maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[scudo] getauxval alternative for Android 

Summary:
`getauxval` was introduced with API level 18. In order to get things to work
at lower API levels (for the toolchain itself which is built at 14 for 32-bit),
we introduce an alternative implementation reading directly from
`/proc/self/auxv`.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D37488

llvm-svn: 312653
This commit is contained in:
Kostya Kortchinsky 2017-09-06 17:51:32 +00:00
parent a353d9cb18
commit 6bc7b26d18
1 changed files with 44 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
compiler-rt/lib/scudo/scudo_utils.cpp
View File

@ -13,15 +13,47 @@
#include "scudo_utils.h"
#include <errno.h>
#include <fcntl.h>
#include "sanitizer_common/sanitizer_posix.h"
#include <stdarg.h>
#include <unistd.h>
#if defined(__x86_64__) || defined(__i386__)
# include <cpuid.h>
#endif
#if defined(__arm__) || defined(__aarch64__)
# include <sys/auxv.h>
# if SANITIZER_ANDROID && __ANDROID_API__ < 18
// getauxval() was introduced with API level 18 on Android. Emulate it using
// /proc/self/auxv for lower API levels.
# include <fcntl.h>
# define AT_HWCAP 16
namespace __sanitizer {
uptr getauxval(uptr Type) {
uptr F = internal_open("/proc/self/auxv", O_RDONLY);
if (internal_iserror(F))
return 0;
struct { uptr Tag; uptr Value; } Entry;
uptr Result = 0;
for (;;) {
uptr N = internal_read(F, &Entry, sizeof(Entry));
if (internal_iserror(N))
break;
if (N == 0 || N != sizeof(Entry) || (Entry.Tag == 0 && Entry.Value == 0))
break;
if (Entry.Tag == Type) {
Result = Entry.Value;
break;
}
}
internal_close(F);
return Result;
}
} // namespace __sanitizer
# else
# include <sys/auxv.h>
# endif
#endif
// TODO(kostyak): remove __sanitizer *Printf uses in favor for our own less
@ -82,9 +114,9 @@ CPUIDRegs getCPUFeatures() {
return FeaturesRegs;
}
#ifndef bit_SSE4_2
# define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
#endif
# ifndef bit_SSE4_2
# define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
# endif
bool testCPUFeature(CPUFeature Feature)
{
@ -99,12 +131,12 @@ bool testCPUFeature(CPUFeature Feature)
return false;
}
#elif defined(__arm__) || defined(__aarch64__)
// For ARM and AArch64, hardware CRC32 support is indicated in the
// AT_HWVAL auxiliary vector.
// For ARM and AArch64, hardware CRC32 support is indicated in the AT_HWVAL
// auxiliary vector.
#ifndef HWCAP_CRC32
# define HWCAP_CRC32 (1<<7) // HWCAP_CRC32 is missing on older platforms.
#endif
# ifndef HWCAP_CRC32
# define HWCAP_CRC32 (1 << 7) // HWCAP_CRC32 is missing on older platforms.
# endif
bool testCPUFeature(CPUFeature Feature) {
uptr HWCap = getauxval(AT_HWCAP);