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qemu/linux-user/aarch64/signal.c
Richard Henderson ddc3e74d9c linux-user: Pass CPUArchState to target_restore_altstack 
In most cases we were already passing get_sp_from_cpustate
directly to the function.  In other cases, we were passing
a local variable which already contained the same value.
In the rest of the cases, we were passing the stack pointer
out of env directly.

Reviewed by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210426025334.1168495-5-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-15 21:43:23 +02:00

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/*
* Emulation of Linux signals
*
* Copyright (c) 2003 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "signal-common.h"
#include "linux-user/trace.h"
struct target_sigcontext {
uint64_t fault_address;
/* AArch64 registers */
uint64_t regs[31];
uint64_t sp;
uint64_t pc;
uint64_t pstate;
/* 4K reserved for FP/SIMD state and future expansion */
char __reserved[4096] __attribute__((__aligned__(16)));
};
struct target_ucontext {
abi_ulong tuc_flags;
abi_ulong tuc_link;
target_stack_t tuc_stack;
target_sigset_t tuc_sigmask;
/* glibc uses a 1024-bit sigset_t */
char __unused[1024 / 8 - sizeof(target_sigset_t)];
/* last for future expansion */
struct target_sigcontext tuc_mcontext;
};
/*
* Header to be used at the beginning of structures extending the user
* context. Such structures must be placed after the rt_sigframe on the stack
* and be 16-byte aligned. The last structure must be a dummy one with the
* magic and size set to 0.
*/
struct target_aarch64_ctx {
uint32_t magic;
uint32_t size;
};
#define TARGET_FPSIMD_MAGIC 0x46508001
struct target_fpsimd_context {
struct target_aarch64_ctx head;
uint32_t fpsr;
uint32_t fpcr;
uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */
};
#define TARGET_EXTRA_MAGIC 0x45585401
struct target_extra_context {
struct target_aarch64_ctx head;
uint64_t datap; /* 16-byte aligned pointer to extra space cast to __u64 */
uint32_t size; /* size in bytes of the extra space */
uint32_t reserved[3];
};
#define TARGET_SVE_MAGIC 0x53564501
struct target_sve_context {
struct target_aarch64_ctx head;
uint16_t vl;
uint16_t reserved[3];
/* The actual SVE data immediately follows. It is laid out
* according to TARGET_SVE_SIG_{Z,P}REG_OFFSET, based off of
* the original struct pointer.
*/
};
#define TARGET_SVE_VQ_BYTES 16
#define TARGET_SVE_SIG_ZREG_SIZE(VQ) ((VQ) * TARGET_SVE_VQ_BYTES)
#define TARGET_SVE_SIG_PREG_SIZE(VQ) ((VQ) * (TARGET_SVE_VQ_BYTES / 8))
#define TARGET_SVE_SIG_REGS_OFFSET \
QEMU_ALIGN_UP(sizeof(struct target_sve_context), TARGET_SVE_VQ_BYTES)
#define TARGET_SVE_SIG_ZREG_OFFSET(VQ, N) \
(TARGET_SVE_SIG_REGS_OFFSET + TARGET_SVE_SIG_ZREG_SIZE(VQ) * (N))
#define TARGET_SVE_SIG_PREG_OFFSET(VQ, N) \
(TARGET_SVE_SIG_ZREG_OFFSET(VQ, 32) + TARGET_SVE_SIG_PREG_SIZE(VQ) * (N))
#define TARGET_SVE_SIG_FFR_OFFSET(VQ) \
(TARGET_SVE_SIG_PREG_OFFSET(VQ, 16))
#define TARGET_SVE_SIG_CONTEXT_SIZE(VQ) \
(TARGET_SVE_SIG_PREG_OFFSET(VQ, 17))
struct target_rt_sigframe {
struct target_siginfo info;
struct target_ucontext uc;
};
struct target_rt_frame_record {
uint64_t fp;
uint64_t lr;
uint32_t tramp[2];
};
static void target_setup_general_frame(struct target_rt_sigframe *sf,
CPUARMState *env, target_sigset_t *set)
{
int i;
__put_user(0, &sf->uc.tuc_flags);
__put_user(0, &sf->uc.tuc_link);
target_save_altstack(&sf->uc.tuc_stack, env);
for (i = 0; i < 31; i++) {
__put_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
}
__put_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
__put_user(env->pc, &sf->uc.tuc_mcontext.pc);
__put_user(pstate_read(env), &sf->uc.tuc_mcontext.pstate);
__put_user(env->exception.vaddress, &sf->uc.tuc_mcontext.fault_address);
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &sf->uc.tuc_sigmask.sig[i]);
}
}
static void target_setup_fpsimd_record(struct target_fpsimd_context *fpsimd,
CPUARMState *env)
{
int i;
__put_user(TARGET_FPSIMD_MAGIC, &fpsimd->head.magic);
__put_user(sizeof(struct target_fpsimd_context), &fpsimd->head.size);
__put_user(vfp_get_fpsr(env), &fpsimd->fpsr);
__put_user(vfp_get_fpcr(env), &fpsimd->fpcr);
for (i = 0; i < 32; i++) {
uint64_t *q = aa64_vfp_qreg(env, i);
#ifdef TARGET_WORDS_BIGENDIAN
__put_user(q[0], &fpsimd->vregs[i * 2 + 1]);
__put_user(q[1], &fpsimd->vregs[i * 2]);
#else
__put_user(q[0], &fpsimd->vregs[i * 2]);
__put_user(q[1], &fpsimd->vregs[i * 2 + 1]);
#endif
}
}
static void target_setup_extra_record(struct target_extra_context *extra,
uint64_t datap, uint32_t extra_size)
{
__put_user(TARGET_EXTRA_MAGIC, &extra->head.magic);
__put_user(sizeof(struct target_extra_context), &extra->head.size);
__put_user(datap, &extra->datap);
__put_user(extra_size, &extra->size);
}
static void target_setup_end_record(struct target_aarch64_ctx *end)
{
__put_user(0, &end->magic);
__put_user(0, &end->size);
}
static void target_setup_sve_record(struct target_sve_context *sve,
CPUARMState *env, int vq, int size)
{
int i, j;
__put_user(TARGET_SVE_MAGIC, &sve->head.magic);
__put_user(size, &sve->head.size);
__put_user(vq * TARGET_SVE_VQ_BYTES, &sve->vl);
/* Note that SVE regs are stored as a byte stream, with each byte element
* at a subsequent address. This corresponds to a little-endian store
* of our 64-bit hunks.
*/
for (i = 0; i < 32; ++i) {
uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
for (j = 0; j < vq * 2; ++j) {
__put_user_e(env->vfp.zregs[i].d[j], z + j, le);
}
}
for (i = 0; i <= 16; ++i) {
uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
for (j = 0; j < vq; ++j) {
uint64_t r = env->vfp.pregs[i].p[j >> 2];
__put_user_e(r >> ((j & 3) * 16), p + j, le);
}
}
}
static void target_restore_general_frame(CPUARMState *env,
struct target_rt_sigframe *sf)
{
sigset_t set;
uint64_t pstate;
int i;
target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
set_sigmask(&set);
for (i = 0; i < 31; i++) {
__get_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
}
__get_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
__get_user(env->pc, &sf->uc.tuc_mcontext.pc);
__get_user(pstate, &sf->uc.tuc_mcontext.pstate);
pstate_write(env, pstate);
}
static void target_restore_fpsimd_record(CPUARMState *env,
struct target_fpsimd_context *fpsimd)
{
uint32_t fpsr, fpcr;
int i;
__get_user(fpsr, &fpsimd->fpsr);
vfp_set_fpsr(env, fpsr);
__get_user(fpcr, &fpsimd->fpcr);
vfp_set_fpcr(env, fpcr);
for (i = 0; i < 32; i++) {
uint64_t *q = aa64_vfp_qreg(env, i);
#ifdef TARGET_WORDS_BIGENDIAN
__get_user(q[0], &fpsimd->vregs[i * 2 + 1]);
__get_user(q[1], &fpsimd->vregs[i * 2]);
#else
__get_user(q[0], &fpsimd->vregs[i * 2]);
__get_user(q[1], &fpsimd->vregs[i * 2 + 1]);
#endif
}
}
static void target_restore_sve_record(CPUARMState *env,
struct target_sve_context *sve, int vq)
{
int i, j;
/* Note that SVE regs are stored as a byte stream, with each byte element
* at a subsequent address. This corresponds to a little-endian load
* of our 64-bit hunks.
*/
for (i = 0; i < 32; ++i) {
uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
for (j = 0; j < vq * 2; ++j) {
__get_user_e(env->vfp.zregs[i].d[j], z + j, le);
}
}
for (i = 0; i <= 16; ++i) {
uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
for (j = 0; j < vq; ++j) {
uint16_t r;
__get_user_e(r, p + j, le);
if (j & 3) {
env->vfp.pregs[i].p[j >> 2] |= (uint64_t)r << ((j & 3) * 16);
} else {
env->vfp.pregs[i].p[j >> 2] = r;
}
}
}
}
static int target_restore_sigframe(CPUARMState *env,
struct target_rt_sigframe *sf)
{
struct target_aarch64_ctx *ctx, *extra = NULL;
struct target_fpsimd_context *fpsimd = NULL;
struct target_sve_context *sve = NULL;
uint64_t extra_datap = 0;
bool used_extra = false;
bool err = false;
int vq = 0, sve_size = 0;
target_restore_general_frame(env, sf);
ctx = (struct target_aarch64_ctx *)sf->uc.tuc_mcontext.__reserved;
while (ctx) {
uint32_t magic, size, extra_size;
__get_user(magic, &ctx->magic);
__get_user(size, &ctx->size);
switch (magic) {
case 0:
if (size != 0) {
err = true;
goto exit;
}
if (used_extra) {
ctx = NULL;
} else {
ctx = extra;
used_extra = true;
}
continue;
case TARGET_FPSIMD_MAGIC:
if (fpsimd || size != sizeof(struct target_fpsimd_context)) {
err = true;
goto exit;
}
fpsimd = (struct target_fpsimd_context *)ctx;
break;
case TARGET_SVE_MAGIC:
if (cpu_isar_feature(aa64_sve, env_archcpu(env))) {
vq = (env->vfp.zcr_el[1] & 0xf) + 1;
sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
if (!sve && size == sve_size) {
sve = (struct target_sve_context *)ctx;
break;
}
}
err = true;
goto exit;
case TARGET_EXTRA_MAGIC:
if (extra || size != sizeof(struct target_extra_context)) {
err = true;
goto exit;
}
__get_user(extra_datap,
&((struct target_extra_context *)ctx)->datap);
__get_user(extra_size,
&((struct target_extra_context *)ctx)->size);
extra = lock_user(VERIFY_READ, extra_datap, extra_size, 0);
break;
default:
/* Unknown record -- we certainly didn't generate it.
* Did we in fact get out of sync?
*/
err = true;
goto exit;
}
ctx = (void *)ctx + size;
}
/* Require FPSIMD always. */
if (fpsimd) {
target_restore_fpsimd_record(env, fpsimd);
} else {
err = true;
}
/* SVE data, if present, overwrites FPSIMD data. */
if (sve) {
target_restore_sve_record(env, sve, vq);
}
exit:
unlock_user(extra, extra_datap, 0);
return err;
}
static abi_ulong get_sigframe(struct target_sigaction *ka,
CPUARMState *env, int size)
{
abi_ulong sp;
sp = target_sigsp(get_sp_from_cpustate(env), ka);
sp = (sp - size) & ~15;
return sp;
}
typedef struct {
int total_size;
int extra_base;
int extra_size;
int std_end_ofs;
int extra_ofs;
int extra_end_ofs;
} target_sigframe_layout;
static int alloc_sigframe_space(int this_size, target_sigframe_layout *l)
{
/* Make sure there will always be space for the end marker. */
const int std_size = sizeof(struct target_rt_sigframe)
- sizeof(struct target_aarch64_ctx);
int this_loc = l->total_size;
if (l->extra_base) {
/* Once we have begun an extra space, all allocations go there. */
l->extra_size += this_size;
} else if (this_size + this_loc > std_size) {
/* This allocation does not fit in the standard space. */
/* Allocate the extra record. */
l->extra_ofs = this_loc;
l->total_size += sizeof(struct target_extra_context);
/* Allocate the standard end record. */
l->std_end_ofs = l->total_size;
l->total_size += sizeof(struct target_aarch64_ctx);
/* Allocate the requested record. */
l->extra_base = this_loc = l->total_size;
l->extra_size = this_size;
}
l->total_size += this_size;
return this_loc;
}
static void target_setup_frame(int usig, struct target_sigaction *ka,
target_siginfo_t *info, target_sigset_t *set,
CPUARMState *env)
{
target_sigframe_layout layout = {
/* Begin with the size pointing to the reserved space. */
.total_size = offsetof(struct target_rt_sigframe,
uc.tuc_mcontext.__reserved),
};
int fpsimd_ofs, fr_ofs, sve_ofs = 0, vq = 0, sve_size = 0;
struct target_rt_sigframe *frame;
struct target_rt_frame_record *fr;
abi_ulong frame_addr, return_addr;
/* FPSIMD record is always in the standard space. */
fpsimd_ofs = alloc_sigframe_space(sizeof(struct target_fpsimd_context),
&layout);
/* SVE state needs saving only if it exists. */
if (cpu_isar_feature(aa64_sve, env_archcpu(env))) {
vq = (env->vfp.zcr_el[1] & 0xf) + 1;
sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
sve_ofs = alloc_sigframe_space(sve_size, &layout);
}
if (layout.extra_ofs) {
/* Reserve space for the extra end marker. The standard end marker
* will have been allocated when we allocated the extra record.
*/
layout.extra_end_ofs
= alloc_sigframe_space(sizeof(struct target_aarch64_ctx), &layout);
} else {
/* Reserve space for the standard end marker.
* Do not use alloc_sigframe_space because we cheat
* std_size therein to reserve space for this.
*/
layout.std_end_ofs = layout.total_size;
layout.total_size += sizeof(struct target_aarch64_ctx);
}
/* We must always provide at least the standard 4K reserved space,
* even if we don't use all of it (this is part of the ABI)
*/
layout.total_size = MAX(layout.total_size,
sizeof(struct target_rt_sigframe));
/* Reserve space for the return code. On a real system this would
* be within the VDSO. So, despite the name this is not a "real"
* record within the frame.
*/
fr_ofs = layout.total_size;
layout.total_size += sizeof(struct target_rt_frame_record);
frame_addr = get_sigframe(ka, env, layout.total_size);
trace_user_setup_frame(env, frame_addr);
frame = lock_user(VERIFY_WRITE, frame_addr, layout.total_size, 0);
if (!frame) {
goto give_sigsegv;
}
target_setup_general_frame(frame, env, set);
target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env);
target_setup_end_record((void *)frame + layout.std_end_ofs);
if (layout.extra_ofs) {
target_setup_extra_record((void *)frame + layout.extra_ofs,
frame_addr + layout.extra_base,
layout.extra_size);
target_setup_end_record((void *)frame + layout.extra_end_ofs);
}
if (sve_ofs) {
target_setup_sve_record((void *)frame + sve_ofs, env, vq, sve_size);
}
/* Set up the stack frame for unwinding. */
fr = (void *)frame + fr_ofs;
__put_user(env->xregs[29], &fr->fp);
__put_user(env->xregs[30], &fr->lr);
if (ka->sa_flags & TARGET_SA_RESTORER) {
return_addr = ka->sa_restorer;
} else {
/*
* mov x8,#__NR_rt_sigreturn; svc #0
* Since these are instructions they need to be put as little-endian
* regardless of target default or current CPU endianness.
*/
__put_user_e(0xd2801168, &fr->tramp[0], le);
__put_user_e(0xd4000001, &fr->tramp[1], le);
return_addr = frame_addr + fr_ofs
+ offsetof(struct target_rt_frame_record, tramp);
}
env->xregs[0] = usig;
env->xregs[29] = frame_addr + fr_ofs;
env->xregs[30] = return_addr;
env->xregs[31] = frame_addr;
env->pc = ka->_sa_handler;
/* Invoke the signal handler as if by indirect call. */
if (cpu_isar_feature(aa64_bti, env_archcpu(env))) {
env->btype = 2;
}
if (info) {
tswap_siginfo(&frame->info, info);
env->xregs[1] = frame_addr + offsetof(struct target_rt_sigframe, info);
env->xregs[2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
}
unlock_user(frame, frame_addr, layout.total_size);
return;
give_sigsegv:
unlock_user(frame, frame_addr, layout.total_size);
force_sigsegv(usig);
}
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info, target_sigset_t *set,
CPUARMState *env)
{
target_setup_frame(sig, ka, info, set, env);
}
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUARMState *env)
{
target_setup_frame(sig, ka, 0, set, env);
}
long do_rt_sigreturn(CPUARMState *env)
{
struct target_rt_sigframe *frame = NULL;
abi_ulong frame_addr = env->xregs[31];
trace_user_do_rt_sigreturn(env, frame_addr);
if (frame_addr & 15) {
goto badframe;
}
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
goto badframe;
}
if (target_restore_sigframe(env, frame)) {
goto badframe;
}
target_restore_altstack(&frame->uc.tuc_stack, env);
unlock_user_struct(frame, frame_addr, 0);
return -TARGET_QEMU_ESIGRETURN;
badframe:
unlock_user_struct(frame, frame_addr, 0);
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}
long do_sigreturn(CPUARMState *env)
{
return do_rt_sigreturn(env);
}
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