diff options
| -rw-r--r-- | target-arm/helper.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/target-arm/helper.c b/target-arm/helper.c index 7fe3d14773..10886c5281 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -4334,6 +4334,16 @@ static void do_v7m_exception_exit(CPUARMState *env) env->regs[12] = v7m_pop(env); env->regs[14] = v7m_pop(env); env->regs[15] = v7m_pop(env); + if (env->regs[15] & 1) { + qemu_log_mask(LOG_GUEST_ERROR, + "M profile return from interrupt with misaligned " + "PC is UNPREDICTABLE\n"); + /* Actual hardware seems to ignore the lsbit, and there are several + * RTOSes out there which incorrectly assume the r15 in the stack + * frame should be a Thumb-style "lsbit indicates ARM/Thumb" value. + */ + env->regs[15] &= ~1U; + } xpsr = v7m_pop(env); xpsr_write(env, xpsr, 0xfffffdff); /* Undo stack alignment. */ |