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

[Kito Cheng]

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>
---
 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;
-- 
2.29.2

On Thu, Dec 10, 2020 at 12:30 AM Keith Packard via
<qemu-devel@nongnu.org> wrote:
>
> Kito Cheng <kito.cheng@gmail.com> writes:
>
> > Hi Keith:
> >
> > Thanks for the patch, I've verified with newlib semihosting support
> > which is contributed by Craig Blackmore from embecosm,
> > and I would like to add semihosting to user mode, do you mind add this
> > patch into this patch series?
>
> I tried to add that already, but I admit that I haven't tested it in a
> while. You should find that there are patches to linux-user/semihost.c
> and linux-user/qemu.h to enable it.
>
> --
> -keith