linux_dsm_epyc7002/arch/s390/kernel/sys_s390.c
Dominik Brodowski a90f590a1b mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff()
Using this helper allows us to avoid the in-kernel calls to the
sys_mmap_pgoff() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_mmap_pgoff().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:16:11 +02:00

93 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* S390 version
* Copyright IBM Corp. 1999, 2000
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Thomas Spatzier (tspat@de.ibm.com)
*
* Derived from "arch/i386/kernel/sys_i386.c"
*
* This file contains various random system calls that
* have a non-standard calling sequence on the Linux/s390
* platform.
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/unistd.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include "entry.h"
/*
* Perform the mmap() system call. Linux for S/390 isn't able to handle more
* than 5 system call parameters, so this system call uses a memory block
* for parameter passing.
*/
struct s390_mmap_arg_struct {
unsigned long addr;
unsigned long len;
unsigned long prot;
unsigned long flags;
unsigned long fd;
unsigned long offset;
};
SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
{
struct s390_mmap_arg_struct a;
int error = -EFAULT;
if (copy_from_user(&a, arg, sizeof(a)))
goto out;
error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
out:
return error;
}
/*
* sys_ipc() is the de-multiplexer for the SysV IPC calls.
*/
SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
unsigned long, third, void __user *, ptr)
{
if (call >> 16)
return -EINVAL;
/* The s390 sys_ipc variant has only five parameters instead of six
* like the generic variant. The only difference is the handling of
* the SEMTIMEDOP subcall where on s390 the third parameter is used
* as a pointer to a struct timespec where the generic variant uses
* the fifth parameter.
* Therefore we can call the generic variant by simply passing the
* third parameter also as fifth parameter.
*/
return sys_ipc(call, first, second, third, ptr, third);
}
SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
{
unsigned int ret;
if (personality(current->personality) == PER_LINUX32 &&
personality(personality) == PER_LINUX)
personality |= PER_LINUX32;
ret = sys_personality(personality);
if (personality(ret) == PER_LINUX32)
ret &= ~PER_LINUX32;
return ret;
}