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 e0e30567b80f..bf5bb881ef67 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 995f8801602b..3465d3328e44 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(¤t->thread), - ¤t->thread.uw.fpsimd_state.fpsr, + ¤t->thread.uw.fpsimd_state.fpsr, true, sve_vq_from_vl(current->thread.sve_vl) - 1); else fpsimd_load_state(¤t->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)