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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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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>
187 lines
4.5 KiB
C
187 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* This file contains various system calls that have different calling
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* conventions on different platforms.
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*
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* Copyright (C) 1999-2000, 2002-2003, 2005 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/task_stack.h>
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#include <linux/shm.h>
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#include <linux/file.h> /* doh, must come after sched.h... */
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#include <linux/smp.h>
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#include <linux/syscalls.h>
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#include <linux/highuid.h>
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#include <linux/hugetlb.h>
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#include <asm/shmparam.h>
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#include <linux/uaccess.h>
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unsigned long
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arch_get_unmapped_area (struct file *filp, unsigned long addr, unsigned long len,
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unsigned long pgoff, unsigned long flags)
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{
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long map_shared = (flags & MAP_SHARED);
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unsigned long align_mask = 0;
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struct mm_struct *mm = current->mm;
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struct vm_unmapped_area_info info;
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if (len > RGN_MAP_LIMIT)
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return -ENOMEM;
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/* handle fixed mapping: prevent overlap with huge pages */
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if (flags & MAP_FIXED) {
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if (is_hugepage_only_range(mm, addr, len))
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return -EINVAL;
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return addr;
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}
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#ifdef CONFIG_HUGETLB_PAGE
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if (REGION_NUMBER(addr) == RGN_HPAGE)
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addr = 0;
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#endif
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if (!addr)
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addr = TASK_UNMAPPED_BASE;
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if (map_shared && (TASK_SIZE > 0xfffffffful))
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/*
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* For 64-bit tasks, align shared segments to 1MB to avoid potential
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* performance penalty due to virtual aliasing (see ASDM). For 32-bit
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* tasks, we prefer to avoid exhausting the address space too quickly by
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* limiting alignment to a single page.
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*/
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align_mask = PAGE_MASK & (SHMLBA - 1);
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info.flags = 0;
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info.length = len;
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info.low_limit = addr;
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info.high_limit = TASK_SIZE;
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info.align_mask = align_mask;
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info.align_offset = 0;
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return vm_unmapped_area(&info);
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}
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asmlinkage long
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ia64_getpriority (int which, int who)
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{
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long prio;
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prio = sys_getpriority(which, who);
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if (prio >= 0) {
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force_successful_syscall_return();
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prio = 20 - prio;
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}
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return prio;
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}
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/* XXX obsolete, but leave it here until the old libc is gone... */
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asmlinkage unsigned long
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sys_getpagesize (void)
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{
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return PAGE_SIZE;
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}
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asmlinkage unsigned long
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ia64_brk (unsigned long brk)
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{
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unsigned long retval = sys_brk(brk);
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force_successful_syscall_return();
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return retval;
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}
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/*
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* On IA-64, we return the two file descriptors in ret0 and ret1 (r8
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* and r9) as this is faster than doing a copy_to_user().
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*/
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asmlinkage long
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sys_ia64_pipe (void)
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{
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struct pt_regs *regs = task_pt_regs(current);
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int fd[2];
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int retval;
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retval = do_pipe_flags(fd, 0);
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if (retval)
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goto out;
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retval = fd[0];
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regs->r9 = fd[1];
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out:
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return retval;
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}
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int ia64_mmap_check(unsigned long addr, unsigned long len,
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unsigned long flags)
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{
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unsigned long roff;
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/*
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* Don't permit mappings into unmapped space, the virtual page table
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* of a region, or across a region boundary. Note: RGN_MAP_LIMIT is
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* equal to 2^n-PAGE_SIZE (for some integer n <= 61) and len > 0.
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*/
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roff = REGION_OFFSET(addr);
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if ((len > RGN_MAP_LIMIT) || (roff > (RGN_MAP_LIMIT - len)))
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return -EINVAL;
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return 0;
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}
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/*
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* mmap2() is like mmap() except that the offset is expressed in units
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* of PAGE_SIZE (instead of bytes). This allows to mmap2() (pieces
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* of) files that are larger than the address space of the CPU.
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*/
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asmlinkage unsigned long
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sys_mmap2 (unsigned long addr, unsigned long len, int prot, int flags, int fd, long pgoff)
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{
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addr = ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
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if (!IS_ERR((void *) addr))
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force_successful_syscall_return();
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return addr;
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}
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asmlinkage unsigned long
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sys_mmap (unsigned long addr, unsigned long len, int prot, int flags, int fd, long off)
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{
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if (offset_in_page(off) != 0)
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return -EINVAL;
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addr = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
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if (!IS_ERR((void *) addr))
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force_successful_syscall_return();
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return addr;
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}
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asmlinkage unsigned long
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ia64_mremap (unsigned long addr, unsigned long old_len, unsigned long new_len, unsigned long flags,
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unsigned long new_addr)
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{
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addr = sys_mremap(addr, old_len, new_len, flags, new_addr);
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if (!IS_ERR((void *) addr))
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force_successful_syscall_return();
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return addr;
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}
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#ifndef CONFIG_PCI
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asmlinkage long
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sys_pciconfig_read (unsigned long bus, unsigned long dfn, unsigned long off, unsigned long len,
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void *buf)
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{
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return -ENOSYS;
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}
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asmlinkage long
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sys_pciconfig_write (unsigned long bus, unsigned long dfn, unsigned long off, unsigned long len,
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void *buf)
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{
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return -ENOSYS;
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}
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#endif /* CONFIG_PCI */
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