Re: [PATCH 14/21] linux-user/openrisc: Implement setup_sigtramp

[Stafford Horne]

On Tue, Jun 15, 2021 at 06:12:02PM -0700, Richard Henderson wrote:
> Create and record the rt signal trampoline.
> 
> Cc: Stafford Horne <shorne@gmail.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Stafford Horne <shorne@gmail.com>

> ---
>  linux-user/openrisc/target_signal.h |  2 ++
>  linux-user/openrisc/signal.c        | 24 ++++++++++++++++--------
>  2 files changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/linux-user/openrisc/target_signal.h 
> b/linux-user/openrisc/target_signal.h
> index 8283eaf544..077ec3d5e8 100644
> --- a/linux-user/openrisc/target_signal.h
> +++ b/linux-user/openrisc/target_signal.h
> @@ -26,4 +26,6 @@ typedef struct target_sigaltstack {
>  
>  #include "../generic/signal.h"
>  
> +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
> +
>  #endif /* OPENRISC_TARGET_SIGNAL_H */
> diff --git a/linux-user/openrisc/signal.c b/linux-user/openrisc/signal.c
> index 5c5640a284..b411b01864 100644
> --- a/linux-user/openrisc/signal.c
> +++ b/linux-user/openrisc/signal.c
> @@ -37,7 +37,6 @@ typedef struct target_ucontext {
>  typedef struct target_rt_sigframe {
>      struct target_siginfo info;
>      target_ucontext uc;
> -    uint32_t retcode[4];  /* trampoline code */
>  } target_rt_sigframe;
>  
>  static void restore_sigcontext(CPUOpenRISCState *env, target_sigcontext *sc)
> @@ -115,14 +114,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
>          __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
>      }
>  
> -    /* This is l.ori r11,r0,__NR_sigreturn; l.sys 1; l.nop; l.nop */
> -    __put_user(0xa9600000 | TARGET_NR_rt_sigreturn, frame->retcode + 0);
> -    __put_user(0x20000001, frame->retcode + 1);
> -    __put_user(0x15000000, frame->retcode + 2);
> -    __put_user(0x15000000, frame->retcode + 3);
> -
>      /* Set up registers for signal handler */
> -    cpu_set_gpr(env, 9, frame_addr + offsetof(target_rt_sigframe, retcode));
> +    cpu_set_gpr(env, 9, default_rt_sigreturn);
>      cpu_set_gpr(env, 3, sig);
>      cpu_set_gpr(env, 4, frame_addr + offsetof(target_rt_sigframe, info));
>      cpu_set_gpr(env, 5, frame_addr + offsetof(target_rt_sigframe, uc));
> @@ -168,3 +161,18 @@ long do_rt_sigreturn(CPUOpenRISCState *env)
>      force_sig(TARGET_SIGSEGV);
>      return 0;
>  }
> +
> +void setup_sigtramp(abi_ulong sigtramp_page)
> +{
> +    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4 * 4, 0);
> +    assert(tramp != NULL);
> +
> +    /* This is l.ori r11,r0,__NR_sigreturn; l.sys 1; l.nop; l.nop */
> +    __put_user(0xa9600000 | TARGET_NR_rt_sigreturn, tramp + 0);
> +    __put_user(0x20000001, tramp + 1);
> +    __put_user(0x15000000, tramp + 2);
> +    __put_user(0x15000000, tramp + 3);
> +
> +    default_rt_sigreturn = sigtramp_page;
> +    unlock_user(tramp, sigtramp_page, 4 * 4);
> +}
> -- 
> 2.25.1
>