patches/cherry/ad40453fc425ee8e1fe43c7bb6e3c1c3afa9cc3b.patch

From ad40453fc425ee8e1fe43c7bb6e3c1c3afa9cc3b Mon Sep 17 00:00:00 2001
From: Daniel Kiss <daniel.kiss@arm.com>
Date: Mon, 15 Mar 2021 10:24:44 +0100
Subject: [PATCH] [AArch64][compiler-rt] Strip PAC from the link register.
X-ARM-No-Footer: FoSSMail

-mbranch-protection protects the LR on the stack with PAC.
When the frames are walked the LR need to be cleared.
This inline assembly later will be replaced with a new builtin.

Test: build with  -DCMAKE_C_FLAGS="-mbranch-protection=standard".

Reviewed By: kubamracek

Differential Revision: https://reviews.llvm.org/D98008
---
 .../lib/sanitizer_common/sanitizer_ptrauth.h  | 20 ++++++++++++++++-
 .../sanitizer_common/sanitizer_stacktrace.cpp |  3 ++-
 compiler-rt/lib/tsan/rtl/tsan_external.cpp    |  4 ++--
 compiler-rt/lib/tsan/rtl/tsan_interface.cpp   |  8 +++----
 compiler-rt/lib/tsan/rtl/tsan_interface_inl.h | 22 +++++++++----------
 5 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_ptrauth.h b/compiler-rt/lib/sanitizer_common/sanitizer_ptrauth.h
index a288068bf943..b6a8bef06ee4 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_ptrauth.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_ptrauth.h
@@ -11,6 +11,24 @@
 
 #if __has_feature(ptrauth_calls)
 #include <ptrauth.h>
+#elif defined(__ARM_FEATURE_PAC_DEFAULT) && !defined(__APPLE__)
+inline unsigned long ptrauth_strip(unsigned long __value, unsigned int __key) {
+  // On the stack the link register is protected with Pointer
+  // Authentication Code when compiled with -mbranch-protection.
+  // Let's stripping the PAC unconditionally because xpaclri is in
+  // the NOP space so will do nothing when it is not enabled or not available.
+  unsigned long ret;
+  asm volatile(
+      "mov x30, %1\n\t"
+      "hint #7\n\t"  // xpaclri
+      "mov %0, x30\n\t"
+      : "=r"(ret)
+      : "r"(__value)
+      : "x30");
+  return ret;
+}
+#define ptrauth_auth_data(__value, __old_key, __old_data) __value
+#define ptrauth_string_discriminator(__string) ((int)0)
 #else
 // Copied from <ptrauth.h>
 #define ptrauth_strip(__value, __key) __value
@@ -18,6 +36,6 @@
 #define ptrauth_string_discriminator(__string) ((int)0)
 #endif
 
-#define STRIP_PC(pc) ((uptr)ptrauth_strip(pc, 0))
+#define STRIP_PAC_PC(pc) ((uptr)ptrauth_strip((uptr)pc, 0))
 
 #endif // SANITIZER_PTRAUTH_H
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp
index b0487d8987db..ea0d49ac2e8f 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp
@@ -15,6 +15,7 @@
 #include "sanitizer_common.h"
 #include "sanitizer_flags.h"
 #include "sanitizer_platform.h"
+#include "sanitizer_ptrauth.h"
 
 namespace __sanitizer {
 
@@ -122,7 +123,7 @@ void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
     // frame[-1] contains the return address
     uhwptr pc1 = frame[-1];
 #else
-    uhwptr pc1 = frame[1];
+    uhwptr pc1 = STRIP_PAC_PC(frame[1]);
 #endif
     // Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and
     // x86_64) is invalid and stop unwinding here.  If we're adding support for
diff --git a/compiler-rt/lib/tsan/rtl/tsan_external.cpp b/compiler-rt/lib/tsan/rtl/tsan_external.cpp
index 466b2bf0f66c..a87e12f2936f 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_external.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_external.cpp
@@ -111,12 +111,12 @@ void __tsan_external_assign_tag(void *addr, void *tag) {
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_external_read(void *addr, void *caller_pc, void *tag) {
-  ExternalAccess(addr, STRIP_PC(caller_pc), tag, MemoryRead);
+  ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, MemoryRead);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_external_write(void *addr, void *caller_pc, void *tag) {
-  ExternalAccess(addr, STRIP_PC(caller_pc), tag, MemoryWrite);
+  ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, MemoryWrite);
 }
 }  // extern "C"
 
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interface.cpp b/compiler-rt/lib/tsan/rtl/tsan_interface.cpp
index 55f1c9834f70..9bd0e8580b17 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interface.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interface.cpp
@@ -40,13 +40,13 @@ void __tsan_write16(void *addr) {
 }
 
 void __tsan_read16_pc(void *addr, void *pc) {
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog8);
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr + 8, kSizeLog8);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog8);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr + 8, kSizeLog8);
 }
 
 void __tsan_write16_pc(void *addr, void *pc) {
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog8);
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr + 8, kSizeLog8);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog8);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr + 8, kSizeLog8);
 }
 
 // __tsan_unaligned_read/write calls are emitted by compiler.
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interface_inl.h b/compiler-rt/lib/tsan/rtl/tsan_interface_inl.h
index f5d743c10772..5e77d4d3d288 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interface_inl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_interface_inl.h
@@ -51,35 +51,35 @@ void __tsan_write8(void *addr) {
 }
 
 void __tsan_read1_pc(void *addr, void *pc) {
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog1);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog1);
 }
 
 void __tsan_read2_pc(void *addr, void *pc) {
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog2);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog2);
 }
 
 void __tsan_read4_pc(void *addr, void *pc) {
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog4);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog4);
 }
 
 void __tsan_read8_pc(void *addr, void *pc) {
-  MemoryRead(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog8);
+  MemoryRead(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog8);
 }
 
 void __tsan_write1_pc(void *addr, void *pc) {
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog1);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog1);
 }
 
 void __tsan_write2_pc(void *addr, void *pc) {
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog2);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog2);
 }
 
 void __tsan_write4_pc(void *addr, void *pc) {
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog4);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog4);
 }
 
 void __tsan_write8_pc(void *addr, void *pc) {
-  MemoryWrite(cur_thread(), STRIP_PC(pc), (uptr)addr, kSizeLog8);
+  MemoryWrite(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, kSizeLog8);
 }
 
 void __tsan_vptr_update(void **vptr_p, void *new_val) {
@@ -101,7 +101,7 @@ void __tsan_vptr_read(void **vptr_p) {
 }
 
 void __tsan_func_entry(void *pc) {
-  FuncEntry(cur_thread(), STRIP_PC(pc));
+  FuncEntry(cur_thread(), STRIP_PAC_PC(pc));
 }
 
 void __tsan_func_exit() {
@@ -125,9 +125,9 @@ void __tsan_write_range(void *addr, uptr size) {
 }
 
 void __tsan_read_range_pc(void *addr, uptr size, void *pc) {
-  MemoryAccessRange(cur_thread(), STRIP_PC(pc), (uptr)addr, size, false);
+  MemoryAccessRange(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, size, false);
 }
 
 void __tsan_write_range_pc(void *addr, uptr size, void *pc) {
-  MemoryAccessRange(cur_thread(), STRIP_PC(pc), (uptr)addr, size, true);
+  MemoryAccessRange(cur_thread(), STRIP_PAC_PC(pc), (uptr)addr, size, true);
 }
-- 
2.25.1