[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH] target/riscv: Disallow WFI instruction from U-mode
From: |
Jonathan Behrens |
Subject: |
[PATCH] target/riscv: Disallow WFI instruction from U-mode |
Date: |
Thu, 23 Jan 2020 14:52:00 -0500 |
>From the RISC-V Priviliged Specification:
"When S-mode is implemented, then executing WFI in U-mode causes an illegal
instruction exception, unless it completes within an implementation-specific,
bounded time limit. A future revision of this specification might add a feature
that allows S-mode to selectively permit WFI in U-mode."
Signed-off-by: Jonathan Behrens <address@hidden>
Reviewed-by: Alistair Francis <address@hidden>
---
target/riscv/op_helper.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 331cc36232..2e5a980192 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -129,10 +129,10 @@ target_ulong helper_mret(CPURISCVState *env, target_ulong
cpu_pc_deb)
void helper_wfi(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
-
- if (env->priv == PRV_S &&
- env->priv_ver >= PRIV_VERSION_1_10_0 &&
- get_field(env->mstatus, MSTATUS_TW)) {
+ if (!(env->priv >= PRV_S) ||
+ (env->priv == PRV_S &&
+ env->priv_ver >= PRIV_VERSION_1_10_0 &&
+ get_field(env->mstatus, MSTATUS_TW))) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
} else {
cs->halted = 1;
--
2.25.0
- [PATCH] target/riscv: Disallow WFI instruction from U-mode,
Jonathan Behrens <=