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qemu-e2k/linux-user/xtensa/signal.c
Max Filippov 1b173d0606 linux-user: xtensa: fix signal delivery in FDPIC 
In FDPIC signal handlers are passed around as FD pointers. Actual code
address and GOT pointer must be fetched from memory by the QEMU code
that implements kernel signal delivery functionality. This change is
equivalent to the following kernel change:
9c2cc74fb31e ("xtensa: fix signal delivery to FDPIC process")

Cc: qemu-stable@nongnu.org
Fixes: d2796be69d ("linux-user: add support for xtensa FDPIC")
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2023-11-19 10:56:26 -08:00

307 lines
8.6 KiB
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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 "user-internals.h"
#include "signal-common.h"
#include "linux-user/trace.h"
struct target_sigcontext {
abi_ulong sc_pc;
abi_ulong sc_ps;
abi_ulong sc_lbeg;
abi_ulong sc_lend;
abi_ulong sc_lcount;
abi_ulong sc_sar;
abi_ulong sc_acclo;
abi_ulong sc_acchi;
abi_ulong sc_a[16];
abi_ulong sc_xtregs;
};
struct target_ucontext {
abi_ulong tuc_flags;
abi_ulong tuc_link;
target_stack_t tuc_stack;
struct target_sigcontext tuc_mcontext;
target_sigset_t tuc_sigmask;
};
struct target_rt_sigframe {
target_siginfo_t info;
struct target_ucontext uc;
/* TODO: xtregs */
uint8_t retcode[6];
abi_ulong window[4];
};
static abi_ulong get_sigframe(struct target_sigaction *sa,
CPUXtensaState *env,
unsigned long framesize)
{
abi_ulong sp;
sp = target_sigsp(get_sp_from_cpustate(env), sa);
return (sp - framesize) & -16;
}
static int flush_window_regs(CPUXtensaState *env)
{
uint32_t wb = env->sregs[WINDOW_BASE];
uint32_t ws = xtensa_replicate_windowstart(env) >> (wb + 1);
unsigned d = ctz32(ws) + 1;
unsigned i;
int ret = 0;
for (i = d; i < env->config->nareg / 4; i += d) {
uint32_t ssp, osp;
unsigned j;
ws >>= d;
xtensa_rotate_window(env, d);
if (ws & 0x1) {
ssp = env->regs[5];
d = 1;
} else if (ws & 0x2) {
ssp = env->regs[9];
ret |= get_user_ual(osp, env->regs[1] - 12);
osp -= 32;
d = 2;
} else if (ws & 0x4) {
ssp = env->regs[13];
ret |= get_user_ual(osp, env->regs[1] - 12);
osp -= 48;
d = 3;
} else {
g_assert_not_reached();
}
for (j = 0; j < 4; ++j) {
ret |= put_user_ual(env->regs[j], ssp - 16 + j * 4);
}
for (j = 4; j < d * 4; ++j) {
ret |= put_user_ual(env->regs[j], osp - 16 + j * 4);
}
}
xtensa_rotate_window(env, d);
g_assert(env->sregs[WINDOW_BASE] == wb);
return ret == 0;
}
static int setup_sigcontext(struct target_rt_sigframe *frame,
CPUXtensaState *env)
{
struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
int i;
__put_user(env->pc, &sc->sc_pc);
__put_user(env->sregs[PS], &sc->sc_ps);
__put_user(env->sregs[LBEG], &sc->sc_lbeg);
__put_user(env->sregs[LEND], &sc->sc_lend);
__put_user(env->sregs[LCOUNT], &sc->sc_lcount);
if (!flush_window_regs(env)) {
return 0;
}
for (i = 0; i < 16; ++i) {
__put_user(env->regs[i], sc->sc_a + i);
}
__put_user(0, &sc->sc_xtregs);
/* TODO: xtregs */
return 1;
}
static void install_sigtramp(uint8_t *tramp)
{
#if TARGET_BIG_ENDIAN
/* Generate instruction: MOVI a2, __NR_rt_sigreturn */
__put_user(0x22, &tramp[0]);
__put_user(0x0a, &tramp[1]);
__put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
/* Generate instruction: SYSCALL */
__put_user(0x00, &tramp[3]);
__put_user(0x05, &tramp[4]);
__put_user(0x00, &tramp[5]);
#else
/* Generate instruction: MOVI a2, __NR_rt_sigreturn */
__put_user(0x22, &tramp[0]);
__put_user(0xa0, &tramp[1]);
__put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
/* Generate instruction: SYSCALL */
__put_user(0x00, &tramp[3]);
__put_user(0x50, &tramp[4]);
__put_user(0x00, &tramp[5]);
#endif
}
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUXtensaState *env)
{
abi_ulong frame_addr;
struct target_rt_sigframe *frame;
int is_fdpic = info_is_fdpic(((TaskState *)thread_cpu->opaque)->info);
abi_ulong handler = 0;
abi_ulong handler_fdpic_GOT = 0;
uint32_t ra;
bool abi_call0;
unsigned base;
int i;
frame_addr = get_sigframe(ka, env, sizeof(*frame));
trace_user_setup_rt_frame(env, frame_addr);
if (is_fdpic) {
abi_ulong funcdesc_ptr = ka->_sa_handler;
if (get_user_ual(handler, funcdesc_ptr)
|| get_user_ual(handler_fdpic_GOT, funcdesc_ptr + 4)) {
goto give_sigsegv;
}
} else {
handler = ka->_sa_handler;
}
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
}
if (ka->sa_flags & SA_SIGINFO) {
tswap_siginfo(&frame->info, info);
}
__put_user(0, &frame->uc.tuc_flags);
__put_user(0, &frame->uc.tuc_link);
target_save_altstack(&frame->uc.tuc_stack, env);
if (!setup_sigcontext(frame, env)) {
unlock_user_struct(frame, frame_addr, 0);
goto give_sigsegv;
}
for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
__put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
}
if (ka->sa_flags & TARGET_SA_RESTORER) {
if (is_fdpic) {
if (get_user_ual(ra, ka->sa_restorer)) {
unlock_user_struct(frame, frame_addr, 0);
goto give_sigsegv;
}
} else {
ra = ka->sa_restorer;
}
} else {
/* Not used, but retain for ABI compatibility. */
install_sigtramp(frame->retcode);
ra = default_rt_sigreturn;
}
memset(env->regs, 0, sizeof(env->regs));
env->pc = handler;
env->regs[1] = frame_addr;
env->sregs[WINDOW_BASE] = 0;
env->sregs[WINDOW_START] = 1;
abi_call0 = (env->sregs[PS] & PS_WOE) == 0;
env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
if (abi_call0) {
base = 0;
env->regs[base] = ra;
} else {
env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
base = 4;
env->regs[base] = (ra & 0x3fffffff) | 0x40000000;
}
env->regs[base + 2] = sig;
env->regs[base + 3] = frame_addr + offsetof(struct target_rt_sigframe,
info);
env->regs[base + 4] = frame_addr + offsetof(struct target_rt_sigframe, uc);
if (is_fdpic) {
env->regs[base + 11] = handler_fdpic_GOT;
}
unlock_user_struct(frame, frame_addr, 1);
return;
give_sigsegv:
force_sigsegv(sig);
return;
}
static void restore_sigcontext(CPUXtensaState *env,
struct target_rt_sigframe *frame)
{
struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
uint32_t ps;
int i;
__get_user(env->pc, &sc->sc_pc);
__get_user(ps, &sc->sc_ps);
__get_user(env->sregs[LBEG], &sc->sc_lbeg);
__get_user(env->sregs[LEND], &sc->sc_lend);
__get_user(env->sregs[LCOUNT], &sc->sc_lcount);
env->sregs[WINDOW_BASE] = 0;
env->sregs[WINDOW_START] = 1;
env->sregs[PS] = deposit32(env->sregs[PS],
PS_CALLINC_SHIFT,
PS_CALLINC_LEN,
extract32(ps, PS_CALLINC_SHIFT,
PS_CALLINC_LEN));
for (i = 0; i < 16; ++i) {
__get_user(env->regs[i], sc->sc_a + i);
}
/* TODO: xtregs */
}
long do_rt_sigreturn(CPUXtensaState *env)
{
abi_ulong frame_addr = env->regs[1];
struct target_rt_sigframe *frame;
sigset_t set;
trace_user_do_rt_sigreturn(env, frame_addr);
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
goto badframe;
}
target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
set_sigmask(&set);
restore_sigcontext(env, frame);
target_restore_altstack(&frame->uc.tuc_stack, env);
unlock_user_struct(frame, frame_addr, 0);
return -QEMU_ESIGRETURN;
badframe:
unlock_user_struct(frame, frame_addr, 0);
force_sig(TARGET_SIGSEGV);
return -QEMU_ESIGRETURN;
}
void setup_sigtramp(abi_ulong sigtramp_page)
{
uint8_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 6, 0);
assert(tramp != NULL);
default_rt_sigreturn = sigtramp_page;
install_sigtramp(tramp);
unlock_user(tramp, sigtramp_page, 6);
}
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