[HWASan] [compiler-rt] support non-4k pages on Android (#95069)

Author: fmayer

compiler-rt/lib/asan/asan_linux.cpp

@@ -93,7 +93,8 @@ uptr FindDynamicShadowStart() {
 #  endif
 
   return MapDynamicShadow(shadow_size_bytes, ASAN_SHADOW_SCALE,
-                          /*min_shadow_base_alignment*/ 0, kHighMemEnd);
+                          /*min_shadow_base_alignment*/ 0, kHighMemEnd,
+                          GetMmapGranularity());
 }
 
 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {

compiler-rt/lib/asan/asan_mac.cpp

@@ -51,7 +51,8 @@ bool IsSystemHeapAddress (uptr addr) { return false; }
 
 uptr FindDynamicShadowStart() {
   return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
-                          /*min_shadow_base_alignment*/ 0, kHighMemEnd);
+                          /*min_shadow_base_alignment*/ 0, kHighMemEnd,
+                          GetMmapGranularity());
 }
 
 // No-op. Mac does not support static linkage anyway.

compiler-rt/lib/asan/asan_premap_shadow.cpp

@@ -33,7 +33,8 @@ uptr PremapShadowSize() {
 // PremapShadowSize() bytes on the right of it are mapped r/o.
 uptr PremapShadow() {
   return MapDynamicShadow(PremapShadowSize(), /*mmap_alignment_scale*/ 3,
-                          /*min_shadow_base_alignment*/ 0, kHighMemEnd);
+                          /*min_shadow_base_alignment*/ 0, kHighMemEnd,
+                          GetMmapGranularity());
 }
 
 bool PremapShadowFailed() {

compiler-rt/lib/hwasan/hwasan_dynamic_shadow.cpp

@@ -36,15 +36,20 @@ decltype(__hwasan_shadow)* __hwasan_premap_shadow();
 
 namespace __hwasan {
 
+// We cannot call anything in libc here (see comment above), so we need to
+// assume the biggest allowed page size.
+// Android max page size is defined as 16k here:
+// https://android.googlesource.com/platform/bionic/+/main/libc/platform/bionic/page.h#41
+static constexpr uptr kMaxGranularity = 16384;
+
 // Conservative upper limit.
 static uptr PremapShadowSize() {
-  return RoundUpTo(GetMaxVirtualAddress() >> kShadowScale,
-                   GetMmapGranularity());
+  return RoundUpTo(GetMaxVirtualAddress() >> kShadowScale, kMaxGranularity);
 }
 
 static uptr PremapShadow() {
   return MapDynamicShadow(PremapShadowSize(), kShadowScale,
-                          kShadowBaseAlignment, kHighMemEnd);
+                          kShadowBaseAlignment, kHighMemEnd, kMaxGranularity);
 }
 
 static bool IsPremapShadowAvailable() {
@@ -56,7 +61,7 @@ static bool IsPremapShadowAvailable() {
 }
 
 static uptr FindPremappedShadowStart(uptr shadow_size_bytes) {
-  const uptr granularity = GetMmapGranularity();
+  const uptr granularity = kMaxGranularity;
   const uptr shadow_start = reinterpret_cast<uptr>(&__hwasan_shadow);
   const uptr premap_shadow_size = PremapShadowSize();
   const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
@@ -109,7 +114,7 @@ uptr FindDynamicShadowStart(uptr shadow_size_bytes) {
   if (IsPremapShadowAvailable())
     return FindPremappedShadowStart(shadow_size_bytes);
   return MapDynamicShadow(shadow_size_bytes, kShadowScale, kShadowBaseAlignment,
-                          kHighMemEnd);
+                          kHighMemEnd, kMaxGranularity);
 }
 
 }  // namespace __hwasan
@@ -135,7 +140,7 @@ uptr FindDynamicShadowStart(uptr shadow_size_bytes) {
                                     RingBufferSize());
 #  endif
   return MapDynamicShadow(shadow_size_bytes, kShadowScale, kShadowBaseAlignment,
-                          kHighMemEnd);
+                          kHighMemEnd, GetMmapGranularity());
 }
 
 }  // namespace __hwasan

compiler-rt/lib/memprof/memprof_linux.cpp

@@ -58,7 +58,8 @@ void InitializePlatformExceptionHandlers() {}
 uptr FindDynamicShadowStart() {
   uptr shadow_size_bytes = MemToShadowSize(kHighMemEnd);
   return MapDynamicShadow(shadow_size_bytes, SHADOW_SCALE,
-                          /*min_shadow_base_alignment*/ 0, kHighMemEnd);
+                          /*min_shadow_base_alignment*/ 0, kHighMemEnd,
+                          GetMmapGranularity());
 }
 
 void *MemprofDlSymNext(const char *sym) { return dlsym(RTLD_NEXT, sym); }

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -60,14 +60,10 @@ inline int Verbosity() {
   return atomic_load(&current_verbosity, memory_order_relaxed);
 }
 
-#if SANITIZER_ANDROID
-inline uptr GetPageSize() {
-// Android post-M sysconf(_SC_PAGESIZE) crashes if called from .preinit_array.
-  return 4096;
-}
-inline uptr GetPageSizeCached() {
-  return 4096;
-}
+#if SANITIZER_ANDROID && !defined(__aarch64__)
+// 32-bit Android only has 4k pages.
+inline uptr GetPageSize() { return 4096; }
+inline uptr GetPageSizeCached() { return 4096; }
 #else
 uptr GetPageSize();
 extern uptr PageSizeCached;
@@ -77,6 +73,7 @@ inline uptr GetPageSizeCached() {
   return PageSizeCached;
 }
 #endif
+
 uptr GetMmapGranularity();
 uptr GetMaxVirtualAddress();
 uptr GetMaxUserVirtualAddress();
@@ -91,6 +88,7 @@ void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 
 // Memory management
 void *MmapOrDie(uptr size, const char *mem_type, bool raw_report = false);
+
 inline void *MmapOrDieQuietly(uptr size, const char *mem_type) {
   return MmapOrDie(size, mem_type, /*raw_report*/ true);
 }
@@ -139,7 +137,8 @@ void UnmapFromTo(uptr from, uptr to);
 // shadow_size_bytes bytes on the right, which on linux is mapped no access.
 // The high_mem_end may be updated if the original shadow size doesn't fit.
 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
-                      uptr min_shadow_base_alignment, uptr &high_mem_end);
+                      uptr min_shadow_base_alignment, uptr &high_mem_end,
+                      uptr granularity);
 
 // Let S = max(shadow_size, num_aliases * alias_size, ring_buffer_size).
 // Reserves 2*S bytes of address space to the right of the returned address and

compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp

@@ -1136,7 +1136,7 @@ uptr GetMaxUserVirtualAddress() {
   return addr;
 }
 
-#  if !SANITIZER_ANDROID
+#  if !SANITIZER_ANDROID || defined(__aarch64__)
 uptr GetPageSize() {
 #    if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__)) && \
         defined(EXEC_PAGESIZE)
@@ -1155,7 +1155,7 @@ uptr GetPageSize() {
   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
 #    endif
 }
-#  endif  // !SANITIZER_ANDROID
+#  endif
 
 uptr ReadBinaryName(/*out*/ char *buf, uptr buf_len) {
 #  if SANITIZER_SOLARIS

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

@@ -995,9 +995,8 @@ void UnmapFromTo(uptr from, uptr to) {
 }
 
 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
-                      uptr min_shadow_base_alignment,
-                      UNUSED uptr &high_mem_end) {
-  const uptr granularity = GetMmapGranularity();
+                      uptr min_shadow_base_alignment, UNUSED uptr &high_mem_end,
+                      uptr granularity) {
   const uptr alignment =
       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
   const uptr left_padding =

compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp

@@ -1188,8 +1188,8 @@ uptr GetMaxVirtualAddress() {
 }
 
 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
-                      uptr min_shadow_base_alignment, uptr &high_mem_end) {
-  const uptr granularity = GetMmapGranularity();
+                      uptr min_shadow_base_alignment, uptr &high_mem_end,
+                      uptr granularity) {
   const uptr alignment =
       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
   const uptr left_padding =

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

@@ -384,9 +384,8 @@ bool DontDumpShadowMemory(uptr addr, uptr length) {
 }
 
 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
-                      uptr min_shadow_base_alignment,
-                      UNUSED uptr &high_mem_end) {
-  const uptr granularity = GetMmapGranularity();
+                      uptr min_shadow_base_alignment, UNUSED uptr &high_mem_end,
+                      uptr granularity) {
   const uptr alignment =
       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
   const uptr left_padding =