[Qemu-devel] [PATCH v2] linux-user/signal.c: Generate opcode data for restorer in setup_rt_frame

[Qemu-devel] [PATCH v2] linux-user/signal.c: Generate opcode data for restorer in setup_rt_frame

[chengang]

From: Chen Gang <chengang@emindsoft.com.cn>

Original implementation uses do_rt_sigreturn directly in host space,
when a guest program is in unwind procedure in guest space, it will get
an incorrect restore address, then causes unwind failure.

Also cleanup the original incorrect indentation.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
---
 linux-user/signal.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 96e86c0..e487f9e 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -5559,8 +5559,13 @@ struct target_rt_sigframe {
     unsigned char save_area[16]; /* caller save area */
     struct target_siginfo info;
     struct target_ucontext uc;
+    abi_ulong retcode[2];
 };
 
+#define INSN_MOVELI_R10_139  0x00045fe551483000ULL /* { moveli r10, 139 } */
+#define INSN_SWINT1          0x286b180051485000ULL /* { swint1 } */
+
+
 static void setup_sigcontext(struct target_sigcontext *sc,
                              CPUArchState *env, int signo)
 {
@@ -5636,9 +5641,12 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
     __put_user(target_sigaltstack_used.ss_size, &frame->uc.tuc_stack.ss_size);
     setup_sigcontext(&frame->uc.tuc_mcontext, env, info->si_signo);
 
-    restorer = (unsigned long) do_rt_sigreturn;
     if (ka->sa_flags & TARGET_SA_RESTORER) {
-            restorer = (unsigned long) ka->sa_restorer;
+        restorer = (unsigned long) ka->sa_restorer;
+    } else {
+        __put_user(INSN_MOVELI_R10_139, &frame->retcode[0]);
+        __put_user(INSN_SWINT1, &frame->retcode[1]);
+        restorer = frame_addr + offsetof(struct target_rt_sigframe, retcode);
     }
     env->pc = (unsigned long) ka->_sa_handler;
     env->regs[TILEGX_R_SP] = (unsigned long) frame;
-- 
1.9.3

Re: [Qemu-devel] [PATCH v2] linux-user/signal.c: Generate opcode data for restorer in setup_rt_frame

[Laurent Vivier]

Le 29/03/2016 15:53, chengang@emindsoft.com.cn a écrit :
> From: Chen Gang <chengang@emindsoft.com.cn>
> 
> Original implementation uses do_rt_sigreturn directly in host space,
> when a guest program is in unwind procedure in guest space, it will get
> an incorrect restore address, then causes unwind failure.
> 
> Also cleanup the original incorrect indentation.
> 
> Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>

Reviewed-by: Laurent Vivier <laurent@vivier.eu>

> ---
>  linux-user/signal.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 96e86c0..e487f9e 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -5559,8 +5559,13 @@ struct target_rt_sigframe {
>      unsigned char save_area[16]; /* caller save area */
>      struct target_siginfo info;
>      struct target_ucontext uc;
> +    abi_ulong retcode[2];
>  };
>  
> +#define INSN_MOVELI_R10_139  0x00045fe551483000ULL /* { moveli r10, 139 } */
> +#define INSN_SWINT1          0x286b180051485000ULL /* { swint1 } */
> +
> +
>  static void setup_sigcontext(struct target_sigcontext *sc,
>                               CPUArchState *env, int signo)
>  {
> @@ -5636,9 +5641,12 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
>      __put_user(target_sigaltstack_used.ss_size, &frame->uc.tuc_stack.ss_size);
>      setup_sigcontext(&frame->uc.tuc_mcontext, env, info->si_signo);
>  
> -    restorer = (unsigned long) do_rt_sigreturn;
>      if (ka->sa_flags & TARGET_SA_RESTORER) {
> -            restorer = (unsigned long) ka->sa_restorer;
> +        restorer = (unsigned long) ka->sa_restorer;
> +    } else {
> +        __put_user(INSN_MOVELI_R10_139, &frame->retcode[0]);
> +        __put_user(INSN_SWINT1, &frame->retcode[1]);
> +        restorer = frame_addr + offsetof(struct target_rt_sigframe, retcode);
>      }
>      env->pc = (unsigned long) ka->_sa_handler;
>      env->regs[TILEGX_R_SP] = (unsigned long) frame;
>