Index: lib/sanitizer_common/sanitizer_linux.cc
===================================================================
--- lib/sanitizer_common/sanitizer_linux.cc
+++ lib/sanitizer_common/sanitizer_linux.cc
@@ -1736,6 +1736,54 @@
   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
 #endif // SANITIZER_FREEBSD
   return err & PF_WRITE ? WRITE : READ;
+#elif defined(__mips64)
+  long *exception_source;
+  uint32_t faulty_instruction;
+  uint32_t op_code;
+
+  exception_source = (long *)ucontext->uc_mcontext.pc;
+  faulty_instruction = (uint32_t)(*exception_source);
+
+  op_code = (faulty_instruction >> 26) & 0x3f;
+
+  switch (op_code) {
+    case 0x28:  // sb
+    case 0x29:  // sh
+    case 0x2b:  // sw
+    case 0x3f:  // sd
+#if __mips_isa_rev < 6
+    case 0x2c:  // sdl
+    case 0x2d:  // sdr
+    case 0x2a:  // swl
+    case 0x2e:  // swr
+#endif
+      return SignalContext::WRITE;
+
+    case 0x20:  // lb
+    case 0x24:  // lbu
+    case 0x21:  // lh
+    case 0x25:  // lhu
+    case 0x23:  // lw
+    case 0x27:  // lwu
+    case 0x37:  // ld
+#if __mips_isa_rev < 6
+    case 0x1a:  // ldl
+    case 0x1b:  // ldr
+    case 0x22:  // lwl
+    case 0x26:  // lwr
+#endif
+      return SignalContext::READ;
+#if __mips_isa_rev == 6
+    case 0x3b:  // pcrel
+      op_code = (faulty_instruction >> 19) & 0x3;
+      switch (op_code) {
+        case 0x1:  // lwpc
+        case 0x2:  // lwupc
+          return SignalContext::READ;
+      }
+#endif
+  }
+  return SignalContext::UNKNOWN;
 #elif defined(__arm__)
   static const uptr FSR_WRITE = 1U << 11;
   uptr fsr = ucontext->uc_mcontext.error_code;
Index: test/sanitizer_common/TestCases/Posix/illegal_read_test.cc
===================================================================
--- /dev/null
+++ test/sanitizer_common/TestCases/Posix/illegal_read_test.cc
@@ -0,0 +1,14 @@
+// Test that there was an illegal READ memory access.
+// RUN: %clangxx -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+// REQUIRES: stable-runtime
+
+volatile int *null = 0;
+volatile int a;
+
+int main(int argc, char **argv) {
+  a = *null;
+  return 0;
+}
+
+// CHECK: The signal is caused by a READ memory access.
Index: test/sanitizer_common/TestCases/Posix/illegal_write_test.cc
===================================================================
--- /dev/null
+++ test/sanitizer_common/TestCases/Posix/illegal_write_test.cc
@@ -0,0 +1,13 @@
+// Test that there was an illegal WRITE memory access.
+// RUN: %clangxx -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+// REQUIRES: stable-runtime
+
+volatile int *null = 0;
+
+int main(int argc, char **argv) {
+  *null = 0;
+  return 0;
+}
+
+// CHECK: The signal is caused by a WRITE memory access.