diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
index 5064f559471f..d9cc9b0158f0 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
@@ -70,14 +70,14 @@ void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
   return internal_mmap((void*)fixed_addr, size,
                       PROT_READ | PROT_WRITE,
                       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
-                      0, 0);
+                      -1, 0);
 }
 
 void *Mprotect(uptr fixed_addr, uptr size) {
   return internal_mmap((void*)fixed_addr, size,
                        PROT_NONE,
                        MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
-                       0, 0);
+                       -1, 0);
 }
 
 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
index 1f7bc3b58f4a..e2fe3e8ac238 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
@@ -12,7 +12,9 @@
 // Linux-specific code.
 //===----------------------------------------------------------------------===//
 
+#include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_libc.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
 #include "tsan_platform.h"
 #include "tsan_rtl.h"
 #include "tsan_flags.h"
@@ -79,10 +81,7 @@ static void ProtectRange(uptr beg, uptr end) {
   CHECK_LE(beg, end);
   if (beg == end)
     return;
-  if (beg != (uptr)internal_mmap((void*)(beg), end - beg,
-      PROT_NONE,
-      MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
-      -1, 0)) {
+  if (beg != (uptr)Mprotect(beg, end - beg)) {
     TsanPrintf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end);
     TsanPrintf("FATAL: Make sure you are not using unlimited stack\n");
     Die();
@@ -94,11 +93,8 @@ void InitializeShadowMemory() {
   const uptr kClosedLowEnd  = kLinuxShadowBeg - 1;
   const uptr kClosedMidBeg = kLinuxShadowEnd + 1;
   const uptr kClosedMidEnd = kLinuxAppMemBeg - 1;
-  uptr shadow = (uptr)internal_mmap((void*)kLinuxShadowBeg,
-      kLinuxShadowEnd - kLinuxShadowBeg,
-      PROT_READ | PROT_WRITE,
-      MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
-      -1, 0);
+  uptr shadow = (uptr)MmapFixedNoReserve(kLinuxShadowBeg,
+    kLinuxShadowEnd - kLinuxShadowBeg);
   if (shadow != kLinuxShadowBeg) {
     TsanPrintf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
     TsanPrintf("FATAL: Make sure to compile with -fPIE and "
@@ -122,23 +118,19 @@ void InitializeShadowMemory() {
 
 static void CheckPIE() {
   // Ensure that the binary is indeed compiled with -pie.
-  fd_t fmaps = internal_open("/proc/self/maps", false);
-  if (fmaps == kInvalidFd)
-    return;
-  char buf[20];
-  if (internal_read(fmaps, buf, sizeof(buf)) == sizeof(buf)) {
-    buf[sizeof(buf) - 1] = 0;
-    u64 addr = strtoll(buf, 0, 16);
-    if ((u64)addr < kLinuxAppMemBeg) {
+  ProcessMaps proc_maps;
+  uptr start, end;
+  if (proc_maps.Next(&start, &end,
+                     /*offset*/0, /*filename*/0, /*filename_size*/0)) {
+    if ((u64)start < kLinuxAppMemBeg) {
       TsanPrintf("FATAL: ThreadSanitizer can not mmap the shadow memory ("
              "something is mapped at 0x%zx < 0x%zx)\n",
-             (uptr)addr, kLinuxAppMemBeg);
+             start, kLinuxAppMemBeg);
       TsanPrintf("FATAL: Make sure to compile with -fPIE"
              " and to link with -pie.\n");
       Die();
     }
   }
-  internal_close(fmaps);
 }
 
 #ifdef __i386__
@@ -191,66 +183,12 @@ void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
   *tls_addr -= g_tls_size;
   *tls_size = g_tls_size;
 
-  if (main) {
-    uptr kBufSize = 1 << 26;
-    char *buf = (char*)internal_mmap(0, kBufSize, PROT_READ | PROT_WRITE,
-                               MAP_PRIVATE | MAP_ANON, -1, 0);
-    fd_t maps = internal_open("/proc/self/maps", false);
-    if (maps == kInvalidFd) {
-      TsanPrintf("Failed to open /proc/self/maps\n");
-      Die();
-    }
-    char *end = buf;
-    while (end + kPageSize < buf + kBufSize) {
-      uptr read = internal_read(maps, end, kPageSize);
-      if ((int)read <= 0)
-        break;
-      end += read;
-    }
-    end[0] = 0;
-    end = (char*)REAL(strstr)(buf, "[stack]");
-    if (end == 0) {
-      TsanPrintf("Can't find [stack] in /proc/self/maps\n");
-      Die();
-    }
-    end[0] = 0;
-    char *pos = (char*)internal_strrchr(buf, '\n');
-    if (pos == 0) {
-      TsanPrintf("Can't find [stack] in /proc/self/maps\n");
-      Die();
-    }
-    pos = (char*)internal_strchr(pos, '-');
-    if (pos == 0) {
-      TsanPrintf("Can't find [stack] in /proc/self/maps\n");
-      Die();
-    }
-    uptr stack = 0;
-    for (; pos++;) {
-      uptr num = 0;
-      if (pos[0] >= '0' && pos[0] <= '9')
-        num = pos[0] - '0';
-      else if (pos[0] >= 'a' && pos[0] <= 'f')
-        num = pos[0] - 'a' + 10;
-      else
-        break;
-      stack = stack * 16 + num;
-    }
-    internal_close(maps);
-    internal_munmap(buf, kBufSize);
-
-    struct rlimit rl;
-    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
-    *stk_addr = stack - rl.rlim_cur;
-    *stk_size = rl.rlim_cur;
-  } else {
-    *stk_addr = 0;
-    *stk_size = 0;
-    pthread_attr_t attr;
-    if (pthread_getattr_np(pthread_self(), &attr) == 0) {
-      pthread_attr_getstack(&attr, (void**)stk_addr, (size_t*)stk_size);
-      pthread_attr_destroy(&attr);
-    }
+  uptr stack_top, stack_bottom;
+  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
+  *stk_addr = stack_bottom;
+  *stk_size = stack_top - stack_bottom;
 
+  if (!main) {
     // If stack and tls intersect, make them non-intersecting.
     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
       CHECK_GT(*tls_addr + *tls_size, *stk_addr);