1 /* 2 * Copyright 2015-2024 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #ifndef OSSL_CRYPTO_ASYNC_POSIX_H 11 #define OSSL_CRYPTO_ASYNC_POSIX_H 12 #include <openssl/e_os2.h> 13 14 #if defined(OPENSSL_SYS_UNIX) \ 15 && defined(OPENSSL_THREADS) && !defined(OPENSSL_NO_ASYNC) \ 16 && !defined(__ANDROID__) && !defined(__OpenBSD__) 17 18 # include <unistd.h> 19 20 # if _POSIX_VERSION >= 200112L \ 21 && (_POSIX_VERSION < 200809L || defined(__GLIBC__) || defined(__FreeBSD__)) 22 23 # include <pthread.h> 24 25 # define ASYNC_POSIX 26 # define ASYNC_ARCH 27 28 # if defined(__CET__) || defined(__ia64__) 29 /* 30 * When Intel CET is enabled, makecontext will create a different 31 * shadow stack for each context. async_fibre_swapcontext cannot 32 * use _longjmp. It must call swapcontext to swap shadow stack as 33 * well as normal stack. 34 * On IA64 the register stack engine is not saved across setjmp/longjmp. Here 35 * swapcontext() performs correctly. 36 */ 37 # define USE_SWAPCONTEXT 38 # endif 39 # if defined(__aarch64__) && defined(__clang__) \ 40 && defined(__ARM_FEATURE_BTI_DEFAULT) && __ARM_FEATURE_BTI_DEFAULT == 1 41 /* 42 * setjmp/longjmp don't currently work with BTI on all libc implementations 43 * when compiled by clang. This is because clang doesn't put a BTI after the 44 * call to setjmp where it returns the second time. This then fails on libc 45 * implementations - notably glibc - which use an indirect jump to there. 46 * So use the swapcontext implementation, which does work. 47 * See https://github.com/llvm/llvm-project/issues/48888. 48 */ 49 # define USE_SWAPCONTEXT 50 # endif 51 # include <ucontext.h> 52 # ifndef USE_SWAPCONTEXT 53 # include <setjmp.h> 54 # endif 55 56 typedef struct async_fibre_st { 57 ucontext_t fibre; 58 # ifndef USE_SWAPCONTEXT 59 jmp_buf env; 60 int env_init; 61 # endif 62 } async_fibre; 63 64 int async_local_init(void); 65 void async_local_deinit(void); 66 async_fibre_swapcontext(async_fibre * o,async_fibre * n,int r)67static ossl_inline int async_fibre_swapcontext(async_fibre *o, async_fibre *n, int r) 68 { 69 # ifdef USE_SWAPCONTEXT 70 swapcontext(&o->fibre, &n->fibre); 71 # else 72 o->env_init = 1; 73 74 if (!r || !_setjmp(o->env)) { 75 if (n->env_init) 76 _longjmp(n->env, 1); 77 else 78 setcontext(&n->fibre); 79 } 80 # endif 81 82 return 1; 83 } 84 85 # define async_fibre_init_dispatcher(d) 86 87 int async_fibre_makecontext(async_fibre *fibre); 88 void async_fibre_free(async_fibre *fibre); 89 90 # endif 91 #endif 92 #endif /* OSSL_CRYPTO_ASYNC_POSIX_H */ 93