xref: /openbmc/linux/arch/mips/kernel/syscall.c (revision be709d48)
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/asm-eva.h>
33 #include <asm/branch.h>
34 #include <asm/cachectl.h>
35 #include <asm/cacheflush.h>
36 #include <asm/asm-offsets.h>
37 #include <asm/signal.h>
38 #include <asm/sim.h>
39 #include <asm/shmparam.h>
40 #include <asm/sysmips.h>
41 #include <asm/switch_to.h>
42 
43 /*
44  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
45  * convention.	It returns results in registers $v0 / $v1 which means there
46  * is no need for it to do verify the validity of a userspace pointer
47  * argument.  Historically that used to be expensive in Linux.	These days
48  * the performance advantage is negligible.
49  */
50 asmlinkage int sysm_pipe(void)
51 {
52 	int fd[2];
53 	int error = do_pipe_flags(fd, 0);
54 	if (error)
55 		return error;
56 	current_pt_regs()->regs[3] = fd[1];
57 	return fd[0];
58 }
59 
60 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
61 	unsigned long, prot, unsigned long, flags, unsigned long,
62 	fd, off_t, offset)
63 {
64 	if (offset & ~PAGE_MASK)
65 		return -EINVAL;
66 	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
67 			       offset >> PAGE_SHIFT);
68 }
69 
70 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
71 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
72 	unsigned long, pgoff)
73 {
74 	if (pgoff & (~PAGE_MASK >> 12))
75 		return -EINVAL;
76 
77 	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
78 			       pgoff >> (PAGE_SHIFT - 12));
79 }
80 
81 save_static_function(sys_fork);
82 save_static_function(sys_clone);
83 
84 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
85 {
86 	struct thread_info *ti = task_thread_info(current);
87 
88 	ti->tp_value = addr;
89 	if (cpu_has_userlocal)
90 		write_c0_userlocal(addr);
91 
92 	return 0;
93 }
94 
95 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
96 {
97 	unsigned long old, tmp;
98 	struct pt_regs *regs;
99 	unsigned int err;
100 
101 	if (unlikely(addr & 3))
102 		return -EINVAL;
103 
104 	if (unlikely(!access_ok((const void __user *)addr, 4)))
105 		return -EINVAL;
106 
107 	if (cpu_has_llsc && R10000_LLSC_WAR) {
108 		__asm__ __volatile__ (
109 		"	.set	push					\n"
110 		"	.set	arch=r4000				\n"
111 		"	li	%[err], 0				\n"
112 		"1:	ll	%[old], (%[addr])			\n"
113 		"	move	%[tmp], %[new]				\n"
114 		"2:	sc	%[tmp], (%[addr])			\n"
115 		"	beqzl	%[tmp], 1b				\n"
116 		"3:							\n"
117 		"	.insn						\n"
118 		"	.section .fixup,\"ax\"				\n"
119 		"4:	li	%[err], %[efault]			\n"
120 		"	j	3b					\n"
121 		"	.previous					\n"
122 		"	.section __ex_table,\"a\"			\n"
123 		"	"STR(PTR)"	1b, 4b				\n"
124 		"	"STR(PTR)"	2b, 4b				\n"
125 		"	.previous					\n"
126 		"	.set	pop					\n"
127 		: [old] "=&r" (old),
128 		  [err] "=&r" (err),
129 		  [tmp] "=&r" (tmp)
130 		: [addr] "r" (addr),
131 		  [new] "r" (new),
132 		  [efault] "i" (-EFAULT)
133 		: "memory");
134 	} else if (cpu_has_llsc) {
135 		__asm__ __volatile__ (
136 		"	.set	push					\n"
137 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
138 		"	li	%[err], 0				\n"
139 		"1:							\n"
140 		user_ll("%[old]", "(%[addr])")
141 		"	move	%[tmp], %[new]				\n"
142 		"2:							\n"
143 		user_sc("%[tmp]", "(%[addr])")
144 		"	beqz	%[tmp], 1b				\n"
145 		"3:							\n"
146 		"	.insn						\n"
147 		"	.section .fixup,\"ax\"				\n"
148 		"5:	li	%[err], %[efault]			\n"
149 		"	j	3b					\n"
150 		"	.previous					\n"
151 		"	.section __ex_table,\"a\"			\n"
152 		"	"STR(PTR)"	1b, 5b				\n"
153 		"	"STR(PTR)"	2b, 5b				\n"
154 		"	.previous					\n"
155 		"	.set	pop					\n"
156 		: [old] "=&r" (old),
157 		  [err] "=&r" (err),
158 		  [tmp] "=&r" (tmp)
159 		: [addr] "r" (addr),
160 		  [new] "r" (new),
161 		  [efault] "i" (-EFAULT)
162 		: "memory");
163 	} else {
164 		do {
165 			preempt_disable();
166 			ll_bit = 1;
167 			ll_task = current;
168 			preempt_enable();
169 
170 			err = __get_user(old, (unsigned int *) addr);
171 			err |= __put_user(new, (unsigned int *) addr);
172 			if (err)
173 				break;
174 			rmb();
175 		} while (!ll_bit);
176 	}
177 
178 	if (unlikely(err))
179 		return err;
180 
181 	regs = current_pt_regs();
182 	regs->regs[2] = old;
183 	regs->regs[7] = 0;	/* No error */
184 
185 	/*
186 	 * Don't let your children do this ...
187 	 */
188 	__asm__ __volatile__(
189 	"	move	$29, %0						\n"
190 	"	j	syscall_exit					\n"
191 	: /* no outputs */
192 	: "r" (regs));
193 
194 	/* unreached.  Honestly.  */
195 	unreachable();
196 }
197 
198 /*
199  * mips_atomic_set() normally returns directly via syscall_exit potentially
200  * clobbering static registers, so be sure to preserve them.
201  */
202 save_static_function(sys_sysmips);
203 
204 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
205 {
206 	switch (cmd) {
207 	case MIPS_ATOMIC_SET:
208 		return mips_atomic_set(arg1, arg2);
209 
210 	case MIPS_FIXADE:
211 		if (arg1 & ~3)
212 			return -EINVAL;
213 
214 		if (arg1 & 1)
215 			set_thread_flag(TIF_FIXADE);
216 		else
217 			clear_thread_flag(TIF_FIXADE);
218 		if (arg1 & 2)
219 			set_thread_flag(TIF_LOGADE);
220 		else
221 			clear_thread_flag(TIF_LOGADE);
222 
223 		return 0;
224 
225 	case FLUSH_CACHE:
226 		__flush_cache_all();
227 		return 0;
228 	}
229 
230 	return -EINVAL;
231 }
232 
233 /*
234  * No implemented yet ...
235  */
236 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
237 {
238 	return -ENOSYS;
239 }
240 
241 /*
242  * If we ever come here the user sp is bad.  Zap the process right away.
243  * Due to the bad stack signaling wouldn't work.
244  */
245 asmlinkage void bad_stack(void)
246 {
247 	do_exit(SIGSEGV);
248 }
249