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![Kirill A. Shutemov](/assets/img/avatar_default.png)
The idea borrowed from Peter's patch from patchset on speculative page faults[1]: Instead of passing around the endless list of function arguments, replace the lot with a single structure so we can change context without endless function signature changes. The changes are mostly mechanical with exception of faultaround code: filemap_map_pages() got reworked a bit. This patch is preparation for the next one. [1] http://lkml.kernel.org/r/20141020222841.302891540@infradead.org Link: http://lkml.kernel.org/r/1466021202-61880-9-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1990 lines
48 KiB
C
1990 lines
48 KiB
C
/*
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* linux/mm/nommu.c
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*
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* Replacement code for mm functions to support CPU's that don't
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* have any form of memory management unit (thus no virtual memory).
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*
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* See Documentation/nommu-mmap.txt
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*
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* Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
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* Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
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* Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
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* Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
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* Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/vmacache.h>
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#include <linux/mman.h>
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#include <linux/swap.h>
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#include <linux/file.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/compiler.h>
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#include <linux/mount.h>
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#include <linux/personality.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/printk.h>
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#include <asm/uaccess.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include "internal.h"
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void *high_memory;
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EXPORT_SYMBOL(high_memory);
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struct page *mem_map;
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unsigned long max_mapnr;
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EXPORT_SYMBOL(max_mapnr);
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unsigned long highest_memmap_pfn;
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int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
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int heap_stack_gap = 0;
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atomic_long_t mmap_pages_allocated;
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EXPORT_SYMBOL(mem_map);
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/* list of mapped, potentially shareable regions */
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static struct kmem_cache *vm_region_jar;
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struct rb_root nommu_region_tree = RB_ROOT;
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DECLARE_RWSEM(nommu_region_sem);
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const struct vm_operations_struct generic_file_vm_ops = {
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};
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/*
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* Return the total memory allocated for this pointer, not
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* just what the caller asked for.
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*
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* Doesn't have to be accurate, i.e. may have races.
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*/
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unsigned int kobjsize(const void *objp)
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{
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struct page *page;
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/*
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* If the object we have should not have ksize performed on it,
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* return size of 0
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*/
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if (!objp || !virt_addr_valid(objp))
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return 0;
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page = virt_to_head_page(objp);
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/*
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* If the allocator sets PageSlab, we know the pointer came from
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* kmalloc().
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*/
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if (PageSlab(page))
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return ksize(objp);
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/*
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* If it's not a compound page, see if we have a matching VMA
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* region. This test is intentionally done in reverse order,
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* so if there's no VMA, we still fall through and hand back
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* PAGE_SIZE for 0-order pages.
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*/
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if (!PageCompound(page)) {
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struct vm_area_struct *vma;
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vma = find_vma(current->mm, (unsigned long)objp);
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if (vma)
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return vma->vm_end - vma->vm_start;
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}
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/*
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* The ksize() function is only guaranteed to work for pointers
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* returned by kmalloc(). So handle arbitrary pointers here.
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*/
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return PAGE_SIZE << compound_order(page);
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}
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long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
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unsigned long start, unsigned long nr_pages,
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unsigned int foll_flags, struct page **pages,
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struct vm_area_struct **vmas, int *nonblocking)
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{
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struct vm_area_struct *vma;
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unsigned long vm_flags;
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int i;
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/* calculate required read or write permissions.
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* If FOLL_FORCE is set, we only require the "MAY" flags.
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*/
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vm_flags = (foll_flags & FOLL_WRITE) ?
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(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
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vm_flags &= (foll_flags & FOLL_FORCE) ?
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(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
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for (i = 0; i < nr_pages; i++) {
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vma = find_vma(mm, start);
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if (!vma)
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goto finish_or_fault;
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/* protect what we can, including chardevs */
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if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
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!(vm_flags & vma->vm_flags))
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goto finish_or_fault;
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if (pages) {
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pages[i] = virt_to_page(start);
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if (pages[i])
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get_page(pages[i]);
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}
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if (vmas)
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vmas[i] = vma;
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start = (start + PAGE_SIZE) & PAGE_MASK;
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}
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return i;
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finish_or_fault:
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return i ? : -EFAULT;
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}
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/*
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* get a list of pages in an address range belonging to the specified process
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* and indicate the VMA that covers each page
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* - this is potentially dodgy as we may end incrementing the page count of a
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* slab page or a secondary page from a compound page
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* - don't permit access to VMAs that don't support it, such as I/O mappings
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*/
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long get_user_pages(unsigned long start, unsigned long nr_pages,
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int write, int force, struct page **pages,
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struct vm_area_struct **vmas)
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{
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int flags = 0;
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if (write)
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flags |= FOLL_WRITE;
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if (force)
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flags |= FOLL_FORCE;
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return __get_user_pages(current, current->mm, start, nr_pages, flags,
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pages, vmas, NULL);
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}
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EXPORT_SYMBOL(get_user_pages);
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long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
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int write, int force, struct page **pages,
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int *locked)
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{
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return get_user_pages(start, nr_pages, write, force, pages, NULL);
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}
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EXPORT_SYMBOL(get_user_pages_locked);
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long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
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unsigned long start, unsigned long nr_pages,
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int write, int force, struct page **pages,
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unsigned int gup_flags)
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{
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long ret;
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down_read(&mm->mmap_sem);
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ret = __get_user_pages(tsk, mm, start, nr_pages, gup_flags, pages,
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NULL, NULL);
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up_read(&mm->mmap_sem);
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return ret;
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}
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EXPORT_SYMBOL(__get_user_pages_unlocked);
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long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
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int write, int force, struct page **pages)
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{
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return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
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write, force, pages, 0);
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}
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EXPORT_SYMBOL(get_user_pages_unlocked);
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/**
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* follow_pfn - look up PFN at a user virtual address
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* @vma: memory mapping
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* @address: user virtual address
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* @pfn: location to store found PFN
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*
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* Only IO mappings and raw PFN mappings are allowed.
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*
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* Returns zero and the pfn at @pfn on success, -ve otherwise.
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*/
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int follow_pfn(struct vm_area_struct *vma, unsigned long address,
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unsigned long *pfn)
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{
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if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
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return -EINVAL;
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*pfn = address >> PAGE_SHIFT;
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return 0;
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}
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EXPORT_SYMBOL(follow_pfn);
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LIST_HEAD(vmap_area_list);
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void vfree(const void *addr)
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{
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kfree(addr);
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}
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EXPORT_SYMBOL(vfree);
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void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
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{
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/*
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* You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
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* returns only a logical address.
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*/
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return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
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}
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EXPORT_SYMBOL(__vmalloc);
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void *vmalloc_user(unsigned long size)
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{
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void *ret;
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ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
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PAGE_KERNEL);
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if (ret) {
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struct vm_area_struct *vma;
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down_write(¤t->mm->mmap_sem);
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vma = find_vma(current->mm, (unsigned long)ret);
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if (vma)
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vma->vm_flags |= VM_USERMAP;
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up_write(¤t->mm->mmap_sem);
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}
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return ret;
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}
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EXPORT_SYMBOL(vmalloc_user);
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struct page *vmalloc_to_page(const void *addr)
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{
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return virt_to_page(addr);
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}
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EXPORT_SYMBOL(vmalloc_to_page);
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unsigned long vmalloc_to_pfn(const void *addr)
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{
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return page_to_pfn(virt_to_page(addr));
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}
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EXPORT_SYMBOL(vmalloc_to_pfn);
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long vread(char *buf, char *addr, unsigned long count)
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{
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/* Don't allow overflow */
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if ((unsigned long) buf + count < count)
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count = -(unsigned long) buf;
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memcpy(buf, addr, count);
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return count;
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}
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long vwrite(char *buf, char *addr, unsigned long count)
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{
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/* Don't allow overflow */
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if ((unsigned long) addr + count < count)
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count = -(unsigned long) addr;
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memcpy(addr, buf, count);
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return count;
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}
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/*
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* vmalloc - allocate virtually contiguous memory
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*
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* @size: allocation size
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc);
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/*
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* vzalloc - allocate virtually contiguous memory with zero fill
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*
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* @size: allocation size
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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* The memory allocated is set to zero.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vzalloc(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
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PAGE_KERNEL);
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}
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EXPORT_SYMBOL(vzalloc);
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/**
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* vmalloc_node - allocate memory on a specific node
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* @size: allocation size
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* @node: numa node
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc_node(unsigned long size, int node)
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{
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return vmalloc(size);
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}
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EXPORT_SYMBOL(vmalloc_node);
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/**
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* vzalloc_node - allocate memory on a specific node with zero fill
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* @size: allocation size
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* @node: numa node
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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* The memory allocated is set to zero.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vzalloc_node(unsigned long size, int node)
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{
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return vzalloc(size);
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}
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EXPORT_SYMBOL(vzalloc_node);
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#ifndef PAGE_KERNEL_EXEC
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# define PAGE_KERNEL_EXEC PAGE_KERNEL
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#endif
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/**
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* vmalloc_exec - allocate virtually contiguous, executable memory
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* @size: allocation size
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*
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* Kernel-internal function to allocate enough pages to cover @size
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* the page level allocator and map them into contiguous and
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* executable kernel virtual space.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc_exec(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
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}
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/**
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* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
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* @size: allocation size
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*
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* Allocate enough 32bit PA addressable pages to cover @size from the
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* page level allocator and map them into contiguous kernel virtual space.
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*/
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void *vmalloc_32(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc_32);
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/**
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* vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
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* @size: allocation size
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*
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* The resulting memory area is 32bit addressable and zeroed so it can be
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* mapped to userspace without leaking data.
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*
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* VM_USERMAP is set on the corresponding VMA so that subsequent calls to
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* remap_vmalloc_range() are permissible.
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*/
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void *vmalloc_32_user(unsigned long size)
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{
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/*
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* We'll have to sort out the ZONE_DMA bits for 64-bit,
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* but for now this can simply use vmalloc_user() directly.
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*/
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return vmalloc_user(size);
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}
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EXPORT_SYMBOL(vmalloc_32_user);
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void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
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{
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BUG();
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return NULL;
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}
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EXPORT_SYMBOL(vmap);
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void vunmap(const void *addr)
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{
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BUG();
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}
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EXPORT_SYMBOL(vunmap);
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void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
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{
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BUG();
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return NULL;
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}
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EXPORT_SYMBOL(vm_map_ram);
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void vm_unmap_ram(const void *mem, unsigned int count)
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{
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BUG();
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}
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EXPORT_SYMBOL(vm_unmap_ram);
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void vm_unmap_aliases(void)
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{
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}
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EXPORT_SYMBOL_GPL(vm_unmap_aliases);
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/*
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* Implement a stub for vmalloc_sync_all() if the architecture chose not to
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* have one.
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*/
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void __weak vmalloc_sync_all(void)
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{
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}
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/**
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* alloc_vm_area - allocate a range of kernel address space
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* @size: size of the area
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*
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* Returns: NULL on failure, vm_struct on success
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*
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* This function reserves a range of kernel address space, and
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* allocates pagetables to map that range. No actual mappings
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* are created. If the kernel address space is not shared
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* between processes, it syncs the pagetable across all
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* processes.
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*/
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struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
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{
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BUG();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(alloc_vm_area);
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void free_vm_area(struct vm_struct *area)
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{
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BUG();
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}
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EXPORT_SYMBOL_GPL(free_vm_area);
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int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
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struct page *page)
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{
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return -EINVAL;
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}
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EXPORT_SYMBOL(vm_insert_page);
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/*
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* sys_brk() for the most part doesn't need the global kernel
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* lock, except when an application is doing something nasty
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* like trying to un-brk an area that has already been mapped
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* to a regular file. in this case, the unmapping will need
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* to invoke file system routines that need the global lock.
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*/
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SYSCALL_DEFINE1(brk, unsigned long, brk)
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{
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struct mm_struct *mm = current->mm;
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if (brk < mm->start_brk || brk > mm->context.end_brk)
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return mm->brk;
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if (mm->brk == brk)
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return mm->brk;
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/*
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* Always allow shrinking brk
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*/
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if (brk <= mm->brk) {
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mm->brk = brk;
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return brk;
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}
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/*
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* Ok, looks good - let it rip.
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*/
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flush_icache_range(mm->brk, brk);
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return mm->brk = brk;
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}
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/*
|
|
* initialise the VMA and region record slabs
|
|
*/
|
|
void __init mmap_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
|
|
VM_BUG_ON(ret);
|
|
vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
|
|
}
|
|
|
|
/*
|
|
* validate the region tree
|
|
* - the caller must hold the region lock
|
|
*/
|
|
#ifdef CONFIG_DEBUG_NOMMU_REGIONS
|
|
static noinline void validate_nommu_regions(void)
|
|
{
|
|
struct vm_region *region, *last;
|
|
struct rb_node *p, *lastp;
|
|
|
|
lastp = rb_first(&nommu_region_tree);
|
|
if (!lastp)
|
|
return;
|
|
|
|
last = rb_entry(lastp, struct vm_region, vm_rb);
|
|
BUG_ON(last->vm_end <= last->vm_start);
|
|
BUG_ON(last->vm_top < last->vm_end);
|
|
|
|
while ((p = rb_next(lastp))) {
|
|
region = rb_entry(p, struct vm_region, vm_rb);
|
|
last = rb_entry(lastp, struct vm_region, vm_rb);
|
|
|
|
BUG_ON(region->vm_end <= region->vm_start);
|
|
BUG_ON(region->vm_top < region->vm_end);
|
|
BUG_ON(region->vm_start < last->vm_top);
|
|
|
|
lastp = p;
|
|
}
|
|
}
|
|
#else
|
|
static void validate_nommu_regions(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* add a region into the global tree
|
|
*/
|
|
static void add_nommu_region(struct vm_region *region)
|
|
{
|
|
struct vm_region *pregion;
|
|
struct rb_node **p, *parent;
|
|
|
|
validate_nommu_regions();
|
|
|
|
parent = NULL;
|
|
p = &nommu_region_tree.rb_node;
|
|
while (*p) {
|
|
parent = *p;
|
|
pregion = rb_entry(parent, struct vm_region, vm_rb);
|
|
if (region->vm_start < pregion->vm_start)
|
|
p = &(*p)->rb_left;
|
|
else if (region->vm_start > pregion->vm_start)
|
|
p = &(*p)->rb_right;
|
|
else if (pregion == region)
|
|
return;
|
|
else
|
|
BUG();
|
|
}
|
|
|
|
rb_link_node(®ion->vm_rb, parent, p);
|
|
rb_insert_color(®ion->vm_rb, &nommu_region_tree);
|
|
|
|
validate_nommu_regions();
|
|
}
|
|
|
|
/*
|
|
* delete a region from the global tree
|
|
*/
|
|
static void delete_nommu_region(struct vm_region *region)
|
|
{
|
|
BUG_ON(!nommu_region_tree.rb_node);
|
|
|
|
validate_nommu_regions();
|
|
rb_erase(®ion->vm_rb, &nommu_region_tree);
|
|
validate_nommu_regions();
|
|
}
|
|
|
|
/*
|
|
* free a contiguous series of pages
|
|
*/
|
|
static void free_page_series(unsigned long from, unsigned long to)
|
|
{
|
|
for (; from < to; from += PAGE_SIZE) {
|
|
struct page *page = virt_to_page(from);
|
|
|
|
atomic_long_dec(&mmap_pages_allocated);
|
|
put_page(page);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* release a reference to a region
|
|
* - the caller must hold the region semaphore for writing, which this releases
|
|
* - the region may not have been added to the tree yet, in which case vm_top
|
|
* will equal vm_start
|
|
*/
|
|
static void __put_nommu_region(struct vm_region *region)
|
|
__releases(nommu_region_sem)
|
|
{
|
|
BUG_ON(!nommu_region_tree.rb_node);
|
|
|
|
if (--region->vm_usage == 0) {
|
|
if (region->vm_top > region->vm_start)
|
|
delete_nommu_region(region);
|
|
up_write(&nommu_region_sem);
|
|
|
|
if (region->vm_file)
|
|
fput(region->vm_file);
|
|
|
|
/* IO memory and memory shared directly out of the pagecache
|
|
* from ramfs/tmpfs mustn't be released here */
|
|
if (region->vm_flags & VM_MAPPED_COPY)
|
|
free_page_series(region->vm_start, region->vm_top);
|
|
kmem_cache_free(vm_region_jar, region);
|
|
} else {
|
|
up_write(&nommu_region_sem);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* release a reference to a region
|
|
*/
|
|
static void put_nommu_region(struct vm_region *region)
|
|
{
|
|
down_write(&nommu_region_sem);
|
|
__put_nommu_region(region);
|
|
}
|
|
|
|
/*
|
|
* update protection on a vma
|
|
*/
|
|
static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
|
|
{
|
|
#ifdef CONFIG_MPU
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
long start = vma->vm_start & PAGE_MASK;
|
|
while (start < vma->vm_end) {
|
|
protect_page(mm, start, flags);
|
|
start += PAGE_SIZE;
|
|
}
|
|
update_protections(mm);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* add a VMA into a process's mm_struct in the appropriate place in the list
|
|
* and tree and add to the address space's page tree also if not an anonymous
|
|
* page
|
|
* - should be called with mm->mmap_sem held writelocked
|
|
*/
|
|
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
|
|
{
|
|
struct vm_area_struct *pvma, *prev;
|
|
struct address_space *mapping;
|
|
struct rb_node **p, *parent, *rb_prev;
|
|
|
|
BUG_ON(!vma->vm_region);
|
|
|
|
mm->map_count++;
|
|
vma->vm_mm = mm;
|
|
|
|
protect_vma(vma, vma->vm_flags);
|
|
|
|
/* add the VMA to the mapping */
|
|
if (vma->vm_file) {
|
|
mapping = vma->vm_file->f_mapping;
|
|
|
|
i_mmap_lock_write(mapping);
|
|
flush_dcache_mmap_lock(mapping);
|
|
vma_interval_tree_insert(vma, &mapping->i_mmap);
|
|
flush_dcache_mmap_unlock(mapping);
|
|
i_mmap_unlock_write(mapping);
|
|
}
|
|
|
|
/* add the VMA to the tree */
|
|
parent = rb_prev = NULL;
|
|
p = &mm->mm_rb.rb_node;
|
|
while (*p) {
|
|
parent = *p;
|
|
pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
|
|
|
|
/* sort by: start addr, end addr, VMA struct addr in that order
|
|
* (the latter is necessary as we may get identical VMAs) */
|
|
if (vma->vm_start < pvma->vm_start)
|
|
p = &(*p)->rb_left;
|
|
else if (vma->vm_start > pvma->vm_start) {
|
|
rb_prev = parent;
|
|
p = &(*p)->rb_right;
|
|
} else if (vma->vm_end < pvma->vm_end)
|
|
p = &(*p)->rb_left;
|
|
else if (vma->vm_end > pvma->vm_end) {
|
|
rb_prev = parent;
|
|
p = &(*p)->rb_right;
|
|
} else if (vma < pvma)
|
|
p = &(*p)->rb_left;
|
|
else if (vma > pvma) {
|
|
rb_prev = parent;
|
|
p = &(*p)->rb_right;
|
|
} else
|
|
BUG();
|
|
}
|
|
|
|
rb_link_node(&vma->vm_rb, parent, p);
|
|
rb_insert_color(&vma->vm_rb, &mm->mm_rb);
|
|
|
|
/* add VMA to the VMA list also */
|
|
prev = NULL;
|
|
if (rb_prev)
|
|
prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
|
|
|
|
__vma_link_list(mm, vma, prev, parent);
|
|
}
|
|
|
|
/*
|
|
* delete a VMA from its owning mm_struct and address space
|
|
*/
|
|
static void delete_vma_from_mm(struct vm_area_struct *vma)
|
|
{
|
|
int i;
|
|
struct address_space *mapping;
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
struct task_struct *curr = current;
|
|
|
|
protect_vma(vma, 0);
|
|
|
|
mm->map_count--;
|
|
for (i = 0; i < VMACACHE_SIZE; i++) {
|
|
/* if the vma is cached, invalidate the entire cache */
|
|
if (curr->vmacache[i] == vma) {
|
|
vmacache_invalidate(mm);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* remove the VMA from the mapping */
|
|
if (vma->vm_file) {
|
|
mapping = vma->vm_file->f_mapping;
|
|
|
|
i_mmap_lock_write(mapping);
|
|
flush_dcache_mmap_lock(mapping);
|
|
vma_interval_tree_remove(vma, &mapping->i_mmap);
|
|
flush_dcache_mmap_unlock(mapping);
|
|
i_mmap_unlock_write(mapping);
|
|
}
|
|
|
|
/* remove from the MM's tree and list */
|
|
rb_erase(&vma->vm_rb, &mm->mm_rb);
|
|
|
|
if (vma->vm_prev)
|
|
vma->vm_prev->vm_next = vma->vm_next;
|
|
else
|
|
mm->mmap = vma->vm_next;
|
|
|
|
if (vma->vm_next)
|
|
vma->vm_next->vm_prev = vma->vm_prev;
|
|
}
|
|
|
|
/*
|
|
* destroy a VMA record
|
|
*/
|
|
static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
|
|
{
|
|
if (vma->vm_ops && vma->vm_ops->close)
|
|
vma->vm_ops->close(vma);
|
|
if (vma->vm_file)
|
|
fput(vma->vm_file);
|
|
put_nommu_region(vma->vm_region);
|
|
kmem_cache_free(vm_area_cachep, vma);
|
|
}
|
|
|
|
/*
|
|
* look up the first VMA in which addr resides, NULL if none
|
|
* - should be called with mm->mmap_sem at least held readlocked
|
|
*/
|
|
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
/* check the cache first */
|
|
vma = vmacache_find(mm, addr);
|
|
if (likely(vma))
|
|
return vma;
|
|
|
|
/* trawl the list (there may be multiple mappings in which addr
|
|
* resides) */
|
|
for (vma = mm->mmap; vma; vma = vma->vm_next) {
|
|
if (vma->vm_start > addr)
|
|
return NULL;
|
|
if (vma->vm_end > addr) {
|
|
vmacache_update(addr, vma);
|
|
return vma;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(find_vma);
|
|
|
|
/*
|
|
* find a VMA
|
|
* - we don't extend stack VMAs under NOMMU conditions
|
|
*/
|
|
struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
return find_vma(mm, addr);
|
|
}
|
|
|
|
/*
|
|
* expand a stack to a given address
|
|
* - not supported under NOMMU conditions
|
|
*/
|
|
int expand_stack(struct vm_area_struct *vma, unsigned long address)
|
|
{
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* look up the first VMA exactly that exactly matches addr
|
|
* - should be called with mm->mmap_sem at least held readlocked
|
|
*/
|
|
static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
|
|
unsigned long addr,
|
|
unsigned long len)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
unsigned long end = addr + len;
|
|
|
|
/* check the cache first */
|
|
vma = vmacache_find_exact(mm, addr, end);
|
|
if (vma)
|
|
return vma;
|
|
|
|
/* trawl the list (there may be multiple mappings in which addr
|
|
* resides) */
|
|
for (vma = mm->mmap; vma; vma = vma->vm_next) {
|
|
if (vma->vm_start < addr)
|
|
continue;
|
|
if (vma->vm_start > addr)
|
|
return NULL;
|
|
if (vma->vm_end == end) {
|
|
vmacache_update(addr, vma);
|
|
return vma;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* determine whether a mapping should be permitted and, if so, what sort of
|
|
* mapping we're capable of supporting
|
|
*/
|
|
static int validate_mmap_request(struct file *file,
|
|
unsigned long addr,
|
|
unsigned long len,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
unsigned long pgoff,
|
|
unsigned long *_capabilities)
|
|
{
|
|
unsigned long capabilities, rlen;
|
|
int ret;
|
|
|
|
/* do the simple checks first */
|
|
if (flags & MAP_FIXED)
|
|
return -EINVAL;
|
|
|
|
if ((flags & MAP_TYPE) != MAP_PRIVATE &&
|
|
(flags & MAP_TYPE) != MAP_SHARED)
|
|
return -EINVAL;
|
|
|
|
if (!len)
|
|
return -EINVAL;
|
|
|
|
/* Careful about overflows.. */
|
|
rlen = PAGE_ALIGN(len);
|
|
if (!rlen || rlen > TASK_SIZE)
|
|
return -ENOMEM;
|
|
|
|
/* offset overflow? */
|
|
if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
|
|
return -EOVERFLOW;
|
|
|
|
if (file) {
|
|
/* files must support mmap */
|
|
if (!file->f_op->mmap)
|
|
return -ENODEV;
|
|
|
|
/* work out if what we've got could possibly be shared
|
|
* - we support chardevs that provide their own "memory"
|
|
* - we support files/blockdevs that are memory backed
|
|
*/
|
|
if (file->f_op->mmap_capabilities) {
|
|
capabilities = file->f_op->mmap_capabilities(file);
|
|
} else {
|
|
/* no explicit capabilities set, so assume some
|
|
* defaults */
|
|
switch (file_inode(file)->i_mode & S_IFMT) {
|
|
case S_IFREG:
|
|
case S_IFBLK:
|
|
capabilities = NOMMU_MAP_COPY;
|
|
break;
|
|
|
|
case S_IFCHR:
|
|
capabilities =
|
|
NOMMU_MAP_DIRECT |
|
|
NOMMU_MAP_READ |
|
|
NOMMU_MAP_WRITE;
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* eliminate any capabilities that we can't support on this
|
|
* device */
|
|
if (!file->f_op->get_unmapped_area)
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
if (!(file->f_mode & FMODE_CAN_READ))
|
|
capabilities &= ~NOMMU_MAP_COPY;
|
|
|
|
/* The file shall have been opened with read permission. */
|
|
if (!(file->f_mode & FMODE_READ))
|
|
return -EACCES;
|
|
|
|
if (flags & MAP_SHARED) {
|
|
/* do checks for writing, appending and locking */
|
|
if ((prot & PROT_WRITE) &&
|
|
!(file->f_mode & FMODE_WRITE))
|
|
return -EACCES;
|
|
|
|
if (IS_APPEND(file_inode(file)) &&
|
|
(file->f_mode & FMODE_WRITE))
|
|
return -EACCES;
|
|
|
|
if (locks_verify_locked(file))
|
|
return -EAGAIN;
|
|
|
|
if (!(capabilities & NOMMU_MAP_DIRECT))
|
|
return -ENODEV;
|
|
|
|
/* we mustn't privatise shared mappings */
|
|
capabilities &= ~NOMMU_MAP_COPY;
|
|
} else {
|
|
/* we're going to read the file into private memory we
|
|
* allocate */
|
|
if (!(capabilities & NOMMU_MAP_COPY))
|
|
return -ENODEV;
|
|
|
|
/* we don't permit a private writable mapping to be
|
|
* shared with the backing device */
|
|
if (prot & PROT_WRITE)
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
}
|
|
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
|
|
((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
|
|
((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
|
|
) {
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
if (flags & MAP_SHARED) {
|
|
pr_warn("MAP_SHARED not completely supported on !MMU\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* handle executable mappings and implied executable
|
|
* mappings */
|
|
if (path_noexec(&file->f_path)) {
|
|
if (prot & PROT_EXEC)
|
|
return -EPERM;
|
|
} else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
|
|
/* handle implication of PROT_EXEC by PROT_READ */
|
|
if (current->personality & READ_IMPLIES_EXEC) {
|
|
if (capabilities & NOMMU_MAP_EXEC)
|
|
prot |= PROT_EXEC;
|
|
}
|
|
} else if ((prot & PROT_READ) &&
|
|
(prot & PROT_EXEC) &&
|
|
!(capabilities & NOMMU_MAP_EXEC)
|
|
) {
|
|
/* backing file is not executable, try to copy */
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
}
|
|
} else {
|
|
/* anonymous mappings are always memory backed and can be
|
|
* privately mapped
|
|
*/
|
|
capabilities = NOMMU_MAP_COPY;
|
|
|
|
/* handle PROT_EXEC implication by PROT_READ */
|
|
if ((prot & PROT_READ) &&
|
|
(current->personality & READ_IMPLIES_EXEC))
|
|
prot |= PROT_EXEC;
|
|
}
|
|
|
|
/* allow the security API to have its say */
|
|
ret = security_mmap_addr(addr);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* looks okay */
|
|
*_capabilities = capabilities;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* we've determined that we can make the mapping, now translate what we
|
|
* now know into VMA flags
|
|
*/
|
|
static unsigned long determine_vm_flags(struct file *file,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
unsigned long capabilities)
|
|
{
|
|
unsigned long vm_flags;
|
|
|
|
vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
|
|
/* vm_flags |= mm->def_flags; */
|
|
|
|
if (!(capabilities & NOMMU_MAP_DIRECT)) {
|
|
/* attempt to share read-only copies of mapped file chunks */
|
|
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
|
|
if (file && !(prot & PROT_WRITE))
|
|
vm_flags |= VM_MAYSHARE;
|
|
} else {
|
|
/* overlay a shareable mapping on the backing device or inode
|
|
* if possible - used for chardevs, ramfs/tmpfs/shmfs and
|
|
* romfs/cramfs */
|
|
vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS);
|
|
if (flags & MAP_SHARED)
|
|
vm_flags |= VM_SHARED;
|
|
}
|
|
|
|
/* refuse to let anyone share private mappings with this process if
|
|
* it's being traced - otherwise breakpoints set in it may interfere
|
|
* with another untraced process
|
|
*/
|
|
if ((flags & MAP_PRIVATE) && current->ptrace)
|
|
vm_flags &= ~VM_MAYSHARE;
|
|
|
|
return vm_flags;
|
|
}
|
|
|
|
/*
|
|
* set up a shared mapping on a file (the driver or filesystem provides and
|
|
* pins the storage)
|
|
*/
|
|
static int do_mmap_shared_file(struct vm_area_struct *vma)
|
|
{
|
|
int ret;
|
|
|
|
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
|
|
if (ret == 0) {
|
|
vma->vm_region->vm_top = vma->vm_region->vm_end;
|
|
return 0;
|
|
}
|
|
if (ret != -ENOSYS)
|
|
return ret;
|
|
|
|
/* getting -ENOSYS indicates that direct mmap isn't possible (as
|
|
* opposed to tried but failed) so we can only give a suitable error as
|
|
* it's not possible to make a private copy if MAP_SHARED was given */
|
|
return -ENODEV;
|
|
}
|
|
|
|
/*
|
|
* set up a private mapping or an anonymous shared mapping
|
|
*/
|
|
static int do_mmap_private(struct vm_area_struct *vma,
|
|
struct vm_region *region,
|
|
unsigned long len,
|
|
unsigned long capabilities)
|
|
{
|
|
unsigned long total, point;
|
|
void *base;
|
|
int ret, order;
|
|
|
|
/* invoke the file's mapping function so that it can keep track of
|
|
* shared mappings on devices or memory
|
|
* - VM_MAYSHARE will be set if it may attempt to share
|
|
*/
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
|
|
if (ret == 0) {
|
|
/* shouldn't return success if we're not sharing */
|
|
BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
|
|
vma->vm_region->vm_top = vma->vm_region->vm_end;
|
|
return 0;
|
|
}
|
|
if (ret != -ENOSYS)
|
|
return ret;
|
|
|
|
/* getting an ENOSYS error indicates that direct mmap isn't
|
|
* possible (as opposed to tried but failed) so we'll try to
|
|
* make a private copy of the data and map that instead */
|
|
}
|
|
|
|
|
|
/* allocate some memory to hold the mapping
|
|
* - note that this may not return a page-aligned address if the object
|
|
* we're allocating is smaller than a page
|
|
*/
|
|
order = get_order(len);
|
|
total = 1 << order;
|
|
point = len >> PAGE_SHIFT;
|
|
|
|
/* we don't want to allocate a power-of-2 sized page set */
|
|
if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
|
|
total = point;
|
|
|
|
base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
|
|
if (!base)
|
|
goto enomem;
|
|
|
|
atomic_long_add(total, &mmap_pages_allocated);
|
|
|
|
region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
|
|
region->vm_start = (unsigned long) base;
|
|
region->vm_end = region->vm_start + len;
|
|
region->vm_top = region->vm_start + (total << PAGE_SHIFT);
|
|
|
|
vma->vm_start = region->vm_start;
|
|
vma->vm_end = region->vm_start + len;
|
|
|
|
if (vma->vm_file) {
|
|
/* read the contents of a file into the copy */
|
|
mm_segment_t old_fs;
|
|
loff_t fpos;
|
|
|
|
fpos = vma->vm_pgoff;
|
|
fpos <<= PAGE_SHIFT;
|
|
|
|
old_fs = get_fs();
|
|
set_fs(KERNEL_DS);
|
|
ret = __vfs_read(vma->vm_file, base, len, &fpos);
|
|
set_fs(old_fs);
|
|
|
|
if (ret < 0)
|
|
goto error_free;
|
|
|
|
/* clear the last little bit */
|
|
if (ret < len)
|
|
memset(base + ret, 0, len - ret);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
error_free:
|
|
free_page_series(region->vm_start, region->vm_top);
|
|
region->vm_start = vma->vm_start = 0;
|
|
region->vm_end = vma->vm_end = 0;
|
|
region->vm_top = 0;
|
|
return ret;
|
|
|
|
enomem:
|
|
pr_err("Allocation of length %lu from process %d (%s) failed\n",
|
|
len, current->pid, current->comm);
|
|
show_free_areas(0);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* handle mapping creation for uClinux
|
|
*/
|
|
unsigned long do_mmap(struct file *file,
|
|
unsigned long addr,
|
|
unsigned long len,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
vm_flags_t vm_flags,
|
|
unsigned long pgoff,
|
|
unsigned long *populate)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct vm_region *region;
|
|
struct rb_node *rb;
|
|
unsigned long capabilities, result;
|
|
int ret;
|
|
|
|
*populate = 0;
|
|
|
|
/* decide whether we should attempt the mapping, and if so what sort of
|
|
* mapping */
|
|
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
|
|
&capabilities);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* we ignore the address hint */
|
|
addr = 0;
|
|
len = PAGE_ALIGN(len);
|
|
|
|
/* we've determined that we can make the mapping, now translate what we
|
|
* now know into VMA flags */
|
|
vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
|
|
|
|
/* we're going to need to record the mapping */
|
|
region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
|
|
if (!region)
|
|
goto error_getting_region;
|
|
|
|
vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
|
|
if (!vma)
|
|
goto error_getting_vma;
|
|
|
|
region->vm_usage = 1;
|
|
region->vm_flags = vm_flags;
|
|
region->vm_pgoff = pgoff;
|
|
|
|
INIT_LIST_HEAD(&vma->anon_vma_chain);
|
|
vma->vm_flags = vm_flags;
|
|
vma->vm_pgoff = pgoff;
|
|
|
|
if (file) {
|
|
region->vm_file = get_file(file);
|
|
vma->vm_file = get_file(file);
|
|
}
|
|
|
|
down_write(&nommu_region_sem);
|
|
|
|
/* if we want to share, we need to check for regions created by other
|
|
* mmap() calls that overlap with our proposed mapping
|
|
* - we can only share with a superset match on most regular files
|
|
* - shared mappings on character devices and memory backed files are
|
|
* permitted to overlap inexactly as far as we are concerned for in
|
|
* these cases, sharing is handled in the driver or filesystem rather
|
|
* than here
|
|
*/
|
|
if (vm_flags & VM_MAYSHARE) {
|
|
struct vm_region *pregion;
|
|
unsigned long pglen, rpglen, pgend, rpgend, start;
|
|
|
|
pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
pgend = pgoff + pglen;
|
|
|
|
for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
|
|
pregion = rb_entry(rb, struct vm_region, vm_rb);
|
|
|
|
if (!(pregion->vm_flags & VM_MAYSHARE))
|
|
continue;
|
|
|
|
/* search for overlapping mappings on the same file */
|
|
if (file_inode(pregion->vm_file) !=
|
|
file_inode(file))
|
|
continue;
|
|
|
|
if (pregion->vm_pgoff >= pgend)
|
|
continue;
|
|
|
|
rpglen = pregion->vm_end - pregion->vm_start;
|
|
rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
rpgend = pregion->vm_pgoff + rpglen;
|
|
if (pgoff >= rpgend)
|
|
continue;
|
|
|
|
/* handle inexactly overlapping matches between
|
|
* mappings */
|
|
if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
|
|
!(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
|
|
/* new mapping is not a subset of the region */
|
|
if (!(capabilities & NOMMU_MAP_DIRECT))
|
|
goto sharing_violation;
|
|
continue;
|
|
}
|
|
|
|
/* we've found a region we can share */
|
|
pregion->vm_usage++;
|
|
vma->vm_region = pregion;
|
|
start = pregion->vm_start;
|
|
start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
|
|
vma->vm_start = start;
|
|
vma->vm_end = start + len;
|
|
|
|
if (pregion->vm_flags & VM_MAPPED_COPY)
|
|
vma->vm_flags |= VM_MAPPED_COPY;
|
|
else {
|
|
ret = do_mmap_shared_file(vma);
|
|
if (ret < 0) {
|
|
vma->vm_region = NULL;
|
|
vma->vm_start = 0;
|
|
vma->vm_end = 0;
|
|
pregion->vm_usage--;
|
|
pregion = NULL;
|
|
goto error_just_free;
|
|
}
|
|
}
|
|
fput(region->vm_file);
|
|
kmem_cache_free(vm_region_jar, region);
|
|
region = pregion;
|
|
result = start;
|
|
goto share;
|
|
}
|
|
|
|
/* obtain the address at which to make a shared mapping
|
|
* - this is the hook for quasi-memory character devices to
|
|
* tell us the location of a shared mapping
|
|
*/
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
addr = file->f_op->get_unmapped_area(file, addr, len,
|
|
pgoff, flags);
|
|
if (IS_ERR_VALUE(addr)) {
|
|
ret = addr;
|
|
if (ret != -ENOSYS)
|
|
goto error_just_free;
|
|
|
|
/* the driver refused to tell us where to site
|
|
* the mapping so we'll have to attempt to copy
|
|
* it */
|
|
ret = -ENODEV;
|
|
if (!(capabilities & NOMMU_MAP_COPY))
|
|
goto error_just_free;
|
|
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
} else {
|
|
vma->vm_start = region->vm_start = addr;
|
|
vma->vm_end = region->vm_end = addr + len;
|
|
}
|
|
}
|
|
}
|
|
|
|
vma->vm_region = region;
|
|
|
|
/* set up the mapping
|
|
* - the region is filled in if NOMMU_MAP_DIRECT is still set
|
|
*/
|
|
if (file && vma->vm_flags & VM_SHARED)
|
|
ret = do_mmap_shared_file(vma);
|
|
else
|
|
ret = do_mmap_private(vma, region, len, capabilities);
|
|
if (ret < 0)
|
|
goto error_just_free;
|
|
add_nommu_region(region);
|
|
|
|
/* clear anonymous mappings that don't ask for uninitialized data */
|
|
if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
|
|
memset((void *)region->vm_start, 0,
|
|
region->vm_end - region->vm_start);
|
|
|
|
/* okay... we have a mapping; now we have to register it */
|
|
result = vma->vm_start;
|
|
|
|
current->mm->total_vm += len >> PAGE_SHIFT;
|
|
|
|
share:
|
|
add_vma_to_mm(current->mm, vma);
|
|
|
|
/* we flush the region from the icache only when the first executable
|
|
* mapping of it is made */
|
|
if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
|
|
flush_icache_range(region->vm_start, region->vm_end);
|
|
region->vm_icache_flushed = true;
|
|
}
|
|
|
|
up_write(&nommu_region_sem);
|
|
|
|
return result;
|
|
|
|
error_just_free:
|
|
up_write(&nommu_region_sem);
|
|
error:
|
|
if (region->vm_file)
|
|
fput(region->vm_file);
|
|
kmem_cache_free(vm_region_jar, region);
|
|
if (vma->vm_file)
|
|
fput(vma->vm_file);
|
|
kmem_cache_free(vm_area_cachep, vma);
|
|
return ret;
|
|
|
|
sharing_violation:
|
|
up_write(&nommu_region_sem);
|
|
pr_warn("Attempt to share mismatched mappings\n");
|
|
ret = -EINVAL;
|
|
goto error;
|
|
|
|
error_getting_vma:
|
|
kmem_cache_free(vm_region_jar, region);
|
|
pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
|
|
len, current->pid);
|
|
show_free_areas(0);
|
|
return -ENOMEM;
|
|
|
|
error_getting_region:
|
|
pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
|
|
len, current->pid);
|
|
show_free_areas(0);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
|
|
unsigned long, prot, unsigned long, flags,
|
|
unsigned long, fd, unsigned long, pgoff)
|
|
{
|
|
struct file *file = NULL;
|
|
unsigned long retval = -EBADF;
|
|
|
|
audit_mmap_fd(fd, flags);
|
|
if (!(flags & MAP_ANONYMOUS)) {
|
|
file = fget(fd);
|
|
if (!file)
|
|
goto out;
|
|
}
|
|
|
|
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
|
|
|
|
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
|
|
|
|
if (file)
|
|
fput(file);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_OLD_MMAP
|
|
struct mmap_arg_struct {
|
|
unsigned long addr;
|
|
unsigned long len;
|
|
unsigned long prot;
|
|
unsigned long flags;
|
|
unsigned long fd;
|
|
unsigned long offset;
|
|
};
|
|
|
|
SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
|
|
{
|
|
struct mmap_arg_struct a;
|
|
|
|
if (copy_from_user(&a, arg, sizeof(a)))
|
|
return -EFAULT;
|
|
if (offset_in_page(a.offset))
|
|
return -EINVAL;
|
|
|
|
return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
|
|
a.offset >> PAGE_SHIFT);
|
|
}
|
|
#endif /* __ARCH_WANT_SYS_OLD_MMAP */
|
|
|
|
/*
|
|
* split a vma into two pieces at address 'addr', a new vma is allocated either
|
|
* for the first part or the tail.
|
|
*/
|
|
int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long addr, int new_below)
|
|
{
|
|
struct vm_area_struct *new;
|
|
struct vm_region *region;
|
|
unsigned long npages;
|
|
|
|
/* we're only permitted to split anonymous regions (these should have
|
|
* only a single usage on the region) */
|
|
if (vma->vm_file)
|
|
return -ENOMEM;
|
|
|
|
if (mm->map_count >= sysctl_max_map_count)
|
|
return -ENOMEM;
|
|
|
|
region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
|
|
if (!region)
|
|
return -ENOMEM;
|
|
|
|
new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
|
|
if (!new) {
|
|
kmem_cache_free(vm_region_jar, region);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* most fields are the same, copy all, and then fixup */
|
|
*new = *vma;
|
|
*region = *vma->vm_region;
|
|
new->vm_region = region;
|
|
|
|
npages = (addr - vma->vm_start) >> PAGE_SHIFT;
|
|
|
|
if (new_below) {
|
|
region->vm_top = region->vm_end = new->vm_end = addr;
|
|
} else {
|
|
region->vm_start = new->vm_start = addr;
|
|
region->vm_pgoff = new->vm_pgoff += npages;
|
|
}
|
|
|
|
if (new->vm_ops && new->vm_ops->open)
|
|
new->vm_ops->open(new);
|
|
|
|
delete_vma_from_mm(vma);
|
|
down_write(&nommu_region_sem);
|
|
delete_nommu_region(vma->vm_region);
|
|
if (new_below) {
|
|
vma->vm_region->vm_start = vma->vm_start = addr;
|
|
vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
|
|
} else {
|
|
vma->vm_region->vm_end = vma->vm_end = addr;
|
|
vma->vm_region->vm_top = addr;
|
|
}
|
|
add_nommu_region(vma->vm_region);
|
|
add_nommu_region(new->vm_region);
|
|
up_write(&nommu_region_sem);
|
|
add_vma_to_mm(mm, vma);
|
|
add_vma_to_mm(mm, new);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* shrink a VMA by removing the specified chunk from either the beginning or
|
|
* the end
|
|
*/
|
|
static int shrink_vma(struct mm_struct *mm,
|
|
struct vm_area_struct *vma,
|
|
unsigned long from, unsigned long to)
|
|
{
|
|
struct vm_region *region;
|
|
|
|
/* adjust the VMA's pointers, which may reposition it in the MM's tree
|
|
* and list */
|
|
delete_vma_from_mm(vma);
|
|
if (from > vma->vm_start)
|
|
vma->vm_end = from;
|
|
else
|
|
vma->vm_start = to;
|
|
add_vma_to_mm(mm, vma);
|
|
|
|
/* cut the backing region down to size */
|
|
region = vma->vm_region;
|
|
BUG_ON(region->vm_usage != 1);
|
|
|
|
down_write(&nommu_region_sem);
|
|
delete_nommu_region(region);
|
|
if (from > region->vm_start) {
|
|
to = region->vm_top;
|
|
region->vm_top = region->vm_end = from;
|
|
} else {
|
|
region->vm_start = to;
|
|
}
|
|
add_nommu_region(region);
|
|
up_write(&nommu_region_sem);
|
|
|
|
free_page_series(from, to);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* release a mapping
|
|
* - under NOMMU conditions the chunk to be unmapped must be backed by a single
|
|
* VMA, though it need not cover the whole VMA
|
|
*/
|
|
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
unsigned long end;
|
|
int ret;
|
|
|
|
len = PAGE_ALIGN(len);
|
|
if (len == 0)
|
|
return -EINVAL;
|
|
|
|
end = start + len;
|
|
|
|
/* find the first potentially overlapping VMA */
|
|
vma = find_vma(mm, start);
|
|
if (!vma) {
|
|
static int limit;
|
|
if (limit < 5) {
|
|
pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
|
|
current->pid, current->comm,
|
|
start, start + len - 1);
|
|
limit++;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* we're allowed to split an anonymous VMA but not a file-backed one */
|
|
if (vma->vm_file) {
|
|
do {
|
|
if (start > vma->vm_start)
|
|
return -EINVAL;
|
|
if (end == vma->vm_end)
|
|
goto erase_whole_vma;
|
|
vma = vma->vm_next;
|
|
} while (vma);
|
|
return -EINVAL;
|
|
} else {
|
|
/* the chunk must be a subset of the VMA found */
|
|
if (start == vma->vm_start && end == vma->vm_end)
|
|
goto erase_whole_vma;
|
|
if (start < vma->vm_start || end > vma->vm_end)
|
|
return -EINVAL;
|
|
if (offset_in_page(start))
|
|
return -EINVAL;
|
|
if (end != vma->vm_end && offset_in_page(end))
|
|
return -EINVAL;
|
|
if (start != vma->vm_start && end != vma->vm_end) {
|
|
ret = split_vma(mm, vma, start, 1);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
return shrink_vma(mm, vma, start, end);
|
|
}
|
|
|
|
erase_whole_vma:
|
|
delete_vma_from_mm(vma);
|
|
delete_vma(mm, vma);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(do_munmap);
|
|
|
|
int vm_munmap(unsigned long addr, size_t len)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
int ret;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
ret = do_munmap(mm, addr, len);
|
|
up_write(&mm->mmap_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vm_munmap);
|
|
|
|
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
|
|
{
|
|
return vm_munmap(addr, len);
|
|
}
|
|
|
|
/*
|
|
* release all the mappings made in a process's VM space
|
|
*/
|
|
void exit_mmap(struct mm_struct *mm)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
if (!mm)
|
|
return;
|
|
|
|
mm->total_vm = 0;
|
|
|
|
while ((vma = mm->mmap)) {
|
|
mm->mmap = vma->vm_next;
|
|
delete_vma_from_mm(vma);
|
|
delete_vma(mm, vma);
|
|
cond_resched();
|
|
}
|
|
}
|
|
|
|
int vm_brk(unsigned long addr, unsigned long len)
|
|
{
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* expand (or shrink) an existing mapping, potentially moving it at the same
|
|
* time (controlled by the MREMAP_MAYMOVE flag and available VM space)
|
|
*
|
|
* under NOMMU conditions, we only permit changing a mapping's size, and only
|
|
* as long as it stays within the region allocated by do_mmap_private() and the
|
|
* block is not shareable
|
|
*
|
|
* MREMAP_FIXED is not supported under NOMMU conditions
|
|
*/
|
|
static unsigned long do_mremap(unsigned long addr,
|
|
unsigned long old_len, unsigned long new_len,
|
|
unsigned long flags, unsigned long new_addr)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
/* insanity checks first */
|
|
old_len = PAGE_ALIGN(old_len);
|
|
new_len = PAGE_ALIGN(new_len);
|
|
if (old_len == 0 || new_len == 0)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
if (offset_in_page(addr))
|
|
return -EINVAL;
|
|
|
|
if (flags & MREMAP_FIXED && new_addr != addr)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
vma = find_vma_exact(current->mm, addr, old_len);
|
|
if (!vma)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
if (vma->vm_end != vma->vm_start + old_len)
|
|
return (unsigned long) -EFAULT;
|
|
|
|
if (vma->vm_flags & VM_MAYSHARE)
|
|
return (unsigned long) -EPERM;
|
|
|
|
if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
|
|
return (unsigned long) -ENOMEM;
|
|
|
|
/* all checks complete - do it */
|
|
vma->vm_end = vma->vm_start + new_len;
|
|
return vma->vm_start;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
|
|
unsigned long, new_len, unsigned long, flags,
|
|
unsigned long, new_addr)
|
|
{
|
|
unsigned long ret;
|
|
|
|
down_write(¤t->mm->mmap_sem);
|
|
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
|
|
up_write(¤t->mm->mmap_sem);
|
|
return ret;
|
|
}
|
|
|
|
struct page *follow_page_mask(struct vm_area_struct *vma,
|
|
unsigned long address, unsigned int flags,
|
|
unsigned int *page_mask)
|
|
{
|
|
*page_mask = 0;
|
|
return NULL;
|
|
}
|
|
|
|
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
|
|
unsigned long pfn, unsigned long size, pgprot_t prot)
|
|
{
|
|
if (addr != (pfn << PAGE_SHIFT))
|
|
return -EINVAL;
|
|
|
|
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(remap_pfn_range);
|
|
|
|
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
|
|
{
|
|
unsigned long pfn = start >> PAGE_SHIFT;
|
|
unsigned long vm_len = vma->vm_end - vma->vm_start;
|
|
|
|
pfn += vma->vm_pgoff;
|
|
return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
|
|
}
|
|
EXPORT_SYMBOL(vm_iomap_memory);
|
|
|
|
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
|
|
unsigned long pgoff)
|
|
{
|
|
unsigned int size = vma->vm_end - vma->vm_start;
|
|
|
|
if (!(vma->vm_flags & VM_USERMAP))
|
|
return -EINVAL;
|
|
|
|
vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
|
|
vma->vm_end = vma->vm_start + size;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(remap_vmalloc_range);
|
|
|
|
unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
|
|
unsigned long len, unsigned long pgoff, unsigned long flags)
|
|
{
|
|
return -ENOMEM;
|
|
}
|
|
|
|
void unmap_mapping_range(struct address_space *mapping,
|
|
loff_t const holebegin, loff_t const holelen,
|
|
int even_cows)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL(unmap_mapping_range);
|
|
|
|
int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
BUG();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(filemap_fault);
|
|
|
|
void filemap_map_pages(struct fault_env *fe,
|
|
pgoff_t start_pgoff, pgoff_t end_pgoff)
|
|
{
|
|
BUG();
|
|
}
|
|
EXPORT_SYMBOL(filemap_map_pages);
|
|
|
|
static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
|
|
unsigned long addr, void *buf, int len, int write)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
|
|
/* the access must start within one of the target process's mappings */
|
|
vma = find_vma(mm, addr);
|
|
if (vma) {
|
|
/* don't overrun this mapping */
|
|
if (addr + len >= vma->vm_end)
|
|
len = vma->vm_end - addr;
|
|
|
|
/* only read or write mappings where it is permitted */
|
|
if (write && vma->vm_flags & VM_MAYWRITE)
|
|
copy_to_user_page(vma, NULL, addr,
|
|
(void *) addr, buf, len);
|
|
else if (!write && vma->vm_flags & VM_MAYREAD)
|
|
copy_from_user_page(vma, NULL, addr,
|
|
buf, (void *) addr, len);
|
|
else
|
|
len = 0;
|
|
} else {
|
|
len = 0;
|
|
}
|
|
|
|
up_read(&mm->mmap_sem);
|
|
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* @access_remote_vm - access another process' address space
|
|
* @mm: the mm_struct of the target address space
|
|
* @addr: start address to access
|
|
* @buf: source or destination buffer
|
|
* @len: number of bytes to transfer
|
|
* @write: whether the access is a write
|
|
*
|
|
* The caller must hold a reference on @mm.
|
|
*/
|
|
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
|
|
void *buf, int len, int write)
|
|
{
|
|
return __access_remote_vm(NULL, mm, addr, buf, len, write);
|
|
}
|
|
|
|
/*
|
|
* Access another process' address space.
|
|
* - source/target buffer must be kernel space
|
|
*/
|
|
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
|
|
{
|
|
struct mm_struct *mm;
|
|
|
|
if (addr + len < addr)
|
|
return 0;
|
|
|
|
mm = get_task_mm(tsk);
|
|
if (!mm)
|
|
return 0;
|
|
|
|
len = __access_remote_vm(tsk, mm, addr, buf, len, write);
|
|
|
|
mmput(mm);
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
|
|
* @inode: The inode to check
|
|
* @size: The current filesize of the inode
|
|
* @newsize: The proposed filesize of the inode
|
|
*
|
|
* Check the shared mappings on an inode on behalf of a shrinking truncate to
|
|
* make sure that that any outstanding VMAs aren't broken and then shrink the
|
|
* vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
|
|
* automatically grant mappings that are too large.
|
|
*/
|
|
int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
|
|
size_t newsize)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct vm_region *region;
|
|
pgoff_t low, high;
|
|
size_t r_size, r_top;
|
|
|
|
low = newsize >> PAGE_SHIFT;
|
|
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
|
|
down_write(&nommu_region_sem);
|
|
i_mmap_lock_read(inode->i_mapping);
|
|
|
|
/* search for VMAs that fall within the dead zone */
|
|
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
|
|
/* found one - only interested if it's shared out of the page
|
|
* cache */
|
|
if (vma->vm_flags & VM_SHARED) {
|
|
i_mmap_unlock_read(inode->i_mapping);
|
|
up_write(&nommu_region_sem);
|
|
return -ETXTBSY; /* not quite true, but near enough */
|
|
}
|
|
}
|
|
|
|
/* reduce any regions that overlap the dead zone - if in existence,
|
|
* these will be pointed to by VMAs that don't overlap the dead zone
|
|
*
|
|
* we don't check for any regions that start beyond the EOF as there
|
|
* shouldn't be any
|
|
*/
|
|
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
|
|
if (!(vma->vm_flags & VM_SHARED))
|
|
continue;
|
|
|
|
region = vma->vm_region;
|
|
r_size = region->vm_top - region->vm_start;
|
|
r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
|
|
|
|
if (r_top > newsize) {
|
|
region->vm_top -= r_top - newsize;
|
|
if (region->vm_end > region->vm_top)
|
|
region->vm_end = region->vm_top;
|
|
}
|
|
}
|
|
|
|
i_mmap_unlock_read(inode->i_mapping);
|
|
up_write(&nommu_region_sem);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Initialise sysctl_user_reserve_kbytes.
|
|
*
|
|
* This is intended to prevent a user from starting a single memory hogging
|
|
* process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
|
|
* mode.
|
|
*
|
|
* The default value is min(3% of free memory, 128MB)
|
|
* 128MB is enough to recover with sshd/login, bash, and top/kill.
|
|
*/
|
|
static int __meminit init_user_reserve(void)
|
|
{
|
|
unsigned long free_kbytes;
|
|
|
|
free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
|
|
|
|
sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_user_reserve);
|
|
|
|
/*
|
|
* Initialise sysctl_admin_reserve_kbytes.
|
|
*
|
|
* The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
|
|
* to log in and kill a memory hogging process.
|
|
*
|
|
* Systems with more than 256MB will reserve 8MB, enough to recover
|
|
* with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
|
|
* only reserve 3% of free pages by default.
|
|
*/
|
|
static int __meminit init_admin_reserve(void)
|
|
{
|
|
unsigned long free_kbytes;
|
|
|
|
free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
|
|
|
|
sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_admin_reserve);
|