96 lines
3.3 KiB
C++
96 lines
3.3 KiB
C++
//===-- scudo_tls_android.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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/// Scudo thread local structure implementation for Android.
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///
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//===----------------------------------------------------------------------===//
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#include "sanitizer_common/sanitizer_platform.h"
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#if SANITIZER_LINUX && SANITIZER_ANDROID
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#include "scudo_tls.h"
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#include <pthread.h>
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namespace __scudo {
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static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
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static pthread_key_t PThreadKey;
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static atomic_uint32_t ThreadContextCurrentIndex;
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static ScudoThreadContext *ThreadContexts;
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static uptr NumberOfContexts;
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// sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used as they allocate memory.
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static uptr getNumberOfCPUs() {
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cpu_set_t CPUs;
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CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
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return CPU_COUNT(&CPUs);
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}
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static void initOnce() {
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// Hack: TLS_SLOT_TSAN was introduced in N. To be able to use it on M for
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// testing, we create an unused key. Since the key_data array follows the tls
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// array, it basically gives us the extra entry we need.
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// TODO(kostyak): remove and restrict to N and above.
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CHECK_EQ(pthread_key_create(&PThreadKey, NULL), 0);
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initScudo();
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NumberOfContexts = getNumberOfCPUs();
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ThreadContexts = reinterpret_cast<ScudoThreadContext *>(
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MmapOrDie(sizeof(ScudoThreadContext) * NumberOfContexts, __func__));
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for (int i = 0; i < NumberOfContexts; i++)
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ThreadContexts[i].init();
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}
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void initThread() {
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pthread_once(&GlobalInitialized, initOnce);
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// Initial context assignment is done in a plain round-robin fashion.
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u32 Index = atomic_fetch_add(&ThreadContextCurrentIndex, 1,
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memory_order_relaxed);
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ScudoThreadContext *ThreadContext =
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&ThreadContexts[Index % NumberOfContexts];
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*get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
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}
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ScudoThreadContext *getThreadContextAndLockSlow() {
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ScudoThreadContext *ThreadContext;
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// Go through all the contexts and find the first unlocked one.
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for (u32 i = 0; i < NumberOfContexts; i++) {
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ThreadContext = &ThreadContexts[i];
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if (ThreadContext->tryLock()) {
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*get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
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return ThreadContext;
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}
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}
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// No luck, find the one with the lowest precedence, and slow lock it.
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u64 Precedence = UINT64_MAX;
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for (u32 i = 0; i < NumberOfContexts; i++) {
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u64 SlowLockPrecedence = ThreadContexts[i].getSlowLockPrecedence();
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if (SlowLockPrecedence && SlowLockPrecedence < Precedence) {
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ThreadContext = &ThreadContexts[i];
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Precedence = SlowLockPrecedence;
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}
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}
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if (LIKELY(Precedence != UINT64_MAX)) {
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ThreadContext->lock();
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*get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
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return ThreadContext;
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}
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// Last resort (can this happen?), stick with the current one.
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ThreadContext =
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reinterpret_cast<ScudoThreadContext *>(*get_android_tls_ptr());
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ThreadContext->lock();
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return ThreadContext;
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}
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} // namespace __scudo
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#endif // SANITIZER_LINUX && SANITIZER_ANDROID
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