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Re: [Qemu-devel] [PATCH v3 2/4] target/arm: handle A-profile semihosting
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/4] target/arm: handle A-profile semihosting at translate time |
Date: |
Fri, 6 Sep 2019 13:54:23 +0100 |
On Fri, 6 Sep 2019 at 13:47, Alex Bennée <address@hidden> wrote:
>
> As for the other semihosting calls we can resolve this at translate
> time.
>
> Signed-off-by: Alex Bennée <address@hidden>
>
> ---
> v2
> - update for change to gen_exception_internal_insn API
> v3
> - update for decode tree, merge T32 & A32 commits
> - dropped r-b due to changes
> ---
> target/arm/translate.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 4cda7812bcb..ed4a97cfb44 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -10222,14 +10222,25 @@ static bool trans_CBZ(DisasContext *s, arg_CBZ *a)
> }
>
> /*
> - * Supervisor call
> + * Supervisor call - both T32 & A32 come here so we need to check
> + * which mode we are in when checking for semihosting.
> */
>
> static bool trans_SVC(DisasContext *s, arg_SVC *a)
> {
> - gen_set_pc_im(s, s->base.pc_next);
> - s->svc_imm = a->imm;
> - s->base.is_jmp = DISAS_SWI;
> + const uint32_t semihost_imm = s->thumb ? 0xab : 0x123456;
> +
> + if (semihosting_enabled() &&
> +#ifndef CONFIG_USER_ONLY
> + s->current_el != 0 &&
> +#endif
> + (a->imm == semihost_imm)) {
> + gen_exception_internal_insn(s, s->base.pc_next, EXCP_SEMIHOST);
> + } else {
> + gen_set_pc_im(s, s->base.pc_next);
> + s->svc_imm = a->imm;
> + s->base.is_jmp = DISAS_SWI;
> + }
> return true;
> }
Doesn't this accidentally enable semihosting via SVC for
M-profile ?
thanks
-- PMM