Commit dc7abe4d authored by Michael Davidsaver's avatar Michael Davidsaver Committed by Peter Maydell
Browse files

armv7m: FAULTMASK should be 0 on reset 



For M profile CPUs, FAULTMASK should be 0 on reset, like PRIMASK.
QEMU stores FAULTMASK in the PSTATE F bit, so (as with PRIMASK in the
I bit) we have to clear these to undo the A profile default of 1.

Update the comment accordingly and move it so that it's closer to the
code it's referring to.

Signed-off-by: default avatarMichael Davidsaver <mdavidsaver@gmail.com>
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Message-id: 1485285380-10565-10-git-send-email-peter.maydell@linaro.org
[PMM: rewrote commit message, moved comments]
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent bdd04fc7

target/arm/cpu.c

+6 −4
Original line number Diff line number Diff line
@@ -179,15 +179,16 @@ static void arm_cpu_reset(CPUState *s) 
    /* SVC mode with interrupts disabled.  */

    env->uncached_cpsr = ARM_CPU_MODE_SVC;

    env->daif = PSTATE_D | PSTATE_A | PSTATE_I | PSTATE_F;

    /* On ARMv7-M the CPSR_I is the value of the PRIMASK register, and is

     * clear at reset. Initial SP and PC are loaded from ROM.

     */



    if (arm_feature(env, ARM_FEATURE_M)) {

        uint32_t initial_msp; /* Loaded from 0x0 */

        uint32_t initial_pc; /* Loaded from 0x4 */

        uint8_t *rom;



        env->daif &= ~PSTATE_I;

        /* For M profile we store FAULTMASK and PRIMASK in the

         * PSTATE F and I bits; these are both clear at reset.

         */

        env->daif &= ~(PSTATE_I | PSTATE_F);



        /* The reset value of this bit is IMPDEF, but ARM recommends

         * that it resets to 1, so QEMU always does that rather than making
@@ -195,6 +196,7 @@ static void arm_cpu_reset(CPUState *s) 
         */

        env->v7m.ccr = R_V7M_CCR_STKALIGN_MASK;



        /* Load the initial SP and PC from the vector table at address 0 */

        rom = rom_ptr(0);

        if (rom) {

            /* Address zero is covered by ROM which hasn't yet been