summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/syscall.c
blob: 58beabf50b3c34a022ec49b9a3c3a245aa130666 (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
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
/*
 * 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) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2001 MIPS Technologies, Inc.
 */
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/mman.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/syscalls.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/unistd.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/elf.h>

#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
#include <asm/asm-offsets.h>
#include <asm/signal.h>
#include <asm/sim.h>
#include <asm/shmparam.h>
#include <asm/sysmips.h>
#include <asm/uaccess.h>

/*
 * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
 * convention.  It returns results in registers $v0 / $v1 which means there
 * is no need for it to do verify the validity of a userspace pointer
 * argument.  Historically that used to be expensive in Linux.  These days
 * the performance advantage is negligible.
 */
asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
{
	int fd[2];
	int error, res;

	error = do_pipe_flags(fd, 0);
	if (error) {
		res = error;
		goto out;
	}
	regs.regs[3] = fd[1];
	res = fd[0];
out:
	return res;
}

unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */

EXPORT_SYMBOL(shm_align_mask);

#define COLOUR_ALIGN(addr,pgoff)				\
	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
	unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct vm_area_struct * vmm;
	int do_color_align;
	unsigned long task_size;

#ifdef CONFIG_32BIT
	task_size = TASK_SIZE;
#else /* Must be CONFIG_64BIT*/
	task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
#endif

	if (len > task_size)
		return -ENOMEM;

	if (flags & MAP_FIXED) {
		/* Even MAP_FIXED mappings must reside within task_size.  */
		if (task_size - len < addr)
			return -EINVAL;

		/*
		 * We do not accept a shared mapping if it would violate
		 * cache aliasing constraints.
		 */
		if ((flags & MAP_SHARED) &&
		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
			return -EINVAL;
		return addr;
	}

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = 1;
	if (addr) {
		if (do_color_align)
			addr = COLOUR_ALIGN(addr, pgoff);
		else
			addr = PAGE_ALIGN(addr);
		vmm = find_vma(current->mm, addr);
		if (task_size - len >= addr &&
		    (!vmm || addr + len <= vmm->vm_start))
			return addr;
	}
	addr = current->mm->mmap_base;
	if (do_color_align)
		addr = COLOUR_ALIGN(addr, pgoff);
	else
		addr = PAGE_ALIGN(addr);

	for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
		/* At this point:  (!vmm || addr < vmm->vm_end). */
		if (task_size - len < addr)
			return -ENOMEM;
		if (!vmm || addr + len <= vmm->vm_start)
			return addr;
		addr = vmm->vm_end;
		if (do_color_align)
			addr = COLOUR_ALIGN(addr, pgoff);
	}
}

void arch_pick_mmap_layout(struct mm_struct *mm)
{
	unsigned long random_factor = 0UL;

	if (current->flags & PF_RANDOMIZE) {
		random_factor = get_random_int();
		random_factor = random_factor << PAGE_SHIFT;
		if (TASK_IS_32BIT_ADDR)
			random_factor &= 0xfffffful;
		else
			random_factor &= 0xffffffful;
	}

	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
	mm->get_unmapped_area = arch_get_unmapped_area;
	mm->unmap_area = arch_unmap_area;
}

static inline unsigned long brk_rnd(void)
{
	unsigned long rnd = get_random_int();

	rnd = rnd << PAGE_SHIFT;
	/* 8MB for 32bit, 256MB for 64bit */
	if (TASK_IS_32BIT_ADDR)
		rnd = rnd & 0x7ffffful;
	else
		rnd = rnd & 0xffffffful;

	return rnd;
}

unsigned long arch_randomize_brk(struct mm_struct *mm)
{
	unsigned long base = mm->brk;
	unsigned long ret;

	ret = PAGE_ALIGN(base + brk_rnd());

	if (ret < mm->brk)
		return mm->brk;

	return ret;
}

SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags, unsigned long,
	fd, off_t, offset)
{
	unsigned long result;

	result = -EINVAL;
	if (offset & ~PAGE_MASK)
		goto out;

	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);

out:
	return result;
}

SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags, unsigned long, fd,
	unsigned long, pgoff)
{
	if (pgoff & (~PAGE_MASK >> 12))
		return -EINVAL;

	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
}

save_static_function(sys_fork);
static int __used noinline
_sys_fork(nabi_no_regargs struct pt_regs regs)
{
	return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
}

save_static_function(sys_clone);
static int __used noinline
_sys_clone(nabi_no_regargs struct pt_regs regs)
{
	unsigned long clone_flags;
	unsigned long newsp;
	int __user *parent_tidptr, *child_tidptr;

	clone_flags = regs.regs[4];
	newsp = regs.regs[5];
	if (!newsp)
		newsp = regs.regs[29];
	parent_tidptr = (int __user *) regs.regs[6];
#ifdef CONFIG_32BIT
	/* We need to fetch the fifth argument off the stack.  */
	child_tidptr = NULL;
	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
		int __user *__user *usp = (int __user *__user *) regs.regs[29];
		if (regs.regs[2] == __NR_syscall) {
			if (get_user (child_tidptr, &usp[5]))
				return -EFAULT;
		}
		else if (get_user (child_tidptr, &usp[4]))
			return -EFAULT;
	}
#else
	child_tidptr = (int __user *) regs.regs[8];
#endif
	return do_fork(clone_flags, newsp, &regs, 0,
	               parent_tidptr, child_tidptr);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
{
	int error;
	char * filename;

	filename = getname((const char __user *) (long)regs.regs[4]);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename,
			  (const char __user *const __user *) (long)regs.regs[5],
	                  (const char __user *const __user *) (long)regs.regs[6],
			  &regs);
	putname(filename);

out:
	return error;
}

SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
{
	struct thread_info *ti = task_thread_info(current);

	ti->tp_value = addr;
	if (cpu_has_userlocal)
		write_c0_userlocal(addr);

	return 0;
}

static inline int mips_atomic_set(struct pt_regs *regs,
	unsigned long addr, unsigned long new)
{
	unsigned long old, tmp;
	unsigned int err;

	if (unlikely(addr & 3))
		return -EINVAL;

	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
		return -EINVAL;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__ (
		"	.set	mips3					\n"
		"	li	%[err], 0				\n"
		"1:	ll	%[old], (%[addr])			\n"
		"	move	%[tmp], %[new]				\n"
		"2:	sc	%[tmp], (%[addr])			\n"
		"	beqzl	%[tmp], 1b				\n"
		"3:							\n"
		"	.section .fixup,\"ax\"				\n"
		"4:	li	%[err], %[efault]			\n"
		"	j	3b					\n"
		"	.previous					\n"
		"	.section __ex_table,\"a\"			\n"
		"	"STR(PTR)"	1b, 4b				\n"
		"	"STR(PTR)"	2b, 4b				\n"
		"	.previous					\n"
		"	.set	mips0					\n"
		: [old] "=&r" (old),
		  [err] "=&r" (err),
		  [tmp] "=&r" (tmp)
		: [addr] "r" (addr),
		  [new] "r" (new),
		  [efault] "i" (-EFAULT)
		: "memory");
	} else if (cpu_has_llsc) {
		__asm__ __volatile__ (
		"	.set	mips3					\n"
		"	li	%[err], 0				\n"
		"1:	ll	%[old], (%[addr])			\n"
		"	move	%[tmp], %[new]				\n"
		"2:	sc	%[tmp], (%[addr])			\n"
		"	bnez	%[tmp], 4f				\n"
		"3:							\n"
		"	.subsection 2					\n"
		"4:	b	1b					\n"
		"	.previous					\n"
		"							\n"
		"	.section .fixup,\"ax\"				\n"
		"5:	li	%[err], %[efault]			\n"
		"	j	3b					\n"
		"	.previous					\n"
		"	.section __ex_table,\"a\"			\n"
		"	"STR(PTR)"	1b, 5b				\n"
		"	"STR(PTR)"	2b, 5b				\n"
		"	.previous					\n"
		"	.set	mips0					\n"
		: [old] "=&r" (old),
		  [err] "=&r" (err),
		  [tmp] "=&r" (tmp)
		: [addr] "r" (addr),
		  [new] "r" (new),
		  [efault] "i" (-EFAULT)
		: "memory");
	} else {
		do {
			preempt_disable();
			ll_bit = 1;
			ll_task = current;
			preempt_enable();

			err = __get_user(old, (unsigned int *) addr);
			err |= __put_user(new, (unsigned int *) addr);
			if (err)
				break;
			rmb();
		} while (!ll_bit);
	}

	if (unlikely(err))
		return err;

	regs->regs[2] = old;
	regs->regs[7] = 0;	/* No error */

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
	"	move	$29, %0						\n"
	"	j	syscall_exit					\n"
	: /* no outputs */
	: "r" (regs));

	/* unreached.  Honestly.  */
	while (1);
}

save_static_function(sys_sysmips);
static int __used noinline
_sys_sysmips(nabi_no_regargs struct pt_regs regs)
{
	long cmd, arg1, arg2;

	cmd = regs.regs[4];
	arg1 = regs.regs[5];
	arg2 = regs.regs[6];

	switch (cmd) {
	case MIPS_ATOMIC_SET:
		return mips_atomic_set(&regs, arg1, arg2);

	case MIPS_FIXADE:
		if (arg1 & ~3)
			return -EINVAL;

		if (arg1 & 1)
			set_thread_flag(TIF_FIXADE);
		else
			clear_thread_flag(TIF_FIXADE);
		if (arg1 & 2)
			set_thread_flag(TIF_LOGADE);
		else
			clear_thread_flag(TIF_LOGADE);

		return 0;

	case FLUSH_CACHE:
		__flush_cache_all();
		return 0;
	}

	return -EINVAL;
}

/*
 * No implemented yet ...
 */
SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
{
	return -ENOSYS;
}

/*
 * If we ever come here the user sp is bad.  Zap the process right away.
 * Due to the bad stack signaling wouldn't work.
 */
asmlinkage void bad_stack(void)
{
	do_exit(SIGSEGV);
}

/*
 * Do a system call from kernel instead of calling sys_execve so we
 * end up with proper pt_regs.
 */
int kernel_execve(const char *filename,
		  const char *const argv[],
		  const char *const envp[])
{
	register unsigned long __a0 asm("$4") = (unsigned long) filename;
	register unsigned long __a1 asm("$5") = (unsigned long) argv;
	register unsigned long __a2 asm("$6") = (unsigned long) envp;
	register unsigned long __a3 asm("$7");
	unsigned long __v0;

	__asm__ volatile ("					\n"
	"	.set	noreorder				\n"
	"	li	$2, %5		# __NR_execve		\n"
	"	syscall						\n"
	"	move	%0, $2					\n"
	"	.set	reorder					\n"
	: "=&r" (__v0), "=r" (__a3)
	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
	  "memory");

	if (__a3 == 0)
		return __v0;

	return -__v0;
}
OpenPOWER on IntegriCloud