target-arm: Minimal implementation of performance counters
Newer Linux kernels assume the existence of the performance counter
cp15 registers. Provide a minimal implementation of these registers.
We support no events. This should be compliant with the ARM ARM,
except that we don't implement the cycle counter.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 9f14781..9785cc5 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -270,6 +270,10 @@
}
env->vfp.xregs[ARM_VFP_FPEXC] = 0;
env->cp15.c2_base_mask = 0xffffc000u;
+ /* v7 performance monitor control register: same implementor
+ * field as main ID register, and we implement no event counters.
+ */
+ env->cp15.c9_pmcr = (id & 0xff000000);
#endif
set_flush_to_zero(1, &env->vfp.standard_fp_status);
set_flush_inputs_to_zero(1, &env->vfp.standard_fp_status);
@@ -1588,6 +1592,81 @@
case 1: /* TCM memory region registers. */
/* Not implemented. */
goto bad_reg;
+ case 12: /* Performance monitor control */
+ /* Performance monitors are implementation defined in v7,
+ * but with an ARM recommended set of registers, which we
+ * follow (although we don't actually implement any counters)
+ */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ goto bad_reg;
+ }
+ switch (op2) {
+ case 0: /* performance monitor control register */
+ /* only the DP, X, D and E bits are writable */
+ env->cp15.c9_pmcr &= ~0x39;
+ env->cp15.c9_pmcr |= (val & 0x39);
+ break;
+ case 1: /* Count enable set register */
+ val &= (1 << 31);
+ env->cp15.c9_pmcnten |= val;
+ break;
+ case 2: /* Count enable clear */
+ val &= (1 << 31);
+ env->cp15.c9_pmcnten &= ~val;
+ break;
+ case 3: /* Overflow flag status */
+ env->cp15.c9_pmovsr &= ~val;
+ break;
+ case 4: /* Software increment */
+ /* RAZ/WI since we don't implement the software-count event */
+ break;
+ case 5: /* Event counter selection register */
+ /* Since we don't implement any events, writing to this register
+ * is actually UNPREDICTABLE. So we choose to RAZ/WI.
+ */
+ break;
+ default:
+ goto bad_reg;
+ }
+ break;
+ case 13: /* Performance counters */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ goto bad_reg;
+ }
+ switch (op2) {
+ case 0: /* Cycle count register: not implemented, so RAZ/WI */
+ break;
+ case 1: /* Event type select */
+ env->cp15.c9_pmxevtyper = val & 0xff;
+ break;
+ case 2: /* Event count register */
+ /* Unimplemented (we have no events), RAZ/WI */
+ break;
+ default:
+ goto bad_reg;
+ }
+ break;
+ case 14: /* Performance monitor control */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ goto bad_reg;
+ }
+ switch (op2) {
+ case 0: /* user enable */
+ env->cp15.c9_pmuserenr = val & 1;
+ /* changes access rights for cp registers, so flush tbs */
+ tb_flush(env);
+ break;
+ case 1: /* interrupt enable set */
+ /* We have no event counters so only the C bit can be changed */
+ val &= (1 << 31);
+ env->cp15.c9_pminten |= val;
+ break;
+ case 2: /* interrupt enable clear */
+ val &= (1 << 31);
+ env->cp15.c9_pminten &= ~val;
+ break;
+ }
+ break;
default:
goto bad_reg;
}
@@ -1879,27 +1958,81 @@
return 0;
case 8: /* MMU TLB control. */
goto bad_reg;
- case 9: /* Cache lockdown. */
- switch (op1) {
- case 0: /* L1 cache. */
- if (arm_feature(env, ARM_FEATURE_OMAPCP))
- return 0;
- switch (op2) {
- case 0:
- return env->cp15.c9_data;
- case 1:
- return env->cp15.c9_insn;
+ case 9:
+ switch (crm) {
+ case 0: /* Cache lockdown */
+ switch (op1) {
+ case 0: /* L1 cache. */
+ if (arm_feature(env, ARM_FEATURE_OMAPCP)) {
+ return 0;
+ }
+ switch (op2) {
+ case 0:
+ return env->cp15.c9_data;
+ case 1:
+ return env->cp15.c9_insn;
+ default:
+ goto bad_reg;
+ }
+ case 1: /* L2 cache */
+ if (crm != 0) {
+ goto bad_reg;
+ }
+ /* L2 Lockdown and Auxiliary control. */
+ return 0;
default:
goto bad_reg;
}
- case 1: /* L2 cache */
- if (crm != 0)
+ break;
+ case 12: /* Performance monitor control */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
goto bad_reg;
- /* L2 Lockdown and Auxiliary control. */
- return 0;
+ }
+ switch (op2) {
+ case 0: /* performance monitor control register */
+ return env->cp15.c9_pmcr;
+ case 1: /* count enable set */
+ case 2: /* count enable clear */
+ return env->cp15.c9_pmcnten;
+ case 3: /* overflow flag status */
+ return env->cp15.c9_pmovsr;
+ case 4: /* software increment */
+ case 5: /* event counter selection register */
+ return 0; /* Unimplemented, RAZ/WI */
+ default:
+ goto bad_reg;
+ }
+ case 13: /* Performance counters */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ goto bad_reg;
+ }
+ switch (op2) {
+ case 1: /* Event type select */
+ return env->cp15.c9_pmxevtyper;
+ case 0: /* Cycle count register */
+ case 2: /* Event count register */
+ /* Unimplemented, so RAZ/WI */
+ return 0;
+ default:
+ goto bad_reg;
+ }
+ case 14: /* Performance monitor control */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ goto bad_reg;
+ }
+ switch (op2) {
+ case 0: /* user enable */
+ return env->cp15.c9_pmuserenr;
+ case 1: /* interrupt enable set */
+ case 2: /* interrupt enable clear */
+ return env->cp15.c9_pminten;
+ default:
+ goto bad_reg;
+ }
default:
goto bad_reg;
}
+ break;
case 10: /* MMU TLB lockdown. */
/* ??? TLB lockdown not implemented. */
return 0;
