summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel/syscalls.c
blob: 4688ba2db84d5c46c8ae060bec50fe891454bf4b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/*
 * 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/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();
}
OpenPOWER on IntegriCloud