[PATCH 4/7] target/arm: Implement v8.3 Pauth2

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

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
---
 target/arm/pauth_helper.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
index a83956652f..6ebf6df75c 100644
--- a/target/arm/pauth_helper.c
+++ b/target/arm/pauth_helper.c
@@ -349,7 +349,7 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
     if (test != 0 && test != -1) {
         if (cpu_isar_feature(aa64_pauth_epac, env_archcpu(env))) {
             pac = 0;
-        } else {
+        } else if (! cpu_isar_feature(aa64_pauth2, env_archcpu(env))) {
             /*
              * Note that our top_bit is one greater than the pseudocode's
              * version, hence "- 2" here.
@@ -362,6 +362,8 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
      * Preserve the determination between upper and lower at bit 55,
      * and insert pointer authentication code.
      */
+    if (cpu_isar_feature(aa64_pauth2, env_archcpu(env)))
+        pac ^= ptr;
     if (param.tbi) {
         ptr &= ~MAKE_64BIT_MASK(bot_bit, 55 - bot_bit + 1);
         pac &= MAKE_64BIT_MASK(bot_bit, 54 - bot_bit + 1);
@@ -389,23 +391,30 @@ static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
     ARMMMUIdx mmu_idx = arm_stage1_mmu_idx(env);
     ARMVAParameters param = aa64_va_parameters(env, ptr, mmu_idx, data);
     int bot_bit, top_bit;
-    uint64_t pac, orig_ptr, test;
+    uint64_t pac, orig_ptr, test, result;
 
     orig_ptr = pauth_original_ptr(ptr, param);
     pac = pauth_computepac(env, orig_ptr, modifier, *key);
     bot_bit = 64 - param.tsz;
     top_bit = 64 - 8 * param.tbi;
 
-    test = (pac ^ ptr) & ~MAKE_64BIT_MASK(55, 1);
-    if (unlikely(extract64(test, bot_bit, top_bit - bot_bit))) {
-        int error_code = (keynumber << 1) | (keynumber ^ 1);
-        if (param.tbi) {
-            return deposit64(orig_ptr, 53, 2, error_code);
-        } else {
-            return deposit64(orig_ptr, 61, 2, error_code);
+    if (cpu_isar_feature(aa64_pauth2, env_archcpu(env))) {
+        uint64_t xor_mask = MAKE_64BIT_MASK(bot_bit, top_bit - bot_bit + 1) &
+            ~MAKE_64BIT_MASK(55, 1);
+        result = ((ptr ^ pac) & xor_mask) | (ptr & ~xor_mask);
+    } else {
+        test = (pac ^ ptr) & ~MAKE_64BIT_MASK(55, 1);
+        if (unlikely(extract64(test, bot_bit, top_bit - bot_bit))) {
+            int error_code = (keynumber << 1) | (keynumber ^ 1);
+            if (param.tbi) {
+                return deposit64(orig_ptr, 53, 2, error_code);
+            } else {
+                return deposit64(orig_ptr, 61, 2, error_code);
+            }
         }
+        result = orig_ptr;
     }
-    return orig_ptr;
+    return result;
 }
 
 static uint64_t pauth_strip(CPUARMState *env, uint64_t ptr, bool data)
-- 
2.25.1