syscall.s revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
.file "%M%"
#include "SYS.h"
#include <sys/trap.h>
ANSI_PRAGMA_WEAK(syscall,function)
/*
* See sparc/sys/syscall.s to understand why _syscall6() exists.
* On x86, the implementation of the two are the same, the only
* difference being that _syscall6 is not an exported symbol.
*/
ENTRY2(syscall,_syscall6)
popl %edx / return address
popl %eax / system call number
pushl %edx
#if defined(_SYSC_INSN)
.byte 0xf, 0x5 /* syscall */
#elif defined(_SEP_INSN)
call 8f
8: popl %edx
movl %esp, %ecx
addl $[9f - 8b], %edx
sysenter
9:
#else
int $T_SYSCALLINT
#endif
movl 0(%esp), %edx
pushl %edx / restore the return address
SYSCERROR
ret
SET_SIZE(syscall)
SET_SIZE(_syscall6)
/*
* See sparc/sys/syscall.s to understand why __systemcall6() exists.
* On x86, the implementation of the two are the same, the only
* difference being that __systemcall6 is not an exported symbol.
*
* WARNING WARNING WARNING:
* The int $T_SYSCALL instruction below is needed by /proc when it scans a
* controlled process's text for a syscall instruction. It must be present in
* all libc variants because /proc cannot use an optimized syscall instruction
* to enter the kernel; optimized syscalls could be disabled by private LDT use.
* We must leave at least one int $T_SYSCALLINT in the text for /proc to find
* (see the Pscantext() routine).
*/
ENTRY2(__systemcall,__systemcall6)
popl %edx / return address
popl %ecx / structure return address
popl %eax / system call number
pushl %edx
int $T_SYSCALLINT
jae 1f
/ error; clear syscall return values in the structure
movl $-1, 0(%ecx) / sys_rval1
movl $-1, 4(%ecx) / sys_rval2
jmp 2f / %eax contains the error number
1:
/ no error; copy syscall return values to the structure
movl %eax, 0(%ecx) / sys_rval1
movl %edx, 4(%ecx) / sys_rval2
xorl %eax, %eax / no error, set %eax to zero
2:
movl 0(%esp), %edx / Restore the stack frame to original size
pushl %ecx
pushl %edx / restore the return address
ret
SET_SIZE(__systemcall)
SET_SIZE(__systemcall6)