commit b9df41f15d36d793eac76368c4c9f36e804def52
author Peter Collingbourne <peter@pcc.me.uk> Thu Dec 17 21:02:01 2020 -0800
committer Copybara-Service <copybara-worker@google.com> Sun Jan 03 16:03:31 2021 -0800
tree 4525e5b9b30d8367f2d6e7752b105c8c172c2db2
parent 19dd965e49bc1119625765a09c757082846ec53f

scudo: Remove ANDROID_EXPERIMENTAL_MTE macro.

Kernel support for MTE has been released in Linux 5.10. This means
that it is a stable API and we no longer need to make the support
conditional on a macro. We do need to provide conditional definitions
of the new macros though in order to avoid a dependency on new
kernel headers.

Differential Revision: https://reviews.llvm.org/D93513

GitOrigin-RevId: dfa40840e0e2fa094c5d3f441affe0785cdc8d09

linux.cpp

diff --git a/linux.cpp b/linux.cpp
index 12f3da6..d246467 100644
--- a/linux.cpp
+++ b/linux.cpp
@@ -35,10 +35,6 @@
 #define ANDROID_PR_SET_VMA_ANON_NAME 0
 #endif
 
-#ifdef ANDROID_EXPERIMENTAL_MTE
-#include <bionic/mte_kernel.h>
-#endif
-
 namespace scudo {
 
 uptr getPageSize() { return static_cast<uptr>(sysconf(_SC_PAGESIZE)); }
@@ -54,7 +50,10 @@
     MmapProt = PROT_NONE;
   } else {
     MmapProt = PROT_READ | PROT_WRITE;
-#if defined(__aarch64__) && defined(ANDROID_EXPERIMENTAL_MTE)
+#if defined(__aarch64__)
+#ifndef PROT_MTE
+#define PROT_MTE 0x20
+#endif
     if (Flags & MAP_MEMTAG)
       MmapProt |= PROT_MTE;
 #endif

memtag.h

diff --git a/memtag.h b/memtag.h
index 4b22c72..c3c4f57 100644
--- a/memtag.h
+++ b/memtag.h
@@ -14,9 +14,6 @@
 #if SCUDO_LINUX
 #include <sys/auxv.h>
 #include <sys/prctl.h>
-#if defined(ANDROID_EXPERIMENTAL_MTE)
-#include <bionic/mte_kernel.h>
-#endif
 #endif
 
 namespace scudo {
@@ -56,20 +53,28 @@
 #if defined(__aarch64__)
 
 inline bool systemSupportsMemoryTagging() {
-#if defined(ANDROID_EXPERIMENTAL_MTE)
-  return getauxval(AT_HWCAP2) & HWCAP2_MTE;
-#else
-  return false;
+#ifndef HWCAP2_MTE
+#define HWCAP2_MTE (1 << 18)
 #endif
+  return getauxval(AT_HWCAP2) & HWCAP2_MTE;
 }
 
 inline bool systemDetectsMemoryTagFaultsTestOnly() {
-#if defined(ANDROID_EXPERIMENTAL_MTE)
-  return (prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0) & PR_MTE_TCF_MASK) !=
-         PR_MTE_TCF_NONE;
-#else
-  return false;
+#ifndef PR_GET_TAGGED_ADDR_CTRL
+#define PR_GET_TAGGED_ADDR_CTRL 56
 #endif
+#ifndef PR_MTE_TCF_SHIFT
+#define PR_MTE_TCF_SHIFT 1
+#endif
+#ifndef PR_MTE_TCF_NONE
+#define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT)
+#endif
+#ifndef PR_MTE_TCF_MASK
+#define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT)
+#endif
+  return (static_cast<unsigned long>(
+              prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0)) &
+          PR_MTE_TCF_MASK) != PR_MTE_TCF_NONE;
 }
 
 inline void disableMemoryTagChecksTestOnly() {