Add bound violation handling for Intel(R) Memory Protection Extensions (Intel(R) MPX)

Summary:
This patch adds support for handling the SIGSEGV signal with 'si_code ==
SEGV_BNDERR', which is thrown when a bound violation is caught by the
Intel(R) MPX technology.

Differential Revision: https://reviews.llvm.org/D25329

llvm-svn: 283474

lldb/packages/Python/lldbsuite/test/functionalities/register/intel_xtended_registers/mpx_bound_violation/Makefile

@@ -0,0 +1,7 @@
+LEVEL = ../../../../make
+
+CXX_SOURCES := main.cpp
+
+CFLAGS_EXTRAS += -mmpx -fcheck-pointer-bounds -fuse-ld=bfd
+
+include $(LEVEL)/Makefile.rules

lldb/packages/Python/lldbsuite/test/functionalities/register/intel_xtended_registers/mpx_bound_violation/TestBoundViolation.py

@@ -0,0 +1,57 @@
+"""
+Test the Intel(R) MPX bound violation signal.
+"""
+
+from __future__ import print_function
+
+
+import os
+import sys
+import time
+import re
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class RegisterCommandsTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipIf(compiler="clang")
+    @skipIf(oslist=no_match(['linux']))
+    @skipIf(archs=no_match(['i386', 'x86_64']))
+    @skipIf(oslist=["linux"], compiler="gcc", compiler_version=["<", "5"]) #GCC version >= 5 supports Intel(R) MPX.
+    def test_mpx_boundary_violation(self):
+        """Test Intel(R) MPX bound violation signal."""
+        self.build()
+        self.mpx_boundary_violation()
+
+    def mpx_boundary_violation(self):
+        exe = os.path.join(os.getcwd(), "a.out")
+        self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
+
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        target = self.dbg.GetSelectedTarget()
+        process = target.GetProcess()
+
+        if (process.GetState() == lldb.eStateExited):
+            self.skipTest("Intel(R) MPX is not supported.")
+
+        if (process.GetState() == lldb.eStateStopped):
+            self.expect("thread backtrace", STOPPED_DUE_TO_SIGNAL,
+                        substrs = ['stop reason = signal SIGSEGV: upper bound violation',
+                                   'fault address:', 'lower bound:', 'upper bound:'])
+
+        self.runCmd("continue")
+
+        if (process.GetState() == lldb.eStateStopped):
+            self.expect("thread backtrace", STOPPED_DUE_TO_SIGNAL,
+                        substrs = ['stop reason = signal SIGSEGV: lower bound violation',
+                                   'fault address:', 'lower bound:', 'upper bound:'])
+
+        self.runCmd("continue")
+        self.assertTrue(process.GetState() == lldb.eStateExited,
+                        PROCESS_EXITED)

lldb/packages/Python/lldbsuite/test/functionalities/register/intel_xtended_registers/mpx_bound_violation/main.cpp

@@ -0,0 +1,40 @@
+//===-- main.cpp ------------------------------------------------*- C++ -*-===//
+////
+////                     The LLVM Compiler Infrastructure
+////
+//// This file is distributed under the University of Illinois Open Source
+//// License. See LICENSE.TXT for details.
+////
+////===----------------------------------------------------------------------===//
+//
+
+#include <cstddef>
+#include <sys/prctl.h>
+
+static void violate_upper_bound(int *ptr, int size)
+{
+  int i;
+  i = *(ptr + size);
+}
+
+static void violate_lower_bound (int *ptr, int size)
+{
+  int i;
+  i = *(ptr - size);
+}
+
+int
+main(int argc, char const *argv[])
+{
+  unsigned int rax, rbx, rcx, rdx;
+  int array[5];
+
+  // This call returns 0 only if the CPU and the kernel support Intel(R) MPX.
+  if (prctl(PR_MPX_ENABLE_MANAGEMENT, 0, 0, 0, 0) != 0)
+    return -1;
+
+  violate_upper_bound(array, 5);
+  violate_lower_bound(array, 5);
+
+  return 0;
+}

lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp

@@ -316,8 +316,7 @@ void NativeThreadLinux::SetStoppedBySignal(uint32_t signo,
           (info->si_signo == SIGBUS && info->si_code == SI_KERNEL)
               ? CrashReason::eInvalidAddress
               : GetCrashReason(*info);
-      m_stop_description = GetCrashReasonString(
-          reason, reinterpret_cast<uintptr_t>(info->si_addr));
+      m_stop_description = GetCrashReasonString(reason, *info);
       break;
     }
   }

lldb/source/Plugins/Process/POSIX/CrashReason.cpp

@@ -9,6 +9,8 @@
 
 #include "CrashReason.h"
 
+#include "llvm/Support/raw_ostream.h"
+
 #include <sstream>
 
 namespace {
@@ -19,6 +21,23 @@ void AppendFaultAddr(std::string &str, lldb::addr_t addr) {
   str += ss.str();
 }
 
+void AppendBounds(std::string &str, lldb::addr_t lower_bound,
+                  lldb::addr_t upper_bound, lldb::addr_t addr) {
+  llvm::raw_string_ostream stream(str);
+  if ((unsigned long)addr < lower_bound)
+    stream << ": lower bound violation ";
+  else
+    stream << ": upper bound violation ";
+  stream << "(fault address: 0x";
+  stream.write_hex(addr);
+  stream << ", lower bound: 0x";
+  stream.write_hex(lower_bound);
+  stream << ", upper bound: 0x";
+  stream.write_hex(upper_bound);
+  stream << ")";
+  stream.flush();
+}
+
 CrashReason GetCrashReasonForSIGSEGV(const siginfo_t &info) {
   assert(info.si_signo == SIGSEGV);
 
@@ -34,6 +53,11 @@ CrashReason GetCrashReasonForSIGSEGV(const siginfo_t &info) {
     return CrashReason::eInvalidAddress;
   case SEGV_ACCERR:
     return CrashReason::ePrivilegedAddress;
+#ifndef SEGV_BNDERR
+#define SEGV_BNDERR 3
+#endif
+  case SEGV_BNDERR:
+    return CrashReason::eBoundViolation;
   }
 
   assert(false && "unexpected si_code for SIGSEGV");
@@ -109,7 +133,7 @@ CrashReason GetCrashReasonForSIGBUS(const siginfo_t &info) {
 }
 }
 
-std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
+std::string GetCrashReasonString(CrashReason reason, const siginfo_t &info) {
   std::string str;
 
   switch (reason) {
@@ -119,11 +143,20 @@ std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
 
   case CrashReason::eInvalidAddress:
     str = "signal SIGSEGV: invalid address";
-    AppendFaultAddr(str, fault_addr);
+    AppendFaultAddr(str, reinterpret_cast<lldb::addr_t>(info.si_addr));
     break;
   case CrashReason::ePrivilegedAddress:
     str = "signal SIGSEGV: address access protected";
-    AppendFaultAddr(str, fault_addr);
+    AppendFaultAddr(str, reinterpret_cast<lldb::addr_t>(info.si_addr));
+    break;
+  case CrashReason::eBoundViolation:
+    str = "signal SIGSEGV";
+// Make sure that siginfo_t has the bound fields available.
+#if defined(si_lower) && defined(si_upper)
+    AppendBounds(str, reinterpret_cast<lldb::addr_t>(info.si_lower),
+                     reinterpret_cast<lldb::addr_t>(info.si_upper),
+                     reinterpret_cast<lldb::addr_t>(info.si_addr));
+#endif
     break;
   case CrashReason::eIllegalOpcode:
     str = "signal SIGILL: illegal instruction";
@@ -207,6 +240,9 @@ const char *CrashReasonAsString(CrashReason reason) {
   case CrashReason::ePrivilegedAddress:
     str = "ePrivilegedAddress";
     break;
+  case CrashReason::eBoundViolation:
+    str = "eBoundViolation";
+    break;
 
   // SIGILL crash reasons.
   case CrashReason::eIllegalOpcode:

lldb/source/Plugins/Process/POSIX/CrashReason.h

@@ -22,6 +22,7 @@ enum class CrashReason {
   // SIGSEGV crash reasons.
   eInvalidAddress,
   ePrivilegedAddress,
+  eBoundViolation,
 
   // SIGILL crash reasons.
   eIllegalOpcode,
@@ -49,7 +50,7 @@ enum class CrashReason {
   eFloatSubscriptRange
 };
 
-std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr);
+std::string GetCrashReasonString(CrashReason reason, const siginfo_t &info);
 
 const char *CrashReasonAsString(CrashReason reason);