syscall.c

  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),
 48const 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 */
 57SYSCALL_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
 74SYSCALL_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
 91SYSCALL_DEFINE0(ni_syscall)
 92{
 93	return -ENOSYS;
 94}
 95
 96void 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	}
139out:
140	syscall_exit_to_user_mode(regs);
141}