Re: [Qemu-devel] [PATCH] linux-user, sh4: fix signal retcode address

[Laurent Vivier <laurent@vivier.eu>]

Ping ?

Le 23/11/2015 11:38, Laurent Vivier a écrit :
> To return from a signal, setup_frame() puts an instruction to
> be executed in the stack. This sequence calls the syscall sigreturn().
> 
> The address of the instruction must be set in the PR register
> to be executed.
> 
> This patch fixes this: the current code sets the register to the address
> of the instruction in the host address space (which can be 64bit whereas
> PR is only 32bit), but the virtual CPU can't access this address space,
> so we put in PR the address of the instruction in the guest address space.
> 
> This patch also removes an useless variable (ret) in the modified functions.
> 
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  linux-user/signal.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 55e5405..5e8f6d8 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -3215,7 +3215,6 @@ static void setup_frame(int sig, struct target_sigaction *ka,
>      struct target_sigframe *frame;
>      abi_ulong frame_addr;
>      int i;
> -    int err = 0;
>  
>      frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
>      if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
> @@ -3233,15 +3232,14 @@ static void setup_frame(int sig, struct target_sigaction *ka,
>          regs->pr = (unsigned long) ka->sa_restorer;
>      } else {
>          /* Generate return code (system call to sigreturn) */
> +        abi_ulong retcode_addr = frame_addr +
> +                                 offsetof(struct target_sigframe, retcode);
>          __put_user(MOVW(2), &frame->retcode[0]);
>          __put_user(TRAP_NOARG, &frame->retcode[1]);
>          __put_user((TARGET_NR_sigreturn), &frame->retcode[2]);
> -        regs->pr = (unsigned long) frame->retcode;
> +        regs->pr = (unsigned long) retcode_addr;
>      }
>  
> -    if (err)
> -        goto give_sigsegv;
> -
>      /* Set up registers for signal handler */
>      regs->gregs[15] = frame_addr;
>      regs->gregs[4] = sig; /* Arg for signal handler */
> @@ -3264,7 +3262,6 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
>      struct target_rt_sigframe *frame;
>      abi_ulong frame_addr;
>      int i;
> -    int err = 0;
>  
>      frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
>      if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
> @@ -3293,15 +3290,14 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
>          regs->pr = (unsigned long) ka->sa_restorer;
>      } else {
>          /* Generate return code (system call to sigreturn) */
> +        abi_ulong retcode_addr = frame_addr +
> +                                 offsetof(struct target_rt_sigframe, retcode);
>          __put_user(MOVW(2), &frame->retcode[0]);
>          __put_user(TRAP_NOARG, &frame->retcode[1]);
>          __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]);
> -        regs->pr = (unsigned long) frame->retcode;
> +        regs->pr = (unsigned long) retcode_addr;
>      }
>  
> -    if (err)
> -        goto give_sigsegv;
> -
>      /* Set up registers for signal handler */
>      regs->gregs[15] = frame_addr;
>      regs->gregs[4] = sig; /* Arg for signal handler */
>