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[Qemu-devel] [PATCH v3 7/7] arm: fix aa64_generate_debug_exceptions to w
From: |
Alex Bennée |
Subject: |
[Qemu-devel] [PATCH v3 7/7] arm: fix aa64_generate_debug_exceptions to work with EL2 |
Date: |
Fri, 9 Nov 2018 15:21:19 +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>
---
v3
- further re-arrangement as suggested by rth
---
target/arm/cpu.h | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 1efff21a18..814ff69bc2 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -2764,23 +2764,35 @@ 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)
{
- 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) {
- return false;
- }
+ int cur_el = arm_current_el(env);
+ int debug_el;
+
+ if (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;
- }
+ /* MDCR_EL3.SDD disables debug events from Secure state */
+ if (arm_is_secure_below_el3(env)
+ && extract32(env->cp15.mdcr_el3, 16, 1)) {
+ return false;
}
- return true;
+
+ /*
+ * 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);
+ }
+
+ /* 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 +2845,6 @@ 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
- [Qemu-devel] [PATCH v3 0/7] KVM Guest Debug fixes (plus TCG EL2 debug tweaks), Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 2/7] target/arm64: hold BQL when calling do_interrupt(), Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 7/7] arm: fix aa64_generate_debug_exceptions to work with EL2,
Alex Bennée <=
- [Qemu-devel] [PATCH v3 1/7] target/arm64: properly handle DBGVR RESS bits, Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 3/7] target/arm64: kvm debug set target_el when passing exception to guest, Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 4/7] tests/guest-debug: fix scoping of failcount, Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 5/7] tests/guest-debug: don't use symbol resolution for PC checks, Alex Bennée, 2018/11/09
- [Qemu-devel] [PATCH v3 6/7] arm: use symbolic MDCR_TDE in arm_debug_target_el, Alex Bennée, 2018/11/09
- Re: [Qemu-devel] [PATCH v3 0/7] KVM Guest Debug fixes (plus TCG EL2 debug tweaks), Alex Bennée, 2018/11/09