[NFC][compiler-rt][hwasan] Move TagMemoryAligned into hwasan_linux.cpp

[leonardchan]

Summary

Based on comments in D91466, we can make the current implementation linux-speciic. The fuchsia implementation will just be a call to __sanitizer_fill_shadow.

compiler-rt/lib/hwasan/hwasan_linux.cpp

void Thread::InitStackAndTls(const InitState *) {
   uptr tls_size;
   uptr stack_size;
   GetThreadStackAndTls(IsMainThread(), &stack_bottom_, &stack_size, &tls_begin_,
                        &tls_size);
   stack_top_ = stack_bottom_ + stack_size;
   tls_end_ = tls_begin_ + tls_size;
 }
 
+uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
+  CHECK(IsAligned(p, kShadowAlignment));
+  CHECK(IsAligned(size, kShadowAlignment));
+  uptr shadow_start = MemToShadow(p);
+  uptr shadow_size = MemToShadowSize(size);
+
+  uptr page_size = GetPageSizeCached();
+  uptr page_start = RoundUpTo(shadow_start, page_size);
+  uptr page_end = RoundDownTo(shadow_start + shadow_size, page_size);
+  uptr threshold = common_flags()->clear_shadow_mmap_threshold;
+  if (SANITIZER_LINUX &&
+      UNLIKELY(page_end >= page_start + threshold && tag == 0)) {
+    internal_memset((void *)shadow_start, tag, page_start - shadow_start);
+    internal_memset((void *)page_end, tag,
+                    shadow_start + shadow_size - page_end);
+    // For an anonymous private mapping MADV_DONTNEED will return a zero page on
+    // Linux.
+    ReleaseMemoryPagesToOSAndZeroFill(page_start, page_end);
+  } else {
+    internal_memset((void *)shadow_start, tag, shadow_size);
+  }
+  return AddTagToPointer(p, tag);
+}
+
 } // namespace __hwasan
 
 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD

compiler-rt/lib/hwasan/hwasan_poisoning.cpp

 
 #include "hwasan_mapping.h"
 #include "interception/interception.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_linux.h"
 
 namespace __hwasan {
 
-uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
-  CHECK(IsAligned(p, kShadowAlignment));
-  CHECK(IsAligned(size, kShadowAlignment));
-  uptr shadow_start = MemToShadow(p);
-  uptr shadow_size = MemToShadowSize(size);
-
-  uptr page_size = GetPageSizeCached();
-  uptr page_start = RoundUpTo(shadow_start, page_size);
-  uptr page_end = RoundDownTo(shadow_start + shadow_size, page_size);
-  uptr threshold = common_flags()->clear_shadow_mmap_threshold;
-  if (SANITIZER_LINUX &&
-      UNLIKELY(page_end >= page_start + threshold && tag == 0)) {
-    internal_memset((void *)shadow_start, tag, page_start - shadow_start);
-    internal_memset((void *)page_end, tag,
-                    shadow_start + shadow_size - page_end);
-    // For an anonymous private mapping MADV_DONTNEED will return a zero page on
-    // Linux.
-    ReleaseMemoryPagesToOSAndZeroFill(page_start, page_end);
-  } else {
-    internal_memset((void *)shadow_start, tag, shadow_size);
-  }
-  return AddTagToPointer(p, tag);
-}
-
 uptr TagMemory(uptr p, uptr size, tag_t tag) {
   uptr start = RoundDownTo(p, kShadowAlignment);
   uptr end = RoundUpTo(p + size, kShadowAlignment);
   return TagMemoryAligned(start, end - start, tag);
 }
 
 }  // namespace __hwasan