xref: /openbmc/linux/arch/loongarch/kernel/syscall.c (revision f05643a0)
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/signal.h>
17 #include <asm/switch_to.h>
18 #include <asm-generic/syscalls.h>
19 
20 #undef __SYSCALL
21 #define __SYSCALL(nr, call)	[nr] = (call),
22 
23 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
24 		prot, unsigned long, flags, unsigned long, fd, off_t, offset)
25 {
26 	if (offset & ~PAGE_MASK)
27 		return -EINVAL;
28 
29 	return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
30 }
31 
32 void *sys_call_table[__NR_syscalls] = {
33 	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
34 #include <asm/unistd.h>
35 };
36 
37 typedef long (*sys_call_fn)(unsigned long, unsigned long,
38 	unsigned long, unsigned long, unsigned long, unsigned long);
39 
40 void noinstr do_syscall(struct pt_regs *regs)
41 {
42 	unsigned long nr;
43 	sys_call_fn syscall_fn;
44 
45 	nr = regs->regs[11];
46 	/* Set for syscall restarting */
47 	if (nr < NR_syscalls)
48 		regs->regs[0] = nr + 1;
49 
50 	regs->csr_era += 4;
51 	regs->orig_a0 = regs->regs[4];
52 	regs->regs[4] = -ENOSYS;
53 
54 	nr = syscall_enter_from_user_mode(regs, nr);
55 
56 	if (nr < NR_syscalls) {
57 		syscall_fn = sys_call_table[nr];
58 		regs->regs[4] = syscall_fn(regs->orig_a0, regs->regs[5], regs->regs[6],
59 					   regs->regs[7], regs->regs[8], regs->regs[9]);
60 	}
61 
62 	syscall_exit_to_user_mode(regs);
63 }
64