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[Qemu-devel] [PATCH v2 5/6] target/arm: Clear CPSR.IL and CPSR.J on 32-b

From: Peter Maydell
Subject: [Qemu-devel] [PATCH v2 5/6] target/arm: Clear CPSR.IL and CPSR.J on 32-bit exception entry
Date: Mon, 20 Aug 2018 16:30:19 +0100

On 32-bit exception entry, CPSR.J must always be set to 0
(see v7A Arm ARM DDI0406C.c B1.8.5). CPSR.IL must also
be cleared on 32-bit exception entry (see v8A Arm ARM
DDI0487C.a G1.10).

Clear these bits. (This fixes a bug which will never be noticed
by non-buggy guests.)

Signed-off-by: Peter Maydell <address@hidden>
Not strictly required for Hyp mode, but a minor nit we
can cross off the todo list, and it fits better here
after the refactoring of the exception-exit function.
 target/arm/helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 21a2d438944..f548ba17697 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -8054,6 +8054,8 @@ static void take_aarch32_exception(CPUARMState *env, int 
     if (env->cp15.sctlr_el[arm_current_el(env)] & SCTLR_EE) {
         env->uncached_cpsr |= CPSR_E;
+    /* J and IL must always be cleared for exception entry */
+    env->uncached_cpsr &= ~(CPSR_IL | CPSR_J);
     env->daif |= mask;
     if (new_mode == ARM_CPU_MODE_HYP) {

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