diff options
Diffstat (limited to 'target-arm')
| -rw-r--r-- | target-arm/helper.h | 1 | ||||
| -rw-r--r-- | target-arm/op_helper.c | 18 | ||||
| -rw-r--r-- | target-arm/translate-a64.c | 6 | ||||
| -rw-r--r-- | target-arm/translate.h | 1 |
4 files changed, 23 insertions, 3 deletions
diff --git a/target-arm/helper.h b/target-arm/helper.h index fc885de..827b33d 100644 --- a/target-arm/helper.h +++ b/target-arm/helper.h @@ -50,6 +50,7 @@ DEF_HELPER_2(exception_internal, void, env, i32) DEF_HELPER_4(exception_with_syndrome, void, env, i32, i32, i32) DEF_HELPER_1(wfi, void, env) DEF_HELPER_1(wfe, void, env) +DEF_HELPER_1(yield, void, env) DEF_HELPER_1(pre_hvc, void, env) DEF_HELPER_2(pre_smc, void, env, i32) diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c index 7fa32c4..663c05d 100644 --- a/target-arm/op_helper.c +++ b/target-arm/op_helper.c @@ -323,13 +323,25 @@ void HELPER(wfi)(CPUARMState *env) void HELPER(wfe)(CPUARMState *env) { - CPUState *cs = CPU(arm_env_get_cpu(env)); - - /* Don't actually halt the CPU, just yield back to top + /* This is a hint instruction that is semantically different + * from YIELD even though we currently implement it identically. + * Don't actually halt the CPU, just yield back to top * 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. */ + HELPER(yield)(env); +} + +void HELPER(yield)(CPUARMState *env) +{ + ARMCPU *cpu = arm_env_get_cpu(env); + CPUState *cs = CPU(cpu); + + /* This is a non-trappable hint instruction that generally indicates + * that the guest is currently busy-looping. Yield control back to the + * top level loop so that a more deserving VCPU has a chance to run. + */ cs->exception_index = EXCP_YIELD; cpu_loop_exit(cs); } diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index e077f2d..689f2be 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -1199,6 +1199,8 @@ static void handle_hint(DisasContext *s, uint32_t insn, s->is_jmp = DISAS_WFI; return; case 1: /* YIELD */ + s->is_jmp = DISAS_YIELD; + return; case 2: /* WFE */ s->is_jmp = DISAS_WFE; return; @@ -11107,6 +11109,10 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, gen_a64_set_pc_im(dc->pc); gen_helper_wfe(cpu_env); break; + case DISAS_YIELD: + gen_a64_set_pc_im(dc->pc); + gen_helper_yield(cpu_env); + break; case DISAS_WFI: /* This is a special case because we don't want to just halt the CPU * if trying to debug across a WFI. diff --git a/target-arm/translate.h b/target-arm/translate.h index bcdcf11..9ab978f 100644 --- a/target-arm/translate.h +++ b/target-arm/translate.h @@ -103,6 +103,7 @@ static inline int default_exception_el(DisasContext *s) #define DISAS_WFE 7 #define DISAS_HVC 8 #define DISAS_SMC 9 +#define DISAS_YIELD 10 #ifdef TARGET_AARCH64 void a64_translate_init(void); |
