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 */
 45SYSCALL_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
 62SYSCALL_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
 79SYSCALL_DEFINE0(ni_syscall)
 80{
 81	return -ENOSYS;
 82}
 83
 84static 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));
119out:
120	syscall_exit_to_user_mode_work(regs);
121}
122
123void 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}