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/objtool.h>
13 #include <linux/randomize_kstack.h>
14 #include <linux/syscalls.h>
15 #include <linux/unistd.h>
16
17 #include <asm/asm.h>
18 #include <asm/exception.h>
19 #include <asm/loongarch.h>
20 #include <asm/signal.h>
21 #include <asm/switch_to.h>
22 #include <asm-generic/syscalls.h>
23
24 #undef __SYSCALL
25 #define __SYSCALL(nr, call) [nr] = (call),
26 #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
27
SYSCALL_DEFINE6(mmap,unsigned long,addr,unsigned long,len,unsigned long,prot,unsigned long,flags,unsigned long,fd,unsigned long,offset)28 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
29 prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
30 {
31 if (offset & ~PAGE_MASK)
32 return -EINVAL;
33
34 return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
35 }
36
SYSCALL_DEFINE6(mmap2,unsigned long,addr,unsigned long,len,unsigned long,prot,unsigned long,flags,unsigned long,fd,unsigned long,offset)37 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len, unsigned long,
38 prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
39 {
40 if (offset & (~PAGE_MASK >> 12))
41 return -EINVAL;
42
43 return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - 12));
44 }
45
46 void *sys_call_table[__NR_syscalls] = {
47 [0 ... __NR_syscalls - 1] = sys_ni_syscall,
48 #ifdef CONFIG_32BIT
49 #include <asm/syscall_table_32.h>
50 #else
51 #include <asm/syscall_table_64.h>
52 #endif
53 };
54
55 typedef long (*sys_call_fn)(unsigned long, unsigned long,
56 unsigned long, unsigned long, unsigned long, unsigned long);
57
do_syscall(struct pt_regs * regs)58 void noinstr __no_stack_protector do_syscall(struct pt_regs *regs)
59 {
60 unsigned long nr;
61 sys_call_fn syscall_fn;
62
63 nr = regs->regs[11];
64 /* Set for syscall restarting */
65 if (nr < NR_syscalls)
66 regs->regs[0] = nr + 1;
67
68 regs->csr_era += 4;
69 regs->orig_a0 = regs->regs[4];
70 regs->regs[4] = -ENOSYS;
71
72 nr = syscall_enter_from_user_mode(regs, nr);
73
74 add_random_kstack_offset();
75
76 if (nr < NR_syscalls) {
77 syscall_fn = sys_call_table[nr];
78 regs->regs[4] = syscall_fn(regs->orig_a0, regs->regs[5], regs->regs[6],
79 regs->regs[7], regs->regs[8], regs->regs[9]);
80 }
81
82 /*
83 * This value will get limited by KSTACK_OFFSET_MAX(), which is 10
84 * bits. The actual entropy will be further reduced by the compiler
85 * when applying stack alignment constraints: 16-bytes (i.e. 4-bits)
86 * aligned, which will remove the 4 low bits from any entropy chosen
87 * here.
88 *
89 * The resulting 6 bits of entropy is seen in SP[9:4].
90 */
91 choose_random_kstack_offset(get_cycles());
92
93 syscall_exit_to_user_mode(regs);
94 }
95