From 2b83714d4ea659899069a4b94aa2dfadc847a013 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 9 Jul 2018 13:45:35 +0100 Subject: [PATCH] target/arm: Use correct mmu_idx for exception-return unstacking For M-profile exception returns, the mmu index to use for exception return unstacking is supposed to be that of wherever we are returning to: * if returning to handler mode, privileged * if returning to thread mode, privileged or unprivileged depending on CONTROL.nPRIV for the destination security state We were passing the wrong thing as the 'priv' argument to arm_v7m_mmu_idx_for_secstate_and_priv(). The effect was that guests which programmed the MPU to behave differently for privileged and unprivileged code could get spurious MemManage Unstack exceptions. Reported-by: Adithya Baglody Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20180709124535.1116-1-peter.maydell@linaro.org --- target/arm/helper.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index a2ac96084e..0604a0efbe 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -7171,9 +7171,11 @@ static void do_v7m_exception_exit(ARMCPU *cpu) uint32_t frameptr = *frame_sp_p; bool pop_ok = true; ARMMMUIdx mmu_idx; + bool return_to_priv = return_to_handler || + !(env->v7m.control[return_to_secure] & R_V7M_CONTROL_NPRIV_MASK); mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, return_to_secure, - !return_to_handler); + return_to_priv); if (!QEMU_IS_ALIGNED(frameptr, 8) && arm_feature(env, ARM_FEATURE_V8)) { -- 2.11.4.GIT