platform_system_core/libunwindstack/MemoryMte.cpp
Peter Collingbourne 118c5ee6e6 Switch to new kernel ptrace interface for reading tags.
Bug: 135772972
Change-Id: I506429d7bff79f83828e1f0d5c0ea0468ee1580b
2020-04-29 09:33:53 -07:00

64 lines
1.6 KiB
C++

/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if defined(ANDROID_EXPERIMENTAL_MTE)
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <bionic/mte.h>
#include <bionic/mte_kernel.h>
#include "MemoryLocal.h"
#include "MemoryRemote.h"
namespace unwindstack {
long MemoryRemote::ReadTag(uint64_t addr) {
#if defined(__aarch64__)
char tag;
iovec iov = {&tag, 1};
if (ptrace(PTRACE_PEEKMTETAGS, pid_, reinterpret_cast<void*>(addr), &iov) != 0 ||
iov.iov_len != 1) {
return -1;
}
return tag;
#else
(void)addr;
return -1;
#endif
}
long MemoryLocal::ReadTag(uint64_t addr) {
#if defined(__aarch64__)
// Check that the memory is readable first. This is racy with the ldg but there's not much
// we can do about it.
char data;
if (!mte_supported() || !Read(addr, &data, 1)) {
return -1;
}
__asm__ __volatile__(".arch_extension mte; ldg %0, [%0]" : "+r"(addr) : : "memory");
return (addr >> 56) & 0xf;
#else
(void)addr;
return -1;
#endif
}
} // namespace unwindstack
#endif