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authorPeter Maydell <peter.maydell@linaro.org>2016-02-15 17:22:49 +0000
committerPeter Maydell <peter.maydell@linaro.org>2016-02-18 18:14:00 +0000
commita97b8a66da2ea4e0cb9be9a36a20d39b795ba245 (patch)
tree5737f80d7f9ff34c21879e0322d881e6da6581d8
parenta60a2f18738fc420664b21a070f12d4966a21c5a (diff)
downloadqemu-arm-a97b8a66da2ea4e0cb9be9a36a20d39b795ba245.tar.gz
target-arm: Raw CPSR writes should skip checks and bank switching
Raw CPSR writes should skip the architectural checks for whether we're allowed to set the A or F bits and should also not do the switching of register banks if the mode changes. Handle this inside cpsr_write(), which allows us to drop the "manually set the mode bits to avoid the bank switch" code from all the callsites which are using CPSRWriteRaw. This fixes a bug in 32-bit KVM handling where we had forgotten the "manually set the mode bits" part and could thus potentially trash the register state if the mode from the last exit to userspace differed from the mode on this exit. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Sergey Fedorov <serge.fdrv@gmail.com> Message-id: 1455556977-3644-4-git-send-email-peter.maydell@linaro.org
-rw-r--r--target-arm/helper.c5
-rw-r--r--target-arm/kvm64.c1
-rw-r--r--target-arm/machine.c2
-rw-r--r--target-arm/op_helper.c5
4 files changed, 7 insertions, 6 deletions
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 014bb80d85..c491cd80ab 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5268,7 +5268,7 @@ void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask,
* 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) &&
+ if (write_type != CPSRWriteRaw && !arm_feature(env, ARM_FEATURE_V8) &&
arm_feature(env, ARM_FEATURE_EL3) &&
!arm_feature(env, ARM_FEATURE_EL2) &&
!arm_is_secure(env)) {
@@ -5315,7 +5315,8 @@ void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask,
env->daif &= ~(CPSR_AIF & mask);
env->daif |= val & CPSR_AIF & mask;
- if ((env->uncached_cpsr ^ val) & mask & CPSR_M) {
+ if (write_type != CPSRWriteRaw &&
+ ((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.
* We choose to ignore the attempt and leave the CPSR M field
diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
index 08c2c81479..e8527bf0cc 100644
--- a/target-arm/kvm64.c
+++ b/target-arm/kvm64.c
@@ -722,7 +722,6 @@ int kvm_arch_get_registers(CPUState *cs)
if (is_a64(env)) {
pstate_write(env, val);
} else {
- env->uncached_cpsr = val & CPSR_M;
cpsr_write(env, val, 0xffffffff, CPSRWriteRaw);
}
diff --git a/target-arm/machine.c b/target-arm/machine.c
index 0fc7df0ee2..03a73d950e 100644
--- a/target-arm/machine.c
+++ b/target-arm/machine.c
@@ -173,8 +173,6 @@ static int get_cpsr(QEMUFile *f, void *opaque, size_t size)
return 0;
}
- /* Avoid mode switch when restoring CPSR */
- env->uncached_cpsr = val & CPSR_M;
cpsr_write(env, val, 0xffffffff, CPSRWriteRaw);
return 0;
}
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index 543d33aad2..4881e34177 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -779,7 +779,10 @@ void HELPER(exception_return)(CPUARMState *env)
if (!return_to_aa64) {
env->aarch64 = 0;
- env->uncached_cpsr = spsr & CPSR_M;
+ /* We do a raw CPSR write because aarch64_sync_64_to_32()
+ * will sort the register banks out for us, and we've already
+ * caught all the bad-mode cases in el_from_spsr().
+ */
cpsr_write(env, spsr, ~0, CPSRWriteRaw);
if (!arm_singlestep_active(env)) {
env->uncached_cpsr &= ~PSTATE_SS;