xref: /linux/arch/mips/kernel/syscall.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 #include <linux/sched/task_stack.h>
30 
31 #include <asm/asm.h>
32 #include <asm/branch.h>
33 #include <asm/cachectl.h>
34 #include <asm/cacheflush.h>
35 #include <asm/asm-offsets.h>
36 #include <asm/signal.h>
37 #include <asm/sim.h>
38 #include <asm/shmparam.h>
39 #include <asm/sysmips.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(void)
50 {
51 	int fd[2];
52 	int error = do_pipe_flags(fd, 0);
53 	if (error)
54 		return error;
55 	current_pt_regs()->regs[3] = fd[1];
56 	return fd[0];
57 }
58 
59 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
60 	unsigned long, prot, unsigned long, flags, unsigned long,
61 	fd, off_t, offset)
62 {
63 	if (offset & ~PAGE_MASK)
64 		return -EINVAL;
65 	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
66 }
67 
68 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
69 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
70 	unsigned long, pgoff)
71 {
72 	if (pgoff & (~PAGE_MASK >> 12))
73 		return -EINVAL;
74 
75 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
76 }
77 
78 save_static_function(sys_fork);
79 save_static_function(sys_clone);
80 
81 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
82 {
83 	struct thread_info *ti = task_thread_info(current);
84 
85 	ti->tp_value = addr;
86 	if (cpu_has_userlocal)
87 		write_c0_userlocal(addr);
88 
89 	return 0;
90 }
91 
92 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
93 {
94 	unsigned long old, tmp;
95 	struct pt_regs *regs;
96 	unsigned int err;
97 
98 	if (unlikely(addr & 3))
99 		return -EINVAL;
100 
101 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
102 		return -EINVAL;
103 
104 	if (cpu_has_llsc && R10000_LLSC_WAR) {
105 		__asm__ __volatile__ (
106 		"	.set	arch=r4000				\n"
107 		"	li	%[err], 0				\n"
108 		"1:	ll	%[old], (%[addr])			\n"
109 		"	move	%[tmp], %[new]				\n"
110 		"2:	sc	%[tmp], (%[addr])			\n"
111 		"	beqzl	%[tmp], 1b				\n"
112 		"3:							\n"
113 		"	.insn						\n"
114 		"	.section .fixup,\"ax\"				\n"
115 		"4:	li	%[err], %[efault]			\n"
116 		"	j	3b					\n"
117 		"	.previous					\n"
118 		"	.section __ex_table,\"a\"			\n"
119 		"	"STR(PTR)"	1b, 4b				\n"
120 		"	"STR(PTR)"	2b, 4b				\n"
121 		"	.previous					\n"
122 		"	.set	mips0					\n"
123 		: [old] "=&r" (old),
124 		  [err] "=&r" (err),
125 		  [tmp] "=&r" (tmp)
126 		: [addr] "r" (addr),
127 		  [new] "r" (new),
128 		  [efault] "i" (-EFAULT)
129 		: "memory");
130 	} else if (cpu_has_llsc) {
131 		__asm__ __volatile__ (
132 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
133 		"	li	%[err], 0				\n"
134 		"1:	ll	%[old], (%[addr])			\n"
135 		"	move	%[tmp], %[new]				\n"
136 		"2:	sc	%[tmp], (%[addr])			\n"
137 		"	bnez	%[tmp], 4f				\n"
138 		"3:							\n"
139 		"	.insn						\n"
140 		"	.subsection 2					\n"
141 		"4:	b	1b					\n"
142 		"	.previous					\n"
143 		"							\n"
144 		"	.section .fixup,\"ax\"				\n"
145 		"5:	li	%[err], %[efault]			\n"
146 		"	j	3b					\n"
147 		"	.previous					\n"
148 		"	.section __ex_table,\"a\"			\n"
149 		"	"STR(PTR)"	1b, 5b				\n"
150 		"	"STR(PTR)"	2b, 5b				\n"
151 		"	.previous					\n"
152 		"	.set	mips0					\n"
153 		: [old] "=&r" (old),
154 		  [err] "=&r" (err),
155 		  [tmp] "=&r" (tmp)
156 		: [addr] "r" (addr),
157 		  [new] "r" (new),
158 		  [efault] "i" (-EFAULT)
159 		: "memory");
160 	} else {
161 		do {
162 			preempt_disable();
163 			ll_bit = 1;
164 			ll_task = current;
165 			preempt_enable();
166 
167 			err = __get_user(old, (unsigned int *) addr);
168 			err |= __put_user(new, (unsigned int *) addr);
169 			if (err)
170 				break;
171 			rmb();
172 		} while (!ll_bit);
173 	}
174 
175 	if (unlikely(err))
176 		return err;
177 
178 	regs = current_pt_regs();
179 	regs->regs[2] = old;
180 	regs->regs[7] = 0;	/* No error */
181 
182 	/*
183 	 * Don't let your children do this ...
184 	 */
185 	__asm__ __volatile__(
186 	"	move	$29, %0						\n"
187 	"	j	syscall_exit					\n"
188 	: /* no outputs */
189 	: "r" (regs));
190 
191 	/* unreached.  Honestly.  */
192 	unreachable();
193 }
194 
195 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
196 {
197 	switch (cmd) {
198 	case MIPS_ATOMIC_SET:
199 		return mips_atomic_set(arg1, arg2);
200 
201 	case MIPS_FIXADE:
202 		if (arg1 & ~3)
203 			return -EINVAL;
204 
205 		if (arg1 & 1)
206 			set_thread_flag(TIF_FIXADE);
207 		else
208 			clear_thread_flag(TIF_FIXADE);
209 		if (arg1 & 2)
210 			set_thread_flag(TIF_LOGADE);
211 		else
212 			clear_thread_flag(TIF_LOGADE);
213 
214 		return 0;
215 
216 	case FLUSH_CACHE:
217 		__flush_cache_all();
218 		return 0;
219 	}
220 
221 	return -EINVAL;
222 }
223 
224 /*
225  * No implemented yet ...
226  */
227 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
228 {
229 	return -ENOSYS;
230 }
231 
232 /*
233  * If we ever come here the user sp is bad.  Zap the process right away.
234  * Due to the bad stack signaling wouldn't work.
235  */
236 asmlinkage void bad_stack(void)
237 {
238 	do_exit(SIGSEGV);
239 }
240