/* * arch/xtensa/kernel/syscall.c * * This file is subject to the terms and conditions of the GNU General Public * License.  See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. * Copyright (C) 2000 Silicon Graphics, Inc. * Copyright (C) 1995 - 2000 by Ralf Baechle * * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca> * Chris Zankel <chris@zankel.net> * Kevin Chea * */ #define DEBUG	0 #include <linux/config.h>#include <linux/linkage.h>#include <linux/mm.h>#include <linux/smp.h>#include <linux/smp_lock.h>#include <linux/mman.h>#include <linux/sched.h>#include <linux/file.h>#include <linux/slab.h>#include <linux/utsname.h>#include <linux/unistd.h>#include <linux/stringify.h>#include <linux/syscalls.h>#include <linux/sem.h>#include <linux/msg.h>#include <linux/shm.h>#include <linux/errno.h>#include <asm/ptrace.h>#include <asm/signal.h>#include <asm/uaccess.h>#include <asm/hardirq.h>#include <asm/mman.h>#include <asm/shmparam.h>#include <asm/page.h> extern void do_syscall_trace(void);typedef int (*syscall_t)(void *a0,...);extern syscall_t sys_call_table[];extern unsigned char sys_narg_table[]; /* * sys_pipe() is the normal C calling standard for creating a pipe. It's not * the way unix traditional does this, though. */ int sys_pipe(int __user *userfds){	int fd[2];	int error; 	error = do_pipe(fd);	if (!error) {		if (copy_to_user(userfds, fd, 2 * sizeof(int)))			error = -EFAULT;	}	return error;} /* * Common code for old and new mmaps. */long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot,	      unsigned long flags, unsigned long fd, unsigned long pgoff){	int error = -EBADF;	struct file * file = NULL; 	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);	if (!(flags & MAP_ANONYMOUS)) {		file = fget(fd);		if (!file)			goto out;	} 	down_write(&current->mm->mmap_sem);	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);	up_write(&current->mm->mmap_sem); 	if (file)		fput(file);out:	return error;} int sys_clone(struct pt_regs *regs){	unsigned long clone_flags;	unsigned long newsp;	int __user *parent_tidptr, *child_tidptr;	clone_flags = regs->areg[4];	newsp = regs->areg[3];	parent_tidptr = (int __user *)regs->areg[5];	child_tidptr = (int __user *)regs->areg[6];	if (!newsp)		newsp = regs->areg[1];	return do_fork(clone_flags,newsp,regs,0,parent_tidptr,child_tidptr);} /* * sys_execve() executes a new program. */ int sys_execve(struct pt_regs *regs){	int error;	char * filename; 	filename = getname((char *) (long)regs->areg[5]);	error = PTR_ERR(filename);	if (IS_ERR(filename))		goto out;	error = do_execve(filename, (char **) (long)regs->areg[3],	                  (char **) (long)regs->areg[4], regs);	putname(filename); out:	return error;} int sys_uname(struct old_utsname * name){	if (name && !copy_to_user(name, &system_utsname, sizeof (*name)))		return 0;	return -EFAULT;} /* * Build the string table for the builtin "poor man's strace". */ #if DEBUG#define SYSCALL(fun, narg) #fun,static char *sfnames[] = {#include "syscalls.h"};#undef SYS#endif void system_call (struct pt_regs *regs){	syscall_t syscall;	unsigned long parm0, parm1, parm2, parm3, parm4, parm5;	int nargs, res;	unsigned int syscallnr;	int ps; #if DEBUG	int i;	unsigned long parms[6];	char *sysname;#endif 	regs->syscall = regs->areg[2]; 	do_syscall_trace(); 	/* Have to load after syscall_trace because strace	 * sometimes changes regs->syscall.	 */	syscallnr = regs->syscall; 	parm0 = parm1 = parm2 = parm3 = parm4 = parm5 = 0; 	/* Restore interrupt level to syscall invoker's.	 * If this were in assembly, we wouldn't disable	 * interrupts in the first place:	 */	local_save_flags (ps);	local_irq_restore((ps & ~XCHAL_PS_INTLEVEL_MASK) |			  (regs->ps & XCHAL_PS_INTLEVEL_MASK) ); 	if (syscallnr > __NR_Linux_syscalls) {		regs->areg[2] = -ENOSYS;		return;	} 	syscall = sys_call_table[syscallnr];	nargs = sys_narg_table[syscallnr]; 	if (syscall == NULL) {		regs->areg[2] = -ENOSYS;		return;	} 	/* There shouldn't be more than six arguments in the table! */ 	if (nargs > 6)		panic("Internal error - too many syscall arguments (%d)!\n",		      nargs); 	/* Linux takes system-call arguments in registers.  The ABI         * and Xtensa software conventions require the system-call         * number in a2.  If an argument exists in a2, we move it to         * the next available register.  Note that for improved         * efficiency, we do NOT shift all parameters down one         * register to maintain the original order.	 *         * At best case (zero arguments), we just write the syscall         * number to a2.  At worst case (1 to 6 arguments), we move         * the argument in a2 to the next available register, then         * write the syscall number to a2.	 *         * For clarity, the following truth table enumerates all         * possibilities.	 *         * arguments	syscall number	arg0, arg1, arg2, arg3, arg4, arg5         * ---------	--------------	----------------------------------	 *	0	      a2	 *	1	      a2	a3	 *	2	      a2	a4,   a3	 *	3	      a2	a5,   a3,   a4	 *	4	      a2	a6,   a3,   a4,   a5	 *	5	      a2	a7,   a3,   a4,   a5,   a6	 *	6	      a2	a8,   a3,   a4,   a5,   a6,   a7	 */	if (nargs) {		parm0 = regs->areg[nargs+2];		parm1 = regs->areg[3];		parm2 = regs->areg[4];		parm3 = regs->areg[5];		parm4 = regs->areg[6];		parm5 = regs->areg[7];	} else /* nargs == 0 */		parm0 = (unsigned long) regs; #if DEBUG	parms[0] = parm0;	parms[1] = parm1;	parms[2] = parm2;	parms[3] = parm3;	parms[4] = parm4;	parms[5] = parm5; 	sysname = sfnames[syscallnr];	if (strncmp(sysname, "sys_", 4) == 0)		sysname = sysname + 4; 	printk("\017SYSCALL:I:%x:%d:%s  %s(", regs->pc, current->pid,	       current->comm, sysname);	for (i = 0; i < nargs; i++)		printk((i>0) ? ", %#lx" : "%#lx", parms[i]);	printk(")\n");#endif 	res = syscall((void *)parm0, parm1, parm2, parm3, parm4, parm5); #if DEBUG	printk("\017SYSCALL:O:%d:%s  %s(",current->pid, current->comm, sysname);	for (i = 0; i < nargs; i++)		printk((i>0) ? ", %#lx" : "%#lx", parms[i]);	if (res < 4096)		printk(") = %d\n", res);	else		printk(") = %#x\n", res);#endif /* DEBUG */ 	regs->areg[2] = res;	do_syscall_trace();}