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linux-user/xtensa: Implement setup_sigtramp

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Create and record the rt signal trampoline.
Use it when the guest does not use SA_RESTORER.

Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210929130553.121567-25-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson 2021-09-29 09:05:51 -04:00 committed by Laurent Vivier
parent 3f7685eaf9
commit 55e83c2005
2 changed files with 38 additions and 20 deletions
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56
linux-user/xtensa/signal.c
View file

@ -128,6 +128,29 @@ static int setup_sigcontext(struct target_rt_sigframe *frame,
return 1;
}
static void install_sigtramp(uint8_t *tramp)
{
#ifdef TARGET_WORDS_BIGENDIAN
/* 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)
@ -164,26 +187,9 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
if (ka->sa_flags & TARGET_SA_RESTORER) {
ra = ka->sa_restorer;
} else {
ra = frame_addr + offsetof(struct target_rt_sigframe, retcode);
#ifdef TARGET_WORDS_BIGENDIAN
/* Generate instruction: MOVI a2, __NR_rt_sigreturn */
__put_user(0x22, &frame->retcode[0]);
__put_user(0x0a, &frame->retcode[1]);
__put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
/* Generate instruction: SYSCALL */
__put_user(0x00, &frame->retcode[3]);
__put_user(0x05, &frame->retcode[4]);
__put_user(0x00, &frame->retcode[5]);
#else
/* Generate instruction: MOVI a2, __NR_rt_sigreturn */
__put_user(0x22, &frame->retcode[0]);
__put_user(0xa0, &frame->retcode[1]);
__put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
/* Generate instruction: SYSCALL */
__put_user(0x00, &frame->retcode[3]);
__put_user(0x50, &frame->retcode[4]);
__put_user(0x00, &frame->retcode[5]);
#endif
/* Not used, but retain for ABI compatibility. */
install_sigtramp(frame->retcode);
ra = default_rt_sigreturn;
}
memset(env->regs, 0, sizeof(env->regs));
env->pc = ka->_sa_handler;
@ -264,3 +270,13 @@ badframe:
force_sig(TARGET_SIGSEGV);
return -TARGET_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);
}

2
linux-user/xtensa/target_signal.h
View file

@ -20,4 +20,6 @@ typedef struct target_sigaltstack {
#include "../generic/signal.h"
#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
#endif