1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22/* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27/* 28 * Copyright 2023 Oxide Computer Company 29 */ 30 31 .file "getcontext.s" 32 33#include <sys/asm_linkage.h> 34 35 ANSI_PRAGMA_WEAK(getcontext,function) 36 ANSI_PRAGMA_WEAK(swapcontext,function) 37 38#include "SYS.h" 39#include <assym.h> 40 41/* 42 * getcontext() and swapcontext() are written in assembler since it has to 43 * capture the correct machine state of the caller, including 44 * the registers: %edi, %esi and %ebx. 45 * 46 * As swapcontext() is actually equivalent to getcontext() + setcontext(), 47 * swapcontext() shares the most code with getcontext(). 48 */ 49 50 51#define GETCONTEXT_IMPL(func) \ 52 movl 4(%esp), %eax; /* %eax <-- first arg: ucp */ \ 53 pushl %eax; /* push ucp for system call */ \ 54 call func; /* call syscall */ \ 55 addl $4, %esp; /* pop arg */ \ 56 andl %eax, %eax; /* if (err_ret_from_syscall) */ \ 57 je 1f; \ 58 ret; /* then return */ \ 591: \ 60 movl 4(%esp), %eax; /* recompute first arg */ \ 61 /* \ 62 * fix up %esp and %eip \ 63 */ \ 64 leal UC_MCONTEXT_GREGS (%eax), %edx; \ 65 /* %edx <-- &ucp->uc_mcontext.gregs */ \ 66 movl 0(%esp), %eax; /* read return PC from stack */ \ 67 movl %eax, EIP_OFF (%edx); \ 68 /* store ret PC in EIP of env var */ \ 69 leal 4(%esp), %eax; /* get caller's sp at time of call */ \ 70 movl %eax, UESP_OFF (%edx); \ 71 /* store the sp into UESP of env var */ \ 72 xorl %eax, %eax; /* return 0 */ \ 73 movl %eax, EAX_OFF (%edx); \ 74 /* getcontext returns 0 after a setcontext */ 75 76/* 77 * int getcontext(ucontext_t *ucp) 78 */ 79 ENTRY(getcontext) 80 GETCONTEXT_IMPL(__getcontext) 81 ret 82 SET_SIZE(getcontext) 83 84 85/* 86 * int swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 87 */ 88 ENTRY(swapcontext) 89 GETCONTEXT_IMPL(__getcontext) 90 /* call setcontext */ 91 movl 8(%esp), %eax /* %eax <-- second arg: ucp */ 92 pushl %eax /* push ucp for setcontext */ 93 call setcontext 94 addl $4, %esp /* pop arg: just in case */ 95 ret 96 SET_SIZE(swapcontext) 97 98/* 99 * int getcontext_extd(ucontext_t *ucp, uint32_t flags) 100 */ 101 ENTRY(getcontext_extd) 102 movl 8(%esp), %eax 103 cmpl $0, %eax /* if (flags != 0) */ 104 jne 2f 105 GETCONTEXT_IMPL(__getcontext_extd) 106 ret 1072: 108 movl $EINVAL, %eax /* errno = EINVAL; */ 109 jmp __cerror /* return (-1) */ 110 SET_SIZE(getcontext_extd) 111 112 113/* 114 * int swapcontext_extd(ucontext_t *oucp, const ucontext_t *ucp) 115 */ 116 ENTRY(swapcontext_extd) 117 movl 8(%esp), %eax 118 cmpl $0, %eax /* if (flags != 0) */ 119 jne 2f 120 GETCONTEXT_IMPL(__getcontext_extd) 121 /* call setcontext */ 122 movl 12(%esp), %eax /* %eax <-- second arg: ucp */ 123 pushl %eax /* push ucp for setcontext */ 124 call setcontext 125 addl $4, %esp /* pop arg: just in case */ 126 ret 1272: 128 movl $EINVAL, %eax /* errno = EINVAL; */ 129 jmp __cerror /* return (-1) */ 130 SET_SIZE(swapcontext_extd) 131