diff options
| -rw-r--r-- | target/arm/m_helper.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/target/arm/m_helper.c b/target/arm/m_helper.c index aad01ea012..721b4b4896 100644 --- a/target/arm/m_helper.c +++ b/target/arm/m_helper.c @@ -897,10 +897,12 @@ static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr, bool dotailchain, * Clear registers if necessary to prevent non-secure exception * code being able to see register values from secure code. * Where register values become architecturally UNKNOWN we leave - * them with their previous values. + * them with their previous values. v8.1M is tighter than v8.0M + * here and always zeroes the caller-saved registers regardless + * of the security state the exception is targeting. */ if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { - if (!targets_secure) { + if (!targets_secure || arm_feature(env, ARM_FEATURE_V8_1M)) { /* * Always clear the caller-saved registers (they have been * pushed to the stack earlier in v7m_push_stack()). @@ -909,10 +911,16 @@ static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr, bool dotailchain, * v7m_push_callee_stack()). */ int i; + /* + * r4..r11 are callee-saves, zero only if background + * state was Secure (EXCRET.S == 1) and exception + * targets Non-secure state + */ + bool zero_callee_saves = !targets_secure && + (lr & R_V7M_EXCRET_S_MASK); for (i = 0; i < 13; i++) { - /* r4..r11 are callee-saves, zero only if EXCRET.S == 1 */ - if (i < 4 || i > 11 || (lr & R_V7M_EXCRET_S_MASK)) { + if (i < 4 || i > 11 || zero_callee_saves) { env->regs[i] = 0; } } |