target/arm: Warn about restoring to unaligned stack

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.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1506092407-26985-8-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2017-10-06 16:46:48 +01:00
parent 224e0c300a
commit cb484f9a6e

View file

@ -6413,6 +6413,13 @@ 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.