| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include "private/bionic_call_ifunc_resolver.h" |
| #include <sys/auxv.h> |
| #include <sys/hwprobe.h> |
| #include <sys/ifunc.h> |
| |
| #include "bionic/macros.h" |
| #include "private/bionic_auxv.h" |
| |
| // This code is called in the linker before it has been relocated, so minimize calls into other |
| // parts of Bionic. In particular, we won't ever have two ifunc resolvers called concurrently, so |
| // initializing the ifunc resolver argument doesn't need to be thread-safe. |
| |
| ElfW(Addr) __bionic_call_ifunc_resolver(ElfW(Addr) resolver_addr) { |
| #if defined(__aarch64__) |
| typedef ElfW(Addr) (*ifunc_resolver_t)(uint64_t, __ifunc_arg_t*); |
| BIONIC_USED_BEFORE_LINKER_RELOCATES static __ifunc_arg_t arg; |
| BIONIC_USED_BEFORE_LINKER_RELOCATES static bool initialized = false; |
| if (!initialized) { |
| initialized = true; |
| arg._size = sizeof(__ifunc_arg_t); |
| arg._hwcap = getauxval(AT_HWCAP); |
| arg._hwcap2 = getauxval(AT_HWCAP2); |
| } |
| return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(arg._hwcap | _IFUNC_ARG_HWCAP, &arg); |
| #elif defined(__arm__) |
| typedef ElfW(Addr) (*ifunc_resolver_t)(unsigned long); |
| static unsigned long hwcap = getauxval(AT_HWCAP); |
| return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(hwcap); |
| #elif defined(__riscv) |
| // The third argument is currently unused, but reserved for future |
| // expansion. If we pass nullptr from the beginning, it'll be easier |
| // to recognize if/when we pass actual data (and matches glibc). |
| typedef ElfW(Addr) (*ifunc_resolver_t)(uint64_t, __riscv_hwprobe_t, void*); |
| static uint64_t hwcap = getauxval(AT_HWCAP); |
| return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(hwcap, __riscv_hwprobe, nullptr); |
| #else |
| typedef ElfW(Addr) (*ifunc_resolver_t)(void); |
| return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(); |
| #endif |
| } |