makecontext.c revision 285830
1/* 2 * Copyright (c) 2003 Marcel Moolenaar 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: releng/10.2/lib/libc/ia64/gen/makecontext.c 124191 2004-01-06 19:40:28Z nectar $"); 29 30#include <sys/types.h> 31#include <sys/ucontext.h> 32#include <machine/fpu.h> 33#include <stdarg.h> 34#include <stdio.h> 35#include <stdlib.h> 36#include <string.h> 37 38struct fdesc { 39 uint64_t ip; 40 uint64_t gp; 41}; 42 43typedef void (*func_t)(uint64_t, uint64_t, uint64_t, uint64_t, uint64_t, 44 uint64_t, uint64_t, uint64_t); 45 46static __inline uint64_t * 47spill(uint64_t *bsp, uint64_t arg) 48{ 49 *bsp++ = arg; 50 if (((intptr_t)bsp & 0x1ff) == 0x1f8) 51 *bsp++ = 0; 52 return (bsp); 53} 54 55static void 56ctx_wrapper(ucontext_t *ucp, func_t func, uint64_t *args) 57{ 58 59 (*func)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], 60 args[7]); 61 if (ucp->uc_link == NULL) 62 exit(0); 63 setcontext((const ucontext_t *)ucp->uc_link); 64 /* should never get here */ 65 abort(); 66 /* NOTREACHED */ 67} 68 69__weak_reference(__makecontext, makecontext); 70 71void 72__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 73{ 74 uint64_t *args, *bsp; 75 va_list ap; 76 int i; 77 78 /* 79 * Drop the ball completely if something's not right. We only 80 * support general registers as arguments and not more than 8 81 * of them. Things get hairy if we need to support FP registers 82 * (alignment issues) or more than 8 arguments (stack based). 83 */ 84 if (argc < 0 || argc > 8 || ucp == NULL || 85 ucp->uc_stack.ss_sp == NULL || (ucp->uc_stack.ss_size & 15) || 86 ((intptr_t)ucp->uc_stack.ss_sp & 15) || 87 ucp->uc_stack.ss_size < MINSIGSTKSZ) 88 abort(); 89 90 /* 91 * Copy the arguments of function 'func' onto the (memory) stack. 92 * Always take up space for 8 arguments. 93 */ 94 va_start(ap, argc); 95 args = (uint64_t*)(ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) - 8; 96 i = 0; 97 while (i < argc) 98 args[i++] = va_arg(ap, uint64_t); 99 while (i < 8) 100 args[i++] = 0; 101 va_end(ap); 102 103 /* 104 * Push (spill) the arguments of the context wrapper onto the register 105 * stack. They get loaded by the RSE on a context switch. 106 */ 107 bsp = (uint64_t*)ucp->uc_stack.ss_sp; 108 bsp = spill(bsp, (intptr_t)ucp); 109 bsp = spill(bsp, (intptr_t)func); 110 bsp = spill(bsp, (intptr_t)args); 111 112 /* 113 * Setup the MD portion of the context. 114 */ 115 memset(&ucp->uc_mcontext, 0, sizeof(ucp->uc_mcontext)); 116 ucp->uc_mcontext.mc_special.sp = (intptr_t)args - 16; 117 ucp->uc_mcontext.mc_special.bspstore = (intptr_t)bsp; 118 ucp->uc_mcontext.mc_special.pfs = (3 << 7) | 3; 119 ucp->uc_mcontext.mc_special.rsc = 0xf; 120 ucp->uc_mcontext.mc_special.rp = ((struct fdesc*)ctx_wrapper)->ip; 121 ucp->uc_mcontext.mc_special.gp = ((struct fdesc*)ctx_wrapper)->gp; 122 ucp->uc_mcontext.mc_special.fpsr = IA64_FPSR_DEFAULT; 123} 124