diff options
| -rw-r--r-- | target-arm/op_helper.c | 60 |
1 files changed, 59 insertions, 1 deletions
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c index 0ea4ed4bae..3f5b9ab596 100644 --- a/target-arm/op_helper.c +++ b/target-arm/op_helper.c @@ -248,9 +248,60 @@ uint32_t HELPER(usat16)(CPUARMState *env, uint32_t x, uint32_t shift) return res; } +/* Function checks whether WFx (WFI/WFE) instructions are set up to be trapped. + * The function returns the target EL (1-3) if the instruction is to be trapped; + * otherwise it returns 0 indicating it is not trapped. + */ +static inline int check_wfx_trap(CPUARMState *env, bool is_wfe) +{ + int cur_el = arm_current_el(env); + uint64_t mask; + + /* If we are currently in EL0 then we need to check if SCTLR is set up for + * WFx instructions being trapped to EL1. These trap bits don't exist in v7. + */ + if (cur_el < 1 && arm_feature(env, ARM_FEATURE_V8)) { + int target_el; + + mask = is_wfe ? SCTLR_nTWE : SCTLR_nTWI; + if (arm_is_secure_below_el3(env) && !arm_el_is_aa64(env, 3)) { + /* Secure EL0 and Secure PL1 is at EL3 */ + target_el = 3; + } else { + target_el = 1; + } + + if (!(env->cp15.sctlr_el[target_el] & mask)) { + return target_el; + } + } + + /* We are not trapping to EL1; trap to EL2 if HCR_EL2 requires it + * No need for ARM_FEATURE check as if HCR_EL2 doesn't exist the + * bits will be zero indicating no trap. + */ + if (cur_el < 2 && !arm_is_secure(env)) { + mask = (is_wfe) ? HCR_TWE : HCR_TWI; + if (env->cp15.hcr_el2 & mask) { + return 2; + } + } + + /* We are not trapping to EL1 or EL2; trap to EL3 if SCR_EL3 requires it */ + if (cur_el < 3) { + mask = (is_wfe) ? SCR_TWE : SCR_TWI; + if (env->cp15.scr_el3 & mask) { + return 3; + } + } + + return 0; +} + void HELPER(wfi)(CPUARMState *env) { CPUState *cs = CPU(arm_env_get_cpu(env)); + int target_el = check_wfx_trap(env, false); if (cpu_has_work(cs)) { /* Don't bother to go into our "low power state" if @@ -259,6 +310,11 @@ void HELPER(wfi)(CPUARMState *env) return; } + if (target_el) { + env->pc -= 4; + raise_exception(env, EXCP_UDEF, syn_wfx(1, 0xe, 0), target_el); + } + cs->exception_index = EXCP_HLT; cs->halted = 1; cpu_loop_exit(cs); @@ -269,7 +325,9 @@ void HELPER(wfe)(CPUARMState *env) CPUState *cs = CPU(arm_env_get_cpu(env)); /* Don't actually halt the CPU, just yield back to top - * level loop + * level loop. This is not going into a "low power state" + * (ie halting until some event occurs), so we never take + * a configurable trap to a different exception level. */ cs->exception_index = EXCP_YIELD; cpu_loop_exit(cs); |