c8cef93f24
An upcoming change to scudo will cause us to start calling android_unsafe_frame_pointer_chase() from within the allocator. Since this function uses ScopedDisableMTE, this would otherwise make it unsafe to use the allocator from within ScopedDisableMTE. This seems like an unreasonable restriction, so make ScopedDisableMTE save the PSTATE.TCO state in the constructor and restore it in the destructor. Bug: 135772972 Change-Id: I47e18d5fb2929efd5a58676488180cd85731007b
67 lines
2.1 KiB
C++
67 lines
2.1 KiB
C++
/*
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* Copyright (C) 2020 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#pragma once
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#include <sys/auxv.h>
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#include <bionic/mte_kernel.h>
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#ifdef __aarch64__
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inline bool mte_supported() {
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#ifdef ANDROID_EXPERIMENTAL_MTE
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static bool supported = getauxval(AT_HWCAP2) & HWCAP2_MTE;
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#else
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static bool supported = false;
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#endif
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return supported;
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}
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#endif
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#ifdef __aarch64__
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class ScopedDisableMTE {
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size_t prev_tco_;
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public:
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ScopedDisableMTE() {
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if (mte_supported()) {
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__asm__ __volatile__(".arch_extension mte; mrs %0, tco; msr tco, #1" : "=r"(prev_tco_));
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}
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}
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~ScopedDisableMTE() {
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if (mte_supported()) {
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__asm__ __volatile__(".arch_extension mte; msr tco, %0" : : "r"(prev_tco_));
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}
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}
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};
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#else
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struct ScopedDisableMTE {
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// Silence unused variable warnings in non-aarch64 builds.
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ScopedDisableMTE() {}
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};
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#endif
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