On 09/22/2017 11:59 AM, Peter Maydell wrote:
Attempting to do an exception return with an exception frame that
is not 8-aligned is UNPREDICTABLE in v8M; warn about this.
(It is not UNPREDICTABLE in v7M, and our implementation can
handle the merely-4-aligned case fine, so we don't need to
do anything except warn.)
Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
---
target/arm/helper.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/target/arm/helper.c b/target/arm/helper.c
index a2e46fb..979129e 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6403,6 +6403,13 @@ static void do_v7m_exception_exit(ARMCPU *cpu)
return_to_sp_process);
uint32_t frameptr = *frame_sp_p;
+ if (!QEMU_IS_ALIGNED(frameptr, 8) &&
+ arm_feature(env, ARM_FEATURE_V8)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "M profile exception return with non-8-aligned SP "
+ "for destination state is UNPREDICTABLE\n");
+ }
+
/* Pop registers. TODO: make these accesses use the correct
* attributes and address space (S/NS, priv/unpriv) and handle
* memory transaction failures.
