[Qemu-devel] [PULL 07/22] armv7m: Clear FAULTMASK on return from non-NMI exceptions

[Peter Maydell <peter.maydell@linaro.org>]

From: Michael Davidsaver <mdavidsaver@gmail.com>

FAULTMASK must be cleared on return from all
exceptions other than NMI.

Signed-off-by: Michael Davidsaver <mdavidsaver@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1484937883-1068-7-git-send-email-peter.maydell@linaro.org
---
 target/arm/helper.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index dc383d1..cfbc622 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5969,8 +5969,13 @@ static void do_v7m_exception_exit(CPUARMState *env)
     uint32_t xpsr;
 
     type = env->regs[15];
-    if (env->v7m.exception != 0)
+    if (env->v7m.exception != ARMV7M_EXCP_NMI) {
+        /* Auto-clear FAULTMASK on return from other than NMI */
+        env->daif &= ~PSTATE_F;
+    }
+    if (env->v7m.exception != 0) {
         armv7m_nvic_complete_irq(env->nvic, env->v7m.exception);
+    }
 
     /* Switch to the target stack.  */
     switch_v7m_sp(env, (type & 4) != 0);
-- 
2.7.4