xref: /linux/arch/mips/kernel/syscall.c (revision 4b660dbd9ee2059850fd30e0df420ca7a38a1856)
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/sync.h>
41 #include <asm/sysmips.h>
42 #include <asm/syscalls.h>
43 #include <asm/switch_to.h>
44 
45 /*
46  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
47  * convention.	It returns results in registers $v0 / $v1 which means there
48  * is no need for it to do verify the validity of a userspace pointer
49  * argument.  Historically that used to be expensive in Linux.	These days
50  * the performance advantage is negligible.
51  */
52 asmlinkage int sysm_pipe(void)
53 {
54 	int fd[2];
55 	int error = do_pipe_flags(fd, 0);
56 	if (error)
57 		return error;
58 	current_pt_regs()->regs[3] = fd[1];
59 	return fd[0];
60 }
61 
62 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
63 	unsigned long, prot, unsigned long, flags, unsigned long,
64 	fd, off_t, offset)
65 {
66 	if (offset & ~PAGE_MASK)
67 		return -EINVAL;
68 	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
69 			       offset >> PAGE_SHIFT);
70 }
71 
72 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
73 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
74 	unsigned long, pgoff)
75 {
76 	if (pgoff & (~PAGE_MASK >> 12))
77 		return -EINVAL;
78 
79 	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
80 			       pgoff >> (PAGE_SHIFT - 12));
81 }
82 
83 save_static_function(sys_fork);
84 save_static_function(sys_clone);
85 save_static_function(sys_clone3);
86 
87 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
88 {
89 	struct thread_info *ti = task_thread_info(current);
90 
91 	ti->tp_value = addr;
92 	if (cpu_has_userlocal)
93 		write_c0_userlocal(addr);
94 
95 	return 0;
96 }
97 
98 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
99 {
100 	unsigned long old, tmp;
101 	struct pt_regs *regs;
102 	unsigned int err;
103 
104 	if (unlikely(addr & 3))
105 		return -EINVAL;
106 
107 	if (unlikely(!access_ok((const void __user *)addr, 4)))
108 		return -EINVAL;
109 
110 	if (cpu_has_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
111 		__asm__ __volatile__ (
112 		"	.set	push					\n"
113 		"	.set	arch=r4000				\n"
114 		"	li	%[err], 0				\n"
115 		"1:	ll	%[old], (%[addr])			\n"
116 		"	move	%[tmp], %[new]				\n"
117 		"2:	sc	%[tmp], (%[addr])			\n"
118 		"	beqzl	%[tmp], 1b				\n"
119 		"3:							\n"
120 		"	.insn						\n"
121 		"	.section .fixup,\"ax\"				\n"
122 		"4:	li	%[err], %[efault]			\n"
123 		"	j	3b					\n"
124 		"	.previous					\n"
125 		"	.section __ex_table,\"a\"			\n"
126 		"	"STR(PTR_WD)"	1b, 4b				\n"
127 		"	"STR(PTR_WD)"	2b, 4b				\n"
128 		"	.previous					\n"
129 		"	.set	pop					\n"
130 		: [old] "=&r" (old),
131 		  [err] "=&r" (err),
132 		  [tmp] "=&r" (tmp)
133 		: [addr] "r" (addr),
134 		  [new] "r" (new),
135 		  [efault] "i" (-EFAULT)
136 		: "memory");
137 	} else if (cpu_has_llsc) {
138 		__asm__ __volatile__ (
139 		"	.set	push					\n"
140 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
141 		"	li	%[err], 0				\n"
142 		"1:							\n"
143 		"	" __SYNC(full, loongson3_war) "			\n"
144 		user_ll("%[old]", "(%[addr])")
145 		"	move	%[tmp], %[new]				\n"
146 		"2:							\n"
147 		user_sc("%[tmp]", "(%[addr])")
148 		"	beqz	%[tmp], 1b				\n"
149 		"3:							\n"
150 		"	.insn						\n"
151 		"	.section .fixup,\"ax\"				\n"
152 		"5:	li	%[err], %[efault]			\n"
153 		"	j	3b					\n"
154 		"	.previous					\n"
155 		"	.section __ex_table,\"a\"			\n"
156 		"	"STR(PTR_WD)"	1b, 5b				\n"
157 		"	"STR(PTR_WD)"	2b, 5b				\n"
158 		"	.previous					\n"
159 		"	.set	pop					\n"
160 		: [old] "=&r" (old),
161 		  [err] "=&r" (err),
162 		  [tmp] "=&r" (tmp)
163 		: [addr] "r" (addr),
164 		  [new] "r" (new),
165 		  [efault] "i" (-EFAULT)
166 		: "memory");
167 	} else {
168 		do {
169 			preempt_disable();
170 			ll_bit = 1;
171 			ll_task = current;
172 			preempt_enable();
173 
174 			err = __get_user(old, (unsigned int *) addr);
175 			err |= __put_user(new, (unsigned int *) addr);
176 			if (err)
177 				break;
178 			rmb();
179 		} while (!ll_bit);
180 	}
181 
182 	if (unlikely(err))
183 		return err;
184 
185 	regs = current_pt_regs();
186 	regs->regs[2] = old;
187 	regs->regs[7] = 0;	/* No error */
188 
189 	/*
190 	 * Don't let your children do this ...
191 	 */
192 	__asm__ __volatile__(
193 	"	move	$29, %0						\n"
194 	"	j	syscall_exit					\n"
195 	: /* no outputs */
196 	: "r" (regs));
197 
198 	/* unreached.  Honestly.  */
199 	unreachable();
200 }
201 
202 /*
203  * mips_atomic_set() normally returns directly via syscall_exit potentially
204  * clobbering static registers, so be sure to preserve them.
205  */
206 save_static_function(sys_sysmips);
207 
208 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
209 {
210 	switch (cmd) {
211 	case MIPS_ATOMIC_SET:
212 		return mips_atomic_set(arg1, arg2);
213 
214 	case MIPS_FIXADE:
215 		if (arg1 & ~3)
216 			return -EINVAL;
217 
218 		if (arg1 & 1)
219 			set_thread_flag(TIF_FIXADE);
220 		else
221 			clear_thread_flag(TIF_FIXADE);
222 		if (arg1 & 2)
223 			set_thread_flag(TIF_LOGADE);
224 		else
225 			clear_thread_flag(TIF_LOGADE);
226 
227 		return 0;
228 
229 	case FLUSH_CACHE:
230 		__flush_cache_all();
231 		return 0;
232 	}
233 
234 	return -EINVAL;
235 }
236 
237 /*
238  * No implemented yet ...
239  */
240 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
241 {
242 	return -ENOSYS;
243 }
244