1209878Snwhitehorn/* 2209878Snwhitehorn * Copyright (c) 2004 Suleiman Souhlal 3209878Snwhitehorn * All rights reserved. 4209878Snwhitehorn * 5209878Snwhitehorn * Redistribution and use in source and binary forms, with or without 6209878Snwhitehorn * modification, are permitted provided that the following conditions 7209878Snwhitehorn * are met: 8209878Snwhitehorn * 1. Redistributions of source code must retain the above copyright 9209878Snwhitehorn * notice, this list of conditions and the following disclaimer. 10209878Snwhitehorn * 2. Redistributions in binary form must reproduce the above copyright 11209878Snwhitehorn * notice, this list of conditions and the following disclaimer in the 12209878Snwhitehorn * documentation and/or other materials provided with the distribution. 13209878Snwhitehorn * 14209878Snwhitehorn * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15209878Snwhitehorn * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16209878Snwhitehorn * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17209878Snwhitehorn * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18209878Snwhitehorn * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19209878Snwhitehorn * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20209878Snwhitehorn * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21209878Snwhitehorn * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22209878Snwhitehorn * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23209878Snwhitehorn * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24209878Snwhitehorn * SUCH DAMAGE. 25209878Snwhitehorn */ 26209878Snwhitehorn 27209878Snwhitehorn#include <sys/cdefs.h> 28209878Snwhitehorn__FBSDID("$FreeBSD$"); 29209878Snwhitehorn 30209878Snwhitehorn#include <sys/param.h> 31209878Snwhitehorn 32209878Snwhitehorn#include <stdarg.h> 33209878Snwhitehorn#include <stdlib.h> 34209878Snwhitehorn#include <unistd.h> 35209878Snwhitehorn#include <stdio.h> 36209878Snwhitehorn#include <ucontext.h> 37209878Snwhitehorn 38209878Snwhitehorn__weak_reference(__makecontext, makecontext); 39209878Snwhitehorn 40209878Snwhitehornvoid _ctx_done(ucontext_t *ucp); 41209878Snwhitehornvoid _ctx_start(void); 42209878Snwhitehorn 43209878Snwhitehornvoid 44209878Snwhitehorn_ctx_done(ucontext_t *ucp) 45209878Snwhitehorn{ 46209878Snwhitehorn if (ucp->uc_link == NULL) 47209878Snwhitehorn exit(0); 48209878Snwhitehorn else { 49209878Snwhitehorn /* invalidate context */ 50209878Snwhitehorn ucp->uc_mcontext.mc_len = 0; 51209878Snwhitehorn 52209878Snwhitehorn setcontext((const ucontext_t *)ucp->uc_link); 53209878Snwhitehorn 54209878Snwhitehorn abort(); /* should never return from above call */ 55209878Snwhitehorn } 56209878Snwhitehorn} 57209878Snwhitehorn 58209878Snwhitehornvoid 59209878Snwhitehorn__makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...) 60209878Snwhitehorn{ 61209878Snwhitehorn mcontext_t *mc; 62209878Snwhitehorn char *sp; 63209878Snwhitehorn va_list ap; 64209878Snwhitehorn int i, regargs, stackargs; 65209878Snwhitehorn 66209878Snwhitehorn /* Sanity checks */ 67209878Snwhitehorn if ((ucp == NULL) || (argc < 0) || (argc > NCARGS) 68209878Snwhitehorn || (ucp->uc_stack.ss_sp == NULL) 69209878Snwhitehorn || (ucp->uc_stack.ss_size < MINSIGSTKSZ)) { 70209878Snwhitehorn /* invalidate context */ 71209878Snwhitehorn ucp->uc_mcontext.mc_len = 0; 72209878Snwhitehorn return; 73209878Snwhitehorn } 74209878Snwhitehorn 75209878Snwhitehorn /* 76209878Snwhitehorn * The stack must have space for the frame pointer, saved 77209878Snwhitehorn * link register, overflow arguments, and be 16-byte 78209878Snwhitehorn * aligned. 79209878Snwhitehorn */ 80209878Snwhitehorn stackargs = (argc > 8) ? argc - 8 : 0; 81209878Snwhitehorn sp = (char *) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size 82209878Snwhitehorn - sizeof(uintptr_t)*(stackargs + 2); 83209878Snwhitehorn sp = (char *)((uintptr_t)sp & ~0x1f); 84209878Snwhitehorn 85209878Snwhitehorn mc = &ucp->uc_mcontext; 86209878Snwhitehorn 87209878Snwhitehorn /* 88209878Snwhitehorn * Up to 8 register args. Assumes all args are 64-bit and 89209878Snwhitehorn * integer only. Not sure how to cater for floating point. 90209878Snwhitehorn */ 91209878Snwhitehorn regargs = (argc > 8) ? 8 : argc; 92209878Snwhitehorn va_start(ap, argc); 93209878Snwhitehorn for (i = 0; i < regargs; i++) 94209878Snwhitehorn mc->mc_gpr[3 + i] = va_arg(ap, uint64_t); 95209878Snwhitehorn 96209878Snwhitehorn /* 97209878Snwhitehorn * Overflow args go onto the stack 98209878Snwhitehorn */ 99209878Snwhitehorn if (argc > 8) { 100209878Snwhitehorn uint64_t *argp; 101209878Snwhitehorn 102209878Snwhitehorn /* Skip past frame pointer and saved LR */ 103209878Snwhitehorn argp = (uint64_t *)sp + 6; 104209878Snwhitehorn 105209878Snwhitehorn for (i = 0; i < stackargs; i++) 106209878Snwhitehorn *argp++ = va_arg(ap, uint64_t); 107209878Snwhitehorn } 108209878Snwhitehorn va_end(ap); 109209878Snwhitehorn 110209878Snwhitehorn /* 111209878Snwhitehorn * Use caller-saved regs 14/15 to hold params that _ctx_start 112209878Snwhitehorn * will use to invoke the user-supplied func 113209878Snwhitehorn */ 114234003Snwhitehorn mc->mc_srr0 = *(uintptr_t *)_ctx_start; 115209878Snwhitehorn mc->mc_gpr[1] = (uintptr_t) sp; /* new stack pointer */ 116209878Snwhitehorn mc->mc_gpr[14] = (uintptr_t) start; /* r14 <- start */ 117209878Snwhitehorn mc->mc_gpr[15] = (uintptr_t) ucp; /* r15 <- ucp */ 118209878Snwhitehorn} 119