Bob Badour | 0756213 | 2020-05-20 13:18:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2020 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include <async_safe/log.h> |
| 18 | |
| 19 | #include "bionic/pthread_internal.h" |
| 20 | #include "native_bridge_support/linker/static_tls_config.h" |
| 21 | #include "private/KernelArgumentBlock.h" |
| 22 | #include "private/bionic_arc4random.h" |
| 23 | #include "private/bionic_elf_tls.h" |
| 24 | #include "private/bionic_globals.h" |
| 25 | #include "private/bionic_ssp.h" |
| 26 | #include "private/bionic_tls.h" |
| 27 | |
| 28 | // Once the loader has calculated the size of static TLS, report the information |
| 29 | // to the host so it can allocate the static TLS of future threads. |
| 30 | extern "C" void __native_bridge_config_static_tls(const NativeBridgeStaticTlsConfig* config); |
| 31 | |
| 32 | // Get the current thread's host pthread_internal_t. |
| 33 | extern "C" pthread_t __native_bridge_get_host_pthread(); |
| 34 | |
| 35 | // The host has already initialized the thread and created its |
| 36 | // pthread_internal_t object. The guest needs to initialize its globals and the |
| 37 | // main thread's guest static TLS memory. |
| 38 | extern "C" void __libc_init_main_thread_early(const KernelArgumentBlock& args, |
| 39 | bionic_tcb* temp_tcb) { |
| 40 | __libc_shared_globals()->auxv = args.auxv; |
| 41 | #if defined(__i386__) |
| 42 | __libc_init_sysinfo(); |
| 43 | #endif |
| 44 | // TCB layout is different between host and guest, so initialize the guest |
| 45 | // TCB. Reuse the host's pthread_internal_t and bionic_tls objects. |
| 46 | auto host_thread = reinterpret_cast<pthread_internal_t*>(__native_bridge_get_host_pthread()); |
| 47 | __init_tcb(temp_tcb, host_thread); |
| 48 | __set_tls(&temp_tcb->tls_slot(0)); |
| 49 | } |
| 50 | |
| 51 | extern "C" void __libc_init_main_thread_late() { |
| 52 | // Reuse the host's bionic_tls structure. |
| 53 | __get_tls()[TLS_SLOT_BIONIC_TLS] = __get_thread()->bionic_tls; |
| 54 | |
| 55 | // There's currently no way for the guest to query the host's stack guard |
| 56 | // cookie, so just generate a new one. |
| 57 | __libc_safe_arc4random_buf(&__stack_chk_guard, sizeof(__stack_chk_guard)); |
| 58 | __init_tcb_stack_guard(__get_bionic_tcb()); |
| 59 | } |
| 60 | |
| 61 | extern "C" void __libc_init_main_thread_final() { |
| 62 | const StaticTlsLayout& layout = __libc_shared_globals()->static_tls_layout; |
| 63 | |
| 64 | // Prepare the initialization image for the host. |
| 65 | char* init_img = new char[layout.size()]{}; |
| 66 | __init_static_tls(init_img); |
| 67 | bionic_tcb img_tcb = {}; |
| 68 | __init_tcb_dtv(&img_tcb); |
| 69 | __init_tcb_stack_guard(&img_tcb); |
| 70 | memcpy(init_img + layout.offset_bionic_tcb(), &img_tcb, sizeof(img_tcb)); |
| 71 | |
| 72 | // Configure the host to create guest static TLS memory for new threads. The |
| 73 | // host will replace the guest main thread's static TLS with memory it |
| 74 | // allocates. |
| 75 | NativeBridgeStaticTlsConfig config{}; |
| 76 | config.size = layout.size(); |
| 77 | config.tpoff = layout.offset_thread_pointer(); |
| 78 | config.tls_slot_thread_id = TLS_SLOT_THREAD_ID; |
| 79 | config.tls_slot_bionic_tls = TLS_SLOT_BIONIC_TLS; |
| 80 | config.init_img = init_img; |
| 81 | __native_bridge_config_static_tls(&config); |
| 82 | } |