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 .file "syscall.s" 28 29#include "SYS.h" 30#include <sys/trap.h> 31 32 ANSI_PRAGMA_WEAK(syscall,function) 33 34/* 35 * See sparc/sys/syscall.s to understand why _syscall6() exists. 36 * On x86, the implementation of the two are the same, the only 37 * difference being that _syscall6 is not an exported symbol. 38 */ 39 ENTRY2(syscall,_syscall6) 40 popl %edx / return address 41 popl %eax / system call number 42 pushl %edx 43#if defined(_SYSC_INSN) 44 .byte 0xf, 0x5 /* syscall */ 45#elif defined(_SEP_INSN) 46 call 8f 478: popl %edx 48 movl %esp, %ecx 49 addl $[9f - 8b], %edx 50 sysenter 519: 52#else 53 int $T_SYSCALLINT 54#endif 55 movl 0(%esp), %edx 56 pushl %edx / restore the return address 57 SYSCERROR 58 ret 59 SET_SIZE(syscall) 60 SET_SIZE(_syscall6) 61 62/* 63 * See sparc/sys/syscall.s to understand why __systemcall6() exists. 64 * On x86, the implementation of the two are the same, the only 65 * difference being that __systemcall6 is not an exported symbol. 66 * 67 * WARNING WARNING WARNING: 68 * The int $T_SYSCALL instruction below is needed by /proc when it scans a 69 * controlled process's text for a syscall instruction. It must be present in 70 * all libc variants because /proc cannot use an optimized syscall instruction 71 * to enter the kernel; optimized syscalls could be disabled by private LDT use. 72 * We must leave at least one int $T_SYSCALLINT in the text for /proc to find 73 * (see the Pscantext() routine). 74 */ 75 ENTRY2(__systemcall,__systemcall6) 76 popl %edx / return address 77 popl %ecx / structure return address 78 popl %eax / system call number 79 pushl %edx 80 int $T_SYSCALLINT 81 jae 1f 82 / error; clear syscall return values in the structure 83 movl $-1, 0(%ecx) / sys_rval1 84 movl $-1, 4(%ecx) / sys_rval2 85 jmp 2f / %eax contains the error number 861: 87 / no error; copy syscall return values to the structure 88 movl %eax, 0(%ecx) / sys_rval1 89 movl %edx, 4(%ecx) / sys_rval2 90 xorl %eax, %eax / no error, set %eax to zero 912: 92 movl 0(%esp), %edx / Restore the stack frame to original size 93 pushl %ecx 94 pushl %edx / restore the return address 95 ret 96 SET_SIZE(__systemcall) 97 SET_SIZE(__systemcall6) 98