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[Qemu-devel] [PULL 01/21] target/arm: Fix cpu_get_tb_cpu_state() for non


From: Peter Maydell
Subject: [Qemu-devel] [PULL 01/21] target/arm: Fix cpu_get_tb_cpu_state() for non-SVE CPUs
Date: Tue, 25 Sep 2018 14:41:24 +0100

From: Richard Henderson <address@hidden>

Not only are the sve-related tb_flags fields unused when SVE is
disabled, but not all of the cpu registers are initialized properly
for computing same.  This can corrupt other fields by ORing in -1,
which might result in QEMU crashing.

This bug was not present in 3.0, but this patch is cc'd to
stable because adf92eab90e3f5f34c285 where the bug was
introduced was marked for stable.

Fixes: adf92eab90e3f5f34c285
Cc: address@hidden (3.0.1)
Signed-off-by: Richard Henderson <address@hidden>
Reviewed-by: Peter Maydell <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>
---
 target/arm/helper.c | 45 ++++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 088f452716e..64b15645944 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -12587,36 +12587,39 @@ void cpu_get_tb_cpu_state(CPUARMState *env, 
target_ulong *pc,
     uint32_t flags;
 
     if (is_a64(env)) {
-        int sve_el = sve_exception_el(env);
-        uint32_t zcr_len;
-
         *pc = env->pc;
         flags = ARM_TBFLAG_AARCH64_STATE_MASK;
         /* Get control bits for tagged addresses */
         flags |= (arm_regime_tbi0(env, mmu_idx) << ARM_TBFLAG_TBI0_SHIFT);
         flags |= (arm_regime_tbi1(env, mmu_idx) << ARM_TBFLAG_TBI1_SHIFT);
-        flags |= sve_el << ARM_TBFLAG_SVEEXC_EL_SHIFT;
 
-        /* If SVE is disabled, but FP is enabled,
-           then the effective len is 0.  */
-        if (sve_el != 0 && fp_el == 0) {
-            zcr_len = 0;
-        } else {
-            int current_el = arm_current_el(env);
-            ARMCPU *cpu = arm_env_get_cpu(env);
+        if (arm_feature(env, ARM_FEATURE_SVE)) {
+            int sve_el = sve_exception_el(env);
+            uint32_t zcr_len;
 
-            zcr_len = cpu->sve_max_vq - 1;
-            if (current_el <= 1) {
-                zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[1]);
-            }
-            if (current_el < 2 && arm_feature(env, ARM_FEATURE_EL2)) {
-                zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[2]);
-            }
-            if (current_el < 3 && arm_feature(env, ARM_FEATURE_EL3)) {
-                zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[3]);
+            /* If SVE is disabled, but FP is enabled,
+             * then the effective len is 0.
+             */
+            if (sve_el != 0 && fp_el == 0) {
+                zcr_len = 0;
+            } else {
+                int current_el = arm_current_el(env);
+                ARMCPU *cpu = arm_env_get_cpu(env);
+
+                zcr_len = cpu->sve_max_vq - 1;
+                if (current_el <= 1) {
+                    zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[1]);
+                }
+                if (current_el < 2 && arm_feature(env, ARM_FEATURE_EL2)) {
+                    zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[2]);
+                }
+                if (current_el < 3 && arm_feature(env, ARM_FEATURE_EL3)) {
+                    zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[3]);
+                }
             }
+            flags |= sve_el << ARM_TBFLAG_SVEEXC_EL_SHIFT;
+            flags |= zcr_len << ARM_TBFLAG_ZCR_LEN_SHIFT;
         }
-        flags |= zcr_len << ARM_TBFLAG_ZCR_LEN_SHIFT;
     } else {
         *pc = env->regs[15];
         flags = (env->thumb << ARM_TBFLAG_THUMB_SHIFT)
-- 
2.19.0




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