[llvm] [llvm-exegesis][AArch64] Check for PAC keys before disabling them (PR #138643)

[Abhilash Majumder via llvm-commits]

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@@ -207,18 +215,50 @@ class ExegesisAArch64Target : public ExegesisTarget {
 
     if (isPointerAuth(Opcode)) {
 #if defined(__aarch64__) && defined(__linux__)
-      // Disable all PAC keys. Note that while we expect the measurements to
-      // be the same with PAC keys disabled, they could potentially be lower
-      // since authentication checks are bypassed.
-      if (prctl(PR_PAC_SET_ENABLED_KEYS,
-                PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY |
-                    PR_PAC_APDBKEY, // all keys
-                0,                  // disable all
-                0, 0) < 0) {
-        return "Failed to disable PAC keys";
+      // Only proceed with PAC key control if explicitly requested
+      if (!AArch64DisablePacControl) {
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abhilash1910 wrote:

@tuliom  could you help to check if regression is there on cortex with the latest commit ? Thanks

https://github.com/llvm/llvm-project/pull/138643