Add support for trapping WFI and WFE instructions to the proper EL when
SCTLR/SCR/HCR settings apply.
Signed-off-by: Greg Bellows <greg.bell...@linaro.org>
---
target-arm/op_helper.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 71 insertions(+), 4 deletions(-)
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index aa175b5..d7e734d 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -209,23 +209,90 @@ uint32_t HELPER(usat16)(CPUARMState *env, uint32_t x,
uint32_t shift)
return res;
}
+static inline uint32_t check_wfx_trap(CPUARMState *env, bool is_wfe)
+{
+ int cur_el = arm_current_el(env), el;
+ uint32_t target_el = 0;
+ uint64_t mask;
+
+ /* Check whether any EL controls above us trap WFx instructions */
+ for (el = cur_el + 1; el <= 3; el++) {
+ switch (el) {
+ case 1:
+ mask = (is_wfe) ? SCTLR_nTWE : SCTLR_nTWI;
+ /* Secure EL1 is only valid in AArch64. If EL0 is AArch64 then so
+ * must be EL1.
+ */
+ if (arm_el_is_aa64(env, 1)) {
+ if ((env->cp15.sctlr_el[1] & mask) == 0) {
+ target_el = el;
+ }
+ } else if (arm_feature(env, ARM_FEATURE_V8) &&
+ !arm_is_secure(env)) {
+ /* SCTLR WFx SCTLR trap bits only exist in ARMv8 */
+ if ((A32_BANKED_CURRENT_REG_GET(env, sctlr) & mask) == 0) {
+ target_el = el;
+ }
+ }
+ break;
+ case 2:
+ if (arm_feature(env, ARM_FEATURE_EL2) && !arm_is_secure(env)) {
+ mask = (is_wfe) ? HCR_TWE : HCR_TWI;
+ if ((env->cp15.hcr_el2 & mask) == mask) {
+ target_el = el;
+ }
+ }
+ break;
+ case 3:
+ if (arm_feature(env, ARM_FEATURE_EL3) &&
+ arm_feature(env, ARM_FEATURE_V8)) {
+ mask = (is_wfe) ? SCR_TWE : SCR_TWI;
+ if ((env->cp15.scr_el3 & mask) == mask) {
+ target_el = el;
+ }
+ }
+ break;
+ }
+ }
+
+ return target_el;
+}
+
void HELPER(wfi)(CPUARMState *env)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
-
- cs->exception_index = EXCP_HLT;
- cs->halted = 1;
+ uint32_t target_el = 0;
+
+ target_el = check_wfx_trap(env, false);
+ if (target_el) {
+ cs->exception_index = EXCP_UDEF;
+ env->exception.syndrome = syn_wfx(1, 0xe, false);
+ env->exception.target_el = target_el;
+ env->pc -= 4;
+ } else {
+ cs->exception_index = EXCP_HLT;
+ cs->halted = 1;
+ }
cpu_loop_exit(cs);
}
void HELPER(wfe)(CPUARMState *env)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
+ uint32_t target_el = 0;
/* Don't actually halt the CPU, just yield back to top
* level loop
*/
- cs->exception_index = EXCP_YIELD;
+ target_el = check_wfx_trap(env, true);
+ if (target_el) {
+ cs->exception_index = EXCP_UDEF;
+ env->exception.syndrome = syn_wfx(1, 0xe, true);
+ env->exception.target_el = target_el;
+ env->pc -= 4;
+ } else {
+ cs->exception_index = EXCP_YIELD;
+ }
cpu_loop_exit(cs);
}
--
1.8.3.2
