qemu/linux-user/hppa/signal.c
Peter Maydell 5bfce0b74f linux-user: Make sigaltstack stacks per-thread
The alternate signal stack set up by the sigaltstack syscall is
supposed to be per-thread.  We were incorrectly implementing it as
process-wide.  This causes problems for guest binaries that rely on
this.  Notably the Go runtime does, and so we were seeing crashes
caused by races where two guest threads might incorrectly both
execute on the same stack simultaneously.

Replace the global target_sigaltstack_used with a field
sigaltstack_used in the TaskState, and make all the references to the
old global instead get a pointer to the TaskState and use the field.

Fixes: https://bugs.launchpad.net/qemu/+bug/1696773
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20190725131645.19501-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2019-07-26 19:24:33 +02:00

205 lines
5.8 KiB
C

/*
* 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 {
abi_ulong sc_flags;
abi_ulong sc_gr[32];
uint64_t sc_fr[32];
abi_ulong sc_iasq[2];
abi_ulong sc_iaoq[2];
abi_ulong sc_sar;
};
struct target_ucontext {
abi_uint tuc_flags;
abi_ulong tuc_link;
target_stack_t tuc_stack;
abi_uint pad[1];
struct target_sigcontext tuc_mcontext;
target_sigset_t tuc_sigmask;
};
struct target_rt_sigframe {
abi_uint tramp[9];
target_siginfo_t info;
struct target_ucontext uc;
/* hidden location of upper halves of pa2.0 64-bit gregs */
};
static void setup_sigcontext(struct target_sigcontext *sc, CPUArchState *env)
{
int flags = 0;
int i;
/* ??? if on_sig_stack, flags |= 1 (PARISC_SC_FLAG_ONSTACK). */
if (env->iaoq_f < TARGET_PAGE_SIZE) {
/* In the gateway page, executing a syscall. */
flags |= 2; /* PARISC_SC_FLAG_IN_SYSCALL */
__put_user(env->gr[31], &sc->sc_iaoq[0]);
__put_user(env->gr[31] + 4, &sc->sc_iaoq[1]);
} else {
__put_user(env->iaoq_f, &sc->sc_iaoq[0]);
__put_user(env->iaoq_b, &sc->sc_iaoq[1]);
}
__put_user(0, &sc->sc_iasq[0]);
__put_user(0, &sc->sc_iasq[1]);
__put_user(flags, &sc->sc_flags);
__put_user(cpu_hppa_get_psw(env), &sc->sc_gr[0]);
for (i = 1; i < 32; ++i) {
__put_user(env->gr[i], &sc->sc_gr[i]);
}
__put_user((uint64_t)env->fr0_shadow << 32, &sc->sc_fr[0]);
for (i = 1; i < 32; ++i) {
__put_user(env->fr[i], &sc->sc_fr[i]);
}
__put_user(env->cr[CR_SAR], &sc->sc_sar);
}
static void restore_sigcontext(CPUArchState *env, struct target_sigcontext *sc)
{
target_ulong psw;
int i;
__get_user(psw, &sc->sc_gr[0]);
cpu_hppa_put_psw(env, psw);
for (i = 1; i < 32; ++i) {
__get_user(env->gr[i], &sc->sc_gr[i]);
}
for (i = 0; i < 32; ++i) {
__get_user(env->fr[i], &sc->sc_fr[i]);
}
cpu_hppa_loaded_fr0(env);
__get_user(env->iaoq_f, &sc->sc_iaoq[0]);
__get_user(env->iaoq_b, &sc->sc_iaoq[1]);
__get_user(env->cr[CR_SAR], &sc->sc_sar);
}
/* No, this doesn't look right, but it's copied straight from the kernel. */
#define PARISC_RT_SIGFRAME_SIZE32 \
((sizeof(struct target_rt_sigframe) + 48 + 64) & -64)
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUArchState *env)
{
abi_ulong frame_addr, sp, haddr;
struct target_rt_sigframe *frame;
int i;
TaskState *ts = (TaskState *)thread_cpu->opaque;
sp = get_sp_from_cpustate(env);
if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) {
sp = (ts->sigaltstack_used.ss_sp + 0x7f) & ~0x3f;
}
frame_addr = QEMU_ALIGN_UP(sp, 64);
sp = frame_addr + PARISC_RT_SIGFRAME_SIZE32;
trace_user_setup_rt_frame(env, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
}
tswap_siginfo(&frame->info, info);
frame->uc.tuc_flags = 0;
frame->uc.tuc_link = 0;
target_save_altstack(&frame->uc.tuc_stack, env);
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
}
setup_sigcontext(&frame->uc.tuc_mcontext, env);
__put_user(0x34190000, frame->tramp + 0); /* ldi 0,%r25 */
__put_user(0x3414015a, frame->tramp + 1); /* ldi __NR_rt_sigreturn,%r20 */
__put_user(0xe4008200, frame->tramp + 2); /* be,l 0x100(%sr2,%r0) */
__put_user(0x08000240, frame->tramp + 3); /* nop */
unlock_user_struct(frame, frame_addr, 1);
env->gr[2] = h2g(frame->tramp);
env->gr[30] = sp;
env->gr[26] = sig;
env->gr[25] = h2g(&frame->info);
env->gr[24] = h2g(&frame->uc);
haddr = ka->_sa_handler;
if (haddr & 2) {
/* Function descriptor. */
target_ulong *fdesc, dest;
haddr &= -4;
if (!lock_user_struct(VERIFY_READ, fdesc, haddr, 1)) {
goto give_sigsegv;
}
__get_user(dest, fdesc);
__get_user(env->gr[19], fdesc + 1);
unlock_user_struct(fdesc, haddr, 1);
haddr = dest;
}
env->iaoq_f = haddr;
env->iaoq_b = haddr + 4;
return;
give_sigsegv:
force_sigsegv(sig);
}
long do_rt_sigreturn(CPUArchState *env)
{
abi_ulong frame_addr = env->gr[30] - PARISC_RT_SIGFRAME_SIZE32;
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->uc.tuc_mcontext);
unlock_user_struct(frame, frame_addr, 0);
if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
uc.tuc_stack),
0, env->gr[30]) == -EFAULT) {
goto badframe;
}
unlock_user_struct(frame, frame_addr, 0);
return -TARGET_QEMU_ESIGRETURN;
badframe:
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}