xref: /openbmc/linux/arch/mips/kernel/syscall.c (revision 81d67439)
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/fs.h>
14 #include <linux/smp.h>
15 #include <linux/ptrace.h>
16 #include <linux/string.h>
17 #include <linux/syscalls.h>
18 #include <linux/file.h>
19 #include <linux/utsname.h>
20 #include <linux/unistd.h>
21 #include <linux/sem.h>
22 #include <linux/msg.h>
23 #include <linux/shm.h>
24 #include <linux/compiler.h>
25 #include <linux/ipc.h>
26 #include <linux/uaccess.h>
27 #include <linux/slab.h>
28 #include <linux/elf.h>
29 
30 #include <asm/asm.h>
31 #include <asm/branch.h>
32 #include <asm/cachectl.h>
33 #include <asm/cacheflush.h>
34 #include <asm/asm-offsets.h>
35 #include <asm/signal.h>
36 #include <asm/sim.h>
37 #include <asm/shmparam.h>
38 #include <asm/sysmips.h>
39 #include <asm/uaccess.h>
40 
41 /*
42  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
43  * convention.  It returns results in registers $v0 / $v1 which means there
44  * is no need for it to do verify the validity of a userspace pointer
45  * argument.  Historically that used to be expensive in Linux.  These days
46  * the performance advantage is negligible.
47  */
48 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
49 {
50 	int fd[2];
51 	int error, res;
52 
53 	error = do_pipe_flags(fd, 0);
54 	if (error) {
55 		res = error;
56 		goto out;
57 	}
58 	regs.regs[3] = fd[1];
59 	res = fd[0];
60 out:
61 	return res;
62 }
63 
64 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
65 	unsigned long, prot, unsigned long, flags, unsigned long,
66 	fd, off_t, offset)
67 {
68 	unsigned long result;
69 
70 	result = -EINVAL;
71 	if (offset & ~PAGE_MASK)
72 		goto out;
73 
74 	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
75 
76 out:
77 	return result;
78 }
79 
80 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
81 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
82 	unsigned long, pgoff)
83 {
84 	if (pgoff & (~PAGE_MASK >> 12))
85 		return -EINVAL;
86 
87 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
88 }
89 
90 save_static_function(sys_fork);
91 static int __used noinline
92 _sys_fork(nabi_no_regargs struct pt_regs regs)
93 {
94 	return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
95 }
96 
97 save_static_function(sys_clone);
98 static int __used noinline
99 _sys_clone(nabi_no_regargs struct pt_regs regs)
100 {
101 	unsigned long clone_flags;
102 	unsigned long newsp;
103 	int __user *parent_tidptr, *child_tidptr;
104 
105 	clone_flags = regs.regs[4];
106 	newsp = regs.regs[5];
107 	if (!newsp)
108 		newsp = regs.regs[29];
109 	parent_tidptr = (int __user *) regs.regs[6];
110 #ifdef CONFIG_32BIT
111 	/* We need to fetch the fifth argument off the stack.  */
112 	child_tidptr = NULL;
113 	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
114 		int __user *__user *usp = (int __user *__user *) regs.regs[29];
115 		if (regs.regs[2] == __NR_syscall) {
116 			if (get_user (child_tidptr, &usp[5]))
117 				return -EFAULT;
118 		}
119 		else if (get_user (child_tidptr, &usp[4]))
120 			return -EFAULT;
121 	}
122 #else
123 	child_tidptr = (int __user *) regs.regs[8];
124 #endif
125 	return do_fork(clone_flags, newsp, &regs, 0,
126 	               parent_tidptr, child_tidptr);
127 }
128 
129 /*
130  * sys_execve() executes a new program.
131  */
132 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
133 {
134 	int error;
135 	char * filename;
136 
137 	filename = getname((const char __user *) (long)regs.regs[4]);
138 	error = PTR_ERR(filename);
139 	if (IS_ERR(filename))
140 		goto out;
141 	error = do_execve(filename,
142 			  (const char __user *const __user *) (long)regs.regs[5],
143 	                  (const char __user *const __user *) (long)regs.regs[6],
144 			  &regs);
145 	putname(filename);
146 
147 out:
148 	return error;
149 }
150 
151 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
152 {
153 	struct thread_info *ti = task_thread_info(current);
154 
155 	ti->tp_value = addr;
156 	if (cpu_has_userlocal)
157 		write_c0_userlocal(addr);
158 
159 	return 0;
160 }
161 
162 static inline int mips_atomic_set(struct pt_regs *regs,
163 	unsigned long addr, unsigned long new)
164 {
165 	unsigned long old, tmp;
166 	unsigned int err;
167 
168 	if (unlikely(addr & 3))
169 		return -EINVAL;
170 
171 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
172 		return -EINVAL;
173 
174 	if (cpu_has_llsc && R10000_LLSC_WAR) {
175 		__asm__ __volatile__ (
176 		"	.set	mips3					\n"
177 		"	li	%[err], 0				\n"
178 		"1:	ll	%[old], (%[addr])			\n"
179 		"	move	%[tmp], %[new]				\n"
180 		"2:	sc	%[tmp], (%[addr])			\n"
181 		"	beqzl	%[tmp], 1b				\n"
182 		"3:							\n"
183 		"	.section .fixup,\"ax\"				\n"
184 		"4:	li	%[err], %[efault]			\n"
185 		"	j	3b					\n"
186 		"	.previous					\n"
187 		"	.section __ex_table,\"a\"			\n"
188 		"	"STR(PTR)"	1b, 4b				\n"
189 		"	"STR(PTR)"	2b, 4b				\n"
190 		"	.previous					\n"
191 		"	.set	mips0					\n"
192 		: [old] "=&r" (old),
193 		  [err] "=&r" (err),
194 		  [tmp] "=&r" (tmp)
195 		: [addr] "r" (addr),
196 		  [new] "r" (new),
197 		  [efault] "i" (-EFAULT)
198 		: "memory");
199 	} else if (cpu_has_llsc) {
200 		__asm__ __volatile__ (
201 		"	.set	mips3					\n"
202 		"	li	%[err], 0				\n"
203 		"1:	ll	%[old], (%[addr])			\n"
204 		"	move	%[tmp], %[new]				\n"
205 		"2:	sc	%[tmp], (%[addr])			\n"
206 		"	bnez	%[tmp], 4f				\n"
207 		"3:							\n"
208 		"	.subsection 2					\n"
209 		"4:	b	1b					\n"
210 		"	.previous					\n"
211 		"							\n"
212 		"	.section .fixup,\"ax\"				\n"
213 		"5:	li	%[err], %[efault]			\n"
214 		"	j	3b					\n"
215 		"	.previous					\n"
216 		"	.section __ex_table,\"a\"			\n"
217 		"	"STR(PTR)"	1b, 5b				\n"
218 		"	"STR(PTR)"	2b, 5b				\n"
219 		"	.previous					\n"
220 		"	.set	mips0					\n"
221 		: [old] "=&r" (old),
222 		  [err] "=&r" (err),
223 		  [tmp] "=&r" (tmp)
224 		: [addr] "r" (addr),
225 		  [new] "r" (new),
226 		  [efault] "i" (-EFAULT)
227 		: "memory");
228 	} else {
229 		do {
230 			preempt_disable();
231 			ll_bit = 1;
232 			ll_task = current;
233 			preempt_enable();
234 
235 			err = __get_user(old, (unsigned int *) addr);
236 			err |= __put_user(new, (unsigned int *) addr);
237 			if (err)
238 				break;
239 			rmb();
240 		} while (!ll_bit);
241 	}
242 
243 	if (unlikely(err))
244 		return err;
245 
246 	regs->regs[2] = old;
247 	regs->regs[7] = 0;	/* No error */
248 
249 	/*
250 	 * Don't let your children do this ...
251 	 */
252 	__asm__ __volatile__(
253 	"	move	$29, %0						\n"
254 	"	j	syscall_exit					\n"
255 	: /* no outputs */
256 	: "r" (regs));
257 
258 	/* unreached.  Honestly.  */
259 	while (1);
260 }
261 
262 save_static_function(sys_sysmips);
263 static int __used noinline
264 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
265 {
266 	long cmd, arg1, arg2;
267 
268 	cmd = regs.regs[4];
269 	arg1 = regs.regs[5];
270 	arg2 = regs.regs[6];
271 
272 	switch (cmd) {
273 	case MIPS_ATOMIC_SET:
274 		return mips_atomic_set(&regs, arg1, arg2);
275 
276 	case MIPS_FIXADE:
277 		if (arg1 & ~3)
278 			return -EINVAL;
279 
280 		if (arg1 & 1)
281 			set_thread_flag(TIF_FIXADE);
282 		else
283 			clear_thread_flag(TIF_FIXADE);
284 		if (arg1 & 2)
285 			set_thread_flag(TIF_LOGADE);
286 		else
287 			clear_thread_flag(TIF_LOGADE);
288 
289 		return 0;
290 
291 	case FLUSH_CACHE:
292 		__flush_cache_all();
293 		return 0;
294 	}
295 
296 	return -EINVAL;
297 }
298 
299 /*
300  * No implemented yet ...
301  */
302 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
303 {
304 	return -ENOSYS;
305 }
306 
307 /*
308  * If we ever come here the user sp is bad.  Zap the process right away.
309  * Due to the bad stack signaling wouldn't work.
310  */
311 asmlinkage void bad_stack(void)
312 {
313 	do_exit(SIGSEGV);
314 }
315 
316 /*
317  * Do a system call from kernel instead of calling sys_execve so we
318  * end up with proper pt_regs.
319  */
320 int kernel_execve(const char *filename,
321 		  const char *const argv[],
322 		  const char *const envp[])
323 {
324 	register unsigned long __a0 asm("$4") = (unsigned long) filename;
325 	register unsigned long __a1 asm("$5") = (unsigned long) argv;
326 	register unsigned long __a2 asm("$6") = (unsigned long) envp;
327 	register unsigned long __a3 asm("$7");
328 	unsigned long __v0;
329 
330 	__asm__ volatile ("					\n"
331 	"	.set	noreorder				\n"
332 	"	li	$2, %5		# __NR_execve		\n"
333 	"	syscall						\n"
334 	"	move	%0, $2					\n"
335 	"	.set	reorder					\n"
336 	: "=&r" (__v0), "=r" (__a3)
337 	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
338 	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
339 	  "memory");
340 
341 	if (__a3 == 0)
342 		return __v0;
343 
344 	return -__v0;
345 }
346