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 .code64 95 /* 96 * There, we are in 64bit mode and need to return to 32bit. 97 * First, convert call frame from 64 to 32 bit format. 98 */ 99 pushq %rax 100 movl 16(%rsp),%eax 101 movl %eax,20(%rsp) /* ret %cs */ 102 movl 8(%rsp),%eax 103 movl %eax,16(%rsp) /* ret %rip -> %eip */ 104 popq %rax 105 addq $8,%rsp 106 /* Now return to 32bit */ 107 pushq $0x33 /* _ucode32sel UPL */ 108 callq 1f 1091: 110 addq $2f-1b,(%rsp) 111 lretq 1122: 113 /* Back in 32bit mode */ 114 .code32 115 cmpl $SYS_vfork,%eax 116 je 4f 117 pushl %ebp 118 movl %esp,%ebp 119 pushl 0x24(%ebp) /* arg 6 */ 120 pushl 0x20(%ebp) 121 pushl 0x1c(%ebp) 122 pushl 0x18(%ebp) 123 pushl 0x14(%ebp) 124 pushl 0x10(%ebp) /* arg 1 */ 125 pushl 0xc(%ebp) /* gap */ 126 int $0x80 127 leavel 1283: 129 lretl 1304: 131 /* 132 * vfork handling is special and relies on the libc stub saving 133 * the return ip in %ecx. If vfork failed, then there is no 134 * child which can corrupt the frame created by call gate. 135 */ 136 int $0x80 137 jb 3b 138 addl $8,%esp 139 jmpl *%ecx 140#endif 141 142 ALIGN_TEXT 143esigcode: 144 145 .data 146 .globl sz_ia32_sigcode 147sz_ia32_sigcode: 148 .long esigcode-ia32_sigcode 149#ifdef COMPAT_FREEBSD4 150 .globl sz_freebsd4_ia32_sigcode 151sz_freebsd4_ia32_sigcode: 152 .long esigcode-freebsd4_ia32_sigcode 153#endif 154#ifdef COMPAT_43 155 .globl sz_ia32_osigcode 156sz_ia32_osigcode: 157 .long esigcode-ia32_osigcode 158 .globl sz_lcall_tramp 159sz_lcall_tramp: 160 .long esigcode-lcall_tramp 161#endif 162