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/errno.h>
16 #include <linux/sched.h>
17 #include <linux/mm.h>
18 #include <linux/fs.h>
19 #include <linux/smp.h>
20 #include <linux/sem.h>
21 #include <linux/msg.h>
22 #include <linux/shm.h>
23 #include <linux/stat.h>
24 #include <linux/syscalls.h>
25 #include <linux/mman.h>
26 #include <linux/file.h>
27 #include <linux/utsname.h>
28 #include <linux/personality.h>
29 #include <linux/unistd.h>
30 #include <linux/ipc.h>
31 #include <linux/uaccess.h>
32 #include <linux/string.h>
33 #include <linux/thread_info.h>
34 #include <linux/entry-common.h>
35
36 #include <asm/ptrace.h>
37 #include <asm/vtime.h>
38
39 #include "entry.h"
40
41 #ifdef CONFIG_SYSVIPC
42 /*
43 * sys_ipc() is the de-multiplexer for the SysV IPC calls.
44 */
45 SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
46 unsigned long, third, void __user *, ptr)
47 {
48 if (call >> 16)
49 return -EINVAL;
50 /* The s390 sys_ipc variant has only five parameters instead of six
51 * like the generic variant. The only difference is the handling of
52 * the SEMTIMEDOP subcall where on s390 the third parameter is used
53 * as a pointer to a struct timespec where the generic variant uses
54 * the fifth parameter.
55 * Therefore we can call the generic variant by simply passing the
56 * third parameter also as fifth parameter.
57 */
58 return ksys_ipc(call, first, second, third, ptr, third);
59 }
60 #endif /* CONFIG_SYSVIPC */
61
62 SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
63 {
64 unsigned int ret = current->personality;
65
66 if (personality(current->personality) == PER_LINUX32 &&
67 personality(personality) == PER_LINUX)
68 personality |= PER_LINUX32;
69
70 if (personality != 0xffffffff)
71 set_personality(personality);
72
73 if (personality(ret) == PER_LINUX32)
74 ret &= ~PER_LINUX32;
75
76 return ret;
77 }
78
79 SYSCALL_DEFINE0(ni_syscall)
80 {
81 return -ENOSYS;
82 }
83
84 static void do_syscall(struct pt_regs *regs)
85 {
86 unsigned long nr;
87
88 nr = regs->int_code & 0xffff;
89 if (!nr) {
90 nr = regs->gprs[1] & 0xffff;
91 regs->int_code &= ~0xffffUL;
92 regs->int_code |= nr;
93 }
94
95 regs->gprs[2] = nr;
96
97 if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
98 regs->psw.addr = current->restart_block.arch_data;
99 current->restart_block.arch_data = 1;
100 }
101 nr = syscall_enter_from_user_mode_work(regs, nr);
102
103 /*
104 * In the s390 ptrace ABI, both the syscall number and the return value
105 * use gpr2. However, userspace puts the syscall number either in the
106 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
107 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
108 * and if set, the syscall will be skipped.
109 */
110
111 if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
112 goto out;
113 regs->gprs[2] = -ENOSYS;
114 if (likely(nr >= NR_syscalls))
115 goto out;
116 do {
117 regs->gprs[2] = current->thread.sys_call_table[nr](regs);
118 } while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
119 out:
120 syscall_exit_to_user_mode_work(regs);
121 }
122
123 void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
124 {
125 add_random_kstack_offset();
126 enter_from_user_mode(regs);
127 regs->psw = get_lowcore()->svc_old_psw;
128 regs->int_code = get_lowcore()->svc_int_code;
129 update_timer_sys();
130 if (static_branch_likely(&cpu_has_bear))
131 current->thread.last_break = regs->last_break;
132
133 local_irq_enable();
134 regs->orig_gpr2 = regs->gprs[2];
135
136 if (per_trap)
137 set_thread_flag(TIF_PER_TRAP);
138
139 regs->flags = 0;
140 set_pt_regs_flag(regs, PIF_SYSCALL);
141 do_syscall(regs);
142 exit_to_user_mode();
143 }
144
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