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linux-user/aarch64: 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: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210929130553.121567-3-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson 2021-09-29 09:05:29 -04:00 committed by Laurent Vivier
parent db2af69d6b
commit c70887a382
2 changed files with 23 additions and 13 deletions
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34
linux-user/aarch64/signal.c
View File

@ -109,7 +109,6 @@ struct target_rt_sigframe {
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,
@ -461,9 +460,9 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
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.
/*
* Reserve space for the standard frame unwind pair: fp, lr.
* 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);
@ -496,15 +495,7 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
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);
return_addr = default_rt_sigreturn;
}
env->xregs[0] = usig;
env->xregs[29] = frame_addr + fr_ofs;
@ -577,3 +568,20 @@ long do_sigreturn(CPUARMState *env)
{
return do_rt_sigreturn(env);
}
void setup_sigtramp(abi_ulong sigtramp_page)
{
uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0);
assert(tramp != NULL);
/*
* 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, &tramp[0], le);
__put_user_e(0xd4000001, &tramp[1], le);
default_rt_sigreturn = sigtramp_page;
unlock_user(tramp, sigtramp_page, 8);
}

2
linux-user/aarch64/target_signal.h
View File

@ -25,4 +25,6 @@ typedef struct target_sigaltstack {
#define TARGET_SEGV_MTESERR 9 /* Synchronous ARM MTE exception */
#define TARGET_ARCH_HAS_SETUP_FRAME
#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
#endif /* AARCH64_TARGET_SIGNAL_H */