// SPDX-License-Identifier: GPL-2.0-only
/*
* Based on arch/arm/kernel/signal.c
*
* Copyright (C) 1995-2009 Russell King
* Copyright (C) 2012 ARM Ltd.
*/
#include <linux/cache.h>
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/irq-entry-common.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/freezer.h>
#include <linux/stddef.h>
#include <linux/uaccess.h>
#include <linux/sizes.h>
#include <linux/string.h>
#include <linux/ratelimit.h>
#include <linux/rseq.h>
#include <linux/syscalls.h>
#include <linux/pkeys.h>
#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
#include <asm/elf.h>
#include <asm/exception.h>
#include <asm/cacheflush.h>
#include <asm/gcs.h>
#include <asm/ucontext.h>
#include <asm/unistd.h>
#include <asm/fpsimd.h>
#include <asm/ptrace.h>
#include <asm/syscall.h>
#include <asm/signal32.h>
#include <asm/traps.h>
#include <asm/vdso.h>
#define GCS_SIGNAL_CAP(addr) (((unsigned long)addr) & GCS_CAP_ADDR_MASK)
/*
* Do a signal return; undo the signal stack. These are aligned to 128-bit.
*/
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
};
struct rt_sigframe_user_layout {
struct rt_sigframe __user *sigframe;
struct frame_record __user *next_frame;
unsigned long size; /* size of allocated sigframe data */
unsigned long limit; /* largest allowed size */
unsigned long fpsimd_offset;
unsigned long esr_offset;
unsigned long gcs_offset;
unsigned long sve_offset;
unsigned long tpidr2_offset;
unsigned long za_offset;
unsigned long zt_offset;
unsigned long fpmr_offset;
unsigned long poe_offset;
unsigned long extra_offset;
unsigned long end_offset;
};
#define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16)
#define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16)
/*
* Holds any EL0-controlled state that influences unprivileged memory accesses.
* This includes both accesses done in userspace and uaccess done in the kernel.
*
* This state needs to be carefully managed to ensure that it doesn't cause
* uaccess to fail when setting up the signal frame, and the signal handler
* itself also expects a well-defined state when entered.
*
* The struct should be zero-initialised. Its members should only be accessed
* via the accessors below. __valid_fields tracks which of the fields are valid
* (have been set to some value).
*/
struct user_access_state {
unsigned int __valid_fields;
u64 __por_el0;
};
#define UA_STATE_HAS_POR_EL0 BIT(0)
static void set_ua_state_por_el0(struct user_access_state *ua_state,
u64 por_el0)
{
ua_state->__por_el0 = por_el0;
ua_state->__valid_fields |= UA_STATE_HAS_POR_EL0;
}
static int get_ua_state_por_el0(const struct user_access_state *ua_state,
u64 *por_el0)
{
if (ua_state->__valid_fields & UA_STATE_HAS_POR_EL0) {
*por_el0 = ua_state->__por_el0;
return 0;
}
return -ENOENT;
}
/*
* Save the user access state into ua_state and reset it to disable any
* restrictions.
*/
static void save_reset_user_access_state(struct user_access_state *ua_state)
{
if (system_supports_poe()) {
u64 por_enable_all = 0;
for (int pkey = 0; pkey < arch_max_pkey(); pkey++)
por_enable_all |= POR_ELx_PERM_PREP(pkey, POE_RWX);
set_ua_state_por_el0(ua_state, read_sysreg_s(SYS_POR_EL0));
write_sysreg_s(por_enable_all, SYS_POR_EL0);
/*
* No ISB required as we can tolerate spurious Overlay faults -
* the fault handler will check again based on the new value
* of POR_EL0.
*/
}
}
/*
* Set the user access state for invoking the signal handler.
*
* No uaccess should be done after that function is called.
*/
static void set_handler_user_access_state(void)
{
if (system_supports_poe())
write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0);
}
/*
* Restore the user access state to the values saved in ua_state.
*
* No uaccess should be done after that function is called.
*/
static void restore_user_access_state(const struct user_access_state *ua_state)
{
u64 por_el0;
if (get_ua_state_por_el0(ua_state, &por_el0) == 0)
write_sysreg_s(por_el0, SYS_POR_EL0);
}
static void init_user_layout(struct rt_sigframe_user_layout *user)
{
const size_t reserved_size =
sizeof(user->sigframe->uc.uc_mcontext.__reserved);
memset(user, 0, sizeof(*user));
user->size = offsetof(struct rt_sigframe, uc.uc_mcontext.__reserved);
user->limit = user->size + reserved_size;
user->limit -= TERMINATOR_SIZE;
user->limit -= EXTRA_CONTEXT_SIZE;
/* Reserve space for extension and terminator ^ */
}
static size_t sigframe_size(struct rt_sigframe_user_layout const *user)
{
return round_up(max(user->size, sizeof(struct rt_sigframe)), 16);
}
/*
* Sanity limit on the approximate maximum size of signal frame we'll
* try to generate. Stack alignment padding and the frame record are
* not taken into account. This limit is not a guarantee and is
* NOT ABI.
*/
#define SIGFRAME_MAXSZ SZ_256K
static int __sigframe_alloc(struct rt_sigframe_user_layout *user,
unsigned long *offset, size_t size, bool extend)
{
size_t padded_size = round_up(size, 16);
if (padded_size > user->limit - user->size &&
!user->extra_offset &&
extend) {
int ret;
user->limit += EXTRA_CONTEXT_SIZE;
ret = __sigframe_alloc(user, &user->extra_offset,
sizeof(struct extra_context), false);
if (ret) {
user->limit -= EXTRA_CONTEXT_SIZE;
return ret;
}
/* Reserve space for the __reserved[] terminator */
user->size += TERMINATOR_SIZE;
/*
* Allow expansion up to SIGFRAME_MAXSZ, ensuring space for
* the terminator:
*/
user->limit = SIGFRAME_MAXSZ - TERMINATOR_SIZE;
}
/* Still not enough space? Bad luck! */
if (padded_size > user->limit - user->size)
return -ENOMEM;
*offset = user->size;
user->size += padded_size;
return 0;
}
/*
* Allocate space for an optional record of <size> bytes in the user
* signal frame. The offset from the signal frame base address to the
* allocated block is assigned to *offset.
*/
static int sigframe_alloc(struct rt_sigframe_user_layout *user,
unsigned long *offset, size_t size)
{
return __sigframe_alloc(user, offset, size, true);
}
/* Allocate the null terminator record and prevent further allocations */
static int sigframe_alloc_end(struct rt_sigframe_user_layout *user)
{
int ret;
/* Un-reserve the space reserved for the terminator: */
user->limit += TERMINATOR_SIZE;
ret = sigframe_alloc(user, &user->end_offset,
sizeof(struct _aarch64_ctx));
if (ret)
return ret;
/* Prevent further allocation: */
user->limit = user->size;
return 0;
}
static void __user *apply_user_offset(
struct rt_sigframe_user_layout const *user, unsigned long offset)
{
char __user *base = (char __user *)user->sigframe;
return base + offset;
}
struct user_ctxs {
struct fpsimd_context __user *fpsimd;
u32 fpsimd_size;
struct sve_context __user *sve;
u32 sve_size;
struct tpidr2_context __user *tpidr2;
u32 tpidr2_size;
struct za_context __user *za;
u32 za_size;
struct zt_context __user *zt;
u32 zt_size;
struct fpmr_context __user *fpmr;
u32 fpmr_size;
struct poe_context __user *poe;
u32 poe_size;
struct gcs_context __user *gcs;
u32 gcs_size;
};
static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
{
struct user_fpsimd_state const *fpsimd =
¤t->thread.uw.fpsimd_state;
int err;
fpsimd_sync_from_effective_state(current);
/* copy the FP and status/control registers */
err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
__put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
__put_user_error(fpsimd->fpcr, &ctx->fpcr, err);
/* copy the magic/size information */
__put_user_error(FPSIMD_MAGIC, &ctx->head.magic, err);
__put_user_error(sizeof(struct fpsimd_context), &ctx->head.size, err);
return err ? -EFAULT : 0;
}
static int read_fpsimd_context(struct user_fpsimd_state *fpsimd,
struct user_ctxs *user)
{
int err;
/* check the size information */
if (user->fpsimd_size != sizeof(struct fpsimd_context))
return -EINVAL;
/* copy the FP and status/control registers */
err = __copy_from_user(fpsimd->vregs, &(user->fpsimd->vregs),
sizeof(fpsimd->vregs));
__get_user_error(fpsimd->fpsr, &(user->fpsimd->fpsr), err);
__get_user_error(fpsimd->fpcr, &(user->fpsimd->fpcr), err);
return err ? -EFAULT : 0;
}
static int restore_fpsimd_context(struct user_ctxs *user)
{
struct user_fpsimd_state fpsimd;
int err;
err = read_fpsimd_context(&fpsimd, user);
if (err)
return err;
clear_thread_flag(TIF_SVE);
current->thread.svcr &= ~SVCR_SM_MASK;
current->thread.fp_type = FP_STATE_FPSIMD;
/* load the hardware registers from the fpsimd_state structure */
fpsimd_update_current_state(&fpsimd);
return 0;
}
static int preserve_fpmr_context(struct fpmr_context __user *ctx)
{
int err = 0;
__put_user_error(FPMR_MAGIC, &ctx->head.magic, err);
__put_user_error(sizeof(*ctx), &ctx->head.size, err);
__put_user_error(current->thread.uw.fpmr, &ctx->fpmr, err);
return err;
}
static int restore_fpmr_context(struct user_ctxs *user)
{
u64 fpmr;
int err = 0;
if (user->fpmr_size != sizeof(*user->fpmr))
return -EINVAL;
__get_user_error(fpmr, &user->fpmr->fpmr, err);
if (!err)
current->thread.uw.fpmr = fpmr;
return err;
}
static int preserve_poe_context(struct poe_context __user *ctx,
const struct user_access_state *ua_state)
{
int err;
u64 por_el0;
err = get_ua_state_por_el0(ua_state, &por_el0);
if (WARN_ON_ONCE(err))
return err;
__put_user_error(POE_MAGIC, &ctx->head.magic, err);
__put_user_error(sizeof(*ctx), &ctx->head.size, err);
__put_user_error(por_el0, &ctx->por_el0, err);
return err;
}
static int restore_poe_context(struct user_ctxs *user,
struct user_access_state *ua_state)
{
u64 por_el0;
int err = 0;
if (user->poe_size != sizeof(*user->poe))
return -EINVAL;
__get_user_error(por_el0, &(user->poe->por_el0), err);
if (!err)
set_ua_state_por_el0(ua_state, por_el0);
return err;
}
#ifdef CONFIG_ARM64_SVE
static int preserve_sve_context(struct sve_context __user *ctx)
{
int err = 0;
u16 reserved[ARRAY_SIZE(ctx->__reserved)];
u16 flags = 0;
unsigned int vl = task_get_sve_vl(current);
unsigned int vq = 0;
if (thread_sm_enabled(¤t->thread)) {
vl = task_get_sme_vl(current);
vq = sve_vq_from_vl(vl);
flags |= SVE_SIG_FLAG_SM;
} else if (current->thread.fp_type == FP_STATE_SVE) {
vq = sve_vq_from_vl(vl);
}
memset(reserved, 0, sizeof(reserved));
__put_user_error(SVE_MAGIC, &ctx->head.magic, err);
__put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16),
&ctx->head.size, err);
__put_user_error(vl, &ctx->vl, err);
__put_user_error(flags, &ctx->flags, err);
BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
if (vq) {
err |= __copy_to_user((char __user *)ctx + SVE_SIG_REGS_OFFSET,
current->thread.sve_state,
SVE_SIG_REGS_SIZE(vq));
}
return err ? -EFAULT : 0;
}
static int restore_sve_fpsimd_context(struct user_ctxs *user)
{
int err = 0;
unsigned int vl, vq;
struct user_fpsimd_state fpsimd;
u16 user_vl, flags;
bool sm;
if (user->sve_size < sizeof(*user->sve))
return -EINVAL;
__get_user_error(user_vl, &(user->sve->vl), err);
__get_user_error(flags, &(user->sve->flags), err);
if (err)
return err;
sm = flags & SVE_SIG_FLAG_SM;
if (sm) {
if (!system_supports_sme())
return -EINVAL;
vl = task_get_sme_vl(current);
} else {
/*
* A SME only system use SVE for streaming mode so can
* have a SVE formatted context with a zero VL and no
* payload data.
*/
if (!system_supports_sve() && !system_supports_sme())
return -EINVAL;
vl = task_get_sve_vl(current);
}
if (user_vl != vl)
return -EINVAL;
/*
* Non-streaming SVE state may be preserved without an SVE payload, in
* which case the SVE context only has a header with VL==0, and all
* state can be restored from the FPSIMD context.
*
* Streaming SVE state is always preserved with an SVE payload. For
* consistency and robustness, reject restoring streaming SVE state
* without an SVE payload.
*/
if (!sm && user->sve_size == sizeof(*user->sve))
return restore_fpsimd_context(user);
vq = sve_vq_from_vl(vl);
if (user->sve_size < SVE_SIG_CONTEXT_SIZE(vq))
return -EINVAL;
if (sm) {
sme_alloc(current, false);
if (!current->thread.sme_state)
return -ENOMEM;
}
sve_alloc(current, true);
if (!current->thread.sve_state) {
clear_thread_flag(TIF_SVE);
return -ENOMEM;
}
if (sm) {
current->thread.svcr |= SVCR_SM_MASK;
set_thread_flag(TIF_SME);
} else {
current->thread.svcr &= ~SVCR_SM_MASK;
set_thread_flag(TIF_SVE);
}
current->thread.fp_type = FP_STATE_SVE;
err = __copy_from_user(current->thread.sve_state,
(char __user const *)user->sve +
SVE_SIG_REGS_OFFSET,
SVE_SIG_REGS_SIZE(vq));
if (err)
return -EFAULT;
err = read_fpsimd_context(&fpsimd, user);
if (err)
return err;
/* Merge the FPSIMD registers into the SVE state */
fpsimd_update_current_state(&fpsimd);
return 0;
}
#else /* ! CONFIG_ARM64_SVE */
static int restore_sve_fpsimd_context(struct user_ctxs *user)
{
WARN_ON_ONCE(1);
return -EINVAL;
}
/* Turn any non-optimised out attempts to use this into a link error: */
extern int preserve_sve_context(void __user *ctx);
#endif /* ! CONFIG_ARM64_SVE */
#ifdef CONFIG_ARM64_SME
static int preserve_tpidr2_context(struct tpidr2_context __user *ctx)
{
u64 tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0);
int err = 0;
__put_user_error(TPIDR2_MAGIC, &ctx->head.magic, err);
__put_user_error(sizeof(*ctx), &ctx->head.size, err);
__put_user_error(tpidr2_el0, &ctx->tpidr2, err);
return err;
}
static int restore_tpidr2_context(struct user_ctxs *user)
{
u64 tpidr2_el0;
int err = 0;
if (user->tpidr2_size != sizeof(*user->tpidr2))
return -EINVAL;
__get_user_error(tpidr2_el0, &user->tpidr2->tpidr2, err);
if (!err)
write_sysreg_s(tpidr2_el0, SYS_TPIDR2_EL0);
return err;
}
static int preserve_za_context(struct za_context __user *ctx)
{
int err = 0;
u16 reserved[ARRAY_SIZE(ctx->__reserved)];
unsigned int vl = task_get_sme_vl(current);
unsigned int vq;
if (thread_za_enabled(¤t->thread))
vq = sve_vq_from_vl(vl);
else
vq = 0;
memset(reserved, 0, sizeof(reserved));
__put_user_error(ZA_MAGIC, &ctx->head.magic, err);
__put_user_error(round_up(ZA_SIG_CONTEXT_SIZE(vq), 16),
&ctx->head.size, err);
__put_user_error(vl, &ctx->vl, err);
BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
if (vq) {
err |= __copy_to_user((char __user *)ctx + ZA_SIG_REGS_OFFSET,
current->thread.sme_state,
ZA_SIG_REGS_SIZE(vq));
}
return err ? -EFAULT : 0;
}
static int restore_za_context(struct user_ctxs *user)
{
int err = 0;
unsigned int vq;
u16 user_vl;
if (user->za_size < sizeof(*user->za))
return -EINVAL;
__get_user_error(user_vl, &(user->za->vl), err);
if (err)
return err;
if (user_vl != task_get_sme_vl(current))
return -EINVAL;
if (user->za_size == sizeof(*user->za)) {
current->thread.svcr &= ~SVCR_ZA_MASK;
return 0;
}
vq = sve_vq_from_vl(user_vl);
if (user->za_size < ZA_SIG_CONTEXT_SIZE(vq))
return -EINVAL;
sve_alloc(current, false);
if (!current->thread.sve_state)
return -ENOMEM;
sme_alloc(current, true);
if (!current->thread.sme_state) {
current->thread.svcr &= ~SVCR_ZA_MASK;
clear_thread_flag(TIF_SME);
return -ENOMEM;
}
err = __copy_from_user(current->thread.sme_state,
(char __user const *)user->za +
ZA_SIG_REGS_OFFSET,
ZA_SIG_REGS_SIZE(vq));
if (err)
return -EFAULT;
set_thread_flag(TIF_SME);
current->thread.svcr |= SVCR_ZA_MASK;
return 0;
}
static int preserve_zt_context(struct zt_context __user *ctx)
{
int err = 0;
u16 reserved[ARRAY_SIZE(ctx->__reserved)];
if (WARN_ON(!thread_za_enabled(¤t->thread)))
return -EINVAL;
memset(reserved, 0, sizeof(reserved));
__put_user_error(ZT_MAGIC, &ctx->head.magic, err);
__put_user_error(round_up(ZT_SIG_CONTEXT_SIZE(1), 16),
&ctx->head.size, err);
__put_user_error(1, &ctx->nregs, err);
BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
err |= __copy_to_user((char __user *)ctx + ZT_SIG_REGS_OFFSET,
thread_zt_state(¤t->thread),
ZT_SIG_REGS_SIZE(1));
return err ? -EFAULT : 0;
}
static int restore_zt_context(struct user_ctxs *user)
{
int err;
u16 nregs;
/* ZA must be restored first for this check to be valid */
if (!thread_za_enabled(¤t->thread))
return -EINVAL;
if (user->zt_size != ZT_SIG_CONTEXT_SIZE(1))
return -EINVAL;
if (__copy_from_user(&nregs, &(user->zt->nregs), sizeof(nregs)))
return -EFAULT;
if (nregs != 1)
return -EINVAL;
err = __copy_from_user(thread_zt_state(¤t->thread),
(char __user const *)user->zt +
ZT_SIG_REGS_OFFSET,
ZT_SIG_REGS_SIZE(1));
if (err)
return -EFAULT;
return 0;
}
#else /* ! CONFIG_ARM64_SME */
/* Turn any non-optimised out attempts to use these into a link error: */
extern int preserve_tpidr2_context(void __user *ctx);
extern int restore_tpidr2_context(struct user_ctxs *user);
extern int preserve_za_context(void __user *ctx);
extern int restore_za_context(struct user_ctxs *user);
extern int preserve_zt_context(void __user *ctx);
extern int restore_zt_context(struct user_ctxs *user);
#endif /* ! CONFIG_ARM64_SME */
#ifdef CONFIG_ARM64_GCS
static int preserve_gcs_context(struct gcs_context __user *ctx)
{
int err = 0;
u64 gcspr = read_sysreg_s(SYS_GCSPR_EL0);
/*
* If GCS is enabled we will add a cap token to the frame,
* include it in the GCSPR_EL0 we report to support stack
* switching via sigreturn if GCS is enabled. We do not allow
* enabling via sigreturn so the token is only relevant for
* threads with GCS enabled.
*/
if (task_gcs_el0_enabled(current))
gcspr -= 8;
__put_user_error(GCS_MAGIC, &ctx->head.magic, err);
__put_user_error(sizeof(*ctx), &ctx->head.size, err);
__put_user_error(gcspr, &ctx->gcspr, err);
__put_user_error(0, &ctx->reserved, err);
__put_user_error(current->thread.gcs_el0_mode,
&ctx->features_enabled, err);
return err;
}
static int restore_gcs_context(struct user_ctxs *user)
{
u64 gcspr, enabled;
int err = 0;
if (user->gcs_size != sizeof(*user->gcs))
return -EINVAL;
__get_user_error(gcspr, &user->gcs->gcspr, err);
__get_user_error(enabled, &user->gcs->features_enabled, err);
if (err)
return err;
/* Don't allow unknown modes */
if (enabled & ~PR_SHADOW_STACK_SUPPORTED_STATUS_MASK)
return -EINVAL;
err = gcs_check_locked(current, enabled);
if (err != 0)
return err;
/* Don't allow enabling */
if (!task_gcs_el0_enabled(current) &&
(enabled & PR_SHADOW_STACK_ENABLE))
return -EINVAL;
/* If we are disabling disable everything */
if (!(enabled & PR_SHADOW_STACK_ENABLE))
enabled = 0;
current->thread.gcs_el0_mode = enabled;
/*
* We let userspace set GCSPR_EL0 to anything here, we will
* validate later in gcs_restore_signal().
*/
write_sysreg_s(gcspr, SYS_GCSPR_EL0);
return 0;
}
#else /* ! CONFIG_ARM64_GCS */
/* Turn any non-optimised out attempts to use these into a link error: */
extern int preserve_gcs_context(void __user *ctx);
extern int restore_gcs_context(struct user_ctxs *user);
#endif /* ! CONFIG_ARM64_GCS */
static int parse_user_sigframe(struct user_ctxs *user,
struct rt_sigframe __user *sf)
{
struct sigcontext __user *const sc = &sf->uc.uc_mcontext;
struct _aarch64_ctx __user *head;
char __user *base = (char __user *)&sc->__reserved;
size_t offset = 0;
size_t limit = sizeof(sc->__reserved);
bool have_extra_context = false;
char const __user *const sfp = (char const __user *)sf;
user->fpsimd = NULL;
user->sve = NULL;
user->tpidr2 = NULL;
user->za = NULL;
user->zt = NULL;
user->fpmr = NULL;
user->poe = NULL;
user->gcs = NULL;
if (!IS_ALIGNED((unsigned long)base, 16))
goto invalid;
while (1) {
int err = 0;
u32 magic, size;
char const __user *userp;
struct extra_context const __user *extra;
u64 extra_datap;
u32 extra_size;
struct _aarch64_ctx const __user *end;
u32 end_magic, end_size;
if (limit - offset < sizeof(*head))
goto invalid;
if (!IS_ALIGNED(offset, 16))
goto invalid;
head = (struct _aarch64_ctx __user *)(base + offset);
__get_user_error(magic, &head->magic, err);
__get_user_error(size, &head->size, err);
if (err)
return err;
if (limit - offset < size)
goto invalid;
switch (magic) {
case 0:
if (size)
goto invalid;
goto done;
case FPSIMD_MAGIC:
if (!system_supports_fpsimd())
goto invalid;
if (user->fpsimd)
goto invalid;
user->fpsimd = (struct fpsimd_context __user *)head;
user->fpsimd_size = size;
break;
case ESR_MAGIC:
/* ignore */
break;
case POE_MAGIC:
if (!system_supports_poe())
goto invalid;
if (user->poe)
goto invalid;
user->poe = (struct poe_context __user *)head;
user->poe_size = size;
break;
case SVE_MAGIC:
if (!system_supports_sve() && !system_supports_sme())
goto invalid;
if (user->sve)
goto invalid;
user->sve = (struct sve_context __user *)head;
user->sve_size = size;
break;
case TPIDR2_MAGIC:
if (!system_supports_tpidr2())
goto invalid;
if (user->tpidr2)
goto invalid;
user->tpidr2 = (struct tpidr2_context __user *)head;
user->tpidr2_size = size;
break;
case ZA_MAGIC:
if (!system_supports_sme())
goto invalid;
if (user->za)
goto invalid;
user->za = (struct za_context __user *)head;
user->za_size = size;
break;
case ZT_MAGIC:
if (!system_supports_sme2())
goto invalid;
if (user->zt)
goto invalid;
user->zt = (struct zt_context __user *)head;
user->zt_size = size;
break;
case FPMR_MAGIC:
if (!system_supports_fpmr())
goto invalid;
if (user->fpmr)
goto invalid;
user->fpmr = (struct fpmr_context __user *)head;
user->fpmr_size = size;
break;
case GCS_MAGIC:
if (!system_supports_gcs())
goto invalid;
if (user->gcs)
goto invalid;
user->gcs = (struct gcs_context __user *)head;
user->gcs_size = size;
break;
case EXTRA_MAGIC:
if (have_extra_context)
goto invalid;
if (size < sizeof(*extra))
goto invalid;
userp = (char const __user *)head;
extra = (struct extra_context const __user *)userp;
userp += size;
__get_user_error(extra_datap, &extra->datap, err);
__get_user_error(extra_size, &extra->size, err);
if (err)
return err;
/* Check for the dummy terminator in __reserved[]: */
if (limit - offset - size < TERMINATOR_SIZE)
goto invalid;
end = (struct _aarch64_ctx const __user *)userp;
userp += TERMINATOR_SIZE;
__get_user_error(end_magic, &end->magic, err);
__get_user_error(end_size, &end->size, err);
if (err)
return err;
if (end_magic || end_size)
goto invalid;
/* Prevent looping/repeated parsing of extra_context */
have_extra_context = true;
base = (__force void __user *)extra_datap;
if (!IS_ALIGNED((unsigned long)base, 16))
goto invalid;
if (!IS_ALIGNED(extra_size, 16))
goto invalid;
if (base != userp)
goto invalid;
/* Reject "unreasonably large" frames: */
if (extra_size > sfp + SIGFRAME_MAXSZ - userp)
goto invalid;
/*
* Ignore trailing terminator in __reserved[]
* and start parsing extra data:
*/
offset = 0;
limit = extra_size;
if (!access_ok(base, limit))
goto invalid;
continue;
default:
goto invalid;
}
if (size < sizeof(*head))
goto invalid;
if (limit - offset < size)
goto invalid;
offset += size;
}
done:
return 0;
invalid:
return -EINVAL;
}
static int restore_sigframe(struct pt_regs *regs,
struct rt_sigframe __user *sf,
struct user_access_state *ua_state)
{
sigset_t set;
int i, err;
struct user_ctxs user;
err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
if (err == 0)
set_current_blocked(&set);
for (i = 0; i < 31; i++)
__get_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
err);
__get_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
__get_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
__get_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
/*
* Avoid sys_rt_sigreturn() restarting.
*/
forget_syscall(regs);
fpsimd_save_and_flush_current_state();
err |= !valid_user_regs(®s->user_regs, current);
if (err == 0)
err = parse_user_sigframe(&user, sf);
if (err == 0 && system_supports_fpsimd()) {
if (!user.fpsimd)
return -EINVAL;
if (user.sve)
err = restore_sve_fpsimd_context(&user);
else
err = restore_fpsimd_context(&user);
}
if (err == 0 && system_supports_gcs() && user.gcs)
err = restore_gcs_context(&user);
if (err == 0 && system_supports_tpidr2() && user.tpidr2)
err = restore_tpidr2_context(&user);
if (err == 0 && system_supports_fpmr() && user.fpmr)
err = restore_fpmr_context(&user);
if (err == 0 && system_supports_sme() && user.za)
err = restore_za_context(&user);
if (err == 0 && system_supports_sme2() && user.zt)
err = restore_zt_context(&user);
if (err == 0 && system_supports_poe() && user.poe)
err = restore_poe_context(&user, ua_state);
return err;
}
#ifdef CONFIG_ARM64_GCS
static int gcs_restore_signal(void)
{
u64 gcspr_el0, cap;
int ret;
if (!system_supports_gcs())
return 0;
if (!(current->thread.gcs_el0_mode & PR_SHADOW_STACK_ENABLE))
return 0;
gcspr_el0 = read_sysreg_s(SYS_GCSPR_EL0);
/*
* Ensure that any changes to the GCS done via GCS operations
* are visible to the normal reads we do to validate the
* token.
*/
gcsb_dsync();
/*
* GCSPR_EL0 should be pointing at a capped GCS, read the cap.
* We don't enforce that this is in a GCS page, if it is not
* then faults will be generated on GCS operations - the main
* concern is to protect GCS pages.
*/
ret = copy_from_user(&cap, (unsigned long __user *)gcspr_el0,
sizeof(cap));
if (ret)
return -EFAULT;
/*
* Check that the cap is the actual GCS before replacing it.
*/
if (cap != GCS_SIGNAL_CAP(gcspr_el0))
return -EINVAL;
/* Invalidate the token to prevent reuse */
put_user_gcs(0, (unsigned long __user *)gcspr_el0, &ret);
if (ret != 0)
return -EFAULT;
write_sysreg_s(gcspr_el0 + 8, SYS_GCSPR_EL0);
return 0;
}
#else
static int gcs_restore_signal(void) { return 0; }
#endif
SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame;
struct user_access_state ua_state = {};
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a 128-bit boundary, then 'sp' should
* be word aligned here.
*/
if (regs->sp & 15)
goto badframe;
frame = (struct rt_sigframe __user *)regs->sp;
if (!access_ok(frame, sizeof (*frame)))
goto badframe;
if (restore_sigframe(regs, frame, &ua_state))
goto badframe;
if (gcs_restore_signal())
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
restore_user_access_state(&ua_state);
return regs->regs[0];
badframe:
arm64_notify_segfault(regs->sp);
return 0;
}
/*
* Determine the layout of optional records in the signal frame
*
* add_all: if true, lays out the biggest possible signal frame for
* this task; otherwise, generates a layout for the current state
* of the task.
*/
static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
bool add_all)
{
int err;
if (system_supports_fpsimd()) {
err = sigframe_alloc(user, &user->fpsimd_offset,
sizeof(struct fpsimd_context));
if (err)
return err;
}
/* fault information, if valid */
if (add_all || current->thread.fault_code) {
err = sigframe_alloc(user, &user->esr_offset,
sizeof(struct esr_context));
if (err)
return err;
}
#ifdef CONFIG_ARM64_GCS
if (system_supports_gcs() && (add_all || current->thread.gcspr_el0)) {
err = sigframe_alloc(user, &user->gcs_offset,
sizeof(struct gcs_context));
if (err)
return err;
}
#endif
if (system_supports_sve() || system_supports_sme()) {
unsigned int vq = 0;
if (add_all || current->thread.fp_type == FP_STATE_SVE ||
thread_sm_enabled(¤t->thread)) {
int vl = max(sve_max_vl(), sme_max_vl());
if (!add_all)
vl = thread_get_cur_vl(¤t->thread);
vq = sve_vq_from_vl(vl);
}
err = sigframe_alloc(user, &user->sve_offset,
SVE_SIG_CONTEXT_SIZE(vq));
if (err)
return err;
}
if (system_supports_tpidr2()) {
err = sigframe_alloc(user, &user->tpidr2_offset,
sizeof(struct tpidr2_context));
if (err)
return err;
}
if (system_supports_sme()) {
unsigned int vl;
unsigned int vq = 0;
if (add_all)
vl = sme_max_vl();
else
vl = task_get_sme_vl(current);
if (thread_za_enabled(¤t->thread))
vq = sve_vq_from_vl(vl);
err = sigframe_alloc(user, &user->za_offset,
ZA_SIG_CONTEXT_SIZE(vq));
if (err)
return err;
}
if (system_supports_sme2()) {
if (add_all || thread_za_enabled(¤t->thread)) {
err = sigframe_alloc(user, &user->zt_offset,
ZT_SIG_CONTEXT_SIZE(1));
if (err)
return err;
}
}
if (system_supports_fpmr()) {
err = sigframe_alloc(user, &user->fpmr_offset,
sizeof(struct fpmr_context));
if (err)
return err;
}
if (system_supports_poe()) {
err = sigframe_alloc(user, &user->poe_offset,
sizeof(struct poe_context));
if (err)
return err;
}
return sigframe_alloc_end(user);
}
static int setup_sigframe(struct rt_sigframe_user_layout *user,
struct pt_regs *regs, sigset_t *set,
const struct user_access_state *ua_state)
{
int i, err = 0;
struct rt_sigframe __user *sf = user->sigframe;
/* set up the stack frame for unwinding */
__put_user_error(regs->regs[29], &user->next_frame->fp, err);
__put_user_error(regs->regs[30], &user->next_frame->lr, err);
for (i = 0; i < 31; i++)
__put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
err);
__put_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
__put_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
__put_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
__put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
if (err == 0 && system_supports_fpsimd()) {
struct fpsimd_context __user *fpsimd_ctx =
apply_user_offset(user, user->fpsimd_offset);
err |= preserve_fpsimd_context(fpsimd_ctx);
}
/* fault information, if valid */
if (err == 0 && user->esr_offset) {
struct esr_context __user *esr_ctx =
apply_user_offset(user, user->esr_offset);
__put_user_error(ESR_MAGIC, &esr_ctx->head.magic, err);
__put_user_error(sizeof(*esr_ctx), &esr_ctx->head.size, err);
__put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
}
if (system_supports_gcs() && err == 0 && user->gcs_offset) {
struct gcs_context __user *gcs_ctx =
apply_user_offset(user, user->gcs_offset);
err |= preserve_gcs_context(gcs_ctx);
}
/* Scalable Vector Extension state (including streaming), if present */
if ((system_supports_sve() || system_supports_sme()) &&
err == 0 && user->sve_offset) {
struct sve_context __user *sve_ctx =
apply_user_offset(user, user->sve_offset);
err |= preserve_sve_context(sve_ctx);
}
/* TPIDR2 if supported */
if (system_supports_tpidr2() && err == 0) {
struct tpidr2_context __user *tpidr2_ctx =
apply_user_offset(user, user->tpidr2_offset);
err |= preserve_tpidr2_context(tpidr2_ctx);
}
/* FPMR if supported */
if (system_supports_fpmr() && err == 0) {
struct fpmr_context __user *fpmr_ctx =
apply_user_offset(user, user->fpmr_offset);
err |= preserve_fpmr_context(fpmr_ctx);
}
if (system_supports_poe() && err == 0) {
struct poe_context __user *poe_ctx =
apply_user_offset(user, user->poe_offset);
err |= preserve_poe_context(poe_ctx, ua_state);
}
/* ZA state if present */
if (system_supports_sme() && err == 0 && user->za_offset) {
struct za_context __user *za_ctx =
apply_user_offset(user, user->za_offset);
err |= preserve_za_context(za_ctx);
}
/* ZT state if present */
if (system_supports_sme2() && err == 0 && user->zt_offset) {
struct zt_context __user *zt_ctx =
apply_user_offset(user, user->zt_offset);
err |= preserve_zt_context(zt_ctx);
}
if (err == 0 && user->extra_offset) {
char __user *sfp = (char __user *)user->sigframe;
char __user *userp =
apply_user_offset(user, user->extra_offset);
struct extra_context __user *extra;
struct _aarch64_ctx __user *end;
u64 extra_datap;
u32 extra_size;
extra = (struct extra_context __user *)userp;
userp += EXTRA_CONTEXT_SIZE;
end = (struct _aarch64_ctx __user *)userp;
userp += TERMINATOR_SIZE;
/*
* extra_datap is just written to the signal frame.
* The value gets cast back to a void __user *
* during sigreturn.
*/
extra_datap = (__force u64)userp;
extra_size = sfp + round_up(user->size, 16) - userp;
__put_user_error(EXTRA_MAGIC, &extra->head.magic, err);
__put_user_error(EXTRA_CONTEXT_SIZE, &extra->head.size, err);
__put_user_error(extra_datap, &extra->datap, err);
__put_user_error(extra_size, &extra->size, err);
/* Add the terminator */
__put_user_error(0, &end->magic, err);
__put_user_error(0, &end->size, err);
}
/* set the "end" magic */
if (err == 0) {
struct _aarch64_ctx __user *end =
apply_user_offset(user, user->end_offset);
__put_user_error(0, &end->magic, err);
__put_user_error(0, &end->size, err);
}
return err;
}
static int get_sigframe(struct rt_sigframe_user_layout *user,
struct ksignal *ksig, struct pt_regs *regs)
{
unsigned long sp, sp_top;
int err;
init_user_layout(user);
err = setup_sigframe_layout(user, false);
if (err)
return err;
sp = sp_top = sigsp(regs->sp, ksig);
sp = round_down(sp - sizeof(struct frame_record), 16);
user->next_frame = (struct frame_record __user *)sp;
sp = round_down(sp, 16) - sigframe_size(user);
user->sigframe = (struct rt_sigframe __user *)sp;
/*
* Check that we can actually write to the signal frame.
*/
if (!access_ok(user->sigframe, sp_top - sp))
return -EFAULT;
return 0;
}
#ifdef CONFIG_ARM64_GCS
static int gcs_signal_entry(__sigrestore_t sigtramp, struct ksignal *ksig)
{
u64 gcspr_el0;
int ret = 0;
if (!system_supports_gcs())
return 0;
if (!task_gcs_el0_enabled(current))
return 0;
/*
* We are entering a signal handler, current register state is
* active.
*/
gcspr_el0 = read_sysreg_s(SYS_GCSPR_EL0);
/*
* Push a cap and the GCS entry for the trampoline onto the GCS.
*/
put_user_gcs((unsigned long)sigtramp,
(unsigned long __user *)(gcspr_el0 - 16), &ret);
put_user_gcs(GCS_SIGNAL_CAP(gcspr_el0 - 8),
(unsigned long __user *)(gcspr_el0 - 8), &ret);
if (ret != 0)
return ret;
gcspr_el0 -= 16;
write_sysreg_s(gcspr_el0, SYS_GCSPR_EL0);
return 0;
}
#else
static int gcs_signal_entry(__sigrestore_t sigtramp, struct ksignal *ksig)
{
return 0;
}
#endif
static int setup_return(struct pt_regs *regs, struct ksignal *ksig,
struct rt_sigframe_user_layout *user, int usig)
{
__sigrestore_t sigtramp;
int err;
if (ksig->ka.sa.sa_flags & SA_RESTORER)
sigtramp = ksig->ka.sa.sa_restorer;
else
sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
err = gcs_signal_entry(sigtramp, ksig);
if (err)
return err;
/*
* We must not fail from this point onwards. We are going to update
* registers, including SP, in order to invoke the signal handler. If
* we failed and attempted to deliver a nested SIGSEGV to a handler
* after that point, the subsequent sigreturn would end up restoring
* the (partial) state for the original signal handler.
*/
regs->regs[0] = usig;
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
regs->regs[1] = (unsigned long)&user->sigframe->info;
regs->regs[2] = (unsigned long)&user->sigframe->uc;
}
regs->sp = (unsigned long)user->sigframe;
regs->regs[29] = (unsigned long)&user->next_frame->fp;
regs->regs[30] = (unsigned long)sigtramp;
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
/*
* Signal delivery is a (wacky) indirect function call in
* userspace, so simulate the same setting of BTYPE as a BLR
* <register containing the signal handler entry point>.
* Signal delivery to a location in a PROT_BTI guarded page
* that is not a function entry point will now trigger a
* SIGILL in userspace.
*
* If the signal handler entry point is not in a PROT_BTI
* guarded page, this is harmless.
*/
if (system_supports_bti()) {
regs->pstate &= ~PSR_BTYPE_MASK;
regs->pstate |= PSR_BTYPE_C;
}
/* TCO (Tag Check Override) always cleared for signal handlers */
regs->pstate &= ~PSR_TCO_BIT;
/* Signal handlers are invoked with ZA and streaming mode disabled */
if (system_supports_sme()) {
task_smstop_sm(current);
current->thread.svcr &= ~SVCR_ZA_MASK;
write_sysreg_s(0, SYS_TPIDR2_EL0);
}
return 0;
}
static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe_user_layout user;
struct rt_sigframe __user *frame;
struct user_access_state ua_state = {};
int err = 0;
fpsimd_save_and_flush_current_state();
if (get_sigframe(&user, ksig, regs))
return 1;
save_reset_user_access_state(&ua_state);
frame = user.sigframe;
__put_user_error(0, &frame->uc.uc_flags, err);
__put_user_error(NULL, &frame->uc.uc_link, err);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigframe(&user, regs, set, &ua_state);
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
if (err == 0)
err = setup_return(regs, ksig, &user, usig);
/*
* We must not fail if setup_return() succeeded - see comment at the
* beginning of setup_return().
*/
if (err == 0)
set_handler_user_access_state();
else
restore_user_access_state(&ua_state);
return err;
}
static void setup_restart_syscall(struct pt_regs *regs)
{
if (is_compat_task())
compat_setup_restart_syscall(regs);
else
regs->regs[8] = __NR_restart_syscall;
}
/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int usig = ksig->sig;
int ret;
rseq_signal_deliver(ksig, regs);
/*
* Set up the stack frame
*/
if (is_compat_task()) {
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
ret = compat_setup_rt_frame(usig, ksig, oldset, regs);
else
ret = compat_setup_frame(usig, ksig, oldset, regs);
} else {
ret = setup_rt_frame(usig, ksig, oldset, regs);
}
/*
* Check that the resulting registers are actually sane.
*/
ret |= !valid_user_regs(®s->user_regs, current);
/* Step into the signal handler if we are stepping */
signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
void arch_do_signal_or_restart(struct pt_regs *regs)
{
unsigned long continue_addr = 0, restart_addr = 0;
int retval = 0;
struct ksignal ksig;
bool syscall = in_syscall(regs);
/*
* If we were from a system call, check for system call restarting...
*/
if (syscall) {
continue_addr = regs->pc;
restart_addr = continue_addr - (compat_thumb_mode(regs) ? 2 : 4);
retval = regs->regs[0];
/*
* Avoid additional syscall restarting via ret_to_user.
*/
forget_syscall(regs);
/*
* Prepare for system call restart. We do this here so that a
* debugger will see the already changed PC.
*/
switch (retval) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTART_RESTARTBLOCK:
regs->regs[0] = regs->orig_x0;
regs->pc = restart_addr;
break;
}
}
/*
* Get the signal to deliver. When running under ptrace, at this point
* the debugger may change all of our registers.
*/
if (get_signal(&ksig)) {
/*
* Depending on the signal settings, we may need to revert the
* decision to restart the system call, but skip this if a
* debugger has chosen to restart at a different PC.
*/
if (regs->pc == restart_addr &&
(retval == -ERESTARTNOHAND ||
retval == -ERESTART_RESTARTBLOCK ||
(retval == -ERESTARTSYS &&
!(ksig.ka.sa.sa_flags & SA_RESTART)))) {
syscall_set_return_value(current, regs, -EINTR, 0);
regs->pc = continue_addr;
}
handle_signal(&ksig, regs);
return;
}
/*
* Handle restarting a different system call. As above, if a debugger
* has chosen to restart at a different PC, ignore the restart.
*/
if (syscall && regs->pc == restart_addr) {
if (retval == -ERESTART_RESTARTBLOCK)
setup_restart_syscall(regs);
user_rewind_single_step(current);
}
restore_saved_sigmask();
}
unsigned long __ro_after_init signal_minsigstksz;
/*
* Determine the stack space required for guaranteed signal devliery.
* This function is used to populate AT_MINSIGSTKSZ at process startup.
* cpufeatures setup is assumed to be complete.
*/
void __init minsigstksz_setup(void)
{
struct rt_sigframe_user_layout user;
init_user_layout(&user);
/*
* If this fails, SIGFRAME_MAXSZ needs to be enlarged. It won't
* be big enough, but it's our best guess:
*/
if (WARN_ON(setup_sigframe_layout(&user, true)))
return;
signal_minsigstksz = sigframe_size(&user) +
round_up(sizeof(struct frame_record), 16) +
16; /* max alignment padding */
}
/*
* Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
* changes likely come with new fields that should be added below.
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
static_assert(NSIGSYS == 2);
static_assert(sizeof(siginfo_t) == 128);
static_assert(__alignof__(siginfo_t) == 8);
static_assert(offsetof(siginfo_t, si_signo) == 0x00);
static_assert(offsetof(siginfo_t, si_errno) == 0x04);
static_assert(offsetof(siginfo_t, si_code) == 0x08);
static_assert(offsetof(siginfo_t, si_pid) == 0x10);
static_assert(offsetof(siginfo_t, si_uid) == 0x14);
static_assert(offsetof(siginfo_t, si_tid) == 0x10);
static_assert(offsetof(siginfo_t, si_overrun) == 0x14);
static_assert(offsetof(siginfo_t, si_status) == 0x18);
static_assert(offsetof(siginfo_t, si_utime) == 0x20);
static_assert(offsetof(siginfo_t, si_stime) == 0x28);
static_assert(offsetof(siginfo_t, si_value) == 0x18);
static_assert(offsetof(siginfo_t, si_int) == 0x18);
static_assert(offsetof(siginfo_t, si_ptr) == 0x18);
static_assert(offsetof(siginfo_t, si_addr) == 0x10);
static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x18);
static_assert(offsetof(siginfo_t, si_lower) == 0x20);
static_assert(offsetof(siginfo_t, si_upper) == 0x28);
static_assert(offsetof(siginfo_t, si_pkey) == 0x20);
static_assert(offsetof(siginfo_t, si_perf_data) == 0x18);
static_assert(offsetof(siginfo_t, si_perf_type) == 0x20);
static_assert(offsetof(siginfo_t, si_perf_flags) == 0x24);
static_assert(offsetof(siginfo_t, si_band) == 0x10);
static_assert(offsetof(siginfo_t, si_fd) == 0x18);
static_assert(offsetof(siginfo_t, si_call_addr) == 0x10);
static_assert(offsetof(siginfo_t, si_syscall) == 0x18);
static_assert(offsetof(siginfo_t, si_arch) == 0x1c);
