xref: /linux/arch/loongarch/kernel/syscall.c (revision 2c9b3512402ed192d1f43f4531fb5da947e72bd0)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Author: Hanlu Li <lihanlu@loongson.cn>
4  *         Huacai Chen <chenhuacai@loongson.cn>
5  *
6  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
7  */
8 #include <linux/capability.h>
9 #include <linux/entry-common.h>
10 #include <linux/errno.h>
11 #include <linux/linkage.h>
12 #include <linux/syscalls.h>
13 #include <linux/unistd.h>
14 
15 #include <asm/asm.h>
16 #include <asm/exception.h>
17 #include <asm/signal.h>
18 #include <asm/switch_to.h>
19 #include <asm-generic/syscalls.h>
20 
21 #undef __SYSCALL
22 #define __SYSCALL(nr, call)	[nr] = (call),
23 #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
24 
25 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
26 		prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
27 {
28 	if (offset & ~PAGE_MASK)
29 		return -EINVAL;
30 
31 	return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
32 }
33 
34 void *sys_call_table[__NR_syscalls] = {
35 	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
36 #include <asm/syscall_table_64.h>
37 };
38 
39 typedef long (*sys_call_fn)(unsigned long, unsigned long,
40 	unsigned long, unsigned long, unsigned long, unsigned long);
41 
42 void noinstr do_syscall(struct pt_regs *regs)
43 {
44 	unsigned long nr;
45 	sys_call_fn syscall_fn;
46 
47 	nr = regs->regs[11];
48 	/* Set for syscall restarting */
49 	if (nr < NR_syscalls)
50 		regs->regs[0] = nr + 1;
51 
52 	regs->csr_era += 4;
53 	regs->orig_a0 = regs->regs[4];
54 	regs->regs[4] = -ENOSYS;
55 
56 	nr = syscall_enter_from_user_mode(regs, nr);
57 
58 	if (nr < NR_syscalls) {
59 		syscall_fn = sys_call_table[nr];
60 		regs->regs[4] = syscall_fn(regs->orig_a0, regs->regs[5], regs->regs[6],
61 					   regs->regs[7], regs->regs[8], regs->regs[9]);
62 	}
63 
64 	syscall_exit_to_user_mode(regs);
65 }
66