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 <peter.mayd...@linaro.org> --- 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. -- 2.7.4