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[Qemu-devel] [PATCH 1/6] target-arm: correct CNTFRQ access rights
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 1/6] target-arm: correct CNTFRQ access rights |
Date: |
Fri, 5 Feb 2016 16:44:59 +0000 |
Correct some corner cases we were getting wrong for
CNTFRQ access rights:
* should UNDEF from 32-bit Secure EL1
* only writable from the highest implemented exception level,
which might not be EL1 now
Signed-off-by: Peter Maydell <address@hidden>
---
target-arm/helper.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 7a8881a..082701a 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1217,9 +1217,34 @@ static const ARMCPRegInfo v6k_cp_reginfo[] = {
static CPAccessResult gt_cntfrq_access(CPUARMState *env, const ARMCPRegInfo
*ri,
bool isread)
{
- /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero */
- if (arm_current_el(env) == 0 && !extract32(env->cp15.c14_cntkctl, 0, 2)) {
- return CP_ACCESS_TRAP;
+ /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero.
+ * Writable only at the highest implemented exception level.
+ */
+ switch (arm_current_el(env)) {
+ case 0:
+ if (!extract32(env->cp15.c14_cntkctl, 0, 2)) {
+ return CP_ACCESS_TRAP;
+ }
+ /* EL0 reads are forbidden by the .access fields */
+ break;
+ case 1:
+ if (!isread && (arm_feature(env, ARM_FEATURE_EL2)
+ || arm_feature(env, ARM_FEATURE_EL3))) {
+ return CP_ACCESS_TRAP_UNCATEGORIZED;
+ }
+ if (!isread && ri->state == ARM_CP_STATE_AA32 &&
+ arm_is_secure_below_el3(env)) {
+ /* Accesses from 32-bit Secure EL1 UNDEF (*not* trap to EL3!) */
+ return CP_ACCESS_TRAP_UNCATEGORIZED;
+ }
+ break;
+ case 2:
+ if (!isread && arm_feature(env, ARM_FEATURE_EL3)) {
+ return CP_ACCESS_TRAP_UNCATEGORIZED;
+ }
+ break;
+ case 3:
+ break;
}
return CP_ACCESS_OK;
}
--
1.9.1