1 /*- 2 * BSD LICENSE 3 * 4 * Copyright(c) 2015 Intel Corporation. All rights reserved. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * * Neither the name of Intel Corporation nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #ifndef _PTHREAD_SHIM_H_ 35 #define _PTHREAD_SHIM_H_ 36 37 #include <rte_lcore.h> 38 39 /* 40 * This pthread shim is an example that demonstrates how legacy code 41 * that makes use of POSIX pthread services can make use of lthreads 42 * with reduced porting effort. 43 * 44 * N.B. The example is not a complete implementation, only a subset of 45 * pthread APIs sufficient to demonstrate the principle of operation 46 * are implemented. 47 * 48 * In general pthread attribute objects do not have equivalent functions 49 * in lthreads, and are ignored. 50 * 51 * There is one exception and that is the use of attr to specify a 52 * core affinity in calls to pthread_create. 53 * 54 * The shim operates as follows:- 55 * 56 * On initialisation a constructor function uses dlsym to obtain and 57 * save the loaded address of the full set of pthread APIs that will 58 * be overridden. 59 * 60 * For each function there is a stub provided that will invoke either 61 * the genuine pthread library function saved saved by the constructor, 62 * or else the corresponding equivalent lthread function. 63 * 64 * The stub functions are implemented in pthread_shim.c 65 * 66 * The stub will take care of adapting parameters, and any police 67 * any constraints where lthread functionality differs. 68 * 69 * The initial thread must always be a pure lthread. 70 * 71 * The decision whether to invoke the real library function or the lthread 72 * function is controlled by a per pthread flag that can be switched 73 * on of off by the pthread_override_set() API described below. Typcially 74 * this should be done as the first action of the initial lthread. 75 * 76 * N.B In general it would be poor practice to revert to invoke a real 77 * pthread function when running as an lthread, since these may block and 78 * effectively stall the lthread scheduler. 79 * 80 */ 81 82 83 /* 84 * An exiting lthread must not terminate the pthread it is running in 85 * since this would mean terminating the lthread scheduler. 86 * We override pthread_exit() with a macro because it is typically declared with 87 * __attribute__((noreturn)) 88 */ 89 void pthread_exit_override(void *v); 90 91 #define pthread_exit(v) do { \ 92 pthread_exit_override((v)); \ 93 return NULL; \ 94 } while (0) 95 96 /* 97 * Enable/Disable pthread override 98 * state 99 * 0 disable 100 * 1 enable 101 */ 102 void pthread_override_set(int state); 103 104 105 /* 106 * Return pthread override state 107 * return 108 * 0 disable 109 * 1 enable 110 */ 111 int pthread_override_get(void); 112 113 114 #endif /* _PTHREAD_SHIM_H_ */ 115