forked from mirrors/gecko-dev
fbd03780ee
MozTaggedMemoryIsSupported doesn't work under ASAN because it tries to prctl the nullptr page. It should be harmless to simply call prctl and ignore the error. Depends on D195064 Differential Revision: https://phabricator.services.mozilla.com/D195065
82 lines
2.9 KiB
C
82 lines
2.9 KiB
C
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// Linux kernels since 5.17 have a feature for assigning names to
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// ranges of anonymous memory (i.e., memory that doesn't have a "name"
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// in the form of an underlying mapped file). These names are
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// reported in /proc/<pid>/smaps alongside system-level memory usage
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// information such as Proportional Set Size (memory usage adjusted
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// for sharing between processes), which allows reporting this
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// information at a finer granularity than would otherwise be possible
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// (e.g., separating malloc() heap from JS heap).
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//
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// Existing memory can be tagged with MozTagAnonymousMemory(); it will
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// tag the range of complete pages containing the given interval, so
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// the results may be inexact if the range isn't page-aligned.
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// MozTaggedAnonymousMmap() can be used like mmap() with an extra
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// parameter, and will tag the returned memory if the mapping was
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// successful (and if it was in fact anonymous).
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//
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// NOTE: The pointer given as the "tag" argument MUST remain valid as
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// long as the mapping exists. The referenced string is read when
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// /proc/<pid>/smaps or /proc/<pid>/maps is read, not when the tag is
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// established, so freeing it or changing its contents will have
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// unexpected results. Using a static string is probably best.
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//
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// Also note that this header can be used by both C and C++ code.
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#ifndef mozilla_TaggedAnonymousMemory_h
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#define mozilla_TaggedAnonymousMemory_h
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#ifndef XP_WIN
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# ifdef __wasi__
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# include <stdlib.h>
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# else
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# include <sys/types.h>
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# include <sys/mman.h>
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# endif // __wasi__
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# include "mozilla/Types.h"
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# ifdef XP_LINUX
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# ifdef __cplusplus
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extern "C" {
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# endif
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MFBT_API void MozTagAnonymousMemory(const void* aPtr, size_t aLength,
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const char* aTag);
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MFBT_API void* MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt,
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int aFlags, int aFd, off_t aOffset,
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const char* aTag);
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# ifdef __cplusplus
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} // extern "C"
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# endif
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# else // XP_LINUX
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static inline void MozTagAnonymousMemory(const void* aPtr, size_t aLength,
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const char* aTag) {}
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static inline void* MozTaggedAnonymousMmap(void* aAddr, size_t aLength,
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int aProt, int aFlags, int aFd,
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off_t aOffset, const char* aTag) {
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# ifdef __wasi__
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MOZ_CRASH("We don't use this memory for WASI right now.");
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return nullptr;
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# else
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return mmap(aAddr, aLength, aProt, aFlags, aFd, aOffset);
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# endif
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}
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# endif // XP_LINUX
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#endif // !XP_WIN
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#endif // mozilla_TaggedAnonymousMemory_h
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