1/*- 2 * Copyright (c) 2003 Peter Wemm 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 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29#include "opt_compat.h" 30 31#include <machine/asmacros.h> 32#include <sys/syscall.h> 33 34#include "ia32_assym.h" 35 36 .text 37 .code32 38/* 39 * Signal trampoline, copied to top of user stack 40 * XXX may need to be MD to match backend sendsig handoff protocol 41 */ 42 ALIGN_TEXT 43 .globl ia32_sigcode 44ia32_sigcode: 45 calll *IA32_SIGF_HANDLER(%esp) 46 leal IA32_SIGF_UC(%esp),%eax /* get ucontext */ 47 pushl %eax 48 movl $SYS_sigreturn,%eax 49 pushl %eax /* junk to fake return addr. */ 50 int $0x80 /* enter kernel with args */ 51 /* on stack */ 521: 53 jmp 1b 54 55#ifdef COMPAT_FREEBSD4 56 ALIGN_TEXT 57freebsd4_ia32_sigcode: 58 calll *IA32_SIGF_HANDLER(%esp) 59 leal IA32_SIGF_UC4(%esp),%eax/* get ucontext */ 60 pushl %eax 61 movl $344,%eax /* 4.x SYS_sigreturn */ 62 pushl %eax /* junk to fake return addr. */ 63 int $0x80 /* enter kernel with args */ 64 /* on stack */ 651: 66 jmp 1b 67#endif 68 69#ifdef COMPAT_43 70 ALIGN_TEXT 71ia32_osigcode: 72 calll *IA32_SIGF_HANDLER(%esp)/* call signal handler */ 73 leal IA32_SIGF_SC(%esp),%eax /* get sigcontext */ 74 pushl %eax 75 movl $103,%eax /* 3.x SYS_sigreturn */ 76 pushl %eax /* junk to fake return addr. */ 77 int $0x80 /* enter kernel with args */ 781: 79 jmp 1b 80 81 82/* 83 * The lcall $7,$0 emulator cannot use the call gate that does an 84 * inter-privilege transition. The reason is that the call gate 85 * does not disable interrupts, and, before the swapgs is 86 * executed, we would have a window where the ring 0 code is 87 * executed with the wrong gsbase. 88 * 89 * Instead, reflect the lcall $7,$0 back to ring 3 trampoline 90 * which sets up the frame for int $0x80. 91 */ 92 ALIGN_TEXT 93lcall_tramp: 94 cmpl $SYS_vfork,%eax 95 je 2f 96 pushl %ebp 97 movl %esp,%ebp 98 pushl 0x24(%ebp) /* arg 6 */ 99 pushl 0x20(%ebp) 100 pushl 0x1c(%ebp) 101 pushl 0x18(%ebp) 102 pushl 0x14(%ebp) 103 pushl 0x10(%ebp) /* arg 1 */ 104 pushl 0xc(%ebp) /* gap */ 105 int $0x80 106 leavel 1071: 108 lretl 1092: 110 /* 111 * vfork handling is special and relies on the libc stub saving 112 * the return ip in %ecx. If vfork failed, then there is no 113 * child which can corrupt the frame created by call gate. 114 */ 115 int $0x80 116 jb 1b 117 addl $8,%esp 118 jmpl *%ecx 119#endif 120 121 ALIGN_TEXT 122esigcode: 123 124 .data 125 .globl sz_ia32_sigcode 126sz_ia32_sigcode: 127 .long esigcode-ia32_sigcode 128#ifdef COMPAT_FREEBSD4 129 .globl sz_freebsd4_ia32_sigcode 130sz_freebsd4_ia32_sigcode: 131 .long esigcode-freebsd4_ia32_sigcode 132#endif 133#ifdef COMPAT_43 134 .globl sz_ia32_osigcode 135sz_ia32_osigcode: 136 .long esigcode-ia32_osigcode 137 .globl sz_lcall_tramp 138sz_lcall_tramp: 139 .long esigcode-lcall_tramp 140#endif 141