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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 <laur...@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 */
>
