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 #ifdef CONFIG_SYSVIPC
43 /*
44  * sys_ipc() is the de-multiplexer for the SysV IPC calls.
45  */
46 SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
47 		unsigned long, third, void __user *, ptr)
48 {
49 	if (call >> 16)
50 		return -EINVAL;
51 	/* The s390 sys_ipc variant has only five parameters instead of six
52 	 * like the generic variant. The only difference is the handling of
53 	 * the SEMTIMEDOP subcall where on s390 the third parameter is used
54 	 * as a pointer to a struct timespec where the generic variant uses
55 	 * the fifth parameter.
56 	 * Therefore we can call the generic variant by simply passing the
57 	 * third parameter also as fifth parameter.
58 	 */
59 	return ksys_ipc(call, first, second, third, ptr, third);
60 }
61 #endif /* CONFIG_SYSVIPC */
62 
63 SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
64 {
65 	unsigned int ret = current->personality;
66 
67 	if (personality(current->personality) == PER_LINUX32 &&
68 	    personality(personality) == PER_LINUX)
69 		personality |= PER_LINUX32;
70 
71 	if (personality != 0xffffffff)
72 		set_personality(personality);
73 
74 	if (personality(ret) == PER_LINUX32)
75 		ret &= ~PER_LINUX32;
76 
77 	return ret;
78 }
79 
80 SYSCALL_DEFINE0(ni_syscall)
81 {
82 	return -ENOSYS;
83 }
84 
85 void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
86 {
87 	unsigned long nr;
88 
89 	add_random_kstack_offset();
90 	enter_from_user_mode(regs);
91 	regs->psw = get_lowcore()->svc_old_psw;
92 	regs->int_code = get_lowcore()->svc_int_code;
93 	update_timer_sys();
94 	if (cpu_has_bear())
95 		current->thread.last_break = regs->last_break;
96 	local_irq_enable();
97 	regs->orig_gpr2 = regs->gprs[2];
98 	if (unlikely(per_trap))
99 		set_thread_flag(TIF_PER_TRAP);
100 	regs->flags = 0;
101 	set_pt_regs_flag(regs, PIF_SYSCALL);
102 	nr = regs->int_code & 0xffff;
103 	if (likely(!nr)) {
104 		nr = regs->gprs[1] & 0xffff;
105 		regs->int_code &= ~0xffffUL;
106 		regs->int_code |= nr;
107 	}
108 	regs->gprs[2] = nr;
109 	if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
110 		regs->psw.addr = current->restart_block.arch_data;
111 		current->restart_block.arch_data = 1;
112 	}
113 	nr = syscall_enter_from_user_mode_work(regs, nr);
114 	/*
115 	 * In the s390 ptrace ABI, both the syscall number and the return value
116 	 * use gpr2. However, userspace puts the syscall number either in the
117 	 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
118 	 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
119 	 * and if set, the syscall will be skipped.
120 	 */
121 	if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
122 		goto out;
123 	regs->gprs[2] = -ENOSYS;
124 	if (likely(nr < NR_syscalls))
125 		regs->gprs[2] = current->thread.sys_call_table[nr](regs);
126 out:
127 	syscall_exit_to_user_mode(regs);
128 }
129