mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
975 lines
24 KiB
975 lines
24 KiB
// 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/kernel.h> |
|
#include <linux/signal.h> |
|
#include <linux/personality.h> |
|
#include <linux/freezer.h> |
|
#include <linux/stddef.h> |
|
#include <linux/uaccess.h> |
|
#include <linux/sizes.h> |
|
#include <linux/string.h> |
|
#include <linux/tracehook.h> |
|
#include <linux/ratelimit.h> |
|
#include <linux/syscalls.h> |
|
|
|
#include <asm/daifflags.h> |
|
#include <asm/debug-monitors.h> |
|
#include <asm/elf.h> |
|
#include <asm/cacheflush.h> |
|
#include <asm/ucontext.h> |
|
#include <asm/unistd.h> |
|
#include <asm/fpsimd.h> |
|
#include <asm/ptrace.h> |
|
#include <asm/signal32.h> |
|
#include <asm/traps.h> |
|
#include <asm/vdso.h> |
|
|
|
/* |
|
* Do a signal return; undo the signal stack. These are aligned to 128-bit. |
|
*/ |
|
struct rt_sigframe { |
|
struct siginfo info; |
|
struct ucontext uc; |
|
}; |
|
|
|
struct frame_record { |
|
u64 fp; |
|
u64 lr; |
|
}; |
|
|
|
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 sve_offset; |
|
unsigned long extra_offset; |
|
unsigned long end_offset; |
|
}; |
|
|
|
#define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16) |
|
#define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16) |
|
#define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16) |
|
|
|
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_64K |
|
|
|
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; |
|
} |
|
|
|
static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) |
|
{ |
|
struct user_fpsimd_state const *fpsimd = |
|
¤t->thread.uw.fpsimd_state; |
|
int err; |
|
|
|
/* 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 restore_fpsimd_context(struct fpsimd_context __user *ctx) |
|
{ |
|
struct user_fpsimd_state fpsimd; |
|
__u32 magic, size; |
|
int err = 0; |
|
|
|
/* check the magic/size information */ |
|
__get_user_error(magic, &ctx->head.magic, err); |
|
__get_user_error(size, &ctx->head.size, err); |
|
if (err) |
|
return -EFAULT; |
|
if (magic != FPSIMD_MAGIC || size != sizeof(struct fpsimd_context)) |
|
return -EINVAL; |
|
|
|
/* copy the FP and status/control registers */ |
|
err = __copy_from_user(fpsimd.vregs, ctx->vregs, |
|
sizeof(fpsimd.vregs)); |
|
__get_user_error(fpsimd.fpsr, &ctx->fpsr, err); |
|
__get_user_error(fpsimd.fpcr, &ctx->fpcr, err); |
|
|
|
clear_thread_flag(TIF_SVE); |
|
|
|
/* load the hardware registers from the fpsimd_state structure */ |
|
if (!err) |
|
fpsimd_update_current_state(&fpsimd); |
|
|
|
return err ? -EFAULT : 0; |
|
} |
|
|
|
|
|
struct user_ctxs { |
|
struct fpsimd_context __user *fpsimd; |
|
struct sve_context __user *sve; |
|
}; |
|
|
|
#ifdef CONFIG_ARM64_SVE |
|
|
|
static int preserve_sve_context(struct sve_context __user *ctx) |
|
{ |
|
int err = 0; |
|
u16 reserved[ARRAY_SIZE(ctx->__reserved)]; |
|
unsigned int vl = current->thread.sve_vl; |
|
unsigned int vq = 0; |
|
|
|
if (test_thread_flag(TIF_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); |
|
BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved)); |
|
err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved)); |
|
|
|
if (vq) { |
|
/* |
|
* This assumes that the SVE state has already been saved to |
|
* the task struct by calling the function |
|
* fpsimd_signal_preserve_current_state(). |
|
*/ |
|
err |= __copy_to_user((char __user *)ctx + 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; |
|
unsigned int vq; |
|
struct user_fpsimd_state fpsimd; |
|
struct sve_context sve; |
|
|
|
if (__copy_from_user(&sve, user->sve, sizeof(sve))) |
|
return -EFAULT; |
|
|
|
if (sve.vl != current->thread.sve_vl) |
|
return -EINVAL; |
|
|
|
if (sve.head.size <= sizeof(*user->sve)) { |
|
clear_thread_flag(TIF_SVE); |
|
goto fpsimd_only; |
|
} |
|
|
|
vq = sve_vq_from_vl(sve.vl); |
|
|
|
if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq)) |
|
return -EINVAL; |
|
|
|
/* |
|
* Careful: we are about __copy_from_user() directly into |
|
* thread.sve_state with preemption enabled, so protection is |
|
* needed to prevent a racing context switch from writing stale |
|
* registers back over the new data. |
|
*/ |
|
|
|
fpsimd_flush_task_state(current); |
|
/* From now, fpsimd_thread_switch() won't touch thread.sve_state */ |
|
|
|
sve_alloc(current); |
|
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; |
|
|
|
set_thread_flag(TIF_SVE); |
|
|
|
fpsimd_only: |
|
/* copy the FP and status/control registers */ |
|
/* restore_sigframe() already checked that user->fpsimd != NULL. */ |
|
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); |
|
|
|
/* load the hardware registers from the fpsimd_state structure */ |
|
if (!err) |
|
fpsimd_update_current_state(&fpsimd); |
|
|
|
return err ? -EFAULT : 0; |
|
} |
|
|
|
#else /* ! CONFIG_ARM64_SVE */ |
|
|
|
/* Turn any non-optimised out attempts to use these into a link error: */ |
|
extern int preserve_sve_context(void __user *ctx); |
|
extern int restore_sve_fpsimd_context(struct user_ctxs *user); |
|
|
|
#endif /* ! CONFIG_ARM64_SVE */ |
|
|
|
|
|
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; |
|
|
|
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; |
|
|
|
if (size < sizeof(*user->fpsimd)) |
|
goto invalid; |
|
|
|
user->fpsimd = (struct fpsimd_context __user *)head; |
|
break; |
|
|
|
case ESR_MAGIC: |
|
/* ignore */ |
|
break; |
|
|
|
case SVE_MAGIC: |
|
if (!system_supports_sve()) |
|
goto invalid; |
|
|
|
if (user->sve) |
|
goto invalid; |
|
|
|
if (size < sizeof(*user->sve)) |
|
goto invalid; |
|
|
|
user->sve = (struct sve_context __user *)head; |
|
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) |
|
{ |
|
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); |
|
|
|
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) { |
|
if (!system_supports_sve()) |
|
return -EINVAL; |
|
|
|
err = restore_sve_fpsimd_context(&user); |
|
} else { |
|
err = restore_fpsimd_context(user.fpsimd); |
|
} |
|
} |
|
|
|
return err; |
|
} |
|
|
|
SYSCALL_DEFINE0(rt_sigreturn) |
|
{ |
|
struct pt_regs *regs = current_pt_regs(); |
|
struct rt_sigframe __user *frame; |
|
|
|
/* 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)) |
|
goto badframe; |
|
|
|
if (restore_altstack(&frame->uc.uc_stack)) |
|
goto badframe; |
|
|
|
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; |
|
|
|
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; |
|
} |
|
|
|
if (system_supports_sve()) { |
|
unsigned int vq = 0; |
|
|
|
if (add_all || test_thread_flag(TIF_SVE)) { |
|
int vl = sve_max_vl; |
|
|
|
if (!add_all) |
|
vl = current->thread.sve_vl; |
|
|
|
vq = sve_vq_from_vl(vl); |
|
} |
|
|
|
err = sigframe_alloc(user, &user->sve_offset, |
|
SVE_SIG_CONTEXT_SIZE(vq)); |
|
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) |
|
{ |
|
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); |
|
} |
|
|
|
/* Scalable Vector Extension state, if present */ |
|
if (system_supports_sve() && err == 0 && user->sve_offset) { |
|
struct sve_context __user *sve_ctx = |
|
apply_user_offset(user, user->sve_offset); |
|
err |= preserve_sve_context(sve_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; |
|
} |
|
|
|
static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, |
|
struct rt_sigframe_user_layout *user, int usig) |
|
{ |
|
__sigrestore_t sigtramp; |
|
|
|
regs->regs[0] = usig; |
|
regs->sp = (unsigned long)user->sigframe; |
|
regs->regs[29] = (unsigned long)&user->next_frame->fp; |
|
regs->pc = (unsigned long)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; |
|
|
|
if (ka->sa.sa_flags & SA_RESTORER) |
|
sigtramp = ka->sa.sa_restorer; |
|
else |
|
sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp); |
|
|
|
regs->regs[30] = (unsigned long)sigtramp; |
|
} |
|
|
|
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; |
|
int err = 0; |
|
|
|
fpsimd_signal_preserve_current_state(); |
|
|
|
if (get_sigframe(&user, ksig, regs)) |
|
return 1; |
|
|
|
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); |
|
if (err == 0) { |
|
setup_return(regs, &ksig->ka, &user, usig); |
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
|
err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
|
regs->regs[1] = (unsigned long)&frame->info; |
|
regs->regs[2] = (unsigned long)&frame->uc; |
|
} |
|
} |
|
|
|
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. |
|
*/ |
|
static void do_signal(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)))) { |
|
regs->regs[0] = -EINTR; |
|
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(); |
|
} |
|
|
|
asmlinkage void do_notify_resume(struct pt_regs *regs, |
|
unsigned long thread_flags) |
|
{ |
|
do { |
|
if (thread_flags & _TIF_NEED_RESCHED) { |
|
/* Unmask Debug and SError for the next task */ |
|
local_daif_restore(DAIF_PROCCTX_NOIRQ); |
|
|
|
schedule(); |
|
} else { |
|
local_daif_restore(DAIF_PROCCTX); |
|
|
|
if (thread_flags & _TIF_UPROBE) |
|
uprobe_notify_resume(regs); |
|
|
|
if (thread_flags & _TIF_MTE_ASYNC_FAULT) { |
|
clear_thread_flag(TIF_MTE_ASYNC_FAULT); |
|
send_sig_fault(SIGSEGV, SEGV_MTEAERR, |
|
(void __user *)NULL, current); |
|
} |
|
|
|
if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) |
|
do_signal(regs); |
|
|
|
if (thread_flags & _TIF_NOTIFY_RESUME) { |
|
tracehook_notify_resume(regs); |
|
rseq_handle_notify_resume(NULL, regs); |
|
} |
|
|
|
if (thread_flags & _TIF_FOREIGN_FPSTATE) |
|
fpsimd_restore_current_state(); |
|
} |
|
|
|
local_daif_mask(); |
|
thread_flags = READ_ONCE(current_thread_info()->flags); |
|
} while (thread_flags & _TIF_WORK_MASK); |
|
} |
|
|
|
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 */ |
|
}
|
|
|