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/nospec.h>
17 #include <linux/errno.h>
18 #include <linux/sched.h>
19 #include <linux/mm.h>
20 #include <linux/fs.h>
21 #include <linux/smp.h>
22 #include <linux/sem.h>
23 #include <linux/msg.h>
24 #include <linux/shm.h>
25 #include <linux/stat.h>
26 #include <linux/syscalls.h>
27 #include <linux/mman.h>
28 #include <linux/file.h>
29 #include <linux/utsname.h>
30 #include <linux/personality.h>
31 #include <linux/unistd.h>
32 #include <linux/ipc.h>
33 #include <linux/uaccess.h>
34 #include <linux/string.h>
35 #include <linux/thread_info.h>
36 #include <linux/entry-common.h>
37
38 #include <asm/ptrace.h>
39 #include <asm/vtime.h>
40
41 #include "entry.h"
42
43 #define __SYSCALL(nr, sym) long __s390x_##sym(struct pt_regs *);
44 #include <asm/syscall_table.h>
45 #undef __SYSCALL
46
47 #define __SYSCALL(nr, sym) [nr] = (__s390x_##sym),
48 const sys_call_ptr_t sys_call_table[__NR_syscalls] = {
49 #include <asm/syscall_table.h>
50 };
51 #undef __SYSCALL
52
53 #ifdef CONFIG_SYSVIPC
54 /*
55 * sys_ipc() is the de-multiplexer for the SysV IPC calls.
56 */
SYSCALL_DEFINE5(s390_ipc,uint,call,int,first,unsigned long,second,unsigned long,third,void __user *,ptr)57 SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
58 unsigned long, third, void __user *, ptr)
59 {
60 if (call >> 16)
61 return -EINVAL;
62 /* The s390 sys_ipc variant has only five parameters instead of six
63 * like the generic variant. The only difference is the handling of
64 * the SEMTIMEDOP subcall where on s390 the third parameter is used
65 * as a pointer to a struct timespec where the generic variant uses
66 * the fifth parameter.
67 * Therefore we can call the generic variant by simply passing the
68 * third parameter also as fifth parameter.
69 */
70 return ksys_ipc(call, first, second, third, ptr, third);
71 }
72 #endif /* CONFIG_SYSVIPC */
73
SYSCALL_DEFINE1(s390_personality,unsigned int,personality)74 SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
75 {
76 unsigned int ret = current->personality;
77
78 if (personality(current->personality) == PER_LINUX32 &&
79 personality(personality) == PER_LINUX)
80 personality |= PER_LINUX32;
81
82 if (personality != 0xffffffff)
83 set_personality(personality);
84
85 if (personality(ret) == PER_LINUX32)
86 ret &= ~PER_LINUX32;
87
88 return ret;
89 }
90
SYSCALL_DEFINE0(ni_syscall)91 SYSCALL_DEFINE0(ni_syscall)
92 {
93 return -ENOSYS;
94 }
95
__do_syscall(struct pt_regs * regs,int per_trap)96 void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
97 {
98 unsigned long nr;
99
100 add_random_kstack_offset();
101 enter_from_user_mode(regs);
102 regs->psw = get_lowcore()->svc_old_psw;
103 regs->int_code = get_lowcore()->svc_int_code;
104 update_timer_sys();
105 if (cpu_has_bear())
106 current->thread.last_break = regs->last_break;
107 local_irq_enable();
108 regs->orig_gpr2 = regs->gprs[2];
109 if (unlikely(per_trap))
110 set_thread_flag(TIF_PER_TRAP);
111 regs->flags = 0;
112 set_pt_regs_flag(regs, PIF_SYSCALL);
113 nr = regs->int_code & 0xffff;
114 if (likely(!nr)) {
115 nr = regs->gprs[1] & 0xffff;
116 regs->int_code &= ~0xffffUL;
117 regs->int_code |= nr;
118 }
119 regs->gprs[2] = nr;
120 if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
121 regs->psw.addr = current->restart_block.arch_data;
122 current->restart_block.arch_data = 1;
123 }
124 nr = syscall_enter_from_user_mode_work(regs, nr);
125 /*
126 * In the s390 ptrace ABI, both the syscall number and the return value
127 * use gpr2. However, userspace puts the syscall number either in the
128 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
129 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
130 * and if set, the syscall will be skipped.
131 */
132 if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
133 goto out;
134 regs->gprs[2] = -ENOSYS;
135 if (likely(nr < NR_syscalls)) {
136 nr = array_index_nospec(nr, NR_syscalls);
137 regs->gprs[2] = sys_call_table[nr](regs);
138 }
139 out:
140 syscall_exit_to_user_mode(regs);
141 }
142