From cb01d3912c8b000ed26d5fe95f6c194b3e3ba7a6 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 23 Feb 2016 15:36:43 +0000 Subject: [PATCH] target-arm: In cpsr_write() ignore mode switches from User mode The only case where we can attempt a cpsr_write() mode switch from User is from the gdbstub; all other cases are handled in the calling code (notably translate.c). Architecturally attempts to alter the mode bits from user mode are simply ignored (and not treated as a bad mode switch, which in v8 sets CPSR.IL). Make mode switches from User ignored in cpsr_write() as well, for consistency. Signed-off-by: Peter Maydell Reviewed-by: Sergey Fedorov Message-id: 1455556977-3644-6-git-send-email-peter.maydell@linaro.org --- target-arm/helper.c | 1 + 1 file changed, 1 insertion(+) diff --git a/target-arm/helper.c b/target-arm/helper.c index c491cd80ab..b2d2440edd 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -5316,6 +5316,7 @@ void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask, env->daif |= val & CPSR_AIF & mask; if (write_type != CPSRWriteRaw && + (env->uncached_cpsr & CPSR_M) != CPSR_USER && ((env->uncached_cpsr ^ val) & mask & CPSR_M)) { if (bad_mode_switch(env, val & CPSR_M)) { /* Attempt to switch to an invalid mode: this is UNPREDICTABLE.