1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S390 version
4 * Copyright IBM Corp. 1999, 2000
5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
6 * Thomas Spatzier (tspat@de.ibm.com)
7 *
8 * Derived from "arch/i386/kernel/sys_i386.c"
9 *
10 * This file contains various random system calls that
11 * have a non-standard calling sequence on the Linux/s390
12 * platform.
13 */
14
15#include <linux/cpufeature.h>
16#include <linux/errno.h>
17#include <linux/sched.h>
18#include <linux/mm.h>
19#include <linux/fs.h>
20#include <linux/smp.h>
21#include <linux/sem.h>
22#include <linux/msg.h>
23#include <linux/shm.h>
24#include <linux/stat.h>
25#include <linux/syscalls.h>
26#include <linux/mman.h>
27#include <linux/file.h>
28#include <linux/utsname.h>
29#include <linux/personality.h>
30#include <linux/unistd.h>
31#include <linux/ipc.h>
32#include <linux/uaccess.h>
33#include <linux/string.h>
34#include <linux/thread_info.h>
35#include <linux/entry-common.h>
36
37#include <asm/ptrace.h>
38#include <asm/vtime.h>
39
40#include "entry.h"
41
42#define __SYSCALL(nr, sym) long __s390x_##sym(struct pt_regs *);
43#include <asm/syscall_table.h>
44#undef __SYSCALL
45
46#define __SYSCALL(nr, sym) [nr] = (__s390x_##sym),
47const sys_call_ptr_t sys_call_table[__NR_syscalls] = {
48#include <asm/syscall_table.h>
49};
50#undef __SYSCALL
51
52#ifdef CONFIG_SYSVIPC
53/*
54 * sys_ipc() is the de-multiplexer for the SysV IPC calls.
55 */
56SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
57 unsigned long, third, void __user *, ptr)
58{
59 if (call >> 16)
60 return -EINVAL;
61 /* The s390 sys_ipc variant has only five parameters instead of six
62 * like the generic variant. The only difference is the handling of
63 * the SEMTIMEDOP subcall where on s390 the third parameter is used
64 * as a pointer to a struct timespec where the generic variant uses
65 * the fifth parameter.
66 * Therefore we can call the generic variant by simply passing the
67 * third parameter also as fifth parameter.
68 */
69 return ksys_ipc(call, first, second, third, ptr, fifth: third);
70}
71#endif /* CONFIG_SYSVIPC */
72
73SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
74{
75 unsigned int ret = current->personality;
76
77 if (personality(current->personality) == PER_LINUX32 &&
78 personality(personality) == PER_LINUX)
79 personality |= PER_LINUX32;
80
81 if (personality != 0xffffffff)
82 set_personality(personality);
83
84 if (personality(ret) == PER_LINUX32)
85 ret &= ~PER_LINUX32;
86
87 return ret;
88}
89
90SYSCALL_DEFINE0(ni_syscall)
91{
92 return -ENOSYS;
93}
94
95void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
96{
97 unsigned long nr;
98
99 add_random_kstack_offset();
100 enter_from_user_mode(regs);
101 regs->psw = get_lowcore()->svc_old_psw;
102 regs->int_code = get_lowcore()->svc_int_code;
103 update_timer_sys();
104 if (cpu_has_bear())
105 current->thread.last_break = regs->last_break;
106 local_irq_enable();
107 regs->orig_gpr2 = regs->gprs[2];
108 if (unlikely(per_trap))
109 set_thread_flag(TIF_PER_TRAP);
110 regs->flags = 0;
111 set_pt_regs_flag(regs, PIF_SYSCALL);
112 nr = regs->int_code & 0xffff;
113 if (likely(!nr)) {
114 nr = regs->gprs[1] & 0xffff;
115 regs->int_code &= ~0xffffUL;
116 regs->int_code |= nr;
117 }
118 regs->gprs[2] = nr;
119 if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
120 regs->psw.addr = current->restart_block.arch_data;
121 current->restart_block.arch_data = 1;
122 }
123 nr = syscall_enter_from_user_mode_work(regs, syscall: nr);
124 /*
125 * In the s390 ptrace ABI, both the syscall number and the return value
126 * use gpr2. However, userspace puts the syscall number either in the
127 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
128 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
129 * and if set, the syscall will be skipped.
130 */
131 if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
132 goto out;
133 regs->gprs[2] = -ENOSYS;
134 if (likely(nr < NR_syscalls))
135 regs->gprs[2] = sys_call_table[nr](regs);
136out:
137 syscall_exit_to_user_mode(regs);
138}
139

source code of linux/arch/s390/kernel/syscall.c