forked from Minki/linux
a90f590a1b
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>
93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* S390 version
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* Copyright IBM Corp. 1999, 2000
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Thomas Spatzier (tspat@de.ibm.com)
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*
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* Derived from "arch/i386/kernel/sys_i386.c"
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*
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* This file contains various random system calls that
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* have a non-standard calling sequence on the Linux/s390
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* platform.
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*/
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/smp.h>
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#include <linux/sem.h>
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#include <linux/msg.h>
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#include <linux/shm.h>
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#include <linux/stat.h>
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#include <linux/syscalls.h>
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#include <linux/mman.h>
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#include <linux/file.h>
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#include <linux/utsname.h>
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#include <linux/personality.h>
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#include <linux/unistd.h>
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#include <linux/ipc.h>
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#include <linux/uaccess.h>
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#include "entry.h"
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/*
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* Perform the mmap() system call. Linux for S/390 isn't able to handle more
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* than 5 system call parameters, so this system call uses a memory block
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* for parameter passing.
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*/
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struct s390_mmap_arg_struct {
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unsigned long addr;
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unsigned long len;
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unsigned long prot;
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unsigned long flags;
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unsigned long fd;
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unsigned long offset;
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};
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SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
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{
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struct s390_mmap_arg_struct a;
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int error = -EFAULT;
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if (copy_from_user(&a, arg, sizeof(a)))
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goto out;
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error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
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out:
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return error;
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}
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/*
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* sys_ipc() is the de-multiplexer for the SysV IPC calls.
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*/
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SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
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unsigned long, third, void __user *, ptr)
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{
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if (call >> 16)
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return -EINVAL;
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/* The s390 sys_ipc variant has only five parameters instead of six
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* like the generic variant. The only difference is the handling of
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* the SEMTIMEDOP subcall where on s390 the third parameter is used
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* as a pointer to a struct timespec where the generic variant uses
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* the fifth parameter.
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* Therefore we can call the generic variant by simply passing the
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* third parameter also as fifth parameter.
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*/
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return sys_ipc(call, first, second, third, ptr, third);
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}
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SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
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{
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unsigned int ret;
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if (personality(current->personality) == PER_LINUX32 &&
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personality(personality) == PER_LINUX)
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personality |= PER_LINUX32;
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ret = sys_personality(personality);
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if (personality(ret) == PER_LINUX32)
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ret &= ~PER_LINUX32;
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return ret;
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}
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