Update ucontext to implement sigreturn.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/arm/target_arch_signal.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/bsd-user/arm/target_arch_signal.h b/bsd-user/arm/target_arch_signal.h
index 1d051af9ae..7da68c727c 100644
--- a/bsd-user/arm/target_arch_signal.h
+++ b/bsd-user/arm/target_arch_signal.h
@@ -232,4 +232,22 @@ static inline abi_long set_mcontext(CPUARMState *regs, target_mcontext_t *mcp,
     return err;
 }
 
+/* Compare to arm/arm/machdep.c sys_sigreturn() */
+static inline abi_long get_ucontext_sigreturn(CPUARMState *regs,
+        abi_ulong target_sf, abi_ulong *target_uc)
+{
+    uint32_t cpsr = cpsr_read(regs);
+
+    *target_uc = 0;
+
+    if ((cpsr & CPSR_M) != ARM_CPU_MODE_USR ||
+            (cpsr & (CPSR_I | CPSR_F)) != 0) {
+        return -TARGET_EINVAL;
+    }
+
+    *target_uc = target_sf;
+
+    return 0;
+}
+
 #endif /* !_TARGET_ARCH_SIGNAL_H_ */
-- 
2.32.0

On Tue, Oct 19, 2021 at 11:45 AM Warner Losh <imp@bsdimp.com> wrote:
>
> Update ucontext to implement sigreturn.
>
> Signed-off-by: Stacey Son <sson@FreeBSD.org>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>  bsd-user/arm/target_arch_signal.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/bsd-user/arm/target_arch_signal.h b/bsd-user/arm/target_arch_signal.h
> index 1d051af9ae..7da68c727c 100644
> --- a/bsd-user/arm/target_arch_signal.h
> +++ b/bsd-user/arm/target_arch_signal.h
> @@ -232,4 +232,22 @@ static inline abi_long set_mcontext(CPUARMState *regs, target_mcontext_t *mcp,
>      return err;
>  }
>
> +/* Compare to arm/arm/machdep.c sys_sigreturn() */
> +static inline abi_long get_ucontext_sigreturn(CPUARMState *regs,
> +        abi_ulong target_sf, abi_ulong *target_uc)
> +{
> +    uint32_t cpsr = cpsr_read(regs);
> +
> +    *target_uc = 0;
> +
> +    if ((cpsr & CPSR_M) != ARM_CPU_MODE_USR ||
> +            (cpsr & (CPSR_I | CPSR_F)) != 0) {
> +        return -TARGET_EINVAL;
> +    }
> +
> +    *target_uc = target_sf;
> +
> +    return 0;
> +}
> +
>  #endif /* !_TARGET_ARCH_SIGNAL_H_ */
> --
> 2.32.0
>

Reviewed-by: Kyle Evans <kevans@FreeBSD.org>

On 10/19/21 9:44 AM, Warner Losh wrote:
> +/* Compare to arm/arm/machdep.c sys_sigreturn() */
> +static inline abi_long get_ucontext_sigreturn(CPUARMState *regs,
> +        abi_ulong target_sf, abi_ulong *target_uc)
> +{
> +    uint32_t cpsr = cpsr_read(regs);
> +
> +    *target_uc = 0;
> +
> +    if ((cpsr & CPSR_M) != ARM_CPU_MODE_USR ||
> +            (cpsr & (CPSR_I | CPSR_F)) != 0) {
> +        return -TARGET_EINVAL;
> +    }
> +
> +    *target_uc = target_sf;
> +
> +    return 0;
> +}

Since you've not yet filled in signal.c, I can't opine too much, but I'll note that the 
kernel has this check in set_mcontext, and sys_sigreturn defers to that for the validation.

So I think this can just be the final assignment.


r~