SME 2 introduces the new ZT0 register, we require that access to this reigster is not trapped when we identify that the feature is supported.

Signed-off-by: Mark Brown broonie@kernel.org --- Documentation/arm64/booting.rst | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index 8c324ad638de..81709132de7b 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst @@ -368,6 +368,16 @@ Before jumping into the kernel, the following conditions must be met:

- HCR_EL2.ATA (bit 56) must be initialised to 0b1.

+ For CPUs with the Scalable Matrix Extension version 2 (FEAT_SME2): + + - If EL3 is present: + + - SMCR_EL3.EZT0 (bit 30) must be initialised to 0b1. + + - If the kernel is entered at EL1 and EL2 is present: + + - SMCR_EL2.EZT0 (bit 30) must be initialised to 0b1. + The requirements described above for CPU mode, caches, MMUs, architected timers, coherency and system registers apply to all CPUs. All CPUs must enter the kernel in the same exception level. Where the values documented

As well as a number of simple features which only add new instructions and require corresponding hwcaps SME2 introduces a new register ZT0 for which we must define ABI. Fortunately this is a fixed size 512 bits and therefore much more straightforward than the base SME state, the only wrinkle is that it is only accessible when ZA is accessible.

While there is only a single register the architecture is written with a view to exensibility, including a number in the name, so follow this in the ABI.

Signed-off-by: Mark Brown broonie@kernel.org --- Documentation/arm64/sme.rst | 52 ++++++++++++++++++++++++++++++------- 1 file changed, 43 insertions(+), 9 deletions(-)

diff --git a/Documentation/arm64/sme.rst b/Documentation/arm64/sme.rst index 16d2db4c2e2e..68d1efb7d171 100644 --- a/Documentation/arm64/sme.rst +++ b/Documentation/arm64/sme.rst @@ -18,14 +18,19 @@ model features for SME is included in Appendix A. 1. General -----------

-* PSTATE.SM, PSTATE.ZA, the streaming mode vector length, the ZA - register state and TPIDR2_EL0 are tracked per thread. +* PSTATE.SM, PSTATE.ZA, the streaming mode vector length, the ZA and (when + present) ZTn register state and TPIDR2_EL0 are tracked per thread.

* The presence of SME 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".

+* The presence of SME2 is reported to userspace via HWCAP2_SME2 in the + aux vector AT_HWCAP2 entry. Presence of this flag implies the presence of + the SME2 instructions and ZT0, and the Linux-specific system interfaces + described in this document. SME2 is reported in /proc/cpuinfo as "sme2". + * 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] @@ -44,6 +49,7 @@ model features for SME is included in Appendix A. HWCAP2_SME_B16F32 HWCAP2_SME_F32F32 HWCAP2_SME_FA64 + HWCAP2_SME2

This list may be extended over time as the SME architecture evolves.

@@ -52,8 +58,8 @@ model features for SME is included in Appendix A. 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 + NT_ARM_SVE, NT_ARM_SSVE, NT_ARM_ZA and NT_ARM_ZT 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). @@ -89,13 +95,13 @@ be zeroed. -------------------------

* On syscall PSTATE.ZA is preserved, if PSTATE.ZA==1 then the contents of the - ZA matrix are preserved. + ZA matrix and ZTn (if present) are preserved.

* On syscall PSTATE.SM will be cleared and the SVE registers will be handled as per the standard SVE ABI.

-* Neither the SVE registers nor ZA are used to pass arguments to or receive - results from any syscall. +* None of the SVE registers, ZA or ZTn are used to pass arguments to + or receive results from any syscall.

* On process creation (eg, clone()) the newly created process will have PSTATE.SM cleared. @@ -134,6 +140,14 @@ be zeroed. __reserved[] referencing this space. za_context is then written in the extra space. Refer to [1] for further details about this mechanism.

+* If ZTn is supported and PSTATE.ZA==1 then a signal frame record for ZTn will + be generated. + +* The signal record for ZTn has magic ZT_MAGIC (0x5a544e01) and consists of a + standard signal frame header followed by a struct zt_context specifying + the number of ZTn registers supported by the system, then zt_context.nregs + blocks of 64 bytes of data per register. +

5. Signal return ----------------- @@ -151,6 +165,9 @@ 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.

+* If ZTn is not supported or PSTATE.ZA==0 then it is illegal to have a + signal frame record for ZTn, resulting in a forced SIGSEGV. +

6. prctl extensions -------------------- @@ -214,8 +231,8 @@ prctl(PR_SME_SET_VL, unsigned long arg) 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 + * Changing the vector length causes all of ZA, ZTn, 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, @@ -317,6 +334,15 @@ The regset data starts with struct user_za_header, containing:

* The effect of writing a partial, incomplete payload is unspecified.

+* A new regset NT_ARM_ZT is defined for access to ZTn state via + PTRACE_GETREGSET and PTRACE_SETREGSET. + +* The NT_ARM_ZT regset consists of a single 512 bit register. + +* When PSTATE.ZA==0 reads of NT_ARM_ZT will report all bits of ZTn as 0. + +* Writes to NT_ARM_ZT will set PSTATE.ZA to 1. +

8. ELF coredump extensions --------------------------- @@ -331,6 +357,11 @@ The regset data starts with struct user_za_header, containing: been read if a PTRACE_GETREGSET of NT_ARM_ZA were executed for each thread when the coredump was generated.

+* A NT_ARM_ZT 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_ZT were executed for each thread + when the coredump was generated. + * The NT_ARM_TLS note will be extended to two registers, the second register will contain TPIDR2_EL0 on systems that support SME and will be read as zero with writes ignored otherwise. @@ -406,6 +437,9 @@ In A64 state, SME adds the following: For best system performance it is strongly encouraged for software to enable ZA only when it is actively being used.

+* A new ZT0 register is introduced when SME2 is present. This is a 512 bit + register which is accessible when PSTATE.ZA is set, as ZA itself is. + * 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:

In order to avoid unrealistic toolchain requirements we manually encode the instructions for loading and storing ZT0.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimdmacros.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index 5e0910cf4832..cd03819a3b68 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -220,6 +220,28 @@ | ((\offset) & 7) .endm

+/* + * LDR (ZT0) + * + * LDR ZT0, nx + */ +.macro _ldr_zt nx + _check_general_reg \nx + .inst 0xe11f8000 \ + | (\nx << 5) +.endm + +/* + * STR (ZT0) + * + * STR ZT0, nx + */ +.macro _str_zt nx + _check_general_reg \nx + .inst 0xe13f8000 \ + | (\nx << 5) +.endm + /* * Zero the entire ZA array * ZERO ZA

Add basic feature detection for SME2, detecting that the feature is present and disabling traps for ZT0.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/cpufeature.h | 6 ++++++ arch/arm64/include/asm/fpsimd.h | 1 + arch/arm64/kernel/cpufeature.c | 14 ++++++++++++++ arch/arm64/kernel/fpsimd.c | 11 +++++++++++ arch/arm64/tools/cpucaps | 1 + 5 files changed, 33 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f73f11b55042..3ad41c26c9e7 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -769,6 +769,12 @@ static __always_inline bool system_supports_sme(void) cpus_have_const_cap(ARM64_SME); }

+static __always_inline bool system_supports_sme2(void) +{ + return IS_ENABLED(CONFIG_ARM64_SME) && + cpus_have_const_cap(ARM64_SME2); +} + static __always_inline bool system_supports_fa64(void) { return IS_ENABLED(CONFIG_ARM64_SME) && diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index a18a86ccfd82..f2bda963cfe5 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -109,6 +109,7 @@ extern void za_load_state(void const *state); 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 void sme2_kernel_enable(const struct arm64_cpu_capabilities *__unused); extern void fa64_kernel_enable(const struct arm64_cpu_capabilities *__unused);

extern u64 read_zcr_features(void); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 3e3af6b8cc85..5b0d79f026aa 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -282,6 +282,8 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = { 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_EL1_FA64_SHIFT, 1, 0), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), + FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I16I64_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), @@ -2647,6 +2649,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, .cpu_enable = fa64_kernel_enable, }, + { + .desc = "SME2", + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .capability = ARM64_SME2, + .sys_reg = SYS_ID_AA64SMFR0_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64SMFR0_EL1_SMEver_SHIFT, + .field_width = ID_AA64SMFR0_EL1_SMEver_WIDTH, + .min_field_value = ID_AA64SMFR0_EL1_SMEver_SME2, + .matches = has_cpuid_feature, + .cpu_enable = sme2_kernel_enable, + }, #endif /* CONFIG_ARM64_SME */ { .desc = "WFx with timeout", diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index b677b5a3e0f6..73ec8850a402 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1254,6 +1254,17 @@ void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) isb(); }

+/* + * This must be called after sme_kernel_enable(), we rely on the + * feature table being sorted to ensure this. + */ +void sme2_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) +{ + /* Allow use of ZT0 */ + write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_EZT0_MASK, + SYS_SMCR_EL1); +} + /* * This must be called after sme_kernel_enable(), we rely on the * feature table being sorted to ensure this. diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index a86ee376920a..1222b0ed63a2 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -50,6 +50,7 @@ MTE MTE_ASYMM SME SME_FA64 +SME2 SPECTRE_V2 SPECTRE_V3A SPECTRE_V4

When the system supports SME2 the ZT0 register must be context switched as part of the floating point state. This register is stored immediately after ZA in memory and is only accessible when PSTATE.ZA is set so we handle it in the same functions we use to save and restore ZA.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 4 ++-- arch/arm64/kernel/entry-fpsimd.S | 30 ++++++++++++++++++++---------- arch/arm64/kernel/fpsimd.c | 6 ++++-- 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 2d7a69b49349..42c019936dfd 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -110,8 +110,8 @@ 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); -extern void za_save_state(void *state); -extern void za_load_state(void const *state); +extern void sme_save_state(void *state, int zt); +extern void sme_load_state(void const *state, int zt);

struct arm64_cpu_capabilities; extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused); diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 229436f33df5..6325db1a2179 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -100,25 +100,35 @@ SYM_FUNC_START(sme_set_vq) SYM_FUNC_END(sme_set_vq)

/* - * Save the SME state + * Save the ZA and ZT state * * x0 - pointer to buffer for state + * x1 - number of ZT registers to save */ -SYM_FUNC_START(za_save_state) - _sme_rdsvl 1, 1 // x1 = VL/8 - sme_save_za 0, x1, 12 +SYM_FUNC_START(sme_save_state) + _sme_rdsvl 2, 1 // x2 = VL/8 + sme_save_za 0, x2, 12 // Leaves x0 pointing to the end of ZA + + cbz x1, 1f + _str_zt 0 +1: ret -SYM_FUNC_END(za_save_state) +SYM_FUNC_END(sme_save_state)

/* - * Load the SME state + * Load the ZA and ZT state * * x0 - pointer to buffer for state + * x1 - number of ZT registers to save */ -SYM_FUNC_START(za_load_state) - _sme_rdsvl 1, 1 // x1 = VL/8 - sme_load_za 0, x1, 12 +SYM_FUNC_START(sme_load_state) + _sme_rdsvl 2, 1 // x2 = VL/8 + sme_load_za 0, x2, 12 // Leaves x0 pointing to the end of ZA + + cbz x1, 1f + _ldr_zt 0 +1: ret -SYM_FUNC_END(za_load_state) +SYM_FUNC_END(sme_load_state)

#endif /* CONFIG_ARM64_SME */ diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 73ec8850a402..b7f4eef42f86 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -396,7 +396,8 @@ static void task_fpsimd_load(void) write_sysreg_s(current->thread.svcr, SYS_SVCR);

if (thread_za_enabled(&current->thread)) - za_load_state(current->thread.sme_state); + sme_load_state(current->thread.sme_state, + system_supports_sme2());

if (thread_sm_enabled(&current->thread)) { restore_sve_regs = true; @@ -449,7 +450,8 @@ static void fpsimd_save(void) *svcr = read_sysreg_s(SYS_SVCR);

if (*svcr & SVCR_ZA_MASK) - za_save_state(last->sme_state); + sme_save_state(last->sme_state, + system_supports_sme2());

/* If we are in streaming mode override regular SVE. */ if (*svcr & SVCR_SM_MASK) {

Implement support for a new note type NT_ARM64_ZT providing access to ZT0 when implemented. Since ZT0 is a register with constant size this is much simpler than for other SME state.

As ZT0 is only accessible when PSTATE.ZA is set writes to ZT0 cause PSTATE.ZA to be set, the main alternative would be to return -EBUSY in this case but this seemed more constructive. Practical users are also going to be working with ZA anyway and have some understanding of the state.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/kernel/ptrace.c | 54 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 55 insertions(+)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 85105375bea5..a508f3a69d9f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1145,6 +1145,51 @@ static int za_set(struct task_struct *target, return ret; }

+static int zt_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + if (!system_supports_sme2()) + return -EINVAL; + + /* + * If PSTATE.ZA is not set then ZT will be zeroed when it is + * enabled so report the current register value as zero. + */ + if (thread_za_enabled(&target->thread)) + membuf_write(&to, thread_zt_state(&target->thread), + ZT_SIG_REG_BYTES); + else + membuf_zero(&to, ZT_SIG_REG_BYTES); + + return 0; +} + +static int zt_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; + + if (!system_supports_sme2()) + return -EINVAL; + + if (!thread_za_enabled(&target->thread)) { + sme_alloc(target); + if (!target->thread.sme_state) + return -ENOMEM; + } + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + thread_zt_state(&target->thread), + 0, ZT_SIG_REG_BYTES); + if (ret == 0) + target->thread.svcr |= SVCR_ZA_MASK; + + return ret; +} + #endif /* CONFIG_ARM64_SME */

#ifdef CONFIG_ARM64_PTR_AUTH @@ -1367,6 +1412,7 @@ enum aarch64_regset { #ifdef CONFIG_ARM64_SVE REGSET_SSVE, REGSET_ZA, + REGSET_ZT, #endif #ifdef CONFIG_ARM64_PTR_AUTH REGSET_PAC_MASK, @@ -1474,6 +1520,14 @@ static const struct user_regset aarch64_regsets[] = { .regset_get = za_get, .set = za_set, }, + [REGSET_ZT] = { /* SME ZA */ + .core_note_type = NT_ARM_ZT, + .n = 1, + .size = ZT_SIG_REG_BYTES, + .align = sizeof(u64), + .regset_get = zt_get, + .set = zt_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 c7b056af9ef0..3a73c853c537 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -434,6 +434,7 @@ typedef struct elf64_shdr { #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_ARM_ZT 0x40d /* ARM SME ZT 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 */

Following the pattern for the other register sets add a stress test program for ZT0 which continually loads and verifies patterns in the register in an effort to discover context switching problems.

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/sme-inst.h | 20 ++ tools/testing/selftests/arm64/fp/zt-test.S | 324 ++++++++++++++++++++ 4 files changed, 348 insertions(+) create mode 100644 tools/testing/selftests/arm64/fp/zt-test.S

diff --git a/tools/testing/selftests/arm64/fp/.gitignore b/tools/testing/selftests/arm64/fp/.gitignore index df79d29664a1..41bde4c97d47 100644 --- a/tools/testing/selftests/arm64/fp/.gitignore +++ b/tools/testing/selftests/arm64/fp/.gitignore @@ -12,3 +12,4 @@ vlset za-fork za-ptrace za-test +zt-test diff --git a/tools/testing/selftests/arm64/fp/Makefile b/tools/testing/selftests/arm64/fp/Makefile index 36db61358ed5..aff3026d3dff 100644 --- a/tools/testing/selftests/arm64/fp/Makefile +++ b/tools/testing/selftests/arm64/fp/Makefile @@ -14,6 +14,7 @@ TEST_GEN_PROGS_EXTENDED := fp-pidbench fpsimd-test \ sve-test \ ssve-test \ za-test \ + zt-test \ vlset TEST_PROGS_EXTENDED := fpsimd-stress sve-stress ssve-stress za-stress

@@ -41,5 +42,7 @@ $(OUTPUT)/za-fork: za-fork.c $(OUTPUT)/za-fork-asm.o $(OUTPUT)/za-ptrace: za-ptrace.c $(OUTPUT)/za-test: za-test.S $(OUTPUT)/asm-utils.o $(CC) -nostdlib $^ -o $@ +$(OUTPUT)/zt-test: zt-test.S $(OUTPUT)/asm-utils.o + $(CC) -nostdlib $^ -o $@

include ../../lib.mk diff --git a/tools/testing/selftests/arm64/fp/sme-inst.h b/tools/testing/selftests/arm64/fp/sme-inst.h index 7191e53ca1c0..9292bba5400b 100644 --- a/tools/testing/selftests/arm64/fp/sme-inst.h +++ b/tools/testing/selftests/arm64/fp/sme-inst.h @@ -48,4 +48,24 @@ | ((\offset) & 7) .endm

+/* + * LDR (ZT0) + * + * LDR ZT0, nx + */ +.macro _ldr_zt nx + .inst 0xe11f8000 \ + | (((\nx) & 0x1f) << 5) +.endm + +/* + * STR (ZT0) + * + * STR ZT0, nx + */ +.macro _str_zt nx + .inst 0xe13f8000 \ + | (((\nx) & 0x1f) << 5) +.endm + #endif diff --git a/tools/testing/selftests/arm64/fp/zt-test.S b/tools/testing/selftests/arm64/fp/zt-test.S new file mode 100644 index 000000000000..6f04a8bf60f6 --- /dev/null +++ b/tools/testing/selftests/arm64/fp/zt-test.S @@ -0,0 +1,324 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2021-2 ARM Limited. +// Original author: Mark Brown broonie@kernel.org +// +// Scalable Matrix Extension ZT context switch test +// Repeatedly writes unique test patterns into ZT0 +// and reads them back to verify integrity. + +#include <asm/unistd.h> +#include "assembler.h" +#include "asm-offsets.h" +#include "sme-inst.h" + +.arch_extension sve + +#define ZT_SZ 512 +#define ZT_B (ZT_SZ / 8) + +// Declare some storage space to shadow ZT register contents and a +// scratch buffer. +.pushsection .text +.data +.align 4 +ztref: + .space ZT_B +scratch: + .space ZT_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 ZT +// x0: pid +// x1: 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 31:24 generation number (increments once per test_loop) +// bits 23: 8 pid +// bits 7: 0 32-bit lane index + +function pattern + mov w3, wzr + bfi w3, w0, #8, #16 // PID + bfi w3, w1, #24, #8 // Generation + + ldr x0, =scratch + mov w1, #ZT_B / 4 + +0: str w3, [x0], #4 + add w3, w3, #1 // Lane + subs w1, w1, #1 + b.ne 0b + + ret +endfunction + +// Set up test pattern in a ZT horizontal vector +// x0: pid +// x1: generation +function setup_zt + mov x4, x30 + + bl pattern // Get pattern in scratch buffer + ldr x0, =ztref + ldr x1, =scratch + mov x2, #ZT_B + bl memcpy + + _ldr_zt 0 // load zt0 from pointer x0 + + ret x4 +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 ZT vector matches its shadow in memory, else abort +// Clobbers x0-x7 and x12. +function check_zt + mov x3, x30 + + ldr x0, =scratch // Poison scratch + mov x1, #ZT_B + bl memfill_ae + + ldr x0, =scratch + _str_zt 0 + + ldr x0, =ztref + ldr x1, =scratch + mov x2, #ZT_B + 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 ZT 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 tickle_handler + // Increment the signal count (x23): + ldr x0, [x2, #ucontext_regs + 8 * 23] + add x0, x0, #1 + str x0, [x2, #ucontext_regs + 8 * 23] + + 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: + mov x23, #0 // 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 w0, #SIGUSR2 + adr x1, tickle_handler + mov w2, #SA_SIGINFO + orr w2, w2, #SA_NODEFER + bl setsignal + + smstart_za + + // 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 x22, #0 // generation number, increments per iteration +.Ltest_loop: + mov x0, x20 + mov x1, x22 + bl setup_zt + + mov x8, #__NR_sched_yield // Encourage preemption + svc #0 + + mov x0, x20 + mov x1, x22 + bl check_zt + + 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 "\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 svcr_barf + mov x10, x0 + + puts "Bad SVCR: " + mov x0, x10 + bl putdecn + + mov x8, #__NR_exit + mov x1, #1 + svc #0 +endfunction

Support test cases for SME2 by adding it to the set of features that we enumerate so test cases can check for it.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/signal/test_signals.h | 2 ++ tools/testing/selftests/arm64/signal/test_signals_utils.c | 3 +++ 2 files changed, 5 insertions(+)

diff --git a/tools/testing/selftests/arm64/signal/test_signals.h b/tools/testing/selftests/arm64/signal/test_signals.h index 0c645834ddc3..1e6273d81575 100644 --- a/tools/testing/selftests/arm64/signal/test_signals.h +++ b/tools/testing/selftests/arm64/signal/test_signals.h @@ -34,6 +34,7 @@ enum { FSVE_BIT, FSME_BIT, FSME_FA64_BIT, + FSME2_BIT, FMAX_END };

@@ -41,6 +42,7 @@ enum { #define FEAT_SVE (1UL << FSVE_BIT) #define FEAT_SME (1UL << FSME_BIT) #define FEAT_SME_FA64 (1UL << FSME_FA64_BIT) +#define FEAT_SME2 (1UL << FSME2_BIT)

/* * A descriptor used to describe and configure a test case. diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c index 308e229e58ab..07f518f0e58d 100644 --- a/tools/testing/selftests/arm64/signal/test_signals_utils.c +++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c @@ -29,6 +29,7 @@ static char const *const feats_names[FMAX_END] = { " SVE ", " SME ", " FA64 ", + " SME2 ", };

#define MAX_FEATS_SZ 128 @@ -323,6 +324,8 @@ int test_init(struct tdescr *td) td->feats_supported |= FEAT_SME; if (getauxval(AT_HWCAP2) & HWCAP2_SME_FA64) td->feats_supported |= FEAT_SME_FA64; + if (getauxval(AT_HWCAP2) & HWCAP2_SME2) + td->feats_supported |= FEAT_SME2; if (feats_ok(td)) { if (td->feats_required & td->feats_supported) fprintf(stderr,

We should have a ZT register frame with an expected size when ZA is enabled and have no ZT frame when ZA is disabled. Since we don't load any data into ZT we expect the data to all be zeros since the architecture guarantees it will be set to 0 as ZA is enabled.

Signed-off-by: Mark Brown broonie@kernel.org --- .../testing/selftests/arm64/signal/.gitignore | 1 + .../arm64/signal/testcases/zt_no_regs.c | 51 +++++++++++ .../arm64/signal/testcases/zt_regs.c | 85 +++++++++++++++++++ 3 files changed, 137 insertions(+) create mode 100644 tools/testing/selftests/arm64/signal/testcases/zt_no_regs.c create mode 100644 tools/testing/selftests/arm64/signal/testcases/zt_regs.c

diff --git a/tools/testing/selftests/arm64/signal/.gitignore b/tools/testing/selftests/arm64/signal/.gitignore index e8d2b57f73ec..b7fbb65183e8 100644 --- a/tools/testing/selftests/arm64/signal/.gitignore +++ b/tools/testing/selftests/arm64/signal/.gitignore @@ -5,4 +5,5 @@ sme_* ssve_* sve_* za_* +zt_* !*.[ch] diff --git a/tools/testing/selftests/arm64/signal/testcases/zt_no_regs.c b/tools/testing/selftests/arm64/signal/testcases/zt_no_regs.c new file mode 100644 index 000000000000..34f69bcf821e --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/zt_no_regs.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 ARM Limited + * + * Verify that using an instruction not supported in streaming mode + * traps when in streaming mode. + */ + +#include <signal.h> +#include <ucontext.h> +#include <sys/prctl.h> + +#include "test_signals_utils.h" +#include "testcases.h" + +static union { + ucontext_t uc; + char buf[1024 * 128]; +} context; + +int zt_no_regs_run(struct tdescr *td, siginfo_t *si, ucontext_t *uc) +{ + size_t offset; + struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context); + + /* + * Get a signal context which should not have a ZT frame and + * registers in it. + */ + if (!get_current_context(td, &context.uc, sizeof(context))) + return 1; + + head = get_header(head, ZT_MAGIC, GET_BUF_RESV_SIZE(context), &offset); + if (head) { + fprintf(stderr, "Got unexpected ZT context\n"); + return 1; + } + + td->pass = 1; + + return 0; +} + +struct tdescr tde = { + .name = "ZT register data not present", + .descr = "Validate that ZT is not present when ZA is disabled", + .feats_required = FEAT_SME2, + .timeout = 3, + .sanity_disabled = true, + .run = zt_no_regs_run, +}; diff --git a/tools/testing/selftests/arm64/signal/testcases/zt_regs.c b/tools/testing/selftests/arm64/signal/testcases/zt_regs.c new file mode 100644 index 000000000000..e1eb4d5c027a --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/zt_regs.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 ARM Limited + * + * Verify that using an instruction not supported in streaming mode + * traps when in streaming mode. + */ + +#include <signal.h> +#include <ucontext.h> +#include <sys/prctl.h> + +#include "test_signals_utils.h" +#include "testcases.h" + +static union { + ucontext_t uc; + char buf[1024 * 128]; +} context; + +static void enable_za(void) +{ + /* smstart za; real data is TODO */ + asm volatile(".inst 0xd503457f" : : : ); +} + +int zt_regs_run(struct tdescr *td, siginfo_t *si, ucontext_t *uc) +{ + size_t offset; + struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context); + struct zt_context *zt; + char *zeros; + + /* + * Get a signal context which should have a ZT frame and registers + * in it. + */ + enable_za(); + if (!get_current_context(td, &context.uc, sizeof(context))) + return 1; + + head = get_header(head, ZT_MAGIC, GET_BUF_RESV_SIZE(context), &offset); + if (!head) { + fprintf(stderr, "No ZT context\n"); + return 1; + } + + zt = (struct zt_context *)head; + if (zt->nregs == 0) { + fprintf(stderr, "Got context with no registers\n"); + return 1; + } + + fprintf(stderr, "Got expected size %u for %d registers\n", + head->size, zt->nregs); + + /* We didn't load any data into ZT so it should be all zeros */ + zeros = malloc(ZT_SIG_REGS_SIZE(zt->nregs)); + if (!zeros) { + fprintf(stderr, "Out of memory, nregs=%u\n", zt->nregs); + return 1; + } + memset(zeros, 0, ZT_SIG_REGS_SIZE(zt->nregs)); + + if (memcmp(zeros, (char *)zt + ZT_SIG_REGS_OFFSET, + ZT_SIG_REGS_SIZE(zt->nregs)) != 0) { + fprintf(stderr, "ZT data invalid\n"); + return 1; + } + + free(zeros); + + td->pass = 1; + + return 0; +} + +struct tdescr tde = { + .name = "ZT register data", + .descr = "Validate that ZT is present and has data when ZA is enabled", + .feats_required = FEAT_SME2, + .timeout = 3, + .sanity_disabled = true, + .run = zt_regs_run, +};

Add coverage of the ZT ptrace interface.

Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/arm64/fp/.gitignore | 1 + tools/testing/selftests/arm64/fp/Makefile | 2 + tools/testing/selftests/arm64/fp/zt-ptrace.c | 365 +++++++++++++++++++ 3 files changed, 368 insertions(+) create mode 100644 tools/testing/selftests/arm64/fp/zt-ptrace.c

diff --git a/tools/testing/selftests/arm64/fp/.gitignore b/tools/testing/selftests/arm64/fp/.gitignore index 41bde4c97d47..ebc86757bdd8 100644 --- a/tools/testing/selftests/arm64/fp/.gitignore +++ b/tools/testing/selftests/arm64/fp/.gitignore @@ -12,4 +12,5 @@ vlset za-fork za-ptrace za-test +zt-ptrace zt-test diff --git a/tools/testing/selftests/arm64/fp/Makefile b/tools/testing/selftests/arm64/fp/Makefile index aff3026d3dff..50a70220ba6c 100644 --- a/tools/testing/selftests/arm64/fp/Makefile +++ b/tools/testing/selftests/arm64/fp/Makefile @@ -14,6 +14,7 @@ TEST_GEN_PROGS_EXTENDED := fp-pidbench fpsimd-test \ sve-test \ ssve-test \ za-test \ + zt-ptrace \ zt-test \ vlset TEST_PROGS_EXTENDED := fpsimd-stress sve-stress ssve-stress za-stress @@ -42,6 +43,7 @@ $(OUTPUT)/za-fork: za-fork.c $(OUTPUT)/za-fork-asm.o $(OUTPUT)/za-ptrace: za-ptrace.c $(OUTPUT)/za-test: za-test.S $(OUTPUT)/asm-utils.o $(CC) -nostdlib $^ -o $@ +$(OUTPUT)/zt-ptrace: zt-ptrace.c $(OUTPUT)/zt-test: zt-test.S $(OUTPUT)/asm-utils.o $(CC) -nostdlib $^ -o $@

diff --git a/tools/testing/selftests/arm64/fp/zt-ptrace.c b/tools/testing/selftests/arm64/fp/zt-ptrace.c new file mode 100644 index 000000000000..996d9614a131 --- /dev/null +++ b/tools/testing/selftests/arm64/fp/zt-ptrace.c @@ -0,0 +1,365 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 ARM Limited. + */ +#include <errno.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/auxv.h> +#include <sys/prctl.h> +#include <sys/ptrace.h> +#include <sys/types.h> +#include <sys/uio.h> +#include <sys/wait.h> +#include <asm/sigcontext.h> +#include <asm/ptrace.h> + +#include "../../kselftest.h" + +/* <linux/elf.h> and <sys/auxv.h> don't like each other, so: */ +#ifndef NT_ARM_ZA +#define NT_ARM_ZA 0x40c +#endif +#ifndef NT_ARM_ZT +#define NT_ARM_ZT 0x40d +#endif + +#define EXPECTED_TESTS 3 + +static int sme_vl; + +static void fill_buf(char *buf, size_t size) +{ + int i; + + for (i = 0; i < size; i++) + buf[i] = random(); +} + +static int do_child(void) +{ + if (ptrace(PTRACE_TRACEME, -1, NULL, NULL)) + ksft_exit_fail_msg("PTRACE_TRACEME", strerror(errno)); + + if (raise(SIGSTOP)) + ksft_exit_fail_msg("raise(SIGSTOP)", strerror(errno)); + + return EXIT_SUCCESS; +} + +static struct user_za_header *get_za(pid_t pid, void **buf, size_t *size) +{ + struct user_za_header *za; + void *p; + size_t sz = sizeof(*za); + struct iovec iov; + + while (1) { + if (*size < sz) { + p = realloc(*buf, sz); + if (!p) { + errno = ENOMEM; + goto error; + } + + *buf = p; + *size = sz; + } + + iov.iov_base = *buf; + iov.iov_len = sz; + if (ptrace(PTRACE_GETREGSET, pid, NT_ARM_ZA, &iov)) + goto error; + + za = *buf; + if (za->size <= sz) + break; + + sz = za->size; + } + + return za; + +error: + return NULL; +} + +static int set_za(pid_t pid, const struct user_za_header *za) +{ + struct iovec iov; + + iov.iov_base = (void *)za; + iov.iov_len = za->size; + return ptrace(PTRACE_SETREGSET, pid, NT_ARM_ZA, &iov); +} + +static int get_zt(pid_t pid, char zt[ZT_SIG_REG_BYTES]) +{ + struct iovec iov; + + iov.iov_base = zt; + iov.iov_len = ZT_SIG_REG_BYTES; + return ptrace(PTRACE_GETREGSET, pid, NT_ARM_ZT, &iov); +} + + +static int set_zt(pid_t pid, const char zt[ZT_SIG_REG_BYTES]) +{ + struct iovec iov; + + iov.iov_base = (void *)zt; + iov.iov_len = ZT_SIG_REG_BYTES; + return ptrace(PTRACE_SETREGSET, pid, NT_ARM_ZT, &iov); +} + +/* Reading with ZA disabled returns all zeros */ +static void ptrace_za_disabled_read_zt(pid_t child) +{ + struct user_za_header za; + char zt[ZT_SIG_REG_BYTES]; + int ret, i; + bool fail = false; + + /* Disable PSTATE.ZA using the ZA interface */ + memset(&za, 0, sizeof(za)); + za.vl = sme_vl; + za.size = sizeof(za); + + ret = set_za(child, &za); + if (ret != 0) { + ksft_print_msg("Failed to disable ZA\n"); + fail = true; + } + + /* Read back ZT */ + ret = get_zt(child, zt); + if (ret != 0) { + ksft_print_msg("Failed to read ZT\n"); + fail = true; + } + + for (i = 0; i < ARRAY_SIZE(zt); i++) { + if (zt[i]) { + ksft_print_msg("zt[%d]: 0x%x != 0\n", i, zt[i]); + fail = true; + } + } + + ksft_test_result(!fail, "ptrace_za_disabled_read_zt\n"); +} + +/* Writing then reading ZT should return the data written */ +static void ptrace_set_get_zt(pid_t child) +{ + char zt_in[ZT_SIG_REG_BYTES]; + char zt_out[ZT_SIG_REG_BYTES]; + int ret, i; + bool fail = false; + + fill_buf(zt_in, sizeof(zt_in)); + + ret = set_zt(child, zt_in); + if (ret != 0) { + ksft_print_msg("Failed to set ZT\n"); + fail = true; + } + + ret = get_zt(child, zt_out); + if (ret != 0) { + ksft_print_msg("Failed to read ZT\n"); + fail = true; + } + + for (i = 0; i < ARRAY_SIZE(zt_in); i++) { + if (zt_in[i] != zt_out[i]) { + ksft_print_msg("zt[%d]: 0x%x != 0x%x\n", i, + zt_in[i], zt_out[i]); + fail = true; + } + } + + ksft_test_result(!fail, "ptrace_set_get_zt\n"); +} + +/* Writing ZT should set PSTATE.ZA */ +static void ptrace_enable_za_via_zt(pid_t child) +{ + struct user_za_header za_in; + struct user_za_header *za_out; + char zt[ZT_SIG_REG_BYTES]; + char *za_data; + size_t za_out_size; + int ret, i, vq; + bool fail = false; + + /* Disable PSTATE.ZA using the ZA interface */ + memset(&za_in, 0, sizeof(za_in)); + za_in.vl = sme_vl; + za_in.size = sizeof(za_in); + + ret = set_za(child, &za_in); + if (ret != 0) { + ksft_print_msg("Failed to disable ZA\n"); + fail = true; + } + + /* Write ZT */ + fill_buf(zt, sizeof(zt)); + ret = set_zt(child, zt); + if (ret != 0) { + ksft_print_msg("Failed to set ZT\n"); + fail = true; + } + + /* Read back ZA and check for register data */ + za_out = NULL; + za_out_size = 0; + if (get_za(child, (void **)&za_out, &za_out_size)) { + /* Should have an unchanged VL */ + if (za_out->vl != sme_vl) { + ksft_print_msg("VL changed from %d to %d\n", + sme_vl, za_out->vl); + fail = true; + } + vq = __sve_vq_from_vl(za_out->vl); + za_data = (char *)za_out + ZA_PT_ZA_OFFSET; + + /* Should have register data */ + if (za_out->size < ZA_PT_SIZE(vq)) { + ksft_print_msg("ZA data less than expected: %u < %u\n", + za_out->size, ZA_PT_SIZE(vq)); + fail = true; + vq = 0; + } + + /* That register data should be non-zero */ + for (i = 0; i < ZA_PT_ZA_SIZE(vq); i++) { + if (za_data[i]) { + ksft_print_msg("ZA byte %d is %x\n", + i, za_data[i]); + fail = true; + } + } + } else { + ksft_print_msg("Failed to read ZA\n"); + fail = true; + } + + ksft_test_result(!fail, "ptrace_enable_za_via_zt\n"); +} + +static int do_parent(pid_t child) +{ + int ret = EXIT_FAILURE; + pid_t pid; + int status; + siginfo_t si; + + /* Attach to the child */ + while (1) { + int sig; + + pid = wait(&status); + if (pid == -1) { + perror("wait"); + goto error; + } + + /* + * This should never happen but it's hard to flag in + * the framework. + */ + if (pid != child) + continue; + + if (WIFEXITED(status) || WIFSIGNALED(status)) + ksft_exit_fail_msg("Child died unexpectedly\n"); + + if (!WIFSTOPPED(status)) + goto error; + + sig = WSTOPSIG(status); + + if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &si)) { + if (errno == ESRCH) + goto disappeared; + + if (errno == EINVAL) { + sig = 0; /* bust group-stop */ + goto cont; + } + + ksft_test_result_fail("PTRACE_GETSIGINFO: %s\n", + strerror(errno)); + goto error; + } + + if (sig == SIGSTOP && si.si_code == SI_TKILL && + si.si_pid == pid) + break; + + cont: + if (ptrace(PTRACE_CONT, pid, NULL, sig)) { + if (errno == ESRCH) + goto disappeared; + + ksft_test_result_fail("PTRACE_CONT: %s\n", + strerror(errno)); + goto error; + } + } + + ksft_print_msg("Parent is %d, child is %d\n", getpid(), child); + + ptrace_za_disabled_read_zt(child); + ptrace_set_get_zt(child); + ptrace_enable_za_via_zt(child); + + ret = EXIT_SUCCESS; + +error: + kill(child, SIGKILL); + +disappeared: + return ret; +} + +int main(void) +{ + int ret = EXIT_SUCCESS; + pid_t child; + + srandom(getpid()); + + ksft_print_header(); + + if (!(getauxval(AT_HWCAP2) & HWCAP2_SME2)) { + ksft_set_plan(1); + ksft_exit_skip("SME2 not available\n"); + } + + /* We need a valid SME VL to enable/disable ZA */ + sme_vl = prctl(PR_SME_GET_VL); + if (sme_vl == -1) { + ksft_set_plan(1); + ksft_exit_skip("Failed to read SME VL: %d (%s)\n", + errno, strerror(errno)); + } + + ksft_set_plan(EXPECTED_TESTS); + + child = fork(); + if (!child) + return do_child(); + + if (do_parent(child)) + ret = EXIT_FAILURE; + + ksft_print_cnts(); + + return ret; +}

On 2022/11/12 5:50, Mark Brown wrote:

In order to allow userspace to discover the presence of the new SME features add hwcaps for them.

Signed-off-by: Mark Brown broonie@kernel.org

Documentation/arm64/elf_hwcaps.rst | 18 ++++++++++++++++++ arch/arm64/include/asm/hwcap.h | 6 ++++++ arch/arm64/include/uapi/asm/hwcap.h | 6 ++++++ arch/arm64/kernel/cpufeature.c | 13 +++++++++++++ arch/arm64/kernel/cpuinfo.c | 6 ++++++ 5 files changed, 49 insertions(+)

diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst index 6fed84f935df..29a3dd1b8f5a 100644 --- a/Documentation/arm64/elf_hwcaps.rst +++ b/Documentation/arm64/elf_hwcaps.rst @@ -284,6 +284,24 @@ HWCAP2_RPRFM HWCAP2_SVE2P1 Functionality implied by ID_AA64ZFR0_EL1.SVEver == 0b0010. +HWCAP2_SME2

• Functionality implied by ID_AA64SMFR0_EL1.SMEver == 0b0001.

+HWCAP2_SME2P1

• Functionality implied by ID_AA64SMFR0_EL1.SMEver == 0b0010.

+HWCAP2_SMEI16I32

• Functionality implied by ID_AA64SMFR0_EL1.I16I32 == 0b0101

+HWCAP2_SMEBI32I32

• Functionality implied by ID_AA64SMFR0_EL1.I32I32 == 0b1

s/I32I32/BI32I32/ ?

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 5b0d79f026aa..efb980ea7653 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c

@@ -2839,11 +2847,16 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { #ifdef CONFIG_ARM64_SME HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_SME_SHIFT, 4, FTR_UNSIGNED, ID_AA64PFR1_EL1_SME_IMP, CAP_HWCAP, KERNEL_HWCAP_SME), HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_FA64_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_FA64_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_FA64),

• HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, FTR_UNSIGNED, ID_AA64SMFR0_EL1_SMEver_SME2p1, CAP_HWCAP, KERNEL_HWCAP_SME2P1),
• HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, FTR_UNSIGNED, ID_AA64SMFR0_EL1_SMEver_SME2, CAP_HWCAP, KERNEL_HWCAP_SME2), HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_I16I64_SHIFT, 4, FTR_UNSIGNED, ID_AA64SMFR0_EL1_I16I64_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_I16I64), HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_F64F64_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_F64F64_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F64F64),
• HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_F64F64_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_B16B16_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_B16B16),

The *field* assignment looks wrong due to a copy-paste mistake.

s/ID_AA64SMFR0_EL1_F64F64_SHIFT/ID_AA64SMFR0_EL1_B16B16_SHIFT/ ?

• HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_F64F64_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_F16F16_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F16F16),

ditto

HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_I8I32_SHIFT, 4, FTR_UNSIGNED, ID_AA64SMFR0_EL1_I8I32_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_I8I32), HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_F16F32_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_F16F32_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F16F32), HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_B16F32_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_B16F32_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_B16F32),

• HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_EL1_B16F32_SHIFT, 1, FTR_UNSIGNED, ID_AA64SMFR0_EL1_BI32I32_IMP, CAP_HWCAP, KERNEL_HWCAP_SME_BI32I32),

ditto

and seems that HWCAP2_SMEI16I32 is missed.