armv7m: honour CCR.STACKALIGN on exception entry

The CCR.STACKALIGN bit controls whether the CPU is supposed to force
8-alignment of the stack pointer on entry to the exception handler.

Signed-off-by: Michael Davidsaver <mdavidsaver@gmail.com>
Message-id: 1485285380-10565-6-git-send-email-peter.maydell@linaro.org
[PMM: commit message and comment tweaks]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Michael Davidsaver 2017-01-27 15:20:23 +00:00 committed by Peter Maydell
parent e6b332097d
commit dc858c6633

View File

@ -6110,10 +6110,8 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
return; /* Never happens. Keep compiler happy. */
}
/* Align stack pointer. */
/* ??? Should only do this if Configuration Control Register
STACKALIGN bit is set. */
if (env->regs[13] & 4) {
/* Align stack pointer if the guest wants that */
if ((env->regs[13] & 4) && (env->v7m.ccr & R_V7M_CCR_STKALIGN_MASK)) {
env->regs[13] -= 4;
xpsr |= 0x200;
}