[PATCH v3 4/8] target/arm: Implement v8.3 EnhancedPAC

[Aaron Lindsay <aaron@os.amperecomputing.com>]

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/pauth_helper.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/target/arm/tcg/pauth_helper.c b/target/arm/tcg/pauth_helper.c
index 122c208de2..7682f139ef 100644
--- a/target/arm/tcg/pauth_helper.c
+++ b/target/arm/tcg/pauth_helper.c
@@ -326,6 +326,7 @@ static uint64_t pauth_computepac(CPUARMState *env, uint64_t data,
 static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
                              ARMPACKey *key, bool data)
 {
+    ARMCPU *cpu = env_archcpu(env);
     ARMMMUIdx mmu_idx = arm_stage1_mmu_idx(env);
     ARMVAParameters param = aa64_va_parameters(env, ptr, mmu_idx, data);
     uint64_t pac, ext_ptr, ext, test;
@@ -351,11 +352,15 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
      */
     test = sextract64(ptr, bot_bit, top_bit - bot_bit);
     if (test != 0 && test != -1) {
-        /*
-         * Note that our top_bit is one greater than the pseudocode's
-         * version, hence "- 2" here.
-         */
-        pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
+        if (cpu_isar_feature(aa64_pauth_epac, cpu)) {
+            pac = 0;
+        } else {
+            /*
+             * Note that our top_bit is one greater than the pseudocode's
+             * version, hence "- 2" here.
+             */
+            pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
+        }
     }
 
     /*
-- 
2.25.1