target/nios2: Stop generating code if gen_check_supervisor fails

Whether the cpu is in user-mode or not is something that we
know at translation-time.  We do not need to generate code
after having raised an exception.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-15-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-04-21 08:16:45 -07:00
parent b106e7b7e4
commit 48b7eac207

View File

@ -169,12 +169,14 @@ static void gen_excp(DisasContext *dc, uint32_t code, uint32_t flags)
t_gen_helper_raise_exception(dc, flags);
}
static void gen_check_supervisor(DisasContext *dc)
static bool gen_check_supervisor(DisasContext *dc)
{
if (dc->base.tb->flags & CR_STATUS_U) {
/* CPU in user mode, privileged instruction called, stop. */
t_gen_helper_raise_exception(dc, EXCP_SUPERI);
return false;
}
return true;
}
/*
@ -384,7 +386,9 @@ static const Nios2Instruction i_type_instructions[] = {
*/
static void eret(DisasContext *dc, uint32_t code, uint32_t flags)
{
gen_check_supervisor(dc);
if (!gen_check_supervisor(dc)) {
return;
}
tcg_gen_mov_tl(cpu_R[CR_STATUS], cpu_R[CR_ESTATUS]);
tcg_gen_mov_tl(cpu_R[R_PC], cpu_R[R_EA]);
@ -447,7 +451,9 @@ static void rdctl(DisasContext *dc, uint32_t code, uint32_t flags)
{
R_TYPE(instr, code);
gen_check_supervisor(dc);
if (!gen_check_supervisor(dc)) {
return;
}
if (unlikely(instr.c == R_ZERO)) {
return;
@ -474,9 +480,13 @@ static void rdctl(DisasContext *dc, uint32_t code, uint32_t flags)
/* ctlN <- rA */
static void wrctl(DisasContext *dc, uint32_t code, uint32_t flags)
{
gen_check_supervisor(dc);
if (!gen_check_supervisor(dc)) {
return;
}
#ifndef CONFIG_USER_ONLY
#ifdef CONFIG_USER_ONLY
g_assert_not_reached();
#else
R_TYPE(instr, code);
TCGv v = load_gpr(dc, instr.a);