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[Qemu-arm] [PATCH v2 6/6] arm: fix aa64_generate_debug_exceptions to wor
From: |
Alex Bennée |
Subject: |
[Qemu-arm] [PATCH v2 6/6] arm: fix aa64_generate_debug_exceptions to work with EL2 |
Date: |
Thu, 8 Nov 2018 16:33:29 +0000 |
The test was incomplete and incorrectly caused debug exceptions to be
generated when returning to EL2 after a failed attempt to single-step
an EL1 instruction. Fix this while cleaning up the function a little.
Signed-off-by: Alex Bennée <address@hidden>
---
target/arm/cpu.h | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 1efff21a18..a6d8eb14f6 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -2764,23 +2764,33 @@ static inline bool arm_v7m_csselr_razwi(ARMCPU *cpu)
return (cpu->clidr & R_V7M_CLIDR_CTYPE_ALL_MASK) != 0;
}
+/* See AArch64.GenerateDebugExceptionsFrom() in ARM ARM pseudocode */
static inline bool aa64_generate_debug_exceptions(CPUARMState *env)
{
+ int cur_el = arm_current_el(env);
+ int debug_el;
+
if (arm_is_secure(env)) {
/* MDCR_EL3.SDD disables debug events from Secure state */
if (extract32(env->cp15.mdcr_el3, 16, 1) != 0
- || arm_current_el(env) == 3) {
+ || cur_el == 3) {
return false;
}
}
- if (arm_current_el(env) == arm_debug_target_el(env)) {
- if ((extract32(env->cp15.mdscr_el1, 13, 1) == 0)
- || (env->daif & PSTATE_D)) {
- return false;
- }
+ /*
+ * Same EL to same EL debug exceptions need MDSCR_KDE enabled
+ * while not masking the (D)ebug bit in DAIF.
+ */
+ debug_el = arm_debug_target_el(env);
+
+ if (cur_el == debug_el) {
+ return extract32(env->cp15.mdscr_el1, 13, 1)
+ && !(env->daif & PSTATE_D);
}
- return true;
+
+ /* Otherwise the debug target needs to be a higher EL */
+ return debug_el > cur_el;
}
static inline bool aa32_generate_debug_exceptions(CPUARMState *env)
@@ -2833,9 +2843,6 @@ static inline bool
aa32_generate_debug_exceptions(CPUARMState *env)
* since the pseudocode has it at all callsites except for the one in
* CheckSoftwareStep(), where it is elided because both branches would
* always return the same value.
- *
- * Parts of the pseudocode relating to EL2 and EL3 are omitted because we
- * don't yet implement those exception levels or their associated trap bits.
*/
static inline bool arm_generate_debug_exceptions(CPUARMState *env)
{
--
2.17.1
- Re: [Qemu-arm] [Qemu-devel] [PATCH v2 3/6] target/arm64: kvm debug set target_el when passing exception to guest, (continued)