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authorFabian Aggeler <aggelerf@ethz.ch>2014-12-11 12:07:50 +0000
committerPeter Maydell <peter.maydell@linaro.org>2014-12-11 12:07:50 +0000
commit6e8801f9dea9e10449f4fd7d85dbe8cab708a686 (patch)
treea5ef60f3661ba2ba765380f561ff05ce5ff1fba3
parent137feaa9a1622620adf19c0b707883dd990738e2 (diff)
downloadqemu-tz-6e8801f9dea9e10449f4fd7d85dbe8cab708a686.tar.gz
target-arm: respect SCR.FW, SCR.AW and SCTLR.NMFI
Add checks of SCR AW/FW bits when performing writes of CPSR. These SCR bits are used to control whether the CPSR masking bits can be adjusted from non-secure state. Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch> Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1416242878-876-15-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--target-arm/helper.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 769a18239..d43d2087a 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -3644,6 +3644,8 @@ uint32_t cpsr_read(CPUARMState *env)
void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask)
{
+ uint32_t changed_daif;
+
if (mask & CPSR_NZCV) {
env->ZF = (~val) & CPSR_Z;
env->NF = val;
@@ -3666,6 +3668,58 @@ void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask)
env->GE = (val >> 16) & 0xf;
}
+ /* In a V7 implementation that includes the security extensions but does
+ * not include Virtualization Extensions the SCR.FW and SCR.AW bits control
+ * whether non-secure software is allowed to change the CPSR_F and CPSR_A
+ * bits respectively.
+ *
+ * In a V8 implementation, it is permitted for privileged software to
+ * change the CPSR A/F bits regardless of the SCR.AW/FW bits.
+ */
+ if (!arm_feature(env, ARM_FEATURE_V8) &&
+ arm_feature(env, ARM_FEATURE_EL3) &&
+ !arm_feature(env, ARM_FEATURE_EL2) &&
+ !arm_is_secure(env)) {
+
+ changed_daif = (env->daif ^ val) & mask;
+
+ if (changed_daif & CPSR_A) {
+ /* Check to see if we are allowed to change the masking of async
+ * abort exceptions from a non-secure state.
+ */
+ if (!(env->cp15.scr_el3 & SCR_AW)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "Ignoring attempt to switch CPSR_A flag from "
+ "non-secure world with SCR.AW bit clear\n");
+ mask &= ~CPSR_A;
+ }
+ }
+
+ if (changed_daif & CPSR_F) {
+ /* Check to see if we are allowed to change the masking of FIQ
+ * exceptions from a non-secure state.
+ */
+ if (!(env->cp15.scr_el3 & SCR_FW)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "Ignoring attempt to switch CPSR_F flag from "
+ "non-secure world with SCR.FW bit clear\n");
+ mask &= ~CPSR_F;
+ }
+
+ /* Check whether non-maskable FIQ (NMFI) support is enabled.
+ * If this bit is set software is not allowed to mask
+ * FIQs, but is allowed to set CPSR_F to 0.
+ */
+ if ((A32_BANKED_CURRENT_REG_GET(env, sctlr) & SCTLR_NMFI) &&
+ (val & CPSR_F)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "Ignoring attempt to enable CPSR_F flag "
+ "(non-maskable FIQ [NMFI] support enabled)\n");
+ mask &= ~CPSR_F;
+ }
+ }
+ }
+
env->daif &= ~(CPSR_AIF & mask);
env->daif |= val & CPSR_AIF & mask;