xref: /openbmc/linux/arch/mips/kernel/syscall.c (revision 7bcae826)
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/switch_to.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(void)
49 {
50 	int fd[2];
51 	int error = do_pipe_flags(fd, 0);
52 	if (error)
53 		return error;
54 	current_pt_regs()->regs[3] = fd[1];
55 	return fd[0];
56 }
57 
58 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
59 	unsigned long, prot, unsigned long, flags, unsigned long,
60 	fd, off_t, offset)
61 {
62 	if (offset & ~PAGE_MASK)
63 		return -EINVAL;
64 	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
65 }
66 
67 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
68 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
69 	unsigned long, pgoff)
70 {
71 	if (pgoff & (~PAGE_MASK >> 12))
72 		return -EINVAL;
73 
74 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
75 }
76 
77 save_static_function(sys_fork);
78 save_static_function(sys_clone);
79 
80 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
81 {
82 	struct thread_info *ti = task_thread_info(current);
83 
84 	ti->tp_value = addr;
85 	if (cpu_has_userlocal)
86 		write_c0_userlocal(addr);
87 
88 	return 0;
89 }
90 
91 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
92 {
93 	unsigned long old, tmp;
94 	struct pt_regs *regs;
95 	unsigned int err;
96 
97 	if (unlikely(addr & 3))
98 		return -EINVAL;
99 
100 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
101 		return -EINVAL;
102 
103 	if (cpu_has_llsc && R10000_LLSC_WAR) {
104 		__asm__ __volatile__ (
105 		"	.set	arch=r4000				\n"
106 		"	li	%[err], 0				\n"
107 		"1:	ll	%[old], (%[addr])			\n"
108 		"	move	%[tmp], %[new]				\n"
109 		"2:	sc	%[tmp], (%[addr])			\n"
110 		"	beqzl	%[tmp], 1b				\n"
111 		"3:							\n"
112 		"	.insn						\n"
113 		"	.section .fixup,\"ax\"				\n"
114 		"4:	li	%[err], %[efault]			\n"
115 		"	j	3b					\n"
116 		"	.previous					\n"
117 		"	.section __ex_table,\"a\"			\n"
118 		"	"STR(PTR)"	1b, 4b				\n"
119 		"	"STR(PTR)"	2b, 4b				\n"
120 		"	.previous					\n"
121 		"	.set	mips0					\n"
122 		: [old] "=&r" (old),
123 		  [err] "=&r" (err),
124 		  [tmp] "=&r" (tmp)
125 		: [addr] "r" (addr),
126 		  [new] "r" (new),
127 		  [efault] "i" (-EFAULT)
128 		: "memory");
129 	} else if (cpu_has_llsc) {
130 		__asm__ __volatile__ (
131 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
132 		"	li	%[err], 0				\n"
133 		"1:	ll	%[old], (%[addr])			\n"
134 		"	move	%[tmp], %[new]				\n"
135 		"2:	sc	%[tmp], (%[addr])			\n"
136 		"	bnez	%[tmp], 4f				\n"
137 		"3:							\n"
138 		"	.insn						\n"
139 		"	.subsection 2					\n"
140 		"4:	b	1b					\n"
141 		"	.previous					\n"
142 		"							\n"
143 		"	.section .fixup,\"ax\"				\n"
144 		"5:	li	%[err], %[efault]			\n"
145 		"	j	3b					\n"
146 		"	.previous					\n"
147 		"	.section __ex_table,\"a\"			\n"
148 		"	"STR(PTR)"	1b, 5b				\n"
149 		"	"STR(PTR)"	2b, 5b				\n"
150 		"	.previous					\n"
151 		"	.set	mips0					\n"
152 		: [old] "=&r" (old),
153 		  [err] "=&r" (err),
154 		  [tmp] "=&r" (tmp)
155 		: [addr] "r" (addr),
156 		  [new] "r" (new),
157 		  [efault] "i" (-EFAULT)
158 		: "memory");
159 	} else {
160 		do {
161 			preempt_disable();
162 			ll_bit = 1;
163 			ll_task = current;
164 			preempt_enable();
165 
166 			err = __get_user(old, (unsigned int *) addr);
167 			err |= __put_user(new, (unsigned int *) addr);
168 			if (err)
169 				break;
170 			rmb();
171 		} while (!ll_bit);
172 	}
173 
174 	if (unlikely(err))
175 		return err;
176 
177 	regs = current_pt_regs();
178 	regs->regs[2] = old;
179 	regs->regs[7] = 0;	/* No error */
180 
181 	/*
182 	 * Don't let your children do this ...
183 	 */
184 	__asm__ __volatile__(
185 	"	move	$29, %0						\n"
186 	"	j	syscall_exit					\n"
187 	: /* no outputs */
188 	: "r" (regs));
189 
190 	/* unreached.  Honestly.  */
191 	unreachable();
192 }
193 
194 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
195 {
196 	switch (cmd) {
197 	case MIPS_ATOMIC_SET:
198 		return mips_atomic_set(arg1, arg2);
199 
200 	case MIPS_FIXADE:
201 		if (arg1 & ~3)
202 			return -EINVAL;
203 
204 		if (arg1 & 1)
205 			set_thread_flag(TIF_FIXADE);
206 		else
207 			clear_thread_flag(TIF_FIXADE);
208 		if (arg1 & 2)
209 			set_thread_flag(TIF_LOGADE);
210 		else
211 			clear_thread_flag(TIF_LOGADE);
212 
213 		return 0;
214 
215 	case FLUSH_CACHE:
216 		__flush_cache_all();
217 		return 0;
218 	}
219 
220 	return -EINVAL;
221 }
222 
223 /*
224  * No implemented yet ...
225  */
226 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
227 {
228 	return -ENOSYS;
229 }
230 
231 /*
232  * If we ever come here the user sp is bad.  Zap the process right away.
233  * Due to the bad stack signaling wouldn't work.
234  */
235 asmlinkage void bad_stack(void)
236 {
237 	do_exit(SIGSEGV);
238 }
239