Re: [PATCH 5/8] riscv: Add semihosting support [v13]

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

Kito Cheng <kito.cheng@gmail.com> writes:

> Hi Keith:
>
> Thanks for your reply, but it seems like we need some more modification in
>  linux-user/riscv/cpu_loop.c to enable that, I guess I should post that in mail
> rather than attachment :)
>
> Patch here:
>
> From 2f1eb5825a6dda177d3289106970eab05cb08445 Mon Sep 17 00:00:00 2001
> From: Kito Cheng <kito.cheng@sifive.com>
> Date: Wed, 9 Dec 2020 14:24:51 +0800
> Subject: [PATCH] riscv: Add semihosting support for user mode
>
> This could make testing easier and ARM/AArch64 has support on
> their linux user mode too, so I think it should be reasonable.
>
> Verified GCC testsuite with newlib/semihosting.
>
> Signed-off-by: Kito Cheng <kito.cheng@sifive.com>

If the riscv linux-user maintainer is happy with it I'll take it through
semihosting/next. It certainly has a use case in the ARM case.

> ---
>  linux-user/riscv/cpu_loop.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/linux-user/riscv/cpu_loop.c b/linux-user/riscv/cpu_loop.c
> index aa9e437875..9665dabb09 100644
> --- a/linux-user/riscv/cpu_loop.c
> +++ b/linux-user/riscv/cpu_loop.c
> @@ -23,6 +23,7 @@
>  #include "qemu.h"
>  #include "cpu_loop-common.h"
>  #include "elf.h"
> +#include "hw/semihosting/common-semi.h"
>
>  void cpu_loop(CPURISCVState *env)
>  {
> @@ -91,6 +92,10 @@ void cpu_loop(CPURISCVState *env)
>              sigcode = TARGET_SEGV_MAPERR;
>              sigaddr = env->badaddr;
>              break;
> +        case RISCV_EXCP_SEMIHOST:
> +            env->gpr[xA0] = do_common_semihosting(cs);
> +            env->pc += 4;
> +            break;
>          case EXCP_DEBUG:
>          gdbstep:
>              signum = TARGET_SIGTRAP;


-- 
Alex Bennée