In preparation for adding support for storage for ZT0 to the thread_struct rename za_state to sme_state. Since ZT0 is accessible when PSTATE.ZA is set just like ZA itself we will extend the allocation done for ZA to cover it, avoiding the need to further expand task_struct for non-SME tasks.

No functional changes.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/fpsimd.h | 13 ++++++---- arch/arm64/include/asm/processor.h | 2 +- arch/arm64/kernel/fpsimd.c | 40 +++++++++++++++--------------- arch/arm64/kernel/process.c | 11 ++++---- arch/arm64/kernel/ptrace.c | 6 ++--- arch/arm64/kernel/signal.c | 8 +++--- 6 files changed, 42 insertions(+), 38 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 6f86b7ab6c28..a18a86ccfd82 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -346,14 +346,17 @@ extern int sme_get_current_vl(void);

/* * 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. + * specific state for task, given task's currently configured vector + * length. */ -static inline size_t za_state_size(struct task_struct const *task) +static inline size_t sme_state_size(struct task_struct const *task) { unsigned int vl = task_get_sme_vl(task); + size_t size;

- return ZA_SIG_REGS_SIZE(sve_vq_from_vl(vl)); + size = ZA_SIG_REGS_SIZE(sve_vq_from_vl(vl)); + + return size; }

#else @@ -373,7 +376,7 @@ static inline int sme_max_virtualisable_vl(void) { return 0; } static inline int sme_set_current_vl(unsigned long arg) { return -EINVAL; } static inline int sme_get_current_vl(void) { return -EINVAL; }

-static inline size_t za_state_size(struct task_struct const *task) +static inline size_t sme_state_size(struct task_struct const *task) { return 0; } diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 445aa3af3b76..923a896229c8 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -154,7 +154,7 @@ struct thread_struct {

unsigned int fpsimd_cpu; void *sve_state; /* SVE registers, if any */ - void *za_state; /* ZA register, if any */ + void *sme_state; /* ZA and ZT state, if any */ unsigned int vl[ARM64_VEC_MAX]; /* vector length */ unsigned int vl_onexec[ARM64_VEC_MAX]; /* vl after next exec */ unsigned long fault_address; /* fault info */ diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 23834d96d1e7..b677b5a3e0f6 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -121,7 +121,7 @@ struct fpsimd_last_state_struct { struct user_fpsimd_state *st; void *sve_state; - void *za_state; + void *sme_state; u64 *svcr; unsigned int sve_vl; unsigned int sme_vl; @@ -307,7 +307,7 @@ void task_set_vl_onexec(struct task_struct *task, enum vec_type type, /* * 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 + * alocated in sve_state and sme_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 @@ -396,7 +396,7 @@ 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.za_state); + za_load_state(current->thread.sme_state);

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

if (*svcr & SVCR_ZA_MASK) - za_save_state(last->za_state); + za_save_state(last->sme_state);

/* If we are in streaming mode override regular SVE. */ if (*svcr & SVCR_SM_MASK) { @@ -1213,30 +1213,30 @@ void fpsimd_release_task(struct task_struct *dead_task) #ifdef CONFIG_ARM64_SME

/* - * Ensure that task->thread.za_state is allocated and sufficiently large. + * Ensure that task->thread.sme_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 + * task->thread.sme_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)); + if (task->thread.sme_state) { + memset(task->thread.sme_state, 0, sme_state_size(task)); return; }

/* This could potentially be up to 64K. */ - task->thread.za_state = - kzalloc(za_state_size(task), GFP_KERNEL); + task->thread.sme_state = + kzalloc(sme_state_size(task), GFP_KERNEL); }

static void sme_free(struct task_struct *task) { - kfree(task->thread.za_state); - task->thread.za_state = NULL; + kfree(task->thread.sme_state); + task->thread.sme_state = NULL; }

void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p) @@ -1443,7 +1443,7 @@ void do_sme_acc(unsigned long esr, struct pt_regs *regs)

sve_alloc(current, false); sme_alloc(current); - if (!current->thread.sve_state || !current->thread.za_state) { + if (!current->thread.sve_state || !current->thread.sme_state) { force_sig(SIGKILL); return; } @@ -1564,7 +1564,7 @@ static void fpsimd_flush_thread_vl(enum vec_type type) void fpsimd_flush_thread(void) { void *sve_state = NULL; - void *za_state = NULL; + void *sme_state = NULL;

if (!system_supports_fpsimd()) return; @@ -1589,8 +1589,8 @@ void fpsimd_flush_thread(void) clear_thread_flag(TIF_SME);

/* Defer kfree() while in atomic context */ - za_state = current->thread.za_state; - current->thread.za_state = NULL; + sme_state = current->thread.sme_state; + current->thread.sme_state = NULL;

fpsimd_flush_thread_vl(ARM64_VEC_SME); current->thread.svcr = 0; @@ -1598,7 +1598,7 @@ void fpsimd_flush_thread(void)

put_cpu_fpsimd_context(); kfree(sve_state); - kfree(za_state); + kfree(sme_state); }

/* @@ -1640,7 +1640,7 @@ 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->za_state = current->thread.za_state; + last->sme_state = current->thread.sme_state; last->sve_vl = task_get_sve_vl(current); last->sme_vl = task_get_sme_vl(current); last->svcr = &current->thread.svcr; @@ -1666,7 +1666,7 @@ 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, void *za_state, + unsigned int sve_vl, void *sme_state, unsigned int sme_vl, u64 *svcr) { struct fpsimd_last_state_struct *last = @@ -1678,7 +1678,7 @@ void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, last->st = st; last->svcr = svcr; last->sve_state = sve_state; - last->za_state = za_state; + last->sme_state = sme_state; last->sve_vl = sve_vl; last->sme_vl = sme_vl; } diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 044a7d7f1f6a..5cfb876c76ee 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -318,16 +318,17 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) GFP_KERNEL); if (!dst->thread.sve_state) return -ENOMEM; - dst->thread.za_state = kmemdup(src->thread.za_state, - za_state_size(src), - GFP_KERNEL); - if (!dst->thread.za_state) { + + dst->thread.sme_state = kmemdup(src->thread.sme_state, + sme_state_size(src), + GFP_KERNEL); + if (!dst->thread.sme_state) { kfree(dst->thread.sve_state); dst->thread.sve_state = NULL; return -ENOMEM; } } else { - dst->thread.za_state = NULL; + dst->thread.sme_state = NULL; clear_tsk_thread_flag(dst, TIF_SME); }

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index c2fb5755bbec..85105375bea5 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1052,7 +1052,7 @@ static int za_get(struct task_struct *target, if (thread_za_enabled(&target->thread)) { start = end; end = ZA_PT_SIZE(vq); - membuf_write(&to, target->thread.za_state, end - start); + membuf_write(&to, target->thread.sme_state, end - start); }

/* Zero any trailing padding */ @@ -1106,7 +1106,7 @@ static int za_set(struct task_struct *target,

/* Allocate/reinit ZA storage */ sme_alloc(target); - if (!target->thread.za_state) { + if (!target->thread.sme_state) { ret = -ENOMEM; goto out; } @@ -1131,7 +1131,7 @@ static int za_set(struct task_struct *target, start = ZA_PT_ZA_OFFSET; end = ZA_PT_SIZE(vq); ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, - target->thread.za_state, + target->thread.sme_state, start, end); if (ret) goto out; diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 9ad911f1647c..335bc7294b3c 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -386,7 +386,7 @@ static int preserve_za_context(struct za_context __user *ctx) * fpsimd_signal_preserve_current_state(). */ err |= __copy_to_user((char __user *)ctx + ZA_SIG_REGS_OFFSET, - current->thread.za_state, + current->thread.sme_state, ZA_SIG_REGS_SIZE(vq)); }

@@ -417,7 +417,7 @@ static int restore_za_context(struct user_ctxs *user)

/* * Careful: we are about __copy_from_user() directly into - * thread.za_state with preemption enabled, so protection is + * thread.sme_state with preemption enabled, so protection is * needed to prevent a racing context switch from writing stale * registers back over the new data. */ @@ -426,13 +426,13 @@ static int restore_za_context(struct user_ctxs *user) /* From now, fpsimd_thread_switch() won't touch thread.sve_state */

sme_alloc(current); - if (!current->thread.za_state) { + if (!current->thread.sme_state) { current->thread.svcr &= ~SVCR_ZA_MASK; clear_thread_flag(TIF_SME); return -ENOMEM; }

- err = __copy_from_user(current->thread.za_state, + err = __copy_from_user(current->thread.sme_state, (char __user const *)user->za + ZA_SIG_REGS_OFFSET, ZA_SIG_REGS_SIZE(vq));

FEAT_SME2 and FEAT_SME2P1 introduce several new SME features which can be enumerated via ID_AA64SMFR0_EL1 and a new register ZT0 access to which is controlled via SMCR_ELn, add the relevant register description.

Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/tools/sysreg | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg index b2782b8faa01..c8f259dbdfb8 100644 --- a/arch/arm64/tools/sysreg +++ b/arch/arm64/tools/sysreg @@ -221,7 +221,9 @@ Enum 63 FA64 EndEnum Res0 62:60 Enum 59:56 SMEver - 0b0000 IMP + 0b0000 SME + 0b0001 SME2 + 0b0010 SME2p1 EndEnum Enum 55:52 I16I64 0b0000 NI @@ -232,7 +234,19 @@ Enum 48 F64F64 0b0 NI 0b1 IMP EndEnum -Res0 47:40 +Enum 47:44 I16I32 + 0b0000 NI + 0b0101 IMP +EndEnum +Enum 43 B16B16 + 0b0 NI + 0b1 IMP +EndEnum +Enum 42 F16F16 + 0b0 NI + 0b1 IMP +EndEnum +Res0 41:40 Enum 39:36 I8I32 0b0000 NI 0b1111 IMP @@ -245,7 +259,10 @@ Enum 34 B16F32 0b0 NI 0b1 IMP EndEnum -Res0 33 +Enum 33 BI32I32 + 0b0 NI + 0b1 IMP +EndEnum Enum 32 F32F32 0b0 NI 0b1 IMP @@ -845,7 +862,8 @@ EndSysreg SysregFields SMCR_ELx Res0 63:32 Field 31 FA64 -Res0 30:9 +Field 30 EZT0 +Res0 29:9 Raz 8:4 Field 3:0 LEN EndSysregFields

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 bb1ef8cf7d04..416785eeb512 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), @@ -2618,6 +2620,18 @@ 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 f1c0347ec31a..79f511ef3195 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -49,6 +49,7 @@ 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; +}