LXR linux/arch/s390/kernel/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/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/*
  42 * Perform the mmap() system call. Linux for S/390 isn't able to handle more
  43 * than 5 system call parameters, so this system call uses a memory block
  44 * for parameter passing.
  45 */
  46
  47struct s390_mmap_arg_struct {
  48        unsigned long addr;
  49        unsigned long len;
  50        unsigned long prot;
  51        unsigned long flags;
  52        unsigned long fd;
  53        unsigned long offset;
  54};
  55
  56SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
  57{
  58        struct s390_mmap_arg_struct a;
  59        int error = -EFAULT;
  60
  61        if (copy_from_user(&a, arg, sizeof(a)))
  62                goto out;
  63        error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
  64out:
  65        return error;
  66}
  67
  68#ifdef CONFIG_SYSVIPC
  69/*
  70 * sys_ipc() is the de-multiplexer for the SysV IPC calls.
  71 */
  72SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
  73                unsigned long, third, void __user *, ptr)
  74{
  75        if (call >> 16)
  76                return -EINVAL;
  77        /* The s390 sys_ipc variant has only five parameters instead of six
  78         * like the generic variant. The only difference is the handling of
  79         * the SEMTIMEDOP subcall where on s390 the third parameter is used
  80         * as a pointer to a struct timespec where the generic variant uses
  81         * the fifth parameter.
  82         * Therefore we can call the generic variant by simply passing the
  83         * third parameter also as fifth parameter.
  84         */
  85        return ksys_ipc(call, first, second, third, ptr, third);
  86}
  87#endif /* CONFIG_SYSVIPC */
  88
  89SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
  90{
  91        unsigned int ret = current->personality;
  92
  93        if (personality(current->personality) == PER_LINUX32 &&
  94            personality(personality) == PER_LINUX)
  95                personality |= PER_LINUX32;
  96
  97        if (personality != 0xffffffff)
  98                set_personality(personality);
  99
 100        if (personality(ret) == PER_LINUX32)
 101                ret &= ~PER_LINUX32;
 102
 103        return ret;
 104}
 105
 106SYSCALL_DEFINE0(ni_syscall)
 107{
 108        return -ENOSYS;
 109}
 110
 111static void do_syscall(struct pt_regs *regs)
 112{
 113        unsigned long nr;
 114
 115        nr = regs->int_code & 0xffff;
 116        if (!nr) {
 117                nr = regs->gprs[1] & 0xffff;
 118                regs->int_code &= ~0xffffUL;
 119                regs->int_code |= nr;
 120        }
 121
 122        regs->gprs[2] = nr;
 123
 124        if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
 125                regs->psw.addr = current->restart_block.arch_data;
 126                current->restart_block.arch_data = 1;
 127        }
 128        nr = syscall_enter_from_user_mode_work(regs, nr);
 129
 130        /*
 131         * In the s390 ptrace ABI, both the syscall number and the return value
 132         * use gpr2. However, userspace puts the syscall number either in the
 133         * svc instruction itself, or uses gpr1. To make at least skipping syscalls
 134         * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
 135         * and if set, the syscall will be skipped.
 136         */
 137
 138        if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
 139                goto out;
 140        regs->gprs[2] = -ENOSYS;
 141        if (likely(nr >= NR_syscalls))
 142                goto out;
 143        do {
 144                regs->gprs[2] = current->thread.sys_call_table[nr](regs);
 145        } while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
 146out:
 147        syscall_exit_to_user_mode_work(regs);
 148}
 149
 150void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
 151{
 152        add_random_kstack_offset();
 153        enter_from_user_mode(regs);
 154        regs->psw = S390_lowcore.svc_old_psw;
 155        regs->int_code = S390_lowcore.svc_int_code;
 156        update_timer_sys();
 157
 158        local_irq_enable();
 159        regs->orig_gpr2 = regs->gprs[2];
 160
 161        if (per_trap)
 162                set_thread_flag(TIF_PER_TRAP);
 163
 164        regs->flags = 0;
 165        set_pt_regs_flag(regs, PIF_SYSCALL);
 166        do_syscall(regs);
 167        exit_to_user_mode();
 168}
 169