xref: /linux/arch/mips/kernel/syscall.c (revision 4dc7ccf7e9d9bca1989b840be9e8e84911387cf2)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8  * Copyright (C) 2001 MIPS Technologies, Inc.
9  */
10 #include <linux/capability.h>
11 #include <linux/errno.h>
12 #include <linux/linkage.h>
13 #include <linux/mm.h>
14 #include <linux/fs.h>
15 #include <linux/smp.h>
16 #include <linux/mman.h>
17 #include <linux/ptrace.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/syscalls.h>
21 #include <linux/file.h>
22 #include <linux/utsname.h>
23 #include <linux/unistd.h>
24 #include <linux/sem.h>
25 #include <linux/msg.h>
26 #include <linux/shm.h>
27 #include <linux/compiler.h>
28 #include <linux/module.h>
29 #include <linux/ipc.h>
30 #include <linux/uaccess.h>
31 #include <linux/slab.h>
32 
33 #include <asm/asm.h>
34 #include <asm/branch.h>
35 #include <asm/cachectl.h>
36 #include <asm/cacheflush.h>
37 #include <asm/asm-offsets.h>
38 #include <asm/signal.h>
39 #include <asm/sim.h>
40 #include <asm/shmparam.h>
41 #include <asm/sysmips.h>
42 #include <asm/uaccess.h>
43 
44 /*
45  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
46  * convention.  It returns results in registers $v0 / $v1 which means there
47  * is no need for it to do verify the validity of a userspace pointer
48  * argument.  Historically that used to be expensive in Linux.  These days
49  * the performance advantage is negligible.
50  */
51 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
52 {
53 	int fd[2];
54 	int error, res;
55 
56 	error = do_pipe_flags(fd, 0);
57 	if (error) {
58 		res = error;
59 		goto out;
60 	}
61 	regs.regs[3] = fd[1];
62 	res = fd[0];
63 out:
64 	return res;
65 }
66 
67 unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
68 
69 EXPORT_SYMBOL(shm_align_mask);
70 
71 #define COLOUR_ALIGN(addr,pgoff)				\
72 	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
73 	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
74 
75 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
76 	unsigned long len, unsigned long pgoff, unsigned long flags)
77 {
78 	struct vm_area_struct * vmm;
79 	int do_color_align;
80 	unsigned long task_size;
81 
82 	task_size = STACK_TOP;
83 
84 	if (len > task_size)
85 		return -ENOMEM;
86 
87 	if (flags & MAP_FIXED) {
88 		/* Even MAP_FIXED mappings must reside within task_size.  */
89 		if (task_size - len < addr)
90 			return -EINVAL;
91 
92 		/*
93 		 * We do not accept a shared mapping if it would violate
94 		 * cache aliasing constraints.
95 		 */
96 		if ((flags & MAP_SHARED) &&
97 		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
98 			return -EINVAL;
99 		return addr;
100 	}
101 
102 	do_color_align = 0;
103 	if (filp || (flags & MAP_SHARED))
104 		do_color_align = 1;
105 	if (addr) {
106 		if (do_color_align)
107 			addr = COLOUR_ALIGN(addr, pgoff);
108 		else
109 			addr = PAGE_ALIGN(addr);
110 		vmm = find_vma(current->mm, addr);
111 		if (task_size - len >= addr &&
112 		    (!vmm || addr + len <= vmm->vm_start))
113 			return addr;
114 	}
115 	addr = TASK_UNMAPPED_BASE;
116 	if (do_color_align)
117 		addr = COLOUR_ALIGN(addr, pgoff);
118 	else
119 		addr = PAGE_ALIGN(addr);
120 
121 	for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
122 		/* At this point:  (!vmm || addr < vmm->vm_end). */
123 		if (task_size - len < addr)
124 			return -ENOMEM;
125 		if (!vmm || addr + len <= vmm->vm_start)
126 			return addr;
127 		addr = vmm->vm_end;
128 		if (do_color_align)
129 			addr = COLOUR_ALIGN(addr, pgoff);
130 	}
131 }
132 
133 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
134 	unsigned long, prot, unsigned long, flags, unsigned long,
135 	fd, off_t, offset)
136 {
137 	unsigned long result;
138 
139 	result = -EINVAL;
140 	if (offset & ~PAGE_MASK)
141 		goto out;
142 
143 	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
144 
145 out:
146 	return result;
147 }
148 
149 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
150 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
151 	unsigned long, pgoff)
152 {
153 	if (pgoff & (~PAGE_MASK >> 12))
154 		return -EINVAL;
155 
156 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
157 }
158 
159 save_static_function(sys_fork);
160 static int __used noinline
161 _sys_fork(nabi_no_regargs struct pt_regs regs)
162 {
163 	return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
164 }
165 
166 save_static_function(sys_clone);
167 static int __used noinline
168 _sys_clone(nabi_no_regargs struct pt_regs regs)
169 {
170 	unsigned long clone_flags;
171 	unsigned long newsp;
172 	int __user *parent_tidptr, *child_tidptr;
173 
174 	clone_flags = regs.regs[4];
175 	newsp = regs.regs[5];
176 	if (!newsp)
177 		newsp = regs.regs[29];
178 	parent_tidptr = (int __user *) regs.regs[6];
179 #ifdef CONFIG_32BIT
180 	/* We need to fetch the fifth argument off the stack.  */
181 	child_tidptr = NULL;
182 	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
183 		int __user *__user *usp = (int __user *__user *) regs.regs[29];
184 		if (regs.regs[2] == __NR_syscall) {
185 			if (get_user (child_tidptr, &usp[5]))
186 				return -EFAULT;
187 		}
188 		else if (get_user (child_tidptr, &usp[4]))
189 			return -EFAULT;
190 	}
191 #else
192 	child_tidptr = (int __user *) regs.regs[8];
193 #endif
194 	return do_fork(clone_flags, newsp, &regs, 0,
195 	               parent_tidptr, child_tidptr);
196 }
197 
198 /*
199  * sys_execve() executes a new program.
200  */
201 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
202 {
203 	int error;
204 	char * filename;
205 
206 	filename = getname((char __user *) (long)regs.regs[4]);
207 	error = PTR_ERR(filename);
208 	if (IS_ERR(filename))
209 		goto out;
210 	error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
211 	                  (char __user *__user *) (long)regs.regs[6], &regs);
212 	putname(filename);
213 
214 out:
215 	return error;
216 }
217 
218 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
219 {
220 	struct thread_info *ti = task_thread_info(current);
221 
222 	ti->tp_value = addr;
223 	if (cpu_has_userlocal)
224 		write_c0_userlocal(addr);
225 
226 	return 0;
227 }
228 
229 static inline int mips_atomic_set(struct pt_regs *regs,
230 	unsigned long addr, unsigned long new)
231 {
232 	unsigned long old, tmp;
233 	unsigned int err;
234 
235 	if (unlikely(addr & 3))
236 		return -EINVAL;
237 
238 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
239 		return -EINVAL;
240 
241 	if (cpu_has_llsc && R10000_LLSC_WAR) {
242 		__asm__ __volatile__ (
243 		"	.set	mips3					\n"
244 		"	li	%[err], 0				\n"
245 		"1:	ll	%[old], (%[addr])			\n"
246 		"	move	%[tmp], %[new]				\n"
247 		"2:	sc	%[tmp], (%[addr])			\n"
248 		"	beqzl	%[tmp], 1b				\n"
249 		"3:							\n"
250 		"	.section .fixup,\"ax\"				\n"
251 		"4:	li	%[err], %[efault]			\n"
252 		"	j	3b					\n"
253 		"	.previous					\n"
254 		"	.section __ex_table,\"a\"			\n"
255 		"	"STR(PTR)"	1b, 4b				\n"
256 		"	"STR(PTR)"	2b, 4b				\n"
257 		"	.previous					\n"
258 		"	.set	mips0					\n"
259 		: [old] "=&r" (old),
260 		  [err] "=&r" (err),
261 		  [tmp] "=&r" (tmp)
262 		: [addr] "r" (addr),
263 		  [new] "r" (new),
264 		  [efault] "i" (-EFAULT)
265 		: "memory");
266 	} else if (cpu_has_llsc) {
267 		__asm__ __volatile__ (
268 		"	.set	mips3					\n"
269 		"	li	%[err], 0				\n"
270 		"1:	ll	%[old], (%[addr])			\n"
271 		"	move	%[tmp], %[new]				\n"
272 		"2:	sc	%[tmp], (%[addr])			\n"
273 		"	bnez	%[tmp], 4f				\n"
274 		"3:							\n"
275 		"	.subsection 2					\n"
276 		"4:	b	1b					\n"
277 		"	.previous					\n"
278 		"							\n"
279 		"	.section .fixup,\"ax\"				\n"
280 		"5:	li	%[err], %[efault]			\n"
281 		"	j	3b					\n"
282 		"	.previous					\n"
283 		"	.section __ex_table,\"a\"			\n"
284 		"	"STR(PTR)"	1b, 5b				\n"
285 		"	"STR(PTR)"	2b, 5b				\n"
286 		"	.previous					\n"
287 		"	.set	mips0					\n"
288 		: [old] "=&r" (old),
289 		  [err] "=&r" (err),
290 		  [tmp] "=&r" (tmp)
291 		: [addr] "r" (addr),
292 		  [new] "r" (new),
293 		  [efault] "i" (-EFAULT)
294 		: "memory");
295 	} else {
296 		do {
297 			preempt_disable();
298 			ll_bit = 1;
299 			ll_task = current;
300 			preempt_enable();
301 
302 			err = __get_user(old, (unsigned int *) addr);
303 			err |= __put_user(new, (unsigned int *) addr);
304 			if (err)
305 				break;
306 			rmb();
307 		} while (!ll_bit);
308 	}
309 
310 	if (unlikely(err))
311 		return err;
312 
313 	regs->regs[2] = old;
314 	regs->regs[7] = 0;	/* No error */
315 
316 	/*
317 	 * Don't let your children do this ...
318 	 */
319 	__asm__ __volatile__(
320 	"	move	$29, %0						\n"
321 	"	j	syscall_exit					\n"
322 	: /* no outputs */
323 	: "r" (regs));
324 
325 	/* unreached.  Honestly.  */
326 	while (1);
327 }
328 
329 save_static_function(sys_sysmips);
330 static int __used noinline
331 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
332 {
333 	long cmd, arg1, arg2, arg3;
334 
335 	cmd = regs.regs[4];
336 	arg1 = regs.regs[5];
337 	arg2 = regs.regs[6];
338 	arg3 = regs.regs[7];
339 
340 	switch (cmd) {
341 	case MIPS_ATOMIC_SET:
342 		return mips_atomic_set(&regs, arg1, arg2);
343 
344 	case MIPS_FIXADE:
345 		if (arg1 & ~3)
346 			return -EINVAL;
347 
348 		if (arg1 & 1)
349 			set_thread_flag(TIF_FIXADE);
350 		else
351 			clear_thread_flag(TIF_FIXADE);
352 		if (arg1 & 2)
353 			set_thread_flag(TIF_LOGADE);
354 		else
355 			clear_thread_flag(TIF_FIXADE);
356 
357 		return 0;
358 
359 	case FLUSH_CACHE:
360 		__flush_cache_all();
361 		return 0;
362 	}
363 
364 	return -EINVAL;
365 }
366 
367 /*
368  * No implemented yet ...
369  */
370 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
371 {
372 	return -ENOSYS;
373 }
374 
375 /*
376  * If we ever come here the user sp is bad.  Zap the process right away.
377  * Due to the bad stack signaling wouldn't work.
378  */
379 asmlinkage void bad_stack(void)
380 {
381 	do_exit(SIGSEGV);
382 }
383 
384 /*
385  * Do a system call from kernel instead of calling sys_execve so we
386  * end up with proper pt_regs.
387  */
388 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
389 {
390 	register unsigned long __a0 asm("$4") = (unsigned long) filename;
391 	register unsigned long __a1 asm("$5") = (unsigned long) argv;
392 	register unsigned long __a2 asm("$6") = (unsigned long) envp;
393 	register unsigned long __a3 asm("$7");
394 	unsigned long __v0;
395 
396 	__asm__ volatile ("					\n"
397 	"	.set	noreorder				\n"
398 	"	li	$2, %5		# __NR_execve		\n"
399 	"	syscall						\n"
400 	"	move	%0, $2					\n"
401 	"	.set	reorder					\n"
402 	: "=&r" (__v0), "=r" (__a3)
403 	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
404 	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
405 	  "memory");
406 
407 	if (__a3 == 0)
408 		return __v0;
409 
410 	return -__v0;
411 }
412