b39dff4551
Summary: ARM & AArch64 runtime detection for hardware support of CRC32 has been added via check of the AT_HWVAL auxiliary vector. Following Michal's suggestions in D28417, the CRC32 code has been further changed and looks better now. When compiled with full relro (which is strongly suggested to benefit from additional hardening), the weak symbol for computeHardwareCRC32 is read-only and the assembly generated is fairly clean and straight forward. As suggested, an additional optimization is to skip the runtime check if SSE 4.2 has been enabled globally, as opposed to only for scudo_crc32.cpp. scudo_crc32.h has no purpose anymore and was removed. Reviewers: alekseyshl, kcc, rengolin, mgorny, phosek Reviewed By: rengolin, mgorny Subscribers: aemerson, rengolin, llvm-commits Differential Revision: https://reviews.llvm.org/D28574 llvm-svn: 292409
217 lines
7.7 KiB
C++
217 lines
7.7 KiB
C++
//===-- scudo_utils.cpp -----------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// Platform specific utility functions.
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///
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//===----------------------------------------------------------------------===//
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#include "scudo_utils.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <unistd.h>
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#if defined(__x86_64__) || defined(__i386__)
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# include <cpuid.h>
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#endif
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#if defined(__arm__) || defined(__aarch64__)
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# include <sys/auxv.h>
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#endif
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// TODO(kostyak): remove __sanitizer *Printf uses in favor for our own less
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// complicated string formatting code. The following is a
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// temporary workaround to be able to use __sanitizer::VSNPrintf.
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namespace __sanitizer {
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extern int VSNPrintf(char *buff, int buff_length, const char *format,
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va_list args);
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} // namespace __sanitizer
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namespace __scudo {
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FORMAT(1, 2)
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void NORETURN dieWithMessage(const char *Format, ...) {
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// Our messages are tiny, 256 characters is more than enough.
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char Message[256];
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va_list Args;
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va_start(Args, Format);
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__sanitizer::VSNPrintf(Message, sizeof(Message), Format, Args);
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va_end(Args);
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RawWrite(Message);
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Die();
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}
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#if defined(__x86_64__) || defined(__i386__)
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// i386 and x86_64 specific code to detect CRC32 hardware support via CPUID.
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// CRC32 requires the SSE 4.2 instruction set.
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typedef struct {
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u32 Eax;
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u32 Ebx;
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u32 Ecx;
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u32 Edx;
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} CPUIDRegs;
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static void getCPUID(CPUIDRegs *Regs, u32 Level)
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{
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__get_cpuid(Level, &Regs->Eax, &Regs->Ebx, &Regs->Ecx, &Regs->Edx);
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}
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CPUIDRegs getCPUFeatures() {
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CPUIDRegs VendorRegs = {};
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getCPUID(&VendorRegs, 0);
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bool IsIntel =
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(VendorRegs.Ebx == signature_INTEL_ebx) &&
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(VendorRegs.Edx == signature_INTEL_edx) &&
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(VendorRegs.Ecx == signature_INTEL_ecx);
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bool IsAMD =
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(VendorRegs.Ebx == signature_AMD_ebx) &&
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(VendorRegs.Edx == signature_AMD_edx) &&
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(VendorRegs.Ecx == signature_AMD_ecx);
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// Default to an empty feature set if not on a supported CPU.
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CPUIDRegs FeaturesRegs = {};
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if (IsIntel || IsAMD) {
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getCPUID(&FeaturesRegs, 1);
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}
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return FeaturesRegs;
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}
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#ifndef bit_SSE4_2
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# define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
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#endif
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bool testCPUFeature(CPUFeature Feature)
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{
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CPUIDRegs FeaturesRegs = getCPUFeatures();
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switch (Feature) {
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case CRC32CPUFeature: // CRC32 is provided by SSE 4.2.
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return !!(FeaturesRegs.Ecx & bit_SSE4_2);
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default:
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break;
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}
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return false;
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}
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#elif defined(__arm__) || defined(__aarch64__)
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// For ARM and AArch64, hardware CRC32 support is indicated in the
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// AT_HWVAL auxiliary vector.
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#ifndef HWCAP_CRC32
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# define HWCAP_CRC32 (1<<7) // HWCAP_CRC32 is missing on older platforms.
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#endif
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bool testCPUFeature(CPUFeature Feature) {
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uptr HWCap = getauxval(AT_HWCAP);
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switch (Feature) {
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case CRC32CPUFeature:
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return !!(HWCap & HWCAP_CRC32);
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default:
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break;
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}
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return false;
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}
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#else
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bool testCPUFeature(CPUFeature Feature) {
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return false;
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}
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#endif // defined(__x86_64__) || defined(__i386__)
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// readRetry will attempt to read Count bytes from the Fd specified, and if
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// interrupted will retry to read additional bytes to reach Count.
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static ssize_t readRetry(int Fd, u8 *Buffer, size_t Count) {
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ssize_t AmountRead = 0;
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while (static_cast<size_t>(AmountRead) < Count) {
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ssize_t Result = read(Fd, Buffer + AmountRead, Count - AmountRead);
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if (Result > 0)
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AmountRead += Result;
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else if (!Result)
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break;
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else if (errno != EINTR) {
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AmountRead = -1;
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break;
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}
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}
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return AmountRead;
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}
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static void fillRandom(u8 *Data, ssize_t Size) {
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int Fd = open("/dev/urandom", O_RDONLY);
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if (Fd < 0) {
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dieWithMessage("ERROR: failed to open /dev/urandom.\n");
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}
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bool Success = readRetry(Fd, Data, Size) == Size;
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close(Fd);
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if (!Success) {
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dieWithMessage("ERROR: failed to read enough data from /dev/urandom.\n");
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}
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}
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// Default constructor for Xorshift128Plus seeds the state with /dev/urandom.
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// TODO(kostyak): investigate using getrandom() if available.
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Xorshift128Plus::Xorshift128Plus() {
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fillRandom(reinterpret_cast<u8 *>(State), sizeof(State));
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}
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const static u32 CRC32Table[] = {
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0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
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0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
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0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
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0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
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0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
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0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
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0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
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0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
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0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
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0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
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0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
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0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
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0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
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0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
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0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
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0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
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0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
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0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
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0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
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0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
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0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
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0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
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0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
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0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
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0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
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0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
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0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
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0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
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0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
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0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
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0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
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0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
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0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
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0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
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0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
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0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
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0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
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0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
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0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
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0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
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0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
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0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
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0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
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};
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u32 computeSoftwareCRC32(u32 Crc, uptr Data) {
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for (uptr i = 0; i < sizeof(Data); i++) {
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Crc = CRC32Table[(Crc ^ Data) & 0xff] ^ (Crc >> 8);
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Data >>= 8;
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}
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return Crc;
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}
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} // namespace __scudo
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