Snap for 8316345 from af2f109a9c6371bf7f7a5a88ba963b0cd1413357 to sc-qpr3-releaseandroid-12.1.0_r9android-12.1.0_r8android-12.1.0_r7android-12.1.0_r22android-12.1.0_r21android-12.1.0_r20android-12.1.0_r19android-12.1.0_r11android-12.1.0_r10android12-qpr3-s7-releaseandroid12-qpr3-s6-releaseandroid12-qpr3-s5-releaseandroid12-qpr3-s4-releaseandroid12-qpr3-s3-releaseandroid12-qpr3-s2-releaseandroid12-qpr3-s1-releaseandroid12-qpr3-release

Change-Id: I63d045c54b64f785a1cc95e1cc2d8e40f551f03c

2 files changed, 3 insertions, 48 deletions

diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index 08fb187dc..121b26f82 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -45,7 +45,6 @@
 #include "private/bionic_defs.h"
 #include "private/bionic_globals.h"
 #include "platform/bionic/macros.h"
-#include "platform/bionic/pac.h"
 #include "private/bionic_ssp.h"
 #include "private/bionic_systrace.h"
 #include "private/bionic_tls.h"
@@ -332,9 +331,11 @@ void __set_stack_and_tls_vma_name(bool is_main_thread) {
 extern "C" int __rt_sigprocmask(int, const sigset64_t*, sigset64_t*, size_t);
 
 __attribute__((no_sanitize("hwaddress")))
+#ifdef __aarch64__
 // This function doesn't return, but it does appear in stack traces. Avoid using return PAC in this
 // function because we may end up resetting IA, which may confuse unwinders due to mismatching keys.
-__BIONIC_DISABLE_PAUTH
+__attribute__((target("branch-protection=bti")))
+#endif
 static int __pthread_start(void* arg) {
   pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(arg);
 
diff --git a/libc/platform/bionic/pac.h b/libc/platform/bionic/pac.h
index 111460818..34efc48ae 100644
--- a/libc/platform/bionic/pac.h
+++ b/libc/platform/bionic/pac.h
@@ -29,7 +29,6 @@
 #pragma once
 
 #include <stddef.h>
-#include <sys/prctl.h>
 
 inline uintptr_t __bionic_clear_pac_bits(uintptr_t ptr) {
 #if defined(__aarch64__)
@@ -41,48 +40,3 @@ inline uintptr_t __bionic_clear_pac_bits(uintptr_t ptr) {
   return ptr;
 #endif
 }
-
-#ifdef __aarch64__
-// The default setting for branch-protection enables both PAC and BTI, so by
-// overriding it to only enable BTI we disable PAC.
-#define __BIONIC_DISABLE_PAUTH __attribute__((target("branch-protection=bti")))
-#else
-#define __BIONIC_DISABLE_PAUTH
-#endif
-
-#ifdef __aarch64__
-
-#ifndef PR_PAC_SET_ENABLED_KEYS
-#define PR_PAC_SET_ENABLED_KEYS 60
-#endif
-
-#ifndef PR_PAC_GET_ENABLED_KEYS
-#define PR_PAC_GET_ENABLED_KEYS 61
-#endif
-
-// Disable PAC (i.e. make the signing and authentication instructions into no-ops) for the lifetime
-// of this object.
-class ScopedDisablePAC {
-  int prev_enabled_keys_;
-
- public:
-  // Disabling IA will invalidate the return address in this function if it is signed, so we need to
-  // make sure that this function does not sign its return address. Likewise for the destructor.
-  __BIONIC_DISABLE_PAUTH
-  ScopedDisablePAC() {
-    // These prctls will fail (resulting in a no-op, the intended behavior) if PAC is not supported.
-    prev_enabled_keys_ = prctl(PR_PAC_GET_ENABLED_KEYS, 0, 0, 0, 0);
-    prctl(PR_PAC_SET_ENABLED_KEYS, prev_enabled_keys_, 0, 0, 0);
-  }
-
-  __BIONIC_DISABLE_PAUTH
-  ~ScopedDisablePAC() {
-    prctl(PR_PAC_SET_ENABLED_KEYS, prev_enabled_keys_, prev_enabled_keys_, 0, 0);
-  }
-};
-#else
-struct ScopedDisablePAC {
-  // Silence unused variable warnings in non-aarch64 builds.
-  ScopedDisablePAC() {}
-};
-#endif