xref: /openbmc/linux/arch/mips/kernel/syscall.c (revision d0b73b48)
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 #include <asm/switch_to.h>
41 
42 /*
43  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
44  * convention.  It returns results in registers $v0 / $v1 which means there
45  * is no need for it to do verify the validity of a userspace pointer
46  * argument.  Historically that used to be expensive in Linux.  These days
47  * the performance advantage is negligible.
48  */
49 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
50 {
51 	int fd[2];
52 	int error, res;
53 
54 	error = do_pipe_flags(fd, 0);
55 	if (error) {
56 		res = error;
57 		goto out;
58 	}
59 	regs.regs[3] = fd[1];
60 	res = fd[0];
61 out:
62 	return res;
63 }
64 
65 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
66 	unsigned long, prot, unsigned long, flags, unsigned long,
67 	fd, off_t, offset)
68 {
69 	unsigned long result;
70 
71 	result = -EINVAL;
72 	if (offset & ~PAGE_MASK)
73 		goto out;
74 
75 	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
76 
77 out:
78 	return result;
79 }
80 
81 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
82 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
83 	unsigned long, pgoff)
84 {
85 	if (pgoff & (~PAGE_MASK >> 12))
86 		return -EINVAL;
87 
88 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
89 }
90 
91 save_static_function(sys_fork);
92 static int __used noinline
93 _sys_fork(nabi_no_regargs struct pt_regs regs)
94 {
95 	return do_fork(SIGCHLD, regs.regs[29], 0, NULL, NULL);
96 }
97 
98 save_static_function(sys_clone);
99 static int __used noinline
100 _sys_clone(nabi_no_regargs struct pt_regs regs)
101 {
102 	unsigned long clone_flags;
103 	unsigned long newsp;
104 	int __user *parent_tidptr, *child_tidptr;
105 
106 	clone_flags = regs.regs[4];
107 	newsp = regs.regs[5];
108 	if (!newsp)
109 		newsp = regs.regs[29];
110 	parent_tidptr = (int __user *) regs.regs[6];
111 #ifdef CONFIG_32BIT
112 	/* We need to fetch the fifth argument off the stack.  */
113 	child_tidptr = NULL;
114 	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
115 		int __user *__user *usp = (int __user *__user *) regs.regs[29];
116 		if (regs.regs[2] == __NR_syscall) {
117 			if (get_user (child_tidptr, &usp[5]))
118 				return -EFAULT;
119 		}
120 		else if (get_user (child_tidptr, &usp[4]))
121 			return -EFAULT;
122 	}
123 #else
124 	child_tidptr = (int __user *) regs.regs[8];
125 #endif
126 	return do_fork(clone_flags, newsp, 0,
127 	               parent_tidptr, child_tidptr);
128 }
129 
130 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
131 {
132 	struct thread_info *ti = task_thread_info(current);
133 
134 	ti->tp_value = addr;
135 	if (cpu_has_userlocal)
136 		write_c0_userlocal(addr);
137 
138 	return 0;
139 }
140 
141 static inline int mips_atomic_set(struct pt_regs *regs,
142 	unsigned long addr, unsigned long new)
143 {
144 	unsigned long old, tmp;
145 	unsigned int err;
146 
147 	if (unlikely(addr & 3))
148 		return -EINVAL;
149 
150 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
151 		return -EINVAL;
152 
153 	if (cpu_has_llsc && R10000_LLSC_WAR) {
154 		__asm__ __volatile__ (
155 		"	.set	mips3					\n"
156 		"	li	%[err], 0				\n"
157 		"1:	ll	%[old], (%[addr])			\n"
158 		"	move	%[tmp], %[new]				\n"
159 		"2:	sc	%[tmp], (%[addr])			\n"
160 		"	beqzl	%[tmp], 1b				\n"
161 		"3:							\n"
162 		"	.section .fixup,\"ax\"				\n"
163 		"4:	li	%[err], %[efault]			\n"
164 		"	j	3b					\n"
165 		"	.previous					\n"
166 		"	.section __ex_table,\"a\"			\n"
167 		"	"STR(PTR)"	1b, 4b				\n"
168 		"	"STR(PTR)"	2b, 4b				\n"
169 		"	.previous					\n"
170 		"	.set	mips0					\n"
171 		: [old] "=&r" (old),
172 		  [err] "=&r" (err),
173 		  [tmp] "=&r" (tmp)
174 		: [addr] "r" (addr),
175 		  [new] "r" (new),
176 		  [efault] "i" (-EFAULT)
177 		: "memory");
178 	} else if (cpu_has_llsc) {
179 		__asm__ __volatile__ (
180 		"	.set	mips3					\n"
181 		"	li	%[err], 0				\n"
182 		"1:	ll	%[old], (%[addr])			\n"
183 		"	move	%[tmp], %[new]				\n"
184 		"2:	sc	%[tmp], (%[addr])			\n"
185 		"	bnez	%[tmp], 4f				\n"
186 		"3:							\n"
187 		"	.subsection 2					\n"
188 		"4:	b	1b					\n"
189 		"	.previous					\n"
190 		"							\n"
191 		"	.section .fixup,\"ax\"				\n"
192 		"5:	li	%[err], %[efault]			\n"
193 		"	j	3b					\n"
194 		"	.previous					\n"
195 		"	.section __ex_table,\"a\"			\n"
196 		"	"STR(PTR)"	1b, 5b				\n"
197 		"	"STR(PTR)"	2b, 5b				\n"
198 		"	.previous					\n"
199 		"	.set	mips0					\n"
200 		: [old] "=&r" (old),
201 		  [err] "=&r" (err),
202 		  [tmp] "=&r" (tmp)
203 		: [addr] "r" (addr),
204 		  [new] "r" (new),
205 		  [efault] "i" (-EFAULT)
206 		: "memory");
207 	} else {
208 		do {
209 			preempt_disable();
210 			ll_bit = 1;
211 			ll_task = current;
212 			preempt_enable();
213 
214 			err = __get_user(old, (unsigned int *) addr);
215 			err |= __put_user(new, (unsigned int *) addr);
216 			if (err)
217 				break;
218 			rmb();
219 		} while (!ll_bit);
220 	}
221 
222 	if (unlikely(err))
223 		return err;
224 
225 	regs->regs[2] = old;
226 	regs->regs[7] = 0;	/* No error */
227 
228 	/*
229 	 * Don't let your children do this ...
230 	 */
231 	__asm__ __volatile__(
232 	"	move	$29, %0						\n"
233 	"	j	syscall_exit					\n"
234 	: /* no outputs */
235 	: "r" (regs));
236 
237 	/* unreached.  Honestly.  */
238 	while (1);
239 }
240 
241 save_static_function(sys_sysmips);
242 static int __used noinline
243 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
244 {
245 	long cmd, arg1, arg2;
246 
247 	cmd = regs.regs[4];
248 	arg1 = regs.regs[5];
249 	arg2 = regs.regs[6];
250 
251 	switch (cmd) {
252 	case MIPS_ATOMIC_SET:
253 		return mips_atomic_set(&regs, arg1, arg2);
254 
255 	case MIPS_FIXADE:
256 		if (arg1 & ~3)
257 			return -EINVAL;
258 
259 		if (arg1 & 1)
260 			set_thread_flag(TIF_FIXADE);
261 		else
262 			clear_thread_flag(TIF_FIXADE);
263 		if (arg1 & 2)
264 			set_thread_flag(TIF_LOGADE);
265 		else
266 			clear_thread_flag(TIF_LOGADE);
267 
268 		return 0;
269 
270 	case FLUSH_CACHE:
271 		__flush_cache_all();
272 		return 0;
273 	}
274 
275 	return -EINVAL;
276 }
277 
278 /*
279  * No implemented yet ...
280  */
281 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
282 {
283 	return -ENOSYS;
284 }
285 
286 /*
287  * If we ever come here the user sp is bad.  Zap the process right away.
288  * Due to the bad stack signaling wouldn't work.
289  */
290 asmlinkage void bad_stack(void)
291 {
292 	do_exit(SIGSEGV);
293 }
294