sve_to_fpsimd(struct task_struct *task) */ static size_t sve_state_size(struct task_struct const *task) { - return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task_get_sve_vl(task))); + unsigned int vl = 0; + + if (system_supports_sve()) + vl = task_get_sve_vl(task); + if (system_supports_sme()) + vl = max(vl, task_get_sme_vl(task)); + + return SVE_SIG_REGS_SIZE(sve_vq_from_vl(vl)); }

/* @@ -738,7 +806,8 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type, }

fpsimd_flush_task_state(task); - if (test_and_clear_tsk_thread_flag(task, TIF_SVE)) + if (test_and_clear_tsk_thread_flag(task, TIF_SVE) || + thread_sm_enabled(&task->thread)) sve_to_fpsimd(task);

if (system_supports_sme() && type == ARM64_VEC_SME) @@ -1364,6 +1433,9 @@ void fpsimd_flush_thread(void) fpsimd_flush_thread_vl(ARM64_VEC_SVE); }

+ if (system_supports_sme()) + fpsimd_flush_thread_vl(ARM64_VEC_SME); + put_cpu_fpsimd_context(); }

@@ -1407,6 +1479,7 @@ static void fpsimd_bind_task_to_cpu(void) last->st = &current->thread.uw.fpsimd_state; last->sve_state = current->thread.sve_state; last->sve_vl = task_get_sve_vl(current); + last->sme_vl = task_get_sme_vl(current); current->thread.fpsimd_cpu = smp_processor_id();

if (system_supports_sve()) { @@ -1421,7 +1494,7 @@ static void fpsimd_bind_task_to_cpu(void) }

void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, - unsigned int sve_vl) + unsigned int sve_vl, unsigned int sme_vl) { struct fpsimd_last_state_struct *last = this_cpu_ptr(&fpsimd_last_state); @@ -1432,6 +1505,7 @@ void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, last->st = st; last->sve_state = sve_state; last->sve_vl = sve_vl; + last->sme_vl = sme_vl; }

/* diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 5621020b28de..d96871002081 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -99,7 +99,8 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { fpsimd_bind_state_to_cpu(&vcpu->arch.ctxt.fp_regs, vcpu->arch.sve_state, - vcpu->arch.sve_max_vl); + vcpu->arch.sve_max_vl, + 0);

clear_thread_flag(TIF_FOREIGN_FPSTATE); update_thread_flag(TIF_SVE, vcpu_has_sve(vcpu));

By default all SME operations in userspace will trap. When this happens we allocate storage space for the SME register state, set up the SVE registers and disable traps. We do not need to initialize ZA since the architecture guarantees that it will be zeroed when enabled and when we trap ZA is disabled.

On syscall we exit streaming mode if we were previously in it and ensure that all but the lower 128 bits of the registers are zeroed while preserving the state of ZA. This follows the aarch64 PCS for SME, ZA state is preserved over a function call and streaming mode is exited. Since the traps for SME do not distinguish between streaming mode SVE and ZA usage if ZA is in use rather than reenabling traps we instead zero the parts of the SVE registers not shared with FPSIMD and leave SME enabled, this simplifies handling SME traps. If ZA is not in use then we reenable SME traps and fall through to normal handling of SVE.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/esr.h | 1 + arch/arm64/include/asm/exception.h | 1 + arch/arm64/include/asm/fpsimd.h | 15 +++ arch/arm64/kernel/entry-common.c | 10 ++ arch/arm64/kernel/fpsimd.c | 176 +++++++++++++++++++++++++---- arch/arm64/kernel/process.c | 12 +- arch/arm64/kernel/syscall.c | 43 ++++++- 7 files changed, 230 insertions(+), 28 deletions(-)

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index 31418bc7644a..f664f31c774b 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -75,6 +75,7 @@ #define ESR_ELx_IL_SHIFT (25) #define ESR_ELx_IL (UL(1) << ESR_ELx_IL_SHIFT) #define ESR_ELx_ISS_MASK (ESR_ELx_IL - 1) +#define ESR_ELx_ISS(esr) ((esr) & ESR_ELx_ISS_MASK)

/* ISS field definitions shared by different classes */ #define ESR_ELx_WNR_SHIFT (6) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 339477dca551..2add7f33b7c2 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -64,6 +64,7 @@ void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, struct pt_regs *regs); void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs); void do_sve_acc(unsigned int esr, struct pt_regs *regs); +void do_sme_acc(unsigned int esr, struct pt_regs *regs); void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs); void do_sysinstr(unsigned int esr, struct pt_regs *regs); void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index c9cefb17d534..180548c13940 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -276,6 +276,17 @@ static inline void sve_setup(void) { } #ifdef CONFIG_ARM64_SME

extern void __init sme_setup(void); +extern void sme_alloc(struct task_struct *task); + +static inline void sme_user_disable(void) +{ + sysreg_clear_set(cpacr_el1, CPACR_EL1_SMEN_EL0EN, 0); +} + +static inline void sme_user_enable(void) +{ + sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_SMEN_EL0EN); +}

static inline void sme_smstart_sm(void) { @@ -307,6 +318,7 @@ extern int sme_get_current_vl(void); static inline void sme_setup(void) { } static inline int sme_max_vl(void) { return 0; } static inline int sme_max_virtualisable_vl(void) { return 0; } +static inline void sme_alloc(struct task_struct *task) { }

static inline void sme_smstart_sm(void) { } static inline void sme_smstop_sm(void) { } @@ -321,6 +333,9 @@ static inline int sme_get_current_vl(void) return -EINVAL; }

+static inline void sme_user_disable(void) { BUILD_BUG(); } +static inline void sme_user_enable(void) { BUILD_BUG(); } + #endif /* ! CONFIG_ARM64_SME */

/* For use by EFI runtime services calls only */ diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 32f9796c4ffe..ed34b783244f 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -516,6 +516,13 @@ static void noinstr el0_sve_acc(struct pt_regs *regs, unsigned long esr) exit_to_user_mode(regs); }

+static void noinstr el0_sme_acc(struct pt_regs *regs, unsigned long esr) +{ + enter_from_user_mode(regs); + local_daif_restore(DAIF_PROCCTX); + do_sme_acc(esr, regs); +} + static void noinstr el0_fpsimd_exc(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(regs); @@ -624,6 +631,9 @@ asmlinkage void noinstr el0t_64_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_SVE: el0_sve_acc(regs, esr); break; + case ESR_ELx_EC_SME: + el0_sme_acc(regs, esr); + break; case ESR_ELx_EC_FP_EXC64: el0_fpsimd_exc(regs, esr); break; diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index b1e5017d1d46..d846a33a499f 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -204,6 +204,12 @@ static void set_sme_default_vl(int val) set_default_vl(ARM64_VEC_SME, val); }

+static void sme_free(struct task_struct *); + +#else + +static inline void sme_free(struct task_struct *t) { } + #endif

DEFINE_PER_CPU(bool, fpsimd_context_busy); @@ -434,11 +440,6 @@ static void fpsimd_save(void) if (system_supports_sme()) { current->thread.svcr = read_sysreg_s(SYS_SVCR_EL0);

- /* Are we still using SME at all? */ - if (!(current->thread.svcr & (SYS_SVCR_EL0_ZA_MASK | - SYS_SVCR_EL0_SM_MASK))) - clear_thread_flag(TIF_SME); - if (thread_za_enabled(&current->thread)) sme_save_state(last->za_state, last->sme_vl);

@@ -812,18 +813,22 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type, thread_sm_enabled(&task->thread)) sve_to_fpsimd(task);

- if (system_supports_sme() && type == ARM64_VEC_SME) + if (system_supports_sme() && type == ARM64_VEC_SME) { task->thread.svcr &= ~(SYS_SVCR_EL0_SM_MASK | SYS_SVCR_EL0_ZA_MASK); + clear_thread_flag(TIF_SME); + }

if (task == current) put_cpu_fpsimd_context();

/* - * Force reallocation of task SVE state to the correct size - * on next use: + * Force reallocation of task SVE and SME state to the correct + * size on next use: */ sve_free(task); + if (system_supports_sme() && type == ARM64_VEC_SME) + sme_free(task);

task_set_vl(task, type, vl);

@@ -1168,12 +1173,55 @@ void __init sve_setup(void) void fpsimd_release_task(struct task_struct *dead_task) { __sve_free(dead_task); + sme_free(dead_task); }

#endif /* CONFIG_ARM64_SVE */

#ifdef CONFIG_ARM64_SME

+/* This will move to uapi/asm/sigcontext.h when signals are implemented */ +#define ZA_SIG_REGS_SIZE(vq) ((vq * __SVE_VQ_BYTES) * (vq * __SVE_VQ_BYTES)) + +/* + * Return how many bytes of memory are required to store the full SME + * specific state (currently just ZA) for task, given task's currently + * configured vector length. + */ +size_t za_state_size(struct task_struct const *task) +{ + unsigned int vl = task_get_sme_vl(task); + + return ZA_SIG_REGS_SIZE(sve_vq_from_vl(vl)); +} + +/* + * Ensure that task->thread.za_state is allocated and sufficiently large. + * + * This function should be used only in preparation for replacing + * task->thread.za_state with new data. The memory is always zeroed + * here to prevent stale data from showing through: this is done in + * the interest of testability and predictability, the architecture + * guarantees that when ZA is enabled it will be zeroed. + */ +void sme_alloc(struct task_struct *task) +{ + if (task->thread.za_state) { + memset(task->thread.za_state, 0, za_state_size(task)); + return; + } + + /* This could potentially be up to 64K. */ + task->thread.za_state = + kzalloc(za_state_size(task), GFP_KERNEL); +} + +static void sme_free(struct task_struct *task) +{ + kfree(task->thread.za_state); + task->thread.za_state = NULL; +} + void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) { /* Set priority for all PEs to architecturally defined minimum */ @@ -1272,6 +1320,26 @@ void __init sme_setup(void)

#endif /* CONFIG_ARM64_SME */

+static void sve_init_regs(void) +{ + /* + * Convert the FPSIMD state to SVE, zeroing all the state that + * is not shared with FPSIMD. If (as is likely) the current + * state is live in the registers then do this there and + * update our metadata for the current task including + * disabling the trap, otherwise update our in-memory copy. + */ + if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { + unsigned long vq_minus_one = + sve_vq_from_vl(task_get_sve_vl(current)) - 1; + sve_set_vq(vq_minus_one); + sve_flush_live(true, vq_minus_one); + fpsimd_bind_task_to_cpu(); + } else { + fpsimd_to_sve(current); + } +} + /* * Trapped SVE access * @@ -1303,22 +1371,77 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) WARN_ON(1); /* SVE access shouldn't have trapped */

/* - * Convert the FPSIMD state to SVE, zeroing all the state that - * is not shared with FPSIMD. If (as is likely) the current - * state is live in the registers then do this there and - * update our metadata for the current task including - * disabling the trap, otherwise update our in-memory copy. + * Even if the task can have used streaming mode we can only + * generate SVE access traps in normal SVE mode and + * transitioning out of streaming mode may discard any + * streaming mode state. Always clear the high bits to avoid + * any potential errors tracking what is properly initialised. */ + sve_init_regs(); + + put_cpu_fpsimd_context(); +} + +/* + * Trapped SME access + * + * Storage is allocated for the full SVE and SME state, the current + * FPSIMD register contents are migrated to SVE if SVE is not already + * active, and the access trap is disabled. + * + * TIF_SME should be clear on entry: otherwise, fpsimd_restore_current_state() + * would have disabled the SME access trap for userspace during + * ret_to_user, making an SVE access trap impossible in that case. + */ +void do_sme_acc(unsigned int esr, struct pt_regs *regs) +{ + /* Even if we chose not to use SME, the hardware could still trap: */ + if (unlikely(!system_supports_sme()) || WARN_ON(is_compat_task())) { + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); + return; + } + + /* + * If this not a trap due to SME being disabled then something + * is being used in the wrong mode, report as SIGILL. + */ + if (ESR_ELx_ISS(esr) != ESR_ELx_SME_ISS_SME_DISABLED) { + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); + return; + } + + sve_alloc(current); + sme_alloc(current); + if (!current->thread.sve_state || !current->thread.za_state) { + force_sig(SIGKILL); + return; + } + + get_cpu_fpsimd_context(); + + /* With TIF_SME userspace shouldn't generate any traps */ + if (test_and_set_thread_flag(TIF_SME)) + WARN_ON(1); + if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { unsigned long vq_minus_one = - sve_vq_from_vl(task_get_sve_vl(current)) - 1; - sve_set_vq(vq_minus_one); - sve_flush_live(true, vq_minus_one); + sve_vq_from_vl(task_get_sme_vl(current)) - 1; + sme_set_vq(vq_minus_one); + fpsimd_bind_task_to_cpu(); - } else { - fpsimd_to_sve(current); }

+ /* + * If SVE was not already active initialise the SVE registers, + * any non-shared state between the streaming and regular SVE + * registers is architecturally guaranteed to be zeroed when + * we enter streaming mode. We do not need to initialize ZA + * since ZA must be disabled at this point and enabling ZA is + * architecturally defined to zero ZA. + */ + if (system_supports_sve() && !test_thread_flag(TIF_SVE)) + sve_init_regs(); + put_cpu_fpsimd_context(); }

@@ -1435,8 +1558,11 @@ void fpsimd_flush_thread(void) fpsimd_flush_thread_vl(ARM64_VEC_SVE); }

- if (system_supports_sme()) + if (system_supports_sme()) { + clear_thread_flag(TIF_SME); + sme_free(current); fpsimd_flush_thread_vl(ARM64_VEC_SME); + }

put_cpu_fpsimd_context(); } @@ -1485,14 +1611,22 @@ static void fpsimd_bind_task_to_cpu(void) last->sme_vl = task_get_sme_vl(current); current->thread.fpsimd_cpu = smp_processor_id();

+ /* + * Toggle SVE and SME trapping for userspace if needed, these + * are serialsied by ret_to_user() + */ if (system_supports_sve()) { - /* Toggle SVE trapping for userspace if needed */ if (test_thread_flag(TIF_SVE)) sve_user_enable(); else sve_user_disable(); + }

- /* Serialised by exception return to user */ + if (system_supports_sme()) { + if (test_thread_flag(TIF_SME)) + sme_user_enable(); + else + sme_user_disable(); } }

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 4dd35619ece6..cbd6b12c4339 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -298,17 +298,19 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) BUILD_BUG_ON(!IS_ENABLED(CONFIG_THREAD_INFO_IN_TASK));

/* - * Detach src's sve_state (if any) from dst so that it does not - * get erroneously used or freed prematurely. dst's sve_state - * will be allocated on demand later on if dst uses SVE. - * For consistency, also clear TIF_SVE here: this could be done + * Detach src's sve/za_state (if any) from dst so that it does not + * get erroneously used or freed prematurely. dst's copies + * will be allocated on demand later on if dst uses SVE/SME. + * For consistency, also clear TIF_SVE/SME here: this could be done * later in copy_process(), but to avoid tripping up future - * maintainers it is best not to leave TIF_SVE and sve_state in + * maintainers it is best not to leave TIF flags and buffers in * an inconsistent state, even temporarily. */ dst->thread.sve_state = NULL; clear_tsk_thread_flag(dst, TIF_SVE);

+ dst->thread.za_state = NULL; + clear_tsk_thread_flag(dst, TIF_SME); dst->thread.svcr = 0;

/* clear any pending asynchronous tag fault raised by the parent */ diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 50a0f1a38e84..66d47ffeae08 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -158,11 +158,50 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, syscall_trace_exit(regs); }

-static inline void sve_user_discard(void) +/* + * As per the ABI exit SME streaming mode and clear the SVE state not + * shared with FPSIMD on syscall entry. + */ +static inline void fp_user_discard(void) { + /* + * If SME is active then exit streaming mode. If ZA is active + * then flush the SVE registers but leave userspace access to + * both SVE and SME enabled, otherwise disable SME for the + * task and fall through to disabling SVE too. + * + * Since with SME traps disabled userspace can freely enter + * and exit streaming mode and SVE register state is shared + * between the two it is simpler to just leave SVE enabled + * while userspace is actively using SME than to track state + * transitions. + */ + if (system_supports_sme() && test_thread_flag(TIF_SME)) { + u64 svcr = read_sysreg_s(SYS_SVCR_EL0); + + if (svcr & SYS_SVCR_EL0_SM_MASK) + sme_smstop_sm(); + + if (svcr & SYS_SVCR_EL0_ZA_MASK) { + unsigned long sve_vq_minus_one = + sve_vq_from_vl(task_get_sve_vl(current)) - 1; + sve_flush_live(false, sve_vq_minus_one); + return; + } else { + clear_thread_flag(TIF_SME); + sme_user_disable(); + } + } + + if (!system_supports_sve()) return;

+ /* + * If SME is not active then disable SVE, the registers will + * be cleared when userspace next attempts to access them and + * we do not need to track the SVE register state until then. + */ clear_thread_flag(TIF_SVE);

/* @@ -177,7 +216,7 @@ static inline void sve_user_discard(void)

void do_el0_svc(struct pt_regs *regs) { - sve_user_discard(); + fp_user_discard(); el0_svc_common(regs, regs->regs[8], __NR_syscalls, sys_call_table); }

Implement support for ZA in signal handling in a very similar way to how we implement support for SVE registers, using a signal context structure with optional register state after it. Where present this register state stores the ZA matrix as a series of horizontal vectors numbered from 0 to VL/8 in the endinanness independent format used for vectors.

As with SVE we do not allow changes in the vector length during signal return but we do allow ZA to be enabled or disabled.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/uapi/asm/sigcontext.h | 41 +++++++ arch/arm64/kernel/fpsimd.c | 3 - arch/arm64/kernel/signal.c | 139 +++++++++++++++++++++++ 3 files changed, 180 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h index 3a3366d4fbc2..d45bdf2c8b26 100644 --- a/arch/arm64/include/uapi/asm/sigcontext.h +++ b/arch/arm64/include/uapi/asm/sigcontext.h @@ -140,6 +140,14 @@ struct sve_context {

#define SVE_SIG_FLAG_SM 0x1 /* Context describes streaming mode */

+#define ZA_MAGIC 0x54366345 + +struct za_context { + struct _aarch64_ctx head; + __u16 vl; + __u16 __reserved[3]; +}; + #endif /* !__ASSEMBLY__ */

#include <asm/sve_context.h> @@ -259,4 +267,37 @@ struct sve_context { #define SVE_SIG_CONTEXT_SIZE(vq) \ (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))

+/* + * If the ZA register is enabled for the thread at signal delivery then, + * za_context.head.size >= ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(za_context.vl)) + * and the register data may be accessed using the ZA_SIG_*() macros. + * + * If za_context.head.size < ZA_SIG_CONTEXT_SIZE(sve_vq_from_vl(za_context.vl)) + * then ZA was not enabled and no register data was included in which case + * ZA register was not enabled for the thread and no register data + * the ZA_SIG_*() macros should not be used except for this check. + * + * The same convention applies when returning from a signal: a caller + * will need to remove or resize the za_context block if it wants to + * enable the ZA register when it was previously non-live or vice-versa. + * This may require the caller to allocate fresh memory and/or move other + * context blocks in the signal frame. + * + * Changing the vector length during signal return is not permitted: + * za_context.vl must equal the thread's current SME vector length when + * doing a sigreturn. + */ + +#define ZA_SIG_REGS_OFFSET \ + ((sizeof(struct za_context) + (__SVE_VQ_BYTES - 1)) \ + / __SVE_VQ_BYTES * __SVE_VQ_BYTES) + +#define ZA_SIG_REGS_SIZE(vq) ((vq * __SVE_VQ_BYTES) * (vq * __SVE_VQ_BYTES)) + +#define ZA_SIG_ZAV_OFFSET(vq, n) (ZA_SIG_REGS_OFFSET + \ + (SVE_SIG_ZREG_SIZE(vq) * n)) + +#define ZA_SIG_CONTEXT_SIZE(vq) \ + (ZA_SIG_REGS_OFFSET + ZA_SIG_REGS_SIZE(vq)) + #endif /* _UAPI__ASM_SIGCONTEXT_H */ diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index d846a33a499f..4b437b78db81 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1180,9 +1180,6 @@ void fpsimd_release_task(struct task_struct *dead_task)

#ifdef CONFIG_ARM64_SME

-/* This will move to uapi/asm/sigcontext.h when signals are implemented */ -#define ZA_SIG_REGS_SIZE(vq) ((vq * __SVE_VQ_BYTES) * (vq * __SVE_VQ_BYTES)) - /* * Return how many bytes of memory are required to store the full SME * specific state (currently just ZA) for task, given task's currently diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index fea0e1d30449..c0007ddf0c06 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -57,6 +57,7 @@ struct rt_sigframe_user_layout { unsigned long fpsimd_offset; unsigned long esr_offset; unsigned long sve_offset; + unsigned long za_offset; unsigned long extra_offset; unsigned long end_offset; }; @@ -219,6 +220,7 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx) struct user_ctxs { struct fpsimd_context __user *fpsimd; struct sve_context __user *sve; + struct za_context __user *za; };

#ifdef CONFIG_ARM64_SVE @@ -347,6 +349,101 @@ extern int restore_sve_fpsimd_context(struct user_ctxs *user);

#endif /* ! CONFIG_ARM64_SVE */

+#ifdef CONFIG_ARM64_SME + +static int preserve_za_context(struct za_context __user *ctx) +{ + int err = 0; + u16 reserved[ARRAY_SIZE(ctx->__reserved)]; + unsigned int vl = task_get_sme_vl(current); + unsigned int vq; + + if (thread_za_enabled(&current->thread)) + vq = sve_vq_from_vl(vl); + else + vq = 0; + + memset(reserved, 0, sizeof(reserved)); + + __put_user_error(ZA_MAGIC, &ctx->head.magic, err); + __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16), + &ctx->head.size, err); + __put_user_error(vl, &ctx->vl, err); + BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved)); + err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved)); + + if (vq) { + /* + * This assumes that the ZA state has already been saved to + * the task struct by calling the function + * fpsimd_signal_preserve_current_state(). + */ + err |= __copy_to_user((char __user *)ctx + ZA_SIG_REGS_OFFSET, + current->thread.za_state, + ZA_SIG_REGS_SIZE(vq)); + } + + return err ? -EFAULT : 0; +} + +static int restore_za_context(struct user_ctxs __user *user) +{ + int err; + unsigned int vq; + struct za_context za; + + if (__copy_from_user(&za, user->za, sizeof(za))) + return -EFAULT; + + if (za.vl != task_get_sme_vl(current)) + return -EINVAL; + + if (za.head.size <= sizeof(*user->za)) { + current->thread.svcr &= ~SYS_SVCR_EL0_ZA_MASK; + return 0; + } + + vq = sve_vq_from_vl(za.vl); + + if (za.head.size < ZA_SIG_CONTEXT_SIZE(vq)) + return -EINVAL; + + /* + * Careful: we are about __copy_from_user() directly into + * thread.za_state with preemption enabled, so protection is + * needed to prevent a racing context switch from writing stale + * registers back over the new data. + */ + + fpsimd_flush_task_state(current); + /* From now, fpsimd_thread_switch() won't touch thread.sve_state */ + + sme_alloc(current); + if (!current->thread.za_state) { + current->thread.svcr &= ~SYS_SVCR_EL0_ZA_MASK; + clear_thread_flag(TIF_SME); + return -ENOMEM; + } + + err = __copy_from_user(current->thread.za_state, + (char __user const *)user->za + + ZA_SIG_REGS_OFFSET, + ZA_SIG_REGS_SIZE(vq)); + if (err) + return -EFAULT; + + set_thread_flag(TIF_SME); + current->thread.svcr |= SYS_SVCR_EL0_ZA_MASK; + + return 0; +} +#else /* ! CONFIG_ARM64_SME */ + +/* Turn any non-optimised out attempts to use these into a link error: */ +extern int preserve_za_context(void __user *ctx); +extern int restore_za_context(struct user_ctxs *user); + +#endif /* ! CONFIG_ARM64_SME */

static int parse_user_sigframe(struct user_ctxs *user, struct rt_sigframe __user *sf) @@ -361,6 +458,7 @@ static int parse_user_sigframe(struct user_ctxs *user,

user->fpsimd = NULL; user->sve = NULL; + user->za = NULL;

if (!IS_ALIGNED((unsigned long)base, 16)) goto invalid; @@ -426,6 +524,19 @@ static int parse_user_sigframe(struct user_ctxs *user, user->sve = (struct sve_context __user *)head; break;

+ case ZA_MAGIC: + if (!system_supports_sme()) + goto invalid; + + if (user->za) + goto invalid; + + if (size < sizeof(*user->za)) + goto invalid; + + user->za = (struct za_context __user *)head; + break; + case EXTRA_MAGIC: if (have_extra_context) goto invalid; @@ -549,6 +660,9 @@ static int restore_sigframe(struct pt_regs *regs, } }

+ if (err == 0 && system_supports_sme() && user.za) + err = restore_za_context(&user); + return err; }

@@ -633,6 +747,24 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, return err; }

+ if (system_supports_sme()) { + unsigned int vl; + unsigned int vq = 0; + + if (add_all) + vl = sme_max_vl(); + else + vl = task_get_sme_vl(current); + + if (thread_za_enabled(&current->thread)) + vq = sve_vq_from_vl(vl); + + err = sigframe_alloc(user, &user->za_offset, + ZA_SIG_CONTEXT_SIZE(vq)); + if (err) + return err; + } + return sigframe_alloc_end(user); }

@@ -681,6 +813,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, err |= preserve_sve_context(sve_ctx); }

+ /* ZA state if present */ + if (system_supports_sme() && err == 0 && user->za_offset) { + struct za_context __user *za_ctx = + apply_user_offset(user, user->za_offset); + err |= preserve_za_context(za_ctx); + } + if (err == 0 && user->extra_offset) { char __user *sfp = (char __user *)user->sigframe; char __user *userp =

The ZA array can be read and written with the NT_ARM_ZA. Similarly to our interface for the SVE vector registers the regset consists of a header with information on the current vector length followed by an optional register data payload, represented as for signals as a series of horizontal vectors from 0 to VL/8 in the endianness independent format used for vectors.

On get if ZA is enabled then register data will be provided, otherwise it will be omitted. On set if register data is provided then ZA is enabled and initialized using the provided data, otherwise it is disabled.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/uapi/asm/ptrace.h | 56 +++++++++++ arch/arm64/kernel/ptrace.c | 144 +++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 3 files changed, 201 insertions(+)

diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 522b925a78c1..7fa2f7036aa7 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -268,6 +268,62 @@ struct user_pac_generic_keys { __uint128_t apgakey; };

+/* ZA state (NT_ARM_ZA) */ + +struct user_za_header { + __u32 size; /* total meaningful regset content in bytes */ + __u32 max_size; /* maxmium possible size for this thread */ + __u16 vl; /* current vector length */ + __u16 max_vl; /* maximum possible vector length */ + __u16 flags; + __u16 __reserved; +}; + +/* + * Common ZA_PT_* flags: + * These must be kept in sync with prctl interface in <linux/prctl.h> + */ +#define ZA_PT_VL_INHERIT ((1 << 17) /* PR_SME_VL_INHERIT */ >> 16) +#define ZA_PT_VL_ONEXEC ((1 << 18) /* PR_SME_SET_VL_ONEXEC */ >> 16) + + +/* + * The remainder of the ZA state follows struct user_za_header. The + * total size of the ZA state (including header) depends on the + * metadata in the header: ZA_PT_SIZE(vq, flags) gives the total size + * of the state in bytes, including the header. + * + * Refer to <asm/sigcontext.h> for details of how to pass the correct + * "vq" argument to these macros. + */ + +/* Offset from the start of struct user_za_header to the register data */ +#define ZA_PT_ZA_OFFSET \ + ((sizeof(struct user_za_header) + (__SVE_VQ_BYTES - 1)) \ + / __SVE_VQ_BYTES * __SVE_VQ_BYTES) + +/* + * The payload starts at offset ZA_PT_ZA_OFFSET, and is of size + * ZA_PT_ZA_SIZE(vq, flags). + * + * The ZA array is stored as a sequence of horizontal vectors ZAV of SVL/8 + * bytes each, starting from vector 0. + * + * Additional data might be appended in the future. + * + * The ZA matrix is represented in memory in an endianness-invariant layout + * which differs from the layout used for the FPSIMD V-registers on big-endian + * systems: see sigcontext.h for more explanation. + */ + +#define ZA_PT_ZAV_OFFSET(vq, n) \ + (ZA_PT_ZA_OFFSET + ((vq * __SVE_VQ_BYTES) * n)) + +#define ZA_PT_ZA_SIZE(vq) ((vq * __SVE_VQ_BYTES) * (vq * __SVE_VQ_BYTES)) + +#define ZA_PT_SIZE(vq) \ + (ZA_PT_ZA_OFFSET + ZA_PT_ZA_SIZE(vq)) + #endif /* __ASSEMBLY__ */

#endif /* _UAPI__ASM_PTRACE_H */ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 414126ce5897..702765f50a47 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -996,6 +996,141 @@ static int ssve_set(struct task_struct *target, ARM64_VEC_SME); }

+static int za_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + struct user_za_header header; + unsigned int vq; + unsigned long start, end; + + if (!system_supports_sme()) + return -EINVAL; + + /* Header */ + memset(&header, 0, sizeof(header)); + + if (test_tsk_thread_flag(target, TIF_SME_VL_INHERIT)) + header.flags |= ZA_PT_VL_INHERIT; + + header.vl = task_get_sme_vl(target); + vq = sve_vq_from_vl(header.vl); + header.max_vl = sme_max_vl(); + header.max_size = ZA_PT_SIZE(vq); + + /* If ZA is not active there is only the header */ + if (thread_za_enabled(&target->thread)) + header.size = ZA_PT_SIZE(vq); + else + header.size = ZA_PT_ZA_OFFSET; + + membuf_write(&to, &header, sizeof(header)); + + BUILD_BUG_ON(ZA_PT_ZA_OFFSET != sizeof(header)); + end = ZA_PT_ZA_OFFSET; +; + if (target == current) + fpsimd_preserve_current_state(); + + /* Any register data to include? */ + if (thread_za_enabled(&target->thread)) { + start = end; + end = ZA_PT_SIZE(vq); + membuf_write(&to, target->thread.za_state, end - start); + } + + /* Zero any trailing padding */ + start = end; + end = ALIGN(header.size, SVE_VQ_BYTES); + return membuf_zero(&to, end - start); +} + +static int za_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int ret; + struct user_za_header header; + unsigned int vq; + unsigned long start, end; + + if (!system_supports_sme()) + return -EINVAL; + + /* Header */ + if (count < sizeof(header)) + return -EINVAL; + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &header, + 0, sizeof(header)); + if (ret) + goto out; + + /* + * All current ZA_PT_* flags are consumed by + * vec_set_vector_length(), which will also validate them for + * us: + */ + ret = vec_set_vector_length(target, ARM64_VEC_SME, header.vl, + ((unsigned long)header.flags) << 16); + if (ret) + goto out; + + /* Actual VL set may be less than the user asked for: */ + vq = sve_vq_from_vl(task_get_sme_vl(target)); + + /* Ensure there is some SVE storage for streaming mode */ + if (!target->thread.sve_state) { + sve_alloc(target); + if (!target->thread.sve_state) { + clear_thread_flag(TIF_SME); + ret = -ENOMEM; + goto out; + } + } + + /* Allocate/reinit ZA storage */ + sme_alloc(target); + if (!target->thread.za_state) { + ret = -ENOMEM; + clear_tsk_thread_flag(target, TIF_SME); + goto out; + } + + /* If there is no data then disable ZA */ + if (!count) { + target->thread.svcr &= ~SYS_SVCR_EL0_ZA_MASK; + goto out; + } + + /* + * If setting a different VL from the requested VL and there is + * register data, the data layout will be wrong: don't even + * try to set the registers in this case. + */ + if (vq != sve_vq_from_vl(header.vl)) { + ret = -EIO; + goto out; + } + + BUILD_BUG_ON(ZA_PT_ZA_OFFSET != sizeof(header)); + start = ZA_PT_ZA_OFFSET; + end = ZA_PT_SIZE(vq); + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + target->thread.za_state, + start, end); + if (ret) + goto out; + + /* Mark ZA as active and let userspace use it */ + set_tsk_thread_flag(target, TIF_SME); + target->thread.svcr |= SYS_SVCR_EL0_ZA_MASK; + +out: + fpsimd_flush_task_state(target); + return ret; +} + #endif /* CONFIG_ARM64_SME */

#ifdef CONFIG_ARM64_PTR_AUTH @@ -1217,6 +1352,7 @@ enum aarch64_regset { #endif #ifdef CONFIG_ARM64_SVE REGSET_SSVE, + REGSET_ZA, #endif #ifdef CONFIG_ARM64_PTR_AUTH REGSET_PAC_MASK, @@ -1308,6 +1444,14 @@ static const struct user_regset aarch64_regsets[] = { .regset_get = ssve_get, .set = ssve_set, }, + [REGSET_ZA] = { /* SME ZA */ + .core_note_type = NT_ARM_ZA, + .n = DIV_ROUND_UP(ZA_PT_ZA_SIZE(SVE_VQ_MAX), SVE_VQ_BYTES), + .size = SVE_VQ_BYTES, + .align = SVE_VQ_BYTES, + .regset_get = za_get, + .set = za_set, + }, #endif #ifdef CONFIG_ARM64_PTR_AUTH [REGSET_PAC_MASK] = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 61502388683f..7ef574f3256a 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -428,6 +428,7 @@ typedef struct elf64_shdr { #define NT_ARM_TAGGED_ADDR_CTRL 0x409 /* arm64 tagged address control (prctl()) */ #define NT_ARM_PAC_ENABLED_KEYS 0x40a /* arm64 ptr auth enabled keys (prctl()) */ #define NT_ARM_SSVE 0x40b /* ARM Streaming SVE registers */ +#define NT_ARM_ZA 0x40c /* ARM SME ZA registers */ #define NT_ARC_V2 0x600 /* ARCv2 accumulator/extra registers */ #define NT_VMCOREDD 0x700 /* Vmcore Device Dump Note */ #define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */

When saving and restoring the floating point state over an EFI runtime call ensure that we handle streaming mode, only handling FFR if we are not in streaming mode and ensuring that we are in normal mode over the call into runtime services.

We currently assume that ZA will not be modified by runtime services, the specification is not yet finalised so this may need updating if that changes.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/kernel/fpsimd.c | 47 +++++++++++++++++++++++++++++++++----- 1 file changed, 41 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index d3665d7f6e78..bd9a0eddf533 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1049,21 +1049,25 @@ int vec_verify_vq_map(enum vec_type type)

static void __init sve_efi_setup(void) { - struct vl_info *info = &vl_info[ARM64_VEC_SVE]; + int max_vl = 0; + int i;

if (!IS_ENABLED(CONFIG_EFI)) return;

+ for (i = 0; i < ARRAY_SIZE(vl_info); i++) + max_vl = max(vl_info[i].max_vl, max_vl); + /* * alloc_percpu() warns and prints a backtrace if this goes wrong. * This is evidence of a crippled system and we are returning void, * so no attempt is made to handle this situation here. */ - if (!sve_vl_valid(info->max_vl)) + if (!sve_vl_valid(max_vl)) goto fail;

efi_sve_state = __alloc_percpu( - SVE_SIG_REGS_SIZE(sve_vq_from_vl(info->max_vl)), SVE_VQ_BYTES); + SVE_SIG_REGS_SIZE(sve_vq_from_vl(max_vl)), SVE_VQ_BYTES); if (!efi_sve_state) goto fail;

@@ -1830,6 +1834,7 @@ EXPORT_SYMBOL(kernel_neon_end); static DEFINE_PER_CPU(struct user_fpsimd_state, efi_fpsimd_state); static DEFINE_PER_CPU(bool, efi_fpsimd_state_used); static DEFINE_PER_CPU(bool, efi_sve_state_used); +static DEFINE_PER_CPU(bool, efi_sm_state);

/* * EFI runtime services support functions @@ -1864,12 +1869,28 @@ void __efi_fpsimd_begin(void) */ if (system_supports_sve() && likely(efi_sve_state)) { char *sve_state = this_cpu_ptr(efi_sve_state); + bool ffr = true; + u64 svcr;

__this_cpu_write(efi_sve_state_used, true);

+ /* If we are in streaming mode don't touch FFR */ + if (system_supports_sme()) { + svcr = read_sysreg_s(SYS_SVCR_EL0); + + ffr = svcr & SYS_SVCR_EL0_SM_MASK; + + __this_cpu_write(efi_sm_state, ffr); + } + sve_save_state(sve_state + sve_ffr_offset(sve_max_vl()), &this_cpu_ptr(&efi_fpsimd_state)->fpsr, - true); + ffr); + + if (system_supports_sme()) + sysreg_clear_set_s(SYS_SVCR_EL0, + SYS_SVCR_EL0_SM_MASK, 0); + } else { fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state)); } @@ -1892,11 +1913,25 @@ void __efi_fpsimd_end(void) if (system_supports_sve() && likely(__this_cpu_read(efi_sve_state_used))) { char const *sve_state = this_cpu_ptr(efi_sve_state); + bool ffr = true; + + /* + * Restore streaming mode; EFI calls are + * normal function calls so should not return in + * streaming mode. + */ + if (system_supports_sme()) { + if (__this_cpu_read(efi_sm_state)) { + sysreg_clear_set_s(SYS_SVCR_EL0, + 0, + SYS_SVCR_EL0_SM_MASK); + ffr = false; + } + }

- sve_set_vq(sve_vq_from_vl(sve_get_vl()) - 1); sve_load_state(sve_state + sve_ffr_offset(sve_max_vl()), &this_cpu_ptr(&efi_fpsimd_state)->fpsr, - true); + ffr);

__this_cpu_write(efi_sve_state_used, false); } else {

The Scalable Matrix Extenions (SME) introduces additional register state with configurable vector lengths, similar to SVE but configured separately. Extend vlset to support configuring this state with a --sme or -s command line option.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/vlset.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/fp/vlset.c b/tools/testing/selftests/arm64/fp/vlset.c index 308d27a68226..76912a581a95 100644 --- a/tools/testing/selftests/arm64/fp/vlset.c +++ b/tools/testing/selftests/arm64/fp/vlset.c @@ -22,12 +22,15 @@ static int inherit = 0; static int no_inherit = 0; static int force = 0; static unsigned long vl; +static int set_ctl = PR_SVE_SET_VL; +static int get_ctl = PR_SVE_GET_VL;

static const struct option options[] = { { "force", no_argument, NULL, 'f' }, { "inherit", no_argument, NULL, 'i' }, { "max", no_argument, NULL, 'M' }, { "no-inherit", no_argument, &no_inherit, 1 }, + { "sme", no_argument, NULL, 's' }, { "help", no_argument, NULL, '?' }, {} }; @@ -50,6 +53,9 @@ static int parse_options(int argc, char **argv) case 'M': vl = SVE_VL_MAX; break; case 'f': force = 1; break; case 'i': inherit = 1; break; + case 's': set_ctl = PR_SME_SET_VL; + get_ctl = PR_SME_GET_VL; + break; case 0: break; default: goto error; } @@ -125,14 +131,14 @@ int main(int argc, char **argv) if (inherit) flags |= PR_SVE_VL_INHERIT;

- t = prctl(PR_SVE_SET_VL, vl | flags); + t = prctl(set_ctl, vl | flags); if (t < 0) { fprintf(stderr, "%s: PR_SVE_SET_VL: %s\n", program_name, strerror(errno)); goto error; }

- t = prctl(PR_SVE_GET_VL); + t = prctl(get_ctl); if (t == -1) { fprintf(stderr, "%s: PR_SVE_GET_VL: %s\n", program_name, strerror(errno));

Provide RDVL helpers for SME and extend the main vector configuration tests to cover SME.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/.gitignore | 1 + tools/testing/selftests/arm64/fp/Makefile | 3 ++- tools/testing/selftests/arm64/fp/rdvl-sme.c | 14 ++++++++++++++ tools/testing/selftests/arm64/fp/rdvl.S | 16 ++++++++++++++++ tools/testing/selftests/arm64/fp/rdvl.h | 1 + tools/testing/selftests/arm64/fp/vec-syscfg.c | 10 ++++++++++ 6 files changed, 44 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/arm64/fp/rdvl-sme.c

diff --git a/tools/testing/selftests/arm64/fp/.gitignore b/tools/testing/selftests/arm64/fp/.gitignore index b67395903b9b..885dd592807b 100644 --- a/tools/testing/selftests/arm64/fp/.gitignore +++ b/tools/testing/selftests/arm64/fp/.gitignore @@ -1,4 +1,5 @@ fpsimd-test +rdvl-sme rdvl-sve sve-probe-vls sve-ptrace diff --git a/tools/testing/selftests/arm64/fp/Makefile b/tools/testing/selftests/arm64/fp/Makefile index 4367125b7c27..ff1c8fde3aed 100644 --- a/tools/testing/selftests/arm64/fp/Makefile +++ b/tools/testing/selftests/arm64/fp/Makefile @@ -3,7 +3,7 @@ CFLAGS += -I../../../../../usr/include/ TEST_GEN_PROGS := sve-ptrace sve-probe-vls vec-syscfg TEST_PROGS_EXTENDED := fpsimd-test fpsimd-stress \ - rdvl-sve \ + rdvl-sme rdvl-sve \ sve-test sve-stress \ vlset

@@ -11,6 +11,7 @@ all: $(TEST_GEN_PROGS) $(TEST_PROGS_EXTENDED)

fpsimd-test: fpsimd-test.o $(CC) -nostdlib $^ -o $@ +rdvl-sme: rdvl-sme.o rdvl.o rdvl-sve: rdvl-sve.o rdvl.o sve-ptrace: sve-ptrace.o sve-probe-vls: sve-probe-vls.o rdvl.o diff --git a/tools/testing/selftests/arm64/fp/rdvl-sme.c b/tools/testing/selftests/arm64/fp/rdvl-sme.c new file mode 100644 index 000000000000..49b0b2e08bac --- /dev/null +++ b/tools/testing/selftests/arm64/fp/rdvl-sme.c @@ -0,0 +1,14 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <stdio.h> + +#include "rdvl.h" + +int main(void) +{ + int vl = rdvl_sme(); + + printf("%d\n", vl); + + return 0; +} diff --git a/tools/testing/selftests/arm64/fp/rdvl.S b/tools/testing/selftests/arm64/fp/rdvl.S index c916c1c9defd..a9a028ba1b79 100644 --- a/tools/testing/selftests/arm64/fp/rdvl.S +++ b/tools/testing/selftests/arm64/fp/rdvl.S @@ -8,3 +8,19 @@ rdvl_sve: hint 34 // BTI C rdvl x0, #1 ret + +.globl rdvl_sme +rdvl_sme: + hint 34 // BTI C + + // Enter streaming mode + mov x16, #1 + msr S3_3_C4_C2_2, x16 + + rdvl x0, #1 + + // Leave streaming mode + mov x16, #0 + msr S3_3_C4_C2_2, x16 + + ret diff --git a/tools/testing/selftests/arm64/fp/rdvl.h b/tools/testing/selftests/arm64/fp/rdvl.h index 7c9d953fc9e7..5d323679fbc9 100644 --- a/tools/testing/selftests/arm64/fp/rdvl.h +++ b/tools/testing/selftests/arm64/fp/rdvl.h @@ -3,6 +3,7 @@ #ifndef RDVL_H #define RDVL_H

+int rdvl_sme(void); int rdvl_sve(void);

#endif diff --git a/tools/testing/selftests/arm64/fp/vec-syscfg.c b/tools/testing/selftests/arm64/fp/vec-syscfg.c index 272b888e018e..0b976eb1c1d1 100644 --- a/tools/testing/selftests/arm64/fp/vec-syscfg.c +++ b/tools/testing/selftests/arm64/fp/vec-syscfg.c @@ -53,6 +53,16 @@ static struct vec_data vec_data[] = { .prctl_set = PR_SVE_SET_VL, .default_vl_file = "/proc/sys/abi/sve_default_vector_length", }, + { + .name = "SME", + .hwcap_type = AT_HWCAP2, + .hwcap = HWCAP2_SME, + .rdvl = rdvl_sme, + .rdvl_binary = "./rdvl-sme", + .prctl_get = PR_SME_GET_VL, + .prctl_set = PR_SME_SET_VL, + .default_vl_file = "/proc/sys/abi/sme_default_vector_length", + }, };

static int stdio_read_integer(FILE *f, const char *what, int *val)

Add a stress test for context switching of the ZA register state based on the similar tests Dave Martin wrote for FPSIMD and SVE registers. The test loops indefinitely writing a data pattern to ZA then reading it back and verifying that it's what was expected.

Unlike the other tests we manually assemble the SME instructions since at present no released toolchain has SME support integrated.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/.gitignore | 1 + tools/testing/selftests/arm64/fp/Makefile | 3 + tools/testing/selftests/arm64/fp/za-stress | 59 ++ tools/testing/selftests/arm64/fp/za-test.S | 582 ++++++++++++++++++++ 4 files changed, 645 insertions(+) create mode 100644 tools/testing/selftests/arm64/fp/za-stress create mode 100644 tools/testing/selftests/arm64/fp/za-test.S

diff --git a/tools/testing/selftests/arm64/fp/.gitignore b/tools/testing/selftests/arm64/fp/.gitignore index 73c600e1ab81..1178fecc7aa1 100644 --- a/tools/testing/selftests/arm64/fp/.gitignore +++ b/tools/testing/selftests/arm64/fp/.gitignore @@ -7,3 +7,4 @@ sve-test ssve-test vec-syscfg vlset +za-test diff --git a/tools/testing/selftests/arm64/fp/Makefile b/tools/testing/selftests/arm64/fp/Makefile index 11dbe05c5070..4f32cb1041a0 100644 --- a/tools/testing/selftests/arm64/fp/Makefile +++ b/tools/testing/selftests/arm64/fp/Makefile @@ -6,6 +6,7 @@ TEST_PROGS_EXTENDED := fpsimd-test fpsimd-stress \ rdvl-sme rdvl-sve \ sve-test sve-stress \ ssve-test ssve-stress \ + za-test za-stress \ vlset

all: $(TEST_GEN_PROGS) $(TEST_PROGS_EXTENDED) @@ -22,5 +23,7 @@ ssve-test: sve-test.S $(CC) -DSSVE -nostdlib $^ -o $@ vec-syscfg: vec-syscfg.o rdvl.o vlset: vlset.o +za-test: za-test.o + $(CC) -nostdlib $^ -o $@

include ../../lib.mk diff --git a/tools/testing/selftests/arm64/fp/za-stress b/tools/testing/selftests/arm64/fp/za-stress new file mode 100644 index 000000000000..5ac386b55b95 --- /dev/null +++ b/tools/testing/selftests/arm64/fp/za-stress @@ -0,0 +1,59 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-only +# Copyright (C) 2015-2019 ARM Limited. +# Original author: Dave Martin Dave.Martin@arm.com + +set -ue + +NR_CPUS=`nproc` + +pids= +logs= + +cleanup () { + trap - INT TERM CHLD + set +e + + if [ -n "$pids" ]; then + kill $pids + wait $pids + pids= + fi + + if [ -n "$logs" ]; then + cat $logs + rm $logs + logs= + fi +} + +interrupt () { + cleanup + exit 0 +} + +child_died () { + cleanup + exit 1 +} + +trap interrupt INT TERM EXIT + +for x in `seq 0 $((NR_CPUS * 4))`; do + log=`mktemp` + logs=$logs\ $log + ./za-test >$log & + pids=$pids\ $! +done + +# Wait for all child processes to be created: +sleep 10 + +while :; do + kill -USR1 $pids +done & +pids=$pids\ $! + +wait + +exit 1 diff --git a/tools/testing/selftests/arm64/fp/za-test.S b/tools/testing/selftests/arm64/fp/za-test.S new file mode 100644 index 000000000000..4b3924446c8d --- /dev/null +++ b/tools/testing/selftests/arm64/fp/za-test.S @@ -0,0 +1,582 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2021 ARM Limited. +// Original author: Mark Brown broonie@kernel.org +// +// Scalable Matrix Extension ZA context switch test +// Repeatedly writes unique test patterns into each ZA tile +// and reads them back to verify integrity. +// +// for x in `seq 1 NR_CPUS`; do sve-test & pids=$pids\ $! ; done +// (leave it running for as long as you want...) +// kill $pids + +#include <asm/unistd.h> +#include "assembler.h" +#include "asm-offsets.h" + +.arch_extension sve + +#define MAXVL 2048 +#define MAXVL_B (MAXVL / 8) + +/* + * LDR (vector to ZA array): + * LDR ZA[\nw, #\offset], [X\nxbase, #\offset, MUL VL] + */ +.macro _ldr_za nw, nxbase, offset=0 + .inst 0xe1000000 \ + | (((\nw) & 3) << 13) \ + | ((\nxbase) << 5) \ + | ((\offset) & 7) +.endm + +/* + * STR (vector from ZA array): + * STR ZA[\nw, #\offset], [X\nxbase, #\offset, MUL VL] + */ +.macro _str_za nw, nxbase, offset=0 + .inst 0xe1200000 \ + | (((\nw) & 3) << 13) \ + | ((\nxbase) << 5) \ + | ((\offset) & 7) +.endm + +.macro smstart + msr S0_3_C4_C7_3, xzr +.endm + +.macro smstart_sm + msr S0_3_C4_C3_3, xzr +.endm + +.macro smstop + msr S0_3_C4_C6_3, xzr +.endm + +.macro smstop_sm + msr S0_3_C4_C2_3, xzr +.endm + +// Print a single character x0 to stdout +// Clobbers x0-x2,x8 +function putc + str x0, [sp, #-16]! + + mov x0, #1 // STDOUT_FILENO + mov x1, sp + mov x2, #1 + mov x8, #__NR_write + svc #0 + + add sp, sp, #16 + ret +endfunction + +// Print a NUL-terminated string starting at address x0 to stdout +// Clobbers x0-x3,x8 +function puts + mov x1, x0 + + mov x2, #0 +0: ldrb w3, [x0], #1 + cbz w3, 1f + add x2, x2, #1 + b 0b + +1: mov w0, #1 // STDOUT_FILENO + mov x8, #__NR_write + svc #0 + + ret +endfunction + +// Utility macro to print a literal string +// Clobbers x0-x4,x8 +.macro puts string + .pushsection .rodata.str1.1, "aMS", 1 +.L__puts_literal@: .string "\string" + .popsection + + ldr x0, =.L__puts_literal@ + bl puts +.endm + +// Print an unsigned decimal number x0 to stdout +// Clobbers x0-x4,x8 +function putdec + mov x1, sp + str x30, [sp, #-32]! // Result can't be > 20 digits + + mov x2, #0 + strb w2, [x1, #-1]! // Write the NUL terminator + + mov x2, #10 +0: udiv x3, x0, x2 // div-mod loop to generate the digits + msub x0, x3, x2, x0 + add w0, w0, #'0' + strb w0, [x1, #-1]! + mov x0, x3 + cbnz x3, 0b + + ldrb w0, [x1] + cbnz w0, 1f + mov w0, #'0' // Print "0" for 0, not "" + strb w0, [x1, #-1]! + +1: mov x0, x1 + bl puts + + ldr x30, [sp], #32 + ret +endfunction + +// Print an unsigned decimal number x0 to stdout, followed by a newline +// Clobbers x0-x5,x8 +function putdecn + mov x5, x30 + + bl putdec + mov x0, #'\n' + bl putc + + ret x5 +endfunction + +// Clobbers x0-x3,x8 +function puthexb + str x30, [sp, #-0x10]! + + mov w3, w0 + lsr w0, w0, #4 + bl puthexnibble + mov w0, w3 + + ldr x30, [sp], #0x10 + // fall through to puthexnibble +endfunction +// Clobbers x0-x2,x8 +function puthexnibble + and w0, w0, #0xf + cmp w0, #10 + blo 1f + add w0, w0, #'a' - ('9' + 1) +1: add w0, w0, #'0' + b putc +endfunction + +// x0=data in, x1=size in, clobbers x0-x5,x8 +function dumphex + str x30, [sp, #-0x10]! + + mov x4, x0 + mov x5, x1 + +0: subs x5, x5, #1 + b.lo 1f + ldrb w0, [x4], #1 + bl puthexb + b 0b + +1: ldr x30, [sp], #0x10 + ret +endfunction + +// Declare some storage space to shadow ZA register contents and a +// scratch buffer for a vector. +.pushsection .text +.data +.align 4 +zaref: + .space MAXVL_B * MAXVL_B +scratch: + .space MAXVL_B +.popsection + +// Trivial memory copy: copy x2 bytes, starting at address x1, to address x0. +// Clobbers x0-x3 +function memcpy + cmp x2, #0 + b.eq 1f +0: ldrb w3, [x1], #1 + strb w3, [x0], #1 + subs x2, x2, #1 + b.ne 0b +1: ret +endfunction + +// Generate a test pattern for storage in ZA +// x0: pid +// x1: row in ZA +// x2: generation + +// These values are used to constuct a 32-bit pattern that is repeated in the +// scratch buffer as many times as will fit: +// bits 31:28 generation number (increments once per test_loop) +// bits 27:16 pid +// bits 15: 8 row number +// bits 7: 0 32-bit lane index + +function pattern + mov w3, wzr + bfi w3, w0, #16, #12 // PID + bfi w3, w1, #8, #8 // Row + bfi w3, w2, #28, #4 // Generation + + ldr x0, =scratch + mov w1, #MAXVL_B / 4 + +0: str w3, [x0], #4 + add w3, w3, #1 // Lane + subs w1, w1, #1 + b.ne 0b + + ret +endfunction + +// Get the address of shadow data for ZA horizontal vector xn +.macro _adrza xd, xn, nrtmp + ldr \xd, =zaref + smstart_sm + rdvl x\nrtmp, #1 + smstop_sm + madd \xd, x\nrtmp, \xn, \xd +.endm + +// Set up test pattern in a ZA horizontal vector +// x0: pid +// x1: row number +// x2: generation +function setup_za + mov x4, x30 + mov x12, x1 // Use x12 for vector select + + bl pattern // Get pattern in scratch buffer + _adrza x0, x12, 2 // Shadow buffer pointer to x0 and x5 + mov x5, x0 + ldr x1, =scratch + bl memcpy // length set up in x2 by _adrza + + _ldr_za 12, 5 // load vector w12 from pointer x5 + + ret x4 +endfunction + +// Fill x1 bytes starting at x0 with 0xae (for canary purposes) +// Clobbers x1, x2. +function memfill_ae + mov w2, #0xae + b memfill +endfunction + +// Fill x1 bytes starting at x0 with 0. +// Clobbers x1, x2. +function memclr + mov w2, #0 + b memfill +endfunction + +// Trivial memory fill: fill x1 bytes starting at address x0 with byte w2 +// Clobbers x1 +function memfill + cmp x1, #0 + b.eq 1f + +0: strb w2, [x0], #1 + subs x1, x1, #1 + b.ne 0b + +1: ret +endfunction + +// Trivial memory compare: compare x2 bytes starting at address x0 with +// bytes starting at address x1. +// Returns only if all bytes match; otherwise, the program is aborted. +// Clobbers x0-x5. +function memcmp + cbz x2, 2f + + stp x0, x1, [sp, #-0x20]! + str x2, [sp, #0x10] + + mov x5, #0 +0: ldrb w3, [x0, x5] + ldrb w4, [x1, x5] + add x5, x5, #1 + cmp w3, w4 + b.ne 1f + subs x2, x2, #1 + b.ne 0b + +1: ldr x2, [sp, #0x10] + ldp x0, x1, [sp], #0x20 + b.ne barf + +2: ret +endfunction + +// Verify that a ZA vector matches its shadow in memory, else abort +// x0: row number +// Clobbers x0-x7 and x12. +function check_za + mov x3, x30 + + mov x12, x0 + _adrza x5, x0, 6 // pointer to expected value in x5 + mov x4, x0 + ldr x7, =scratch // x7 is scratch + + mov x0, x7 // Poison scratch + mov x1, x6 + bl memfill_ae + + _str_za 12, 7 // save vector w12 to pointer x7 + + mov x0, x5 + mov x1, x7 + mov x2, x6 + mov x30, x3 + b memcmp +endfunction + +// Any SME register modified here can cause corruption in the main +// thread -- but *only* the locations modified here. +function irritator_handler + // Increment the irritation signal count (x23): + ldr x0, [x2, #ucontext_regs + 8 * 23] + add x0, x0, #1 + str x0, [x2, #ucontext_regs + 8 * 23] + + // Corrupt some random ZA data +#if 0 + adr x0, .text + (irritator_handler - .text) / 16 * 16 + movi v0.8b, #1 + movi v9.16b, #2 + movi v31.8b, #3 +#endif + + ret +endfunction + +function terminate_handler + mov w21, w0 + mov x20, x2 + + puts "Terminated by signal " + mov w0, w21 + bl putdec + puts ", no error, iterations=" + ldr x0, [x20, #ucontext_regs + 8 * 22] + bl putdec + puts ", signals=" + ldr x0, [x20, #ucontext_regs + 8 * 23] + bl putdecn + + mov x0, #0 + mov x8, #__NR_exit + svc #0 +endfunction + +// w0: signal number +// x1: sa_action +// w2: sa_flags +// Clobbers x0-x6,x8 +function setsignal + str x30, [sp, #-((sa_sz + 15) / 16 * 16 + 16)]! + + mov w4, w0 + mov x5, x1 + mov w6, w2 + + add x0, sp, #16 + mov x1, #sa_sz + bl memclr + + mov w0, w4 + add x1, sp, #16 + str w6, [x1, #sa_flags] + str x5, [x1, #sa_handler] + mov x2, #0 + mov x3, #sa_mask_sz + mov x8, #__NR_rt_sigaction + svc #0 + + cbz w0, 1f + + puts "sigaction failure\n" + b .Labort + +1: ldr x30, [sp], #((sa_sz + 15) / 16 * 16 + 16) + ret +endfunction + +// Main program entry point +.globl _start +function _start +_start: + puts "Streaming mode " + smstart + + // Sanity-check and report the vector length + + rdvl x19, #8 + cmp x19, #128 + b.lo 1f + cmp x19, #2048 + b.hi 1f + tst x19, #(8 - 1) + b.eq 2f + +1: puts "bad vector length: " + mov x0, x19 + bl putdecn + b .Labort + +2: puts "vector length:\t" + mov x0, x19 + bl putdec + puts " bits\n" + + // Obtain our PID, to ensure test pattern uniqueness between processes + mov x8, #__NR_getpid + svc #0 + mov x20, x0 + + puts "PID:\t" + mov x0, x20 + bl putdecn + + mov x23, #0 // Irritation signal count + + mov w0, #SIGINT + adr x1, terminate_handler + mov w2, #SA_SIGINFO + bl setsignal + + mov w0, #SIGTERM + adr x1, terminate_handler + mov w2, #SA_SIGINFO + bl setsignal + + mov w0, #SIGUSR1 + adr x1, irritator_handler + mov w2, #SA_SIGINFO + orr w2, w2, #SA_NODEFER + bl setsignal + + mov x22, #0 // generation number, increments per iteration +.Ltest_loop: + smstart_sm // printing/signals/yielding dropped out of SM + rdvl x0, #8 + cmp x0, x19 + b.ne vl_barf + + rdvl x21, #1 // Set up ZA & shadow with test pattern + smstop_sm +0: mov x0, x20 + sub x1, x21, #1 + mov x2, x22 + bl setup_za + subs x21, x21, #1 + b.ne 0b + + and x8, x22, #127 // Every 128 interations... + cbz x8, 0f + mov x8, #__NR_getpid // (otherwise minimal syscall) + b 1f +0: + mov x8, #__NR_sched_yield // ...encourage preemption +1: + svc #0 + + mrs x0, S3_3_C4_C2_2 // SVCR should have ZA=1,SM=0 + and x1, x0, #3 + cmp x1, #2 + b.ne svcr_barf + + smstart_sm + rdvl x21, #1 // Verify that the data made it through + rdvl x24, #1 // Verify that the data made it through + smstop_sm +0: sub x0, x24, x21 + bl check_za + subs x21, x21, #1 + bne 0b + + add x22, x22, #1 // Everything still working + b .Ltest_loop + +.Labort: + mov x0, #0 + mov x1, #SIGABRT + mov x8, #__NR_kill + svc #0 +endfunction + +function barf +// fpsimd.c acitivty log dump hack +// ldr w0, =0xdeadc0de +// mov w8, #__NR_exit +// svc #0 +// end hack + smstop + mov x10, x0 // expected data + mov x11, x1 // actual data + mov x12, x2 // data size + + puts "Mismatch: PID=" + mov x0, x20 + bl putdec + puts ", iteration=" + mov x0, x22 + bl putdec + puts ", row=" + mov x0, x21 + bl putdecn + puts "\tExpected [" + mov x0, x10 + mov x1, x12 + bl dumphex + puts "]\n\tGot [" + mov x0, x11 + mov x1, x12 + bl dumphex + puts "]\n" + + mov x8, #__NR_getpid + svc #0 +// fpsimd.c acitivty log dump hack +// ldr w0, =0xdeadc0de +// mov w8, #__NR_exit +// svc #0 +// ^ end of hack + mov x1, #SIGABRT + mov x8, #__NR_kill + svc #0 +// mov x8, #__NR_exit +// mov x1, #1 +// svc #0 +endfunction + +function vl_barf + mov x10, x0 + + puts "Bad active VL: " + mov x0, x10 + bl putdecn + + mov x8, #__NR_exit + mov x1, #1 + svc #0 +endfunction + +function svcr_barf + mov x10, x0 + + puts "Bad SVCR: " + mov x0, x10 + bl putdecn + + mov x8, #__NR_exit + mov x1, #1 + svc #0 +endfunction

In order to allow ptrace of streaming mode SVE registers we have added a new regset for streaming mode which in isolation offers the same ABI as regular SVE with a different vector type. Add this to the array of regsets we handle, together with additional tests for the interoperation of the two regsets.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/sve-ptrace.c | 11 +++++++++++ 1 file changed, 11 insertions(+)

diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c index af798b9d232c..00c35b9db27f 100644 --- a/tools/testing/selftests/arm64/fp/sve-ptrace.c +++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c @@ -28,6 +28,10 @@ #define NT_ARM_SVE 0x405 #endif

+#ifndef NT_ARM_SSVE +#define NT_ARM_SSVE 0x40b +#endif + struct vec_type { const char *name; unsigned long hwcap_type; @@ -44,6 +48,13 @@ static const struct vec_type vec_types[] = { .regset = NT_ARM_SVE, .prctl_set = PR_SVE_SET_VL, }, + { + .name = "Streaming SVE", + .hwcap_type = AT_HWCAP2, + .hwcap = HWCAP2_SME, + .regset = NT_ARM_SSVE, + .prctl_set = PR_SME_SET_VL, + }, };

#define VL_TESTS (((SVE_VQ_MAX - SVE_VQ_MIN) + 1) * 3)