Re: [Qemu-devel] [PATCH v4 2/5] aarch64-linux-user: Split out helpers for guest signal handling

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> Split out helpers from target_setup_frame and target_restore_sigframe
> for dealing with general registers, fpsimd registers, and the end record.
>
> When we add support for sve registers, the relative positions of
> these will change.
>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  linux-user/signal.c | 120 ++++++++++++++++++++++++++++++----------------------
>  1 file changed, 69 insertions(+), 51 deletions(-)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 9a380b9e31..25c9743aed 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -1462,16 +1462,17 @@ struct target_rt_sigframe {
>      uint32_t tramp[2];
>  };
>
> -static int target_setup_sigframe(struct target_rt_sigframe *sf,
> -                                 CPUARMState *env, target_sigset_t *set)
> +static void target_setup_general_frame(struct target_rt_sigframe *sf,
> +                                       CPUARMState *env, target_sigset_t *set)
>  {
>      int i;
> -    struct target_aux_context *aux =
> -        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
>
> -    /* set up the stack frame for unwinding */
> -    __put_user(env->xregs[29], &sf->fp);
> -    __put_user(env->xregs[30], &sf->lr);
> +    __put_user(0, &sf->uc.tuc_flags);
> +    __put_user(0, &sf->uc.tuc_link);
> +
> +    __put_user(target_sigaltstack_used.ss_sp, &sf->uc.tuc_stack.ss_sp);
> +    __put_user(sas_ss_flags(env->xregs[31]), &sf->uc.tuc_stack.ss_flags);
> +    __put_user(target_sigaltstack_used.ss_size, &sf->uc.tuc_stack.ss_size);
>
>      for (i = 0; i < 31; i++) {
>          __put_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
> @@ -1485,39 +1486,42 @@ static int target_setup_sigframe(struct target_rt_sigframe *sf,
>      for (i = 0; i < TARGET_NSIG_WORDS; i++) {
>          __put_user(set->sig[i], &sf->uc.tuc_sigmask.sig[i]);
>      }
> +}
> +
> +static void target_setup_fpsimd_record(struct target_fpsimd_context *fpsimd,
> +                                       CPUARMState *env)
> +{
> +    int i;
> +
> +    __put_user(TARGET_FPSIMD_MAGIC, &fpsimd->head.magic);
> +    __put_user(sizeof(struct target_fpsimd_context), &fpsimd->head.size);
> +    __put_user(vfp_get_fpsr(env), &fpsimd->fpsr);
> +    __put_user(vfp_get_fpcr(env), &fpsimd->fpcr);
>
>      for (i = 0; i < 32; i++) {
>          uint64_t *q = aa64_vfp_qreg(env, i);
>  #ifdef TARGET_WORDS_BIGENDIAN
> -        __put_user(q[0], &aux->fpsimd.vregs[i * 2 + 1]);
> -        __put_user(q[1], &aux->fpsimd.vregs[i * 2]);
> +        __put_user(q[0], &fpsimd->vregs[i * 2 + 1]);
> +        __put_user(q[1], &fpsimd->vregs[i * 2]);
>  #else
> -        __put_user(q[0], &aux->fpsimd.vregs[i * 2]);
> -        __put_user(q[1], &aux->fpsimd.vregs[i * 2 + 1]);
> +        __put_user(q[0], &fpsimd->vregs[i * 2]);
> +        __put_user(q[1], &fpsimd->vregs[i * 2 + 1]);
>  #endif
>      }
> -    __put_user(vfp_get_fpsr(env), &aux->fpsimd.fpsr);
> -    __put_user(vfp_get_fpcr(env), &aux->fpsimd.fpcr);
> -    __put_user(TARGET_FPSIMD_MAGIC, &aux->fpsimd.head.magic);
> -    __put_user(sizeof(struct target_fpsimd_context),
> -            &aux->fpsimd.head.size);
> -
> -    /* set the "end" magic */
> -    __put_user(0, &aux->end.magic);
> -    __put_user(0, &aux->end.size);
> -
> -    return 0;
>  }
>
> -static int target_restore_sigframe(CPUARMState *env,
> -                                   struct target_rt_sigframe *sf)
> +static void target_setup_end_record(struct target_aarch64_ctx *end)
> +{
> +    __put_user(0, &end->magic);
> +    __put_user(0, &end->size);
> +}
> +
> +static void target_restore_general_frame(CPUARMState *env,
> +                                         struct target_rt_sigframe *sf)
>  {
>      sigset_t set;
> -    int i;
> -    struct target_aux_context *aux =
> -        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
> -    uint32_t magic, size, fpsr, fpcr;
>      uint64_t pstate;
> +    int i;
>
>      target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
>      set_sigmask(&set);
> @@ -1530,30 +1534,48 @@ static int target_restore_sigframe(CPUARMState *env,
>      __get_user(env->pc, &sf->uc.tuc_mcontext.pc);
>      __get_user(pstate, &sf->uc.tuc_mcontext.pstate);
>      pstate_write(env, pstate);
> +}
>
> -    __get_user(magic, &aux->fpsimd.head.magic);
> -    __get_user(size, &aux->fpsimd.head.size);
> +static void target_restore_fpsimd_record(CPUARMState *env,
> +                                         struct target_fpsimd_context *fpsimd)
> +{
> +    uint32_t fpsr, fpcr;
> +    int i;
>
> -    if (magic != TARGET_FPSIMD_MAGIC
> -        || size != sizeof(struct target_fpsimd_context)) {
> -        return 1;
> -    }
> +    __get_user(fpsr, &fpsimd->fpsr);
> +    vfp_set_fpsr(env, fpsr);
> +    __get_user(fpcr, &fpsimd->fpcr);
> +    vfp_set_fpcr(env, fpcr);
>
>      for (i = 0; i < 32; i++) {
>          uint64_t *q = aa64_vfp_qreg(env, i);
>  #ifdef TARGET_WORDS_BIGENDIAN
> -        __get_user(q[0], &aux->fpsimd.vregs[i * 2 + 1]);
> -        __get_user(q[1], &aux->fpsimd.vregs[i * 2]);
> +        __get_user(q[0], &fpsimd->vregs[i * 2 + 1]);
> +        __get_user(q[1], &fpsimd->vregs[i * 2]);
>  #else
> -        __get_user(q[0], &aux->fpsimd.vregs[i * 2]);
> -        __get_user(q[1], &aux->fpsimd.vregs[i * 2 + 1]);
> +        __get_user(q[0], &fpsimd->vregs[i * 2]);
> +        __get_user(q[1], &fpsimd->vregs[i * 2 + 1]);
>  #endif
>      }
> -    __get_user(fpsr, &aux->fpsimd.fpsr);
> -    vfp_set_fpsr(env, fpsr);
> -    __get_user(fpcr, &aux->fpsimd.fpcr);
> -    vfp_set_fpcr(env, fpcr);
> +}
>
> +static int target_restore_sigframe(CPUARMState *env,
> +                                   struct target_rt_sigframe *sf)
> +{
> +    struct target_aux_context *aux
> +        = (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
> +    uint32_t magic, size;
> +
> +    target_restore_general_frame(env, sf);
> +
> +    __get_user(magic, &aux->fpsimd.head.magic);
> +    __get_user(size, &aux->fpsimd.head.size);
> +    if (magic == TARGET_FPSIMD_MAGIC
> +        && size == sizeof(struct target_fpsimd_context)) {
> +        target_restore_fpsimd_record(env, &aux->fpsimd);
> +    } else {
> +        return 1;
> +    }
>      return 0;
>  }
>
> @@ -1580,6 +1602,7 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
>                                 CPUARMState *env)
>  {
>      struct target_rt_sigframe *frame;
> +    struct target_aux_context *aux;
>      abi_ulong frame_addr, return_addr;
>
>      frame_addr = get_sigframe(ka, env);
> @@ -1587,17 +1610,12 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
>      if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
>          goto give_sigsegv;
>      }
> +    aux = (struct target_aux_context *)frame->uc.tuc_mcontext.__reserved;
>
> -    __put_user(0, &frame->uc.tuc_flags);
> -    __put_user(0, &frame->uc.tuc_link);
> +    target_setup_general_frame(frame, env, set);
> +    target_setup_fpsimd_record(&aux->fpsimd, env);
> +    target_setup_end_record(&aux->end);
>
> -    __put_user(target_sigaltstack_used.ss_sp,
> -                      &frame->uc.tuc_stack.ss_sp);
> -    __put_user(sas_ss_flags(env->xregs[31]),
> -                      &frame->uc.tuc_stack.ss_flags);
> -    __put_user(target_sigaltstack_used.ss_size,
> -                      &frame->uc.tuc_stack.ss_size);
> -    target_setup_sigframe(frame, env, set);
>      if (ka->sa_flags & TARGET_SA_RESTORER) {
>          return_addr = ka->sa_restorer;
>      } else {


--
Alex Bennée