On 15.02.2016 20:22, Peter Maydell wrote:
> 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 <peter.mayd...@linaro.org>
Reviewed-by: Sergey Fedorov <serge.f...@gmail.com>
> ---
> target-arm/helper.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index d1919bb..9998a25 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -5282,6 +5282,7 @@ 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.
