[HWASan] Introduce non-zero based and dynamic shadow memory (compiler-rt).

Retire the fixed shadow memory mapping to avoid conflicts with default
process memory mapping (currently manifests on Android).

Tests on AArch64 show <1% performance loss and code size increase,
making it possible to use dynamic shadow memory by default.

Keep the fixed shadow memory mapping around to be able to run
performance comparison tests later.

Re-commiting D45847 with fixed shadow for x86-64.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@330624 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 169 insertions, 70 deletions

diff --git a/lib/hwasan/CMakeLists.txt b/lib/hwasan/CMakeLists.txt
index 88a1e8c53..a808d9e23 100644
--- a/lib/hwasan/CMakeLists.txt
+++ b/lib/hwasan/CMakeLists.txt
@@ -4,11 +4,12 @@ include_directories(..)
 set(HWASAN_RTL_SOURCES
   hwasan.cc
   hwasan_allocator.cc
+  hwasan_dynamic_shadow.cc
   hwasan_interceptors.cc
   hwasan_linux.cc
+  hwasan_poisoning.cc
   hwasan_report.cc
   hwasan_thread.cc
-  hwasan_poisoning.cc
   )
 
 set(HWASAN_RTL_CXX_SOURCES
diff --git a/lib/hwasan/hwasan.cc b/lib/hwasan/hwasan.cc
index 5aa69a510..d300e0bde 100644
--- a/lib/hwasan/hwasan.cc
+++ b/lib/hwasan/hwasan.cc
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "hwasan.h"
+#include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 #include "hwasan_poisoning.h"
 #include "sanitizer_common/sanitizer_atomic.h"
@@ -157,6 +158,8 @@ static void HWAsanCheckFailed(const char *file, int line, const char *cond,
 
 using namespace __hwasan;
 
+uptr __hwasan_shadow_memory_dynamic_address;  // Global interface symbol.
+
 void __hwasan_init() {
   CHECK(!hwasan_init_is_running);
   if (hwasan_inited) return;
@@ -179,11 +182,13 @@ void __hwasan_init() {
 
   DisableCoreDumperIfNecessary();
   if (!InitShadow()) {
-    Printf("FATAL: HWAddressSanitizer can not mmap the shadow memory.\n");
-    Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
-    Printf("FATAL: Disabling ASLR is known to cause this error.\n");
-    Printf("FATAL: If running under GDB, try "
-           "'set disable-randomization off'.\n");
+    Printf("FATAL: HWAddressSanitizer cannot mmap the shadow memory.\n");
+    if (HWASAN_FIXED_MAPPING) {
+      Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
+      Printf("FATAL: Disabling ASLR is known to cause this error.\n");
+      Printf("FATAL: If running under GDB, try "
+             "'set disable-randomization off'.\n");
+    }
     DumpProcessMap();
     Die();
   }
diff --git a/lib/hwasan/hwasan.h b/lib/hwasan/hwasan.h
index 604c97024..3c6b44f7f 100644
--- a/lib/hwasan/hwasan.h
+++ b/lib/hwasan/hwasan.h
@@ -32,16 +32,6 @@
 
 typedef u8 tag_t;
 
-// Reasonable values are 4 (for 1/16th shadow) and 6 (for 1/64th).
-const uptr kShadowScale = 4;
-const uptr kShadowAlignment = 1UL << kShadowScale;
-
-#define MEM_TO_SHADOW_OFFSET(mem) ((uptr)(mem) >> kShadowScale)
-#define MEM_TO_SHADOW(mem) ((uptr)(mem) >> kShadowScale)
-#define SHADOW_TO_MEM(shadow) ((uptr)(shadow) << kShadowScale)
-
-#define MEM_IS_APP(mem) MemIsApp((uptr)(mem))
-
 // TBI (Top Byte Ignore) feature of AArch64: bits [63:56] are ignored in address
 // translation and can be used to store a tag.
 const unsigned kAddressTagShift = 56;
@@ -69,8 +59,6 @@ extern int hwasan_inited;
 extern bool hwasan_init_is_running;
 extern int hwasan_report_count;
 
-bool MemIsApp(uptr p);
-
 bool ProtectRange(uptr beg, uptr end);
 bool InitShadow();
 char *GetProcSelfMaps();
diff --git a/lib/hwasan/hwasan_allocator.cc b/lib/hwasan/hwasan_allocator.cc
index d1df1452f..3a9da80d9 100644
--- a/lib/hwasan/hwasan_allocator.cc
+++ b/lib/hwasan/hwasan_allocator.cc
@@ -20,6 +20,7 @@
 #include "sanitizer_common/sanitizer_stackdepot.h"
 #include "hwasan.h"
 #include "hwasan_allocator.h"
+#include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 #include "hwasan_poisoning.h"
 
diff --git a/lib/hwasan/hwasan_interceptors.cc b/lib/hwasan/hwasan_interceptors.cc
index 7b89e56f5..dfd35b59c 100644
--- a/lib/hwasan/hwasan_interceptors.cc
+++ b/lib/hwasan/hwasan_interceptors.cc
@@ -17,6 +17,7 @@
 
 #include "interception/interception.h"
 #include "hwasan.h"
+#include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 #include "hwasan_poisoning.h"
 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
diff --git a/lib/hwasan/hwasan_interface_internal.h b/lib/hwasan/hwasan_interface_internal.h
index 54639f9c1..b4e5c8090 100644
--- a/lib/hwasan/hwasan_interface_internal.h
+++ b/lib/hwasan/hwasan_interface_internal.h
@@ -18,6 +18,7 @@
 #include "sanitizer_common/sanitizer_internal_defs.h"
 
 extern "C" {
+
 SANITIZER_INTERFACE_ATTRIBUTE
 void __hwasan_init();
 
@@ -32,6 +33,9 @@ using __sanitizer::u16;
 using __sanitizer::u8;
 
 SANITIZER_INTERFACE_ATTRIBUTE
+extern uptr __hwasan_shadow_memory_dynamic_address;
+
+SANITIZER_INTERFACE_ATTRIBUTE
 void __hwasan_loadN(uptr, uptr);
 SANITIZER_INTERFACE_ATTRIBUTE
 void __hwasan_load1(uptr);
diff --git a/lib/hwasan/hwasan_linux.cc b/lib/hwasan/hwasan_linux.cc
index 69e4a8d48..693e3b5b3 100644
--- a/lib/hwasan/hwasan_linux.cc
+++ b/lib/hwasan/hwasan_linux.cc
@@ -1,4 +1,4 @@
-//===-- hwasan_linux.cc -----------------------------------------------------===//
+//===-- hwasan_linux.cc -----------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -6,35 +6,39 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
-//
-// This file is a part of HWAddressSanitizer.
-//
-// Linux-, NetBSD- and FreeBSD-specific code.
+///
+/// \file
+/// This file is a part of HWAddressSanitizer and contains Linux-, NetBSD- and
+/// FreeBSD-specific code.
+///
 //===----------------------------------------------------------------------===//
 
 #include "sanitizer_common/sanitizer_platform.h"
 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
 
 #include "hwasan.h"
+#include "hwasan_dynamic_shadow.h"
+#include "hwasan_interface_internal.h"
+#include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 
 #include <elf.h>
 #include <link.h>
 #include <pthread.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <signal.h>
+#include <sys/resource.h>
+#include <sys/time.h>
 #include <unistd.h>
 #include <unwind.h>
-#include <sys/time.h>
-#include <sys/resource.h>
 
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_procmaps.h"
 
 namespace __hwasan {
 
-void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name) {
+static void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name) {
   CHECK_EQ((beg % GetMmapGranularity()), 0);
   CHECK_EQ(((end + 1) % GetMmapGranularity()), 0);
   uptr size = end - beg + 1;
@@ -52,8 +56,11 @@ void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name) {
 }
 
 static void ProtectGap(uptr addr, uptr size) {
+  if (!size)
+    return;
   void *res = MmapFixedNoAccess(addr, size, "shadow gap");
-  if (addr == (uptr)res) return;
+  if (addr == (uptr)res)
+    return;
   // A few pages at the start of the address space can not be protected.
   // But we really want to protect as much as possible, to prevent this memory
   // being returned as a result of a non-FIXED mmap().
@@ -63,69 +70,158 @@ static void ProtectGap(uptr addr, uptr size) {
       addr += step;
       size -= step;
       void *res = MmapFixedNoAccess(addr, size, "shadow gap");
-      if (addr == (uptr)res) return;
+      if (addr == (uptr)res)
+        return;
     }
   }
 
   Report(
-      "ERROR: Failed to protect the shadow gap. "
-      "HWASan cannot proceed correctly. ABORTING.\n");
+      "ERROR: Failed to protect shadow gap [%p, %p]. "
+      "HWASan cannot proceed correctly. ABORTING.\n", (void *)addr,
+      (void *)(addr + size));
   DumpProcessMap();
   Die();
 }
 
-// LowMem covers as much of the first 4GB as possible.
-const uptr kLowMemEnd = 1UL << 32;
-const uptr kLowShadowEnd = kLowMemEnd >> kShadowScale;
-const uptr kLowShadowStart = kLowShadowEnd >> kShadowScale;
+static uptr kLowMemStart;
+static uptr kLowMemEnd;
+static uptr kLowShadowEnd;
+static uptr kLowShadowStart;
 static uptr kHighShadowStart;
 static uptr kHighShadowEnd;
 static uptr kHighMemStart;
+static uptr kHighMemEnd;
 
-bool InitShadow() {
-  const uptr maxVirtualAddress = GetMaxUserVirtualAddress();
+static void PrintRange(uptr start, uptr end, const char *name) {
+  Printf("|| [%p, %p] || %.*s ||\n", (void *)start, (void *)end, 10, name);
+}
+
+static void PrintAddressSpaceLayout() {
+  PrintRange(kHighMemStart, kHighMemEnd, "HighMem");
+  if (kHighShadowEnd + 1 < kHighMemStart)
+    PrintRange(kHighShadowEnd + 1, kHighMemStart - 1, "ShadowGap");
+  else
+    CHECK_EQ(kHighShadowEnd + 1, kHighMemStart);
+  PrintRange(kHighShadowStart, kHighShadowEnd, "HighShadow");
+  if (SHADOW_OFFSET) {
+    if (kLowShadowEnd + 1 < kHighShadowStart)
+      PrintRange(kLowShadowEnd + 1, kHighShadowStart - 1, "ShadowGap");
+    else
+      CHECK_EQ(kLowMemEnd + 1, kHighShadowStart);
+    PrintRange(kLowShadowStart, kLowShadowEnd, "LowShadow");
+    if (kLowMemEnd + 1 < kLowShadowStart)
+      PrintRange(kLowMemEnd + 1, kLowShadowStart - 1, "ShadowGap");
+    else
+      CHECK_EQ(kLowMemEnd + 1, kLowShadowStart);
+    PrintRange(kLowMemStart, kLowMemEnd, "LowMem");
+    CHECK_EQ(0, kLowMemStart);
+  } else {
+    if (kLowMemEnd + 1 < kHighShadowStart)
+      PrintRange(kLowMemEnd + 1, kHighShadowStart - 1, "ShadowGap");
+    else
+      CHECK_EQ(kLowMemEnd + 1, kHighShadowStart);
+    PrintRange(kLowMemStart, kLowMemEnd, "LowMem");
+    CHECK_EQ(kLowShadowEnd + 1, kLowMemStart);
+    PrintRange(kLowShadowStart, kLowShadowEnd, "LowShadow");
+    PrintRange(0, kLowShadowStart - 1, "ShadowGap");
+  }
+}
 
+static uptr GetHighMemEnd() {
   // HighMem covers the upper part of the address space.
-  kHighShadowEnd = (maxVirtualAddress >> kShadowScale) + 1;
-  kHighShadowStart = Max(kLowMemEnd, kHighShadowEnd >> kShadowScale);
-  CHECK(kHighShadowStart < kHighShadowEnd);
-
-  kHighMemStart = kHighShadowStart << kShadowScale;
-  CHECK(kHighShadowEnd <= kHighMemStart);
-
-  if (Verbosity()) {
-    Printf("|| `[%p, %p]` || HighMem    ||\n", (void *)kHighMemStart,
-           (void *)maxVirtualAddress);
-    if (kHighMemStart > kHighShadowEnd)
-      Printf("|| `[%p, %p]` || ShadowGap2 ||\n", (void *)kHighShadowEnd,
-             (void *)kHighMemStart);
-    Printf("|| `[%p, %p]` || HighShadow ||\n", (void *)kHighShadowStart,
-           (void *)kHighShadowEnd);
-    if (kHighShadowStart > kLowMemEnd)
-      Printf("|| `[%p, %p]` || ShadowGap2 ||\n", (void *)kHighShadowEnd,
-             (void *)kHighMemStart);
-    Printf("|| `[%p, %p]` || LowMem     ||\n", (void *)kLowShadowEnd,
-           (void *)kLowMemEnd);
-    Printf("|| `[%p, %p]` || LowShadow  ||\n", (void *)kLowShadowStart,
-           (void *)kLowShadowEnd);
-    Printf("|| `[%p, %p]` || ShadowGap1 ||\n", (void *)0,
-           (void *)kLowShadowStart);
+  uptr max_address = GetMaxUserVirtualAddress();
+  if (SHADOW_OFFSET)
+    // Adjust max address to make sure that kHighMemEnd and kHighMemStart are
+    // properly aligned:
+    max_address |= SHADOW_GRANULARITY * GetMmapGranularity() - 1;
+  return max_address;
+}
+
+static void InitializeShadowBaseAddress(uptr shadow_size_bytes) {
+  // Set the shadow memory address to uninitialized.
+  __hwasan_shadow_memory_dynamic_address = kDefaultShadowSentinel;
+  uptr shadow_start = SHADOW_OFFSET;
+  // Detect if a dynamic shadow address must be used and find the available
+  // location when necessary. When dynamic address is used, the macro
+  // kLowShadowBeg expands to __hwasan_shadow_memory_dynamic_address which
+  // was just set to kDefaultShadowSentinel.
+  if (shadow_start == kDefaultShadowSentinel) {
+    __hwasan_shadow_memory_dynamic_address = 0;
+    CHECK_EQ(0, SHADOW_OFFSET);
+    shadow_start = FindDynamicShadowStart(shadow_size_bytes);
   }
+  // Update the shadow memory address (potentially) used by instrumentation.
+  __hwasan_shadow_memory_dynamic_address = shadow_start;
+}
 
-  ReserveShadowMemoryRange(kLowShadowStart, kLowShadowEnd - 1, "low shadow");
-  ReserveShadowMemoryRange(kHighShadowStart, kHighShadowEnd - 1, "high shadow");
-  ProtectGap(0, kLowShadowStart);
-  if (kHighShadowStart > kLowMemEnd)
-    ProtectGap(kLowMemEnd, kHighShadowStart - kLowMemEnd);
-  if (kHighMemStart > kHighShadowEnd)
-    ProtectGap(kHighShadowEnd, kHighMemStart - kHighShadowEnd);
+bool InitShadow() {
+  // Define the entire memory range.
+  kHighMemEnd = GetHighMemEnd();
+
+  // Determine shadow memory base offset.
+  InitializeShadowBaseAddress(MEM_TO_SHADOW_SIZE(kHighMemEnd));
+
+  // Place the low memory first.
+  if (SHADOW_OFFSET) {
+    kLowMemEnd = SHADOW_OFFSET - 1;
+    kLowMemStart = 0;
+  } else {
+    // LowMem covers as much of the first 4GB as possible.
+    kLowMemEnd = (1UL << 32) - 1;
+    kLowMemStart = MEM_TO_SHADOW(kLowMemEnd) + 1;
+  }
+
+  // Define the low shadow based on the already placed low memory.
+  kLowShadowEnd = MEM_TO_SHADOW(kLowMemEnd);
+  kLowShadowStart = SHADOW_OFFSET ? SHADOW_OFFSET : MEM_TO_SHADOW(kLowMemStart);
+
+  // High shadow takes whatever memory is left up there (making sure it is not
+  // interfering with low memory in the fixed case).
+  kHighShadowEnd = MEM_TO_SHADOW(kHighMemEnd);
+  kHighShadowStart = Max(kLowMemEnd, MEM_TO_SHADOW(kHighShadowEnd)) + 1;
+
+  // High memory starts where allocated shadow allows.
+  kHighMemStart = SHADOW_TO_MEM(kHighShadowStart);
+
+  // Check the sanity of the defined memory ranges (there might be gaps).
+  CHECK_EQ(kHighMemStart % GetMmapGranularity(), 0);
+  CHECK_GT(kHighMemStart, kHighShadowEnd);
+  CHECK_GT(kHighShadowEnd, kHighShadowStart);
+  CHECK_GT(kHighShadowStart, kLowMemEnd);
+  CHECK_GT(kLowMemEnd, kLowMemStart);
+  CHECK_GT(kLowShadowEnd, kLowShadowStart);
+  if (SHADOW_OFFSET)
+    CHECK_GT(kLowShadowStart, kLowMemEnd);
+  else
+    CHECK_GT(kLowMemEnd, kLowShadowStart);
+
+  if (Verbosity())
+    PrintAddressSpaceLayout();
+
+  // Reserve shadow memory.
+  ReserveShadowMemoryRange(kLowShadowStart, kLowShadowEnd, "low shadow");
+  ReserveShadowMemoryRange(kHighShadowStart, kHighShadowEnd, "high shadow");
+
+  // Protect all the gaps.
+  ProtectGap(0, Min(kLowMemStart, kLowShadowStart));
+  if (SHADOW_OFFSET) {
+    if (kLowMemEnd + 1 < kLowShadowStart)
+      ProtectGap(kLowMemEnd + 1, kLowShadowStart - kLowMemEnd - 1);
+    if (kLowShadowEnd + 1 < kHighShadowStart)
+      ProtectGap(kLowShadowEnd + 1, kHighShadowStart - kLowShadowEnd - 1);
+  } else {
+    if (kLowMemEnd + 1 < kHighShadowStart)
+      ProtectGap(kLowMemEnd + 1, kHighShadowStart - kLowMemEnd - 1);
+  }
+  if (kHighShadowEnd + 1 < kHighMemStart)
+    ProtectGap(kHighShadowEnd + 1, kHighMemStart - kHighShadowEnd - 1);
 
   return true;
 }
 
 bool MemIsApp(uptr p) {
   CHECK(GetTagFromPointer(p) == 0);
-  return p >= kHighMemStart || (p >= kLowShadowEnd && p < kLowMemEnd);
+  return p >= kHighMemStart || (p >= kLowMemStart && p <= kLowMemEnd);
 }
 
 static void HwasanAtExit(void) {
diff --git a/lib/hwasan/hwasan_poisoning.cc b/lib/hwasan/hwasan_poisoning.cc
index 411fd05b1..b99d8ed0b 100644
--- a/lib/hwasan/hwasan_poisoning.cc
+++ b/lib/hwasan/hwasan_poisoning.cc
@@ -13,6 +13,7 @@
 
 #include "hwasan_poisoning.h"
 
+#include "hwasan_mapping.h"
 #include "interception/interception.h"
 #include "sanitizer_common/sanitizer_common.h"
 
@@ -22,7 +23,7 @@ uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
   CHECK(IsAligned(p, kShadowAlignment));
   CHECK(IsAligned(size, kShadowAlignment));
   uptr shadow_start = MEM_TO_SHADOW(p);
-  uptr shadow_size = MEM_TO_SHADOW_OFFSET(size);
+  uptr shadow_size = MEM_TO_SHADOW_SIZE(size);
   internal_memset((void *)shadow_start, tag, shadow_size);
   return AddTagToPointer(p, tag);
 }
diff --git a/lib/hwasan/hwasan_report.cc b/lib/hwasan/hwasan_report.cc
index a3c670949..438a153f0 100644
--- a/lib/hwasan/hwasan_report.cc
+++ b/lib/hwasan/hwasan_report.cc
@@ -14,6 +14,7 @@
 
 #include "hwasan.h"
 #include "hwasan_allocator.h"
+#include "hwasan_mapping.h"
 #include "sanitizer_common/sanitizer_allocator_internal.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_flags.h"
diff --git a/lib/hwasan/hwasan_thread.cc b/lib/hwasan/hwasan_thread.cc
index 75b831b31..b50c0fc76 100644
--- a/lib/hwasan/hwasan_thread.cc
+++ b/lib/hwasan/hwasan_thread.cc
@@ -1,5 +1,6 @@
 
 #include "hwasan.h"
+#include "hwasan_mapping.h"
 #include "hwasan_thread.h"
 #include "hwasan_poisoning.h"
 #include "hwasan_interface_internal.h"