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Differential D111080

[compiler-rt][scudo] Simplify TBI checks
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Authored by leonardchan on Oct 4 2021, 11:14 AM.

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pcc
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rGf6038cdca031: [compiler-rt][scudo] Simplify TBI checks

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Event Timeline

leonardchan created this revision.Oct 4 2021, 11:14 AM
Herald added subscribers: cryptoad, dberris. · View Herald TranscriptOct 4 2021, 11:14 AM
leonardchan requested review of this revision.Oct 4 2021, 11:14 AM
Herald added a project: Restricted Project. · View Herald TranscriptOct 4 2021, 11:14 AM
Herald added a subscriber: Restricted Project. · View Herald Transcript
leonardchan mentioned this in D110888: [compiler-rt][scudo] Check for failing prctl call.Oct 4 2021, 11:15 AM
Harbormaster completed remote builds in B126867: Diff 376956.Oct 4 2021, 11:40 AM
pcc accepted this revision.Oct 4 2021, 11:59 AM

LGTM

compiler-rt/lib/scudo/standalone/memtag.h
21–29

This comment belongs above the #if on line 21 now.

This revision is now accepted and ready to land.Oct 4 2021, 11:59 AM
Closed by commit rGf6038cdca031: [compiler-rt][scudo] Simplify TBI checks (authored by leonardchan). · Explain WhyMay 24 2022, 10:53 AM
This revision was automatically updated to reflect the committed changes.
leonardchan marked an inline comment as done.
leonardchan added a commit: rGf6038cdca031: [compiler-rt][scudo] Simplify TBI checks.
Herald added a project: Restricted Project. · View Herald TranscriptMay 24 2022, 10:53 AM
leonardchan added a reverting change: rG6edbdf80cac1: Revert "[compiler-rt][scudo] Add missing preprocessor token" and "[compiler-rt]….May 24 2022, 11:31 AM

Revision Contents

PathSize
compiler-rt/
lib/
scudo/
standalone/
13 lines

Diff 431722

compiler-rt/lib/scudo/standalone/memtag.h

Show All 12 Lines
#if SCUDO_LINUX #if SCUDO_LINUX
#include <sys/auxv.h> #include <sys/auxv.h>
#include <sys/prctl.h> #include <sys/prctl.h>
#endif #endif
namespace scudo { namespace scudo {
#if (__clang_major__ >= 12 && defined(__aarch64__) && !defined(__ILP32__)) || \
defined(SCUDO_FUZZ)
// We assume that Top-Byte Ignore is enabled if the architecture supports memory // We assume that Top-Byte Ignore is enabled if the architecture supports memory
// tagging. Not all operating systems enable TBI, so we only claim architectural // tagging. Not all operating systems enable TBI, so we only claim architectural
// support for memory tagging if the operating system enables TBI. // support for memory tagging if the operating system enables TBI.
// HWASan uses the top byte for its own purpose and Scudo should not touch it. // HWASan uses the top byte for its own purpose and Scudo should not touch it.
#if SCUDO_LINUX && !defined(SCUDO_DISABLE_TBI) && \ #if (__clang_major__ >= 12 && defined(__aarch64__) && !defined(__ILP32__) && \
!__has_feature(hwaddress_sanitizer) SCUDO_LINUX && \
!defined(SCUDO_DISABLE_TBI) !__has_feature(hwaddress_sanitizer)) || \
defined(SCUDO_FUZZ)
pccUnsubmitted
Done
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This comment belongs above the #if on line 21 now.

pcc: This comment belongs above the #if on line 21 now.
inline constexpr bool archSupportsMemoryTagging() { return true; } inline constexpr bool archSupportsMemoryTagging() { return true; }
#else
inline constexpr bool archSupportsMemoryTagging() { return false; }
#endif
inline constexpr uptr archMemoryTagGranuleSize() { return 16; } inline constexpr uptr archMemoryTagGranuleSize() { return 16; }
inline uptr untagPointer(uptr Ptr) { return Ptr & ((1ULL << 56) - 1); } inline uptr untagPointer(uptr Ptr) { return Ptr & ((1ULL << 56) - 1); }
inline uint8_t extractTag(uptr Ptr) { return (Ptr >> 56) & 0xf; } inline uint8_t extractTag(uptr Ptr) { return (Ptr >> 56) & 0xf; }
#else #else
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