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mm/nommu.c
44.5 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * linux/mm/nommu.c * * Replacement code for mm functions to support CPU's that don't * have any form of memory management unit (thus no virtual memory). * |
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* See Documentation/admin-guide/mm/nommu-mmap.rst |
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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> * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> * 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/sched/mm.h> |
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#include <linux/vmacache.h> |
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#include <linux/mman.h> #include <linux/swap.h> #include <linux/file.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/vmalloc.h> |
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#include <linux/blkdev.h> #include <linux/backing-dev.h> |
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#include <linux/compiler.h> |
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#include <linux/mount.h> #include <linux/personality.h> #include <linux/security.h> #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 <linux/uaccess.h> |
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#include <asm/tlb.h> #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; 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 */ static struct kmem_cache *vm_region_jar; struct rb_root nommu_region_tree = RB_ROOT; 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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* Return the total memory allocated for this pointer, not * just what the caller asked for. * * Doesn't have to be accurate, i.e. may have races. */ unsigned int kobjsize(const void *objp) { struct page *page; |
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/* * If the object we have should not have ksize performed on it, * return size of 0 */ |
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if (!objp || !virt_addr_valid(objp)) |
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return 0; page = virt_to_head_page(objp); |
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/* * If the allocator sets PageSlab, we know the pointer came from * kmalloc(). */ |
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if (PageSlab(page)) 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 * region. This test is intentionally done in reverse order, * so if there's no VMA, we still fall through and hand back * PAGE_SIZE for 0-order pages. */ if (!PageCompound(page)) { struct vm_area_struct *vma; vma = find_vma(current->mm, (unsigned long)objp); if (vma) return vma->vm_end - vma->vm_start; } /* |
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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(page); |
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} |
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/** * follow_pfn - look up PFN at a user virtual address * @vma: memory mapping * @address: user virtual address * @pfn: location to store found PFN * * Only IO mappings and raw PFN mappings are allowed. * * Returns zero and the pfn at @pfn on success, -ve otherwise. */ int follow_pfn(struct vm_area_struct *vma, unsigned long address, unsigned long *pfn) { if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) return -EINVAL; *pfn = address >> PAGE_SHIFT; return 0; } 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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{ kfree(addr); } |
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EXPORT_SYMBOL(vfree); |
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void *__vmalloc(unsigned long size, gfp_t gfp_mask) |
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{ /* |
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* You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() * 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_node_range(unsigned long size, unsigned long align, unsigned long start, unsigned long end, gfp_t gfp_mask, pgprot_t prot, unsigned long vm_flags, int node, const void *caller) { return __vmalloc(size, gfp_mask); } |
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void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, int node, const void *caller) |
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{ |
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return __vmalloc(size, gfp_mask); |
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} |
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static void *__vmalloc_user_flags(unsigned long size, gfp_t flags) |
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{ void *ret; |
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ret = __vmalloc(size, flags); |
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if (ret) { struct vm_area_struct *vma; |
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mmap_write_lock(current->mm); |
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vma = find_vma(current->mm, (unsigned long)ret); if (vma) vma->vm_flags |= VM_USERMAP; |
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mmap_write_unlock(current->mm); |
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} return ret; } |
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void *vmalloc_user(unsigned long size) { return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO); } |
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EXPORT_SYMBOL(vmalloc_user); |
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struct page *vmalloc_to_page(const void *addr) |
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{ return virt_to_page(addr); } |
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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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{ return page_to_pfn(virt_to_page(addr)); } |
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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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/* Don't allow overflow */ if ((unsigned long) buf + count < count) count = -(unsigned long) buf; |
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memcpy(buf, addr, count); return count; } |
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/* |
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* vmalloc - allocate virtually contiguous memory |
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* * @size: allocation size * * 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. */ void *vmalloc(unsigned long size) { |
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return __vmalloc(size, GFP_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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* * @size: allocation size * * 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. * * For tight control over page level allocator and protection flags * use __vmalloc() instead. */ void *vzalloc(unsigned long size) { |
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return __vmalloc(size, GFP_KERNEL | __GFP_ZERO); |
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} EXPORT_SYMBOL(vzalloc); /** * vmalloc_node - allocate memory on a specific node * @size: allocation size * @node: numa node * * Allocate enough pages to cover @size from the page level * allocator and map them into contiguous kernel virtual space. * * For tight control over page level allocator and protection flags * use __vmalloc() instead. */ |
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void *vmalloc_node(unsigned long size, int node) { return vmalloc(size); } |
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EXPORT_SYMBOL(vmalloc_node); |
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/** * vzalloc_node - allocate memory on a specific node with zero fill * @size: allocation size * @node: numa node * * Allocate enough pages to cover @size from the page level * allocator and map them into contiguous kernel virtual space. * The memory allocated is set to zero. * * For tight control over page level allocator and protection flags * use __vmalloc() instead. */ void *vzalloc_node(unsigned long size, int node) { return vzalloc(size); } EXPORT_SYMBOL(vzalloc_node); |
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/** |
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* vmalloc_32 - allocate virtually contiguous memory (32bit addressable) |
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* @size: allocation size * * 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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*/ void *vmalloc_32(unsigned long size) { |
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return __vmalloc(size, GFP_KERNEL); |
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} |
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EXPORT_SYMBOL(vmalloc_32); /** * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory * @size: allocation size * * The resulting memory area is 32bit addressable and zeroed so it can be * mapped to userspace without leaking data. |
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* * VM_USERMAP is set on the corresponding VMA so that subsequent calls to * remap_vmalloc_range() are permissible. |
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*/ void *vmalloc_32_user(unsigned long size) { |
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/* * We'll have to sort out the ZONE_DMA bits for 64-bit, * but for now this can simply use vmalloc_user() directly. */ return vmalloc_user(size); |
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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) { BUG(); return NULL; } |
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EXPORT_SYMBOL(vmap); |
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void vunmap(const void *addr) |
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{ BUG(); } |
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EXPORT_SYMBOL(vunmap); |
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void *vm_map_ram(struct page **pages, unsigned int count, int node) |
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{ BUG(); return NULL; } EXPORT_SYMBOL(vm_map_ram); void vm_unmap_ram(const void *mem, unsigned int count) { BUG(); } EXPORT_SYMBOL(vm_unmap_ram); void vm_unmap_aliases(void) { } EXPORT_SYMBOL_GPL(vm_unmap_aliases); |
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void free_vm_area(struct vm_struct *area) { BUG(); } EXPORT_SYMBOL_GPL(free_vm_area); |
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int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) { return -EINVAL; } EXPORT_SYMBOL(vm_insert_page); |
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int vm_map_pages(struct vm_area_struct *vma, struct page **pages, unsigned long num) { return -EINVAL; } EXPORT_SYMBOL(vm_map_pages); int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, unsigned long num) { return -EINVAL; } EXPORT_SYMBOL(vm_map_pages_zero); |
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/* |
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* sys_brk() for the most part doesn't need the global kernel * lock, except when an application is doing something nasty * like trying to un-brk an area that has already been mapped * to a regular file. in this case, the unmapping will need * to invoke file system routines that need the global lock. */ |
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SYSCALL_DEFINE1(brk, unsigned long, brk) |
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{ struct mm_struct *mm = current->mm; if (brk < mm->start_brk || brk > mm->context.end_brk) return mm->brk; if (mm->brk == brk) return mm->brk; /* * Always allow shrinking brk */ if (brk <= mm->brk) { mm->brk = brk; return brk; } /* * Ok, looks good - let it rip. */ |
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flush_icache_user_range(mm->brk, brk); |
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return mm->brk = brk; } |
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/* |
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* initialise the percpu counter for VM and region record slabs |
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*/ void __init mmap_init(void) |
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{ |
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int ret; |
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ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); |
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VM_BUG_ON(ret); |
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vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT); |
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} |
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/* |
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* validate the region tree * - the caller must hold the region lock |
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*/ |
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#ifdef CONFIG_DEBUG_NOMMU_REGIONS static noinline void validate_nommu_regions(void) |
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{ |
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struct vm_region *region, *last; struct rb_node *p, *lastp; |
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lastp = rb_first(&nommu_region_tree); if (!lastp) return; last = rb_entry(lastp, struct vm_region, vm_rb); |
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BUG_ON(last->vm_end <= last->vm_start); BUG_ON(last->vm_top < last->vm_end); |
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while ((p = rb_next(lastp))) { region = rb_entry(p, struct vm_region, vm_rb); last = rb_entry(lastp, struct vm_region, vm_rb); |
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BUG_ON(region->vm_end <= region->vm_start); BUG_ON(region->vm_top < region->vm_end); BUG_ON(region->vm_start < last->vm_top); |
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lastp = p; } |
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} |
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#else |
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static void validate_nommu_regions(void) { } |
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#endif |
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/* |
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* add a region into the global tree |
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*/ |
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static void add_nommu_region(struct vm_region *region) |
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{ |
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struct vm_region *pregion; struct rb_node **p, *parent; |
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validate_nommu_regions(); |
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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(); |
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} |
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rb_link_node(®ion->vm_rb, parent, p); rb_insert_color(®ion->vm_rb, &nommu_region_tree); |
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validate_nommu_regions(); |
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} |
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/* |
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* delete a region from the global tree |
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*/ |
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static void delete_nommu_region(struct vm_region *region) |
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{ |
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BUG_ON(!nommu_region_tree.rb_node); |
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validate_nommu_regions(); rb_erase(®ion->vm_rb, &nommu_region_tree); validate_nommu_regions(); |
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} |
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/* |
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* free a contiguous series of pages |
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*/ |
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static void free_page_series(unsigned long from, unsigned long to) |
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{ |
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for (; from < to; from += PAGE_SIZE) { struct page *page = virt_to_page(from); |
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atomic_long_dec(&mmap_pages_allocated); |
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put_page(page); |
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} |
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} /* |
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* release a reference to a region |
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* - the caller must hold the region semaphore for writing, which this releases |
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* - the region may not have been added to the tree yet, in which case vm_top |
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* will equal vm_start |
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*/ |
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static void __put_nommu_region(struct vm_region *region) __releases(nommu_region_sem) |
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{ |
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BUG_ON(!nommu_region_tree.rb_node); |
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|
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if (--region->vm_usage == 0) { |
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if (region->vm_top > region->vm_start) |
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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 */ |
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if (region->vm_flags & VM_MAPPED_COPY) |
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free_page_series(region->vm_start, region->vm_top); |
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kmem_cache_free(vm_region_jar, region); } else { up_write(&nommu_region_sem); |
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} |
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} |
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/* * release a reference to a region */ static void put_nommu_region(struct vm_region *region) { down_write(&nommu_region_sem); __put_nommu_region(region); |
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} |
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/* |
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* 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 |
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* - should be called with mm->mmap_lock held writelocked |
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*/ |
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|
525 |
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4c
|
526 |
{ |
6038def0d
|
527 |
struct vm_area_struct *pvma, *prev; |
1da177e4c
|
528 |
struct address_space *mapping; |
6038def0d
|
529 |
struct rb_node **p, *parent, *rb_prev; |
8feae1311
|
530 |
|
8feae1311
|
531 532 533 534 |
BUG_ON(!vma->vm_region); mm->map_count++; vma->vm_mm = mm; |
1da177e4c
|
535 536 537 538 |
/* add the VMA to the mapping */ if (vma->vm_file) { mapping = vma->vm_file->f_mapping; |
83cde9e8b
|
539 |
i_mmap_lock_write(mapping); |
1da177e4c
|
540 |
flush_dcache_mmap_lock(mapping); |
6b2dbba8b
|
541 |
vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4c
|
542 |
flush_dcache_mmap_unlock(mapping); |
83cde9e8b
|
543 |
i_mmap_unlock_write(mapping); |
1da177e4c
|
544 |
} |
8feae1311
|
545 |
/* add the VMA to the tree */ |
6038def0d
|
546 |
parent = rb_prev = NULL; |
8feae1311
|
547 |
p = &mm->mm_rb.rb_node; |
1da177e4c
|
548 549 550 |
while (*p) { parent = *p; pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
8feae1311
|
551 552 553 |
/* 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) |
1da177e4c
|
554 |
p = &(*p)->rb_left; |
6038def0d
|
555 556 |
else if (vma->vm_start > pvma->vm_start) { rb_prev = parent; |
1da177e4c
|
557 |
p = &(*p)->rb_right; |
6038def0d
|
558 |
} else if (vma->vm_end < pvma->vm_end) |
8feae1311
|
559 |
p = &(*p)->rb_left; |
6038def0d
|
560 561 |
else if (vma->vm_end > pvma->vm_end) { rb_prev = parent; |
8feae1311
|
562 |
p = &(*p)->rb_right; |
6038def0d
|
563 |
} else if (vma < pvma) |
8feae1311
|
564 |
p = &(*p)->rb_left; |
6038def0d
|
565 566 |
else if (vma > pvma) { rb_prev = parent; |
8feae1311
|
567 |
p = &(*p)->rb_right; |
6038def0d
|
568 |
} else |
8feae1311
|
569 |
BUG(); |
1da177e4c
|
570 571 572 |
} rb_link_node(&vma->vm_rb, parent, p); |
8feae1311
|
573 574 575 |
rb_insert_color(&vma->vm_rb, &mm->mm_rb); /* add VMA to the VMA list also */ |
6038def0d
|
576 577 578 |
prev = NULL; if (rb_prev) prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
8feae1311
|
579 |
|
aba6dfb75
|
580 |
__vma_link_list(mm, vma, prev); |
1da177e4c
|
581 |
} |
3034097a5
|
582 |
/* |
8feae1311
|
583 |
* delete a VMA from its owning mm_struct and address space |
3034097a5
|
584 |
*/ |
8feae1311
|
585 |
static void delete_vma_from_mm(struct vm_area_struct *vma) |
1da177e4c
|
586 |
{ |
615d6e875
|
587 |
int i; |
1da177e4c
|
588 |
struct address_space *mapping; |
8feae1311
|
589 |
struct mm_struct *mm = vma->vm_mm; |
615d6e875
|
590 |
struct task_struct *curr = current; |
8feae1311
|
591 |
|
8feae1311
|
592 |
mm->map_count--; |
615d6e875
|
593 594 |
for (i = 0; i < VMACACHE_SIZE; i++) { /* if the vma is cached, invalidate the entire cache */ |
314ff7851
|
595 |
if (curr->vmacache.vmas[i] == vma) { |
e020d5bd8
|
596 |
vmacache_invalidate(mm); |
615d6e875
|
597 598 599 |
break; } } |
1da177e4c
|
600 601 602 603 |
/* remove the VMA from the mapping */ if (vma->vm_file) { mapping = vma->vm_file->f_mapping; |
83cde9e8b
|
604 |
i_mmap_lock_write(mapping); |
1da177e4c
|
605 |
flush_dcache_mmap_lock(mapping); |
6b2dbba8b
|
606 |
vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4c
|
607 |
flush_dcache_mmap_unlock(mapping); |
83cde9e8b
|
608 |
i_mmap_unlock_write(mapping); |
1da177e4c
|
609 |
} |
8feae1311
|
610 611 |
/* remove from the MM's tree and list */ rb_erase(&vma->vm_rb, &mm->mm_rb); |
b951bf2c4
|
612 |
|
1b9fc5b24
|
613 |
__vma_unlink_list(mm, vma); |
8feae1311
|
614 615 616 617 618 619 620 |
} /* * destroy a VMA record */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { |
8feae1311
|
621 622 |
if (vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); |
e9714acf8
|
623 |
if (vma->vm_file) |
8feae1311
|
624 |
fput(vma->vm_file); |
8feae1311
|
625 |
put_nommu_region(vma->vm_region); |
3928d4f5e
|
626 |
vm_area_free(vma); |
8feae1311
|
627 628 629 630 |
} /* * look up the first VMA in which addr resides, NULL if none |
c1e8d7c6a
|
631 |
* - should be called with mm->mmap_lock at least held readlocked |
8feae1311
|
632 633 634 635 |
*/ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) { struct vm_area_struct *vma; |
8feae1311
|
636 637 |
/* check the cache first */ |
615d6e875
|
638 639 |
vma = vmacache_find(mm, addr); if (likely(vma)) |
8feae1311
|
640 |
return vma; |
e922c4c53
|
641 |
/* trawl the list (there may be multiple mappings in which addr |
8feae1311
|
642 |
* resides) */ |
e922c4c53
|
643 |
for (vma = mm->mmap; vma; vma = vma->vm_next) { |
8feae1311
|
644 645 646 |
if (vma->vm_start > addr) return NULL; if (vma->vm_end > addr) { |
615d6e875
|
647 |
vmacache_update(addr, vma); |
8feae1311
|
648 649 650 651 652 653 654 655 656 657 658 659 660 661 |
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) { |
7561e8ca0
|
662 |
return find_vma(mm, addr); |
8feae1311
|
663 664 665 666 667 668 669 670 671 672 673 674 675 |
} /* * 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 |
c1e8d7c6a
|
676 |
* - should be called with mm->mmap_lock at least held readlocked |
8feae1311
|
677 678 679 680 681 682 |
*/ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, unsigned long addr, unsigned long len) { struct vm_area_struct *vma; |
8feae1311
|
683 684 685 |
unsigned long end = addr + len; /* check the cache first */ |
615d6e875
|
686 687 |
vma = vmacache_find_exact(mm, addr, end); if (vma) |
8feae1311
|
688 |
return vma; |
e922c4c53
|
689 |
/* trawl the list (there may be multiple mappings in which addr |
8feae1311
|
690 |
* resides) */ |
e922c4c53
|
691 |
for (vma = mm->mmap; vma; vma = vma->vm_next) { |
8feae1311
|
692 693 694 695 696 |
if (vma->vm_start < addr) continue; if (vma->vm_start > addr) return NULL; if (vma->vm_end == end) { |
615d6e875
|
697 |
vmacache_update(addr, vma); |
8feae1311
|
698 699 700 701 702 |
return vma; } } return NULL; |
1da177e4c
|
703 704 705 706 707 708 709 710 711 712 713 714 715 716 |
} /* * 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) { |
8feae1311
|
717 |
unsigned long capabilities, rlen; |
1da177e4c
|
718 719 720 |
int ret; /* do the simple checks first */ |
22cc877b3
|
721 |
if (flags & MAP_FIXED) |
1da177e4c
|
722 |
return -EINVAL; |
1da177e4c
|
723 724 725 726 |
if ((flags & MAP_TYPE) != MAP_PRIVATE && (flags & MAP_TYPE) != MAP_SHARED) return -EINVAL; |
f81cff0d4
|
727 |
if (!len) |
1da177e4c
|
728 |
return -EINVAL; |
f81cff0d4
|
729 |
/* Careful about overflows.. */ |
8feae1311
|
730 731 |
rlen = PAGE_ALIGN(len); if (!rlen || rlen > TASK_SIZE) |
f81cff0d4
|
732 |
return -ENOMEM; |
1da177e4c
|
733 |
/* offset overflow? */ |
8feae1311
|
734 |
if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
f81cff0d4
|
735 |
return -EOVERFLOW; |
1da177e4c
|
736 737 |
if (file) { |
1da177e4c
|
738 |
/* files must support mmap */ |
72c2d5319
|
739 |
if (!file->f_op->mmap) |
1da177e4c
|
740 741 742 743 744 745 |
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 */ |
b4caecd48
|
746 747 748 |
if (file->f_op->mmap_capabilities) { capabilities = file->f_op->mmap_capabilities(file); } else { |
1da177e4c
|
749 750 |
/* no explicit capabilities set, so assume some * defaults */ |
496ad9aa8
|
751 |
switch (file_inode(file)->i_mode & S_IFMT) { |
1da177e4c
|
752 753 |
case S_IFREG: case S_IFBLK: |
b4caecd48
|
754 |
capabilities = NOMMU_MAP_COPY; |
1da177e4c
|
755 756 757 758 |
break; case S_IFCHR: capabilities = |
b4caecd48
|
759 760 761 |
NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; |
1da177e4c
|
762 763 764 765 766 767 768 769 770 771 |
break; default: return -EINVAL; } } /* eliminate any capabilities that we can't support on this * device */ if (!file->f_op->get_unmapped_area) |
b4caecd48
|
772 |
capabilities &= ~NOMMU_MAP_DIRECT; |
6e242a1ce
|
773 |
if (!(file->f_mode & FMODE_CAN_READ)) |
b4caecd48
|
774 |
capabilities &= ~NOMMU_MAP_COPY; |
1da177e4c
|
775 |
|
28d7a6ae9
|
776 777 778 |
/* The file shall have been opened with read permission. */ if (!(file->f_mode & FMODE_READ)) return -EACCES; |
1da177e4c
|
779 780 781 782 783 |
if (flags & MAP_SHARED) { /* do checks for writing, appending and locking */ if ((prot & PROT_WRITE) && !(file->f_mode & FMODE_WRITE)) return -EACCES; |
496ad9aa8
|
784 |
if (IS_APPEND(file_inode(file)) && |
1da177e4c
|
785 786 |
(file->f_mode & FMODE_WRITE)) return -EACCES; |
b4caecd48
|
787 |
if (!(capabilities & NOMMU_MAP_DIRECT)) |
1da177e4c
|
788 |
return -ENODEV; |
1da177e4c
|
789 |
/* we mustn't privatise shared mappings */ |
b4caecd48
|
790 |
capabilities &= ~NOMMU_MAP_COPY; |
ac7149045
|
791 |
} else { |
1da177e4c
|
792 793 |
/* we're going to read the file into private memory we * allocate */ |
b4caecd48
|
794 |
if (!(capabilities & NOMMU_MAP_COPY)) |
1da177e4c
|
795 796 797 798 799 |
return -ENODEV; /* we don't permit a private writable mapping to be * shared with the backing device */ if (prot & PROT_WRITE) |
b4caecd48
|
800 |
capabilities &= ~NOMMU_MAP_DIRECT; |
1da177e4c
|
801 |
} |
b4caecd48
|
802 803 804 805 |
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)) |
3c7b20454
|
806 |
) { |
b4caecd48
|
807 |
capabilities &= ~NOMMU_MAP_DIRECT; |
3c7b20454
|
808 |
if (flags & MAP_SHARED) { |
22cc877b3
|
809 810 |
pr_warn("MAP_SHARED not completely supported on !MMU "); |
3c7b20454
|
811 812 813 814 |
return -EINVAL; } } } |
1da177e4c
|
815 816 |
/* handle executable mappings and implied executable * mappings */ |
90f8572b0
|
817 |
if (path_noexec(&file->f_path)) { |
1da177e4c
|
818 819 |
if (prot & PROT_EXEC) return -EPERM; |
ac7149045
|
820 |
} else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
1da177e4c
|
821 822 |
/* handle implication of PROT_EXEC by PROT_READ */ if (current->personality & READ_IMPLIES_EXEC) { |
b4caecd48
|
823 |
if (capabilities & NOMMU_MAP_EXEC) |
1da177e4c
|
824 825 |
prot |= PROT_EXEC; } |
ac7149045
|
826 |
} else if ((prot & PROT_READ) && |
1da177e4c
|
827 |
(prot & PROT_EXEC) && |
b4caecd48
|
828 |
!(capabilities & NOMMU_MAP_EXEC) |
1da177e4c
|
829 830 |
) { /* backing file is not executable, try to copy */ |
b4caecd48
|
831 |
capabilities &= ~NOMMU_MAP_DIRECT; |
1da177e4c
|
832 |
} |
ac7149045
|
833 |
} else { |
1da177e4c
|
834 835 836 |
/* anonymous mappings are always memory backed and can be * privately mapped */ |
b4caecd48
|
837 |
capabilities = NOMMU_MAP_COPY; |
1da177e4c
|
838 839 840 841 842 843 844 845 |
/* 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 */ |
e5467859f
|
846 847 848 |
ret = security_mmap_addr(addr); if (ret < 0) return ret; |
1da177e4c
|
849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 |
/* 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; |
e6bfb7095
|
865 |
vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); |
1da177e4c
|
866 |
/* vm_flags |= mm->def_flags; */ |
b4caecd48
|
867 |
if (!(capabilities & NOMMU_MAP_DIRECT)) { |
1da177e4c
|
868 |
/* attempt to share read-only copies of mapped file chunks */ |
3c7b20454
|
869 |
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1da177e4c
|
870 871 |
if (file && !(prot & PROT_WRITE)) vm_flags |= VM_MAYSHARE; |
3c7b20454
|
872 |
} else { |
1da177e4c
|
873 874 875 |
/* overlay a shareable mapping on the backing device or inode * if possible - used for chardevs, ramfs/tmpfs/shmfs and * romfs/cramfs */ |
b4caecd48
|
876 |
vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS); |
1da177e4c
|
877 |
if (flags & MAP_SHARED) |
3c7b20454
|
878 |
vm_flags |= VM_SHARED; |
1da177e4c
|
879 880 881 882 883 884 |
} /* 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 */ |
a288eecce
|
885 |
if ((flags & MAP_PRIVATE) && current->ptrace) |
1da177e4c
|
886 887 888 889 890 891 |
vm_flags &= ~VM_MAYSHARE; return vm_flags; } /* |
8feae1311
|
892 893 |
* set up a shared mapping on a file (the driver or filesystem provides and * pins the storage) |
1da177e4c
|
894 |
*/ |
8feae1311
|
895 |
static int do_mmap_shared_file(struct vm_area_struct *vma) |
1da177e4c
|
896 897 |
{ int ret; |
f74ac0152
|
898 |
ret = call_mmap(vma->vm_file, vma); |
dd8632a12
|
899 900 |
if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; |
645d83c5d
|
901 |
return 0; |
dd8632a12
|
902 |
} |
1da177e4c
|
903 904 |
if (ret != -ENOSYS) return ret; |
3fa30460e
|
905 906 907 |
/* 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 */ |
1da177e4c
|
908 909 910 911 912 913 |
return -ENODEV; } /* * set up a private mapping or an anonymous shared mapping */ |
8feae1311
|
914 915 |
static int do_mmap_private(struct vm_area_struct *vma, struct vm_region *region, |
645d83c5d
|
916 917 |
unsigned long len, unsigned long capabilities) |
1da177e4c
|
918 |
{ |
dbc8358c7
|
919 |
unsigned long total, point; |
1da177e4c
|
920 |
void *base; |
8feae1311
|
921 |
int ret, order; |
1da177e4c
|
922 923 924 925 926 |
/* 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 */ |
b4caecd48
|
927 |
if (capabilities & NOMMU_MAP_DIRECT) { |
f74ac0152
|
928 |
ret = call_mmap(vma->vm_file, vma); |
dd8632a12
|
929 |
if (ret == 0) { |
1da177e4c
|
930 |
/* shouldn't return success if we're not sharing */ |
dd8632a12
|
931 932 |
BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); vma->vm_region->vm_top = vma->vm_region->vm_end; |
645d83c5d
|
933 |
return 0; |
1da177e4c
|
934 |
} |
dd8632a12
|
935 936 |
if (ret != -ENOSYS) return ret; |
1da177e4c
|
937 938 939 940 941 |
/* 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 */ } |
8feae1311
|
942 |
|
1da177e4c
|
943 944 945 946 |
/* 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 */ |
f67d9b157
|
947 |
order = get_order(len); |
8feae1311
|
948 |
total = 1 << order; |
f67d9b157
|
949 |
point = len >> PAGE_SHIFT; |
dd8632a12
|
950 |
|
dbc8358c7
|
951 |
/* we don't want to allocate a power-of-2 sized page set */ |
22cc877b3
|
952 |
if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) |
dbc8358c7
|
953 |
total = point; |
8feae1311
|
954 |
|
da616534e
|
955 |
base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL); |
dbc8358c7
|
956 957 958 959 |
if (!base) goto enomem; atomic_long_add(total, &mmap_pages_allocated); |
1da177e4c
|
960 |
|
8feae1311
|
961 962 |
region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; region->vm_start = (unsigned long) base; |
f67d9b157
|
963 |
region->vm_end = region->vm_start + len; |
dd8632a12
|
964 |
region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
8feae1311
|
965 966 967 |
vma->vm_start = region->vm_start; vma->vm_end = region->vm_start + len; |
1da177e4c
|
968 969 970 |
if (vma->vm_file) { /* read the contents of a file into the copy */ |
1da177e4c
|
971 972 973 974 |
loff_t fpos; fpos = vma->vm_pgoff; fpos <<= PAGE_SHIFT; |
b4bf802a5
|
975 |
ret = kernel_read(vma->vm_file, base, len, &fpos); |
1da177e4c
|
976 977 978 979 |
if (ret < 0) goto error_free; /* clear the last little bit */ |
f67d9b157
|
980 981 |
if (ret < len) memset(base + ret, 0, len - ret); |
1da177e4c
|
982 |
|
bfd40eaff
|
983 984 |
} else { vma_set_anonymous(vma); |
1da177e4c
|
985 986 987 988 989 |
} return 0; error_free: |
7223bb4a8
|
990 |
free_page_series(region->vm_start, region->vm_top); |
8feae1311
|
991 992 |
region->vm_start = vma->vm_start = 0; region->vm_end = vma->vm_end = 0; |
dd8632a12
|
993 |
region->vm_top = 0; |
1da177e4c
|
994 995 996 |
return ret; enomem: |
b1de0d139
|
997 998 |
pr_err("Allocation of length %lu from process %d (%s) failed ", |
05ae6fa31
|
999 |
len, current->pid, current->comm); |
9af744d74
|
1000 |
show_free_areas(0, NULL); |
1da177e4c
|
1001 1002 1003 1004 1005 1006 |
return -ENOMEM; } /* * handle mapping creation for uClinux */ |
1fcfd8db7
|
1007 1008 1009 1010 1011 |
unsigned long do_mmap(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, |
1fcfd8db7
|
1012 |
unsigned long pgoff, |
897ab3e0c
|
1013 1014 |
unsigned long *populate, struct list_head *uf) |
1da177e4c
|
1015 |
{ |
8feae1311
|
1016 1017 |
struct vm_area_struct *vma; struct vm_region *region; |
1da177e4c
|
1018 |
struct rb_node *rb; |
45e55300f
|
1019 |
vm_flags_t vm_flags; |
1fcfd8db7
|
1020 |
unsigned long capabilities, result; |
1da177e4c
|
1021 |
int ret; |
41badc15c
|
1022 |
*populate = 0; |
bebeb3d68
|
1023 |
|
1da177e4c
|
1024 1025 1026 1027 |
/* 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); |
22cc877b3
|
1028 |
if (ret < 0) |
1da177e4c
|
1029 |
return ret; |
06aab5a30
|
1030 1031 |
/* we ignore the address hint */ addr = 0; |
f67d9b157
|
1032 |
len = PAGE_ALIGN(len); |
06aab5a30
|
1033 |
|
1da177e4c
|
1034 1035 |
/* we've determined that we can make the mapping, now translate what we * now know into VMA flags */ |
45e55300f
|
1036 |
vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
1da177e4c
|
1037 |
|
8feae1311
|
1038 1039 1040 1041 |
/* we're going to need to record the mapping */ region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); if (!region) goto error_getting_region; |
490fc0538
|
1042 |
vma = vm_area_alloc(current->mm); |
8feae1311
|
1043 1044 |
if (!vma) goto error_getting_vma; |
1da177e4c
|
1045 |
|
1e2ae599d
|
1046 |
region->vm_usage = 1; |
8feae1311
|
1047 1048 |
region->vm_flags = vm_flags; region->vm_pgoff = pgoff; |
8feae1311
|
1049 1050 |
vma->vm_flags = vm_flags; vma->vm_pgoff = pgoff; |
1da177e4c
|
1051 |
|
8feae1311
|
1052 |
if (file) { |
cb0942b81
|
1053 1054 |
region->vm_file = get_file(file); vma->vm_file = get_file(file); |
8feae1311
|
1055 1056 1057 1058 1059 |
} down_write(&nommu_region_sem); /* if we want to share, we need to check for regions created by other |
1da177e4c
|
1060 |
* mmap() calls that overlap with our proposed mapping |
8feae1311
|
1061 |
* - we can only share with a superset match on most regular files |
1da177e4c
|
1062 1063 1064 1065 1066 1067 |
* - 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) { |
8feae1311
|
1068 1069 |
struct vm_region *pregion; unsigned long pglen, rpglen, pgend, rpgend, start; |
1da177e4c
|
1070 |
|
8feae1311
|
1071 1072 |
pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; pgend = pgoff + pglen; |
165b23927
|
1073 |
|
8feae1311
|
1074 1075 |
for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { pregion = rb_entry(rb, struct vm_region, vm_rb); |
1da177e4c
|
1076 |
|
8feae1311
|
1077 |
if (!(pregion->vm_flags & VM_MAYSHARE)) |
1da177e4c
|
1078 1079 1080 |
continue; /* search for overlapping mappings on the same file */ |
496ad9aa8
|
1081 1082 |
if (file_inode(pregion->vm_file) != file_inode(file)) |
1da177e4c
|
1083 |
continue; |
8feae1311
|
1084 |
if (pregion->vm_pgoff >= pgend) |
1da177e4c
|
1085 |
continue; |
8feae1311
|
1086 1087 1088 1089 |
rpglen = pregion->vm_end - pregion->vm_start; rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; rpgend = pregion->vm_pgoff + rpglen; if (pgoff >= rpgend) |
1da177e4c
|
1090 |
continue; |
8feae1311
|
1091 1092 1093 1094 1095 |
/* 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 */ |
b4caecd48
|
1096 |
if (!(capabilities & NOMMU_MAP_DIRECT)) |
1da177e4c
|
1097 1098 1099 |
goto sharing_violation; continue; } |
8feae1311
|
1100 |
/* we've found a region we can share */ |
1e2ae599d
|
1101 |
pregion->vm_usage++; |
8feae1311
|
1102 1103 1104 1105 1106 |
vma->vm_region = pregion; start = pregion->vm_start; start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; vma->vm_start = start; vma->vm_end = start + len; |
22cc877b3
|
1107 |
if (pregion->vm_flags & VM_MAPPED_COPY) |
8feae1311
|
1108 |
vma->vm_flags |= VM_MAPPED_COPY; |
22cc877b3
|
1109 |
else { |
8feae1311
|
1110 1111 1112 1113 1114 |
ret = do_mmap_shared_file(vma); if (ret < 0) { vma->vm_region = NULL; vma->vm_start = 0; vma->vm_end = 0; |
1e2ae599d
|
1115 |
pregion->vm_usage--; |
8feae1311
|
1116 1117 1118 1119 1120 1121 1122 1123 1124 |
pregion = NULL; goto error_just_free; } } fput(region->vm_file); kmem_cache_free(vm_region_jar, region); region = pregion; result = start; goto share; |
1da177e4c
|
1125 |
} |
1da177e4c
|
1126 1127 1128 1129 |
/* 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 */ |
b4caecd48
|
1130 |
if (capabilities & NOMMU_MAP_DIRECT) { |
1da177e4c
|
1131 1132 |
addr = file->f_op->get_unmapped_area(file, addr, len, pgoff, flags); |
bb005a59e
|
1133 |
if (IS_ERR_VALUE(addr)) { |
1da177e4c
|
1134 |
ret = addr; |
bb005a59e
|
1135 |
if (ret != -ENOSYS) |
8feae1311
|
1136 |
goto error_just_free; |
1da177e4c
|
1137 1138 1139 1140 |
/* the driver refused to tell us where to site * the mapping so we'll have to attempt to copy * it */ |
bb005a59e
|
1141 |
ret = -ENODEV; |
b4caecd48
|
1142 |
if (!(capabilities & NOMMU_MAP_COPY)) |
8feae1311
|
1143 |
goto error_just_free; |
1da177e4c
|
1144 |
|
b4caecd48
|
1145 |
capabilities &= ~NOMMU_MAP_DIRECT; |
8feae1311
|
1146 1147 1148 |
} else { vma->vm_start = region->vm_start = addr; vma->vm_end = region->vm_end = addr + len; |
1da177e4c
|
1149 1150 1151 |
} } } |
8feae1311
|
1152 |
vma->vm_region = region; |
1da177e4c
|
1153 |
|
645d83c5d
|
1154 |
/* set up the mapping |
b4caecd48
|
1155 |
* - the region is filled in if NOMMU_MAP_DIRECT is still set |
645d83c5d
|
1156 |
*/ |
1da177e4c
|
1157 |
if (file && vma->vm_flags & VM_SHARED) |
8feae1311
|
1158 |
ret = do_mmap_shared_file(vma); |
1da177e4c
|
1159 |
else |
645d83c5d
|
1160 |
ret = do_mmap_private(vma, region, len, capabilities); |
1da177e4c
|
1161 |
if (ret < 0) |
645d83c5d
|
1162 1163 |
goto error_just_free; add_nommu_region(region); |
8feae1311
|
1164 |
|
ea6376395
|
1165 |
/* clear anonymous mappings that don't ask for uninitialized data */ |
0bf5f9492
|
1166 1167 1168 |
if (!vma->vm_file && (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) || !(flags & MAP_UNINITIALIZED))) |
ea6376395
|
1169 1170 |
memset((void *)region->vm_start, 0, region->vm_end - region->vm_start); |
1da177e4c
|
1171 |
/* okay... we have a mapping; now we have to register it */ |
8feae1311
|
1172 |
result = vma->vm_start; |
1da177e4c
|
1173 |
|
1da177e4c
|
1174 |
current->mm->total_vm += len >> PAGE_SHIFT; |
8feae1311
|
1175 1176 |
share: add_vma_to_mm(current->mm, vma); |
1da177e4c
|
1177 |
|
cfe79c00a
|
1178 1179 1180 |
/* 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) { |
a75a2df68
|
1181 |
flush_icache_user_range(region->vm_start, region->vm_end); |
cfe79c00a
|
1182 1183 |
region->vm_icache_flushed = true; } |
1da177e4c
|
1184 |
|
cfe79c00a
|
1185 |
up_write(&nommu_region_sem); |
1da177e4c
|
1186 |
|
8feae1311
|
1187 |
return result; |
1da177e4c
|
1188 |
|
8feae1311
|
1189 1190 1191 |
error_just_free: up_write(&nommu_region_sem); error: |
89a864027
|
1192 1193 |
if (region->vm_file) fput(region->vm_file); |
8feae1311
|
1194 |
kmem_cache_free(vm_region_jar, region); |
89a864027
|
1195 1196 |
if (vma->vm_file) fput(vma->vm_file); |
3928d4f5e
|
1197 |
vm_area_free(vma); |
8feae1311
|
1198 1199 1200 1201 |
return ret; sharing_violation: up_write(&nommu_region_sem); |
22cc877b3
|
1202 1203 |
pr_warn("Attempt to share mismatched mappings "); |
8feae1311
|
1204 1205 |
ret = -EINVAL; goto error; |
1da177e4c
|
1206 |
|
8feae1311
|
1207 1208 |
error_getting_vma: kmem_cache_free(vm_region_jar, region); |
22cc877b3
|
1209 1210 1211 |
pr_warn("Allocation of vma for %lu byte allocation from process %d failed ", len, current->pid); |
9af744d74
|
1212 |
show_free_areas(0, NULL); |
1da177e4c
|
1213 |
return -ENOMEM; |
8feae1311
|
1214 |
error_getting_region: |
22cc877b3
|
1215 1216 1217 |
pr_warn("Allocation of vm region for %lu byte allocation from process %d failed ", len, current->pid); |
9af744d74
|
1218 |
show_free_areas(0, NULL); |
1da177e4c
|
1219 1220 |
return -ENOMEM; } |
6be5ceb02
|
1221 |
|
a90f590a1
|
1222 1223 1224 |
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long fd, unsigned long pgoff) |
66f0dc481
|
1225 1226 1227 |
{ struct file *file = NULL; unsigned long retval = -EBADF; |
120a795da
|
1228 |
audit_mmap_fd(fd, flags); |
66f0dc481
|
1229 1230 1231 1232 1233 |
if (!(flags & MAP_ANONYMOUS)) { file = fget(fd); if (!file) goto out; } |
ad1ed2937
|
1234 |
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
66f0dc481
|
1235 1236 1237 1238 1239 1240 |
if (file) fput(file); out: return retval; } |
a90f590a1
|
1241 1242 1243 1244 1245 1246 |
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, unsigned long, prot, unsigned long, flags, unsigned long, fd, unsigned long, pgoff) { return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); } |
a4679373c
|
1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 |
#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; |
1824cb753
|
1263 |
if (offset_in_page(a.offset)) |
a4679373c
|
1264 |
return -EINVAL; |
a90f590a1
|
1265 1266 |
return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT); |
a4679373c
|
1267 1268 |
} #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
1da177e4c
|
1269 |
/* |
8feae1311
|
1270 1271 |
* split a vma into two pieces at address 'addr', a new vma is allocated either * for the first part or the tail. |
1da177e4c
|
1272 |
*/ |
8feae1311
|
1273 1274 |
int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, int new_below) |
1da177e4c
|
1275 |
{ |
8feae1311
|
1276 1277 1278 |
struct vm_area_struct *new; struct vm_region *region; unsigned long npages; |
1da177e4c
|
1279 |
|
779c10232
|
1280 1281 1282 |
/* we're only permitted to split anonymous regions (these should have * only a single usage on the region) */ if (vma->vm_file) |
8feae1311
|
1283 |
return -ENOMEM; |
1da177e4c
|
1284 |
|
8feae1311
|
1285 1286 |
if (mm->map_count >= sysctl_max_map_count) return -ENOMEM; |
1da177e4c
|
1287 |
|
8feae1311
|
1288 1289 1290 |
region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); if (!region) return -ENOMEM; |
1da177e4c
|
1291 |
|
3928d4f5e
|
1292 |
new = vm_area_dup(vma); |
8feae1311
|
1293 1294 1295 1296 1297 1298 |
if (!new) { kmem_cache_free(vm_region_jar, region); return -ENOMEM; } /* most fields are the same, copy all, and then fixup */ |
8feae1311
|
1299 1300 1301 1302 1303 1304 |
*region = *vma->vm_region; new->vm_region = region; npages = (addr - vma->vm_start) >> PAGE_SHIFT; if (new_below) { |
dd8632a12
|
1305 |
region->vm_top = region->vm_end = new->vm_end = addr; |
8feae1311
|
1306 1307 1308 |
} else { region->vm_start = new->vm_start = addr; region->vm_pgoff = new->vm_pgoff += npages; |
1da177e4c
|
1309 |
} |
8feae1311
|
1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 |
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; |
dd8632a12
|
1322 |
vma->vm_region->vm_top = addr; |
8feae1311
|
1323 1324 1325 1326 1327 1328 1329 |
} 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; |
1da177e4c
|
1330 |
} |
3034097a5
|
1331 |
/* |
8feae1311
|
1332 1333 |
* shrink a VMA by removing the specified chunk from either the beginning or * the end |
3034097a5
|
1334 |
*/ |
8feae1311
|
1335 1336 1337 |
static int shrink_vma(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long from, unsigned long to) |
1da177e4c
|
1338 |
{ |
8feae1311
|
1339 |
struct vm_region *region; |
1da177e4c
|
1340 |
|
8feae1311
|
1341 1342 1343 1344 1345 1346 1347 1348 |
/* 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); |
1da177e4c
|
1349 |
|
8feae1311
|
1350 1351 |
/* cut the backing region down to size */ region = vma->vm_region; |
1e2ae599d
|
1352 |
BUG_ON(region->vm_usage != 1); |
8feae1311
|
1353 1354 1355 |
down_write(&nommu_region_sem); delete_nommu_region(region); |
dd8632a12
|
1356 1357 1358 1359 |
if (from > region->vm_start) { to = region->vm_top; region->vm_top = region->vm_end = from; } else { |
8feae1311
|
1360 |
region->vm_start = to; |
dd8632a12
|
1361 |
} |
8feae1311
|
1362 1363 1364 1365 1366 1367 |
add_nommu_region(region); up_write(&nommu_region_sem); free_page_series(from, to); return 0; } |
1da177e4c
|
1368 |
|
8feae1311
|
1369 1370 1371 1372 1373 |
/* * 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 */ |
897ab3e0c
|
1374 |
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf) |
8feae1311
|
1375 1376 |
{ struct vm_area_struct *vma; |
f67d9b157
|
1377 |
unsigned long end; |
8feae1311
|
1378 |
int ret; |
1da177e4c
|
1379 |
|
f67d9b157
|
1380 |
len = PAGE_ALIGN(len); |
8feae1311
|
1381 1382 |
if (len == 0) return -EINVAL; |
365e9c87a
|
1383 |
|
f67d9b157
|
1384 |
end = start + len; |
8feae1311
|
1385 1386 1387 |
/* find the first potentially overlapping VMA */ vma = find_vma(mm, start); if (!vma) { |
ac7149045
|
1388 |
static int limit; |
33e5d7697
|
1389 |
if (limit < 5) { |
22cc877b3
|
1390 1391 1392 1393 |
pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx ", current->pid, current->comm, start, start + len - 1); |
33e5d7697
|
1394 1395 |
limit++; } |
8feae1311
|
1396 1397 |
return -EINVAL; } |
1da177e4c
|
1398 |
|
8feae1311
|
1399 1400 1401 |
/* we're allowed to split an anonymous VMA but not a file-backed one */ if (vma->vm_file) { do { |
22cc877b3
|
1402 |
if (start > vma->vm_start) |
8feae1311
|
1403 |
return -EINVAL; |
8feae1311
|
1404 1405 |
if (end == vma->vm_end) goto erase_whole_vma; |
d75a310c4
|
1406 1407 |
vma = vma->vm_next; } while (vma); |
8feae1311
|
1408 1409 1410 1411 1412 |
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; |
22cc877b3
|
1413 |
if (start < vma->vm_start || end > vma->vm_end) |
8feae1311
|
1414 |
return -EINVAL; |
1824cb753
|
1415 |
if (offset_in_page(start)) |
8feae1311
|
1416 |
return -EINVAL; |
1824cb753
|
1417 |
if (end != vma->vm_end && offset_in_page(end)) |
8feae1311
|
1418 |
return -EINVAL; |
8feae1311
|
1419 1420 |
if (start != vma->vm_start && end != vma->vm_end) { ret = split_vma(mm, vma, start, 1); |
22cc877b3
|
1421 |
if (ret < 0) |
8feae1311
|
1422 |
return ret; |
8feae1311
|
1423 1424 1425 |
} return shrink_vma(mm, vma, start, end); } |
1da177e4c
|
1426 |
|
8feae1311
|
1427 1428 1429 |
erase_whole_vma: delete_vma_from_mm(vma); delete_vma(mm, vma); |
1da177e4c
|
1430 1431 |
return 0; } |
bfce281c2
|
1432 |
int vm_munmap(unsigned long addr, size_t len) |
3034097a5
|
1433 |
{ |
bfce281c2
|
1434 |
struct mm_struct *mm = current->mm; |
3034097a5
|
1435 |
int ret; |
3034097a5
|
1436 |
|
d8ed45c5d
|
1437 |
mmap_write_lock(mm); |
897ab3e0c
|
1438 |
ret = do_munmap(mm, addr, len, NULL); |
d8ed45c5d
|
1439 |
mmap_write_unlock(mm); |
3034097a5
|
1440 1441 |
return ret; } |
a46ef99d8
|
1442 1443 1444 1445 |
EXPORT_SYMBOL(vm_munmap); SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) { |
bfce281c2
|
1446 |
return vm_munmap(addr, len); |
a46ef99d8
|
1447 |
} |
3034097a5
|
1448 1449 |
/* |
8feae1311
|
1450 |
* release all the mappings made in a process's VM space |
3034097a5
|
1451 |
*/ |
8feae1311
|
1452 |
void exit_mmap(struct mm_struct *mm) |
1da177e4c
|
1453 |
{ |
8feae1311
|
1454 |
struct vm_area_struct *vma; |
1da177e4c
|
1455 |
|
8feae1311
|
1456 1457 |
if (!mm) return; |
1da177e4c
|
1458 |
|
8feae1311
|
1459 |
mm->total_vm = 0; |
1da177e4c
|
1460 |
|
8feae1311
|
1461 1462 1463 1464 |
while ((vma = mm->mmap)) { mm->mmap = vma->vm_next; delete_vma_from_mm(vma); delete_vma(mm, vma); |
04c349615
|
1465 |
cond_resched(); |
1da177e4c
|
1466 1467 |
} } |
5d22fc25d
|
1468 |
int vm_brk(unsigned long addr, unsigned long len) |
1da177e4c
|
1469 1470 1471 1472 1473 |
{ return -ENOMEM; } /* |
6fa5f80bc
|
1474 1475 |
* expand (or shrink) an existing mapping, potentially moving it at the same * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
1da177e4c
|
1476 |
* |
6fa5f80bc
|
1477 |
* under NOMMU conditions, we only permit changing a mapping's size, and only |
8feae1311
|
1478 1479 |
* as long as it stays within the region allocated by do_mmap_private() and the * block is not shareable |
1da177e4c
|
1480 |
* |
6fa5f80bc
|
1481 |
* MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4c
|
1482 |
*/ |
4b377bab2
|
1483 |
static unsigned long do_mremap(unsigned long addr, |
1da177e4c
|
1484 1485 1486 |
unsigned long old_len, unsigned long new_len, unsigned long flags, unsigned long new_addr) { |
6fa5f80bc
|
1487 |
struct vm_area_struct *vma; |
1da177e4c
|
1488 1489 |
/* insanity checks first */ |
f67d9b157
|
1490 1491 |
old_len = PAGE_ALIGN(old_len); new_len = PAGE_ALIGN(new_len); |
8feae1311
|
1492 |
if (old_len == 0 || new_len == 0) |
1da177e4c
|
1493 |
return (unsigned long) -EINVAL; |
1824cb753
|
1494 |
if (offset_in_page(addr)) |
8feae1311
|
1495 |
return -EINVAL; |
1da177e4c
|
1496 1497 |
if (flags & MREMAP_FIXED && new_addr != addr) return (unsigned long) -EINVAL; |
8feae1311
|
1498 |
vma = find_vma_exact(current->mm, addr, old_len); |
6fa5f80bc
|
1499 1500 |
if (!vma) return (unsigned long) -EINVAL; |
1da177e4c
|
1501 |
|
6fa5f80bc
|
1502 |
if (vma->vm_end != vma->vm_start + old_len) |
1da177e4c
|
1503 |
return (unsigned long) -EFAULT; |
6fa5f80bc
|
1504 |
if (vma->vm_flags & VM_MAYSHARE) |
1da177e4c
|
1505 |
return (unsigned long) -EPERM; |
8feae1311
|
1506 |
if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1da177e4c
|
1507 1508 1509 |
return (unsigned long) -ENOMEM; /* all checks complete - do it */ |
6fa5f80bc
|
1510 |
vma->vm_end = vma->vm_start + new_len; |
6fa5f80bc
|
1511 1512 |
return vma->vm_start; } |
6a6160a7b
|
1513 1514 1515 |
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, unsigned long, new_len, unsigned long, flags, unsigned long, new_addr) |
6fa5f80bc
|
1516 1517 |
{ unsigned long ret; |
d8ed45c5d
|
1518 |
mmap_write_lock(current->mm); |
6fa5f80bc
|
1519 |
ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
d8ed45c5d
|
1520 |
mmap_write_unlock(current->mm); |
6fa5f80bc
|
1521 |
return ret; |
1da177e4c
|
1522 |
} |
df06b37ff
|
1523 1524 |
struct page *follow_page(struct vm_area_struct *vma, unsigned long address, unsigned int foll_flags) |
1da177e4c
|
1525 1526 1527 |
{ return NULL; } |
8f3b1327a
|
1528 1529 |
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t prot) |
1da177e4c
|
1530 |
{ |
8f3b1327a
|
1531 1532 |
if (addr != (pfn << PAGE_SHIFT)) return -EINVAL; |
314e51b98
|
1533 |
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
66aa2b4b1
|
1534 |
return 0; |
1da177e4c
|
1535 |
} |
22c4af409
|
1536 |
EXPORT_SYMBOL(remap_pfn_range); |
1da177e4c
|
1537 |
|
3c0b9de6d
|
1538 1539 1540 1541 1542 1543 1544 1545 1546 |
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); |
f905bc447
|
1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 |
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); |
1da177e4c
|
1561 1562 1563 1564 1565 |
unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { return -ENOMEM; } |
2bcd6454b
|
1566 |
vm_fault_t filemap_fault(struct vm_fault *vmf) |
b0e15190e
|
1567 1568 |
{ BUG(); |
d0217ac04
|
1569 |
return 0; |
b0e15190e
|
1570 |
} |
b50731732
|
1571 |
EXPORT_SYMBOL(filemap_fault); |
0ec76a110
|
1572 |
|
3f98a28cc
|
1573 |
vm_fault_t filemap_map_pages(struct vm_fault *vmf, |
bae473a42
|
1574 |
pgoff_t start_pgoff, pgoff_t end_pgoff) |
f1820361f
|
1575 1576 |
{ BUG(); |
3f98a28cc
|
1577 |
return 0; |
f1820361f
|
1578 1579 |
} EXPORT_SYMBOL(filemap_map_pages); |
d3f5ffcac
|
1580 1581 |
int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags) |
0ec76a110
|
1582 |
{ |
0ec76a110
|
1583 |
struct vm_area_struct *vma; |
442486ec1
|
1584 |
int write = gup_flags & FOLL_WRITE; |
0ec76a110
|
1585 |
|
d8ed45c5d
|
1586 |
if (mmap_read_lock_killable(mm)) |
1e426fe28
|
1587 |
return 0; |
0ec76a110
|
1588 1589 |
/* the access must start within one of the target process's mappings */ |
0159b141d
|
1590 1591 |
vma = find_vma(mm, addr); if (vma) { |
0ec76a110
|
1592 1593 1594 1595 1596 |
/* 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 */ |
d00c7b993
|
1597 |
if (write && vma->vm_flags & VM_MAYWRITE) |
7959722b9
|
1598 1599 |
copy_to_user_page(vma, NULL, addr, (void *) addr, buf, len); |
d00c7b993
|
1600 |
else if (!write && vma->vm_flags & VM_MAYREAD) |
7959722b9
|
1601 1602 |
copy_from_user_page(vma, NULL, addr, buf, (void *) addr, len); |
0ec76a110
|
1603 1604 1605 1606 1607 |
else len = 0; } else { len = 0; } |
d8ed45c5d
|
1608 |
mmap_read_unlock(mm); |
f55f199b7
|
1609 1610 1611 1612 1613 |
return len; } /** |
b7701a5f2
|
1614 |
* access_remote_vm - access another process' address space |
f55f199b7
|
1615 1616 1617 1618 |
* @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 |
6347e8d5b
|
1619 |
* @gup_flags: flags modifying lookup behaviour |
f55f199b7
|
1620 1621 1622 1623 |
* * The caller must hold a reference on @mm. */ int access_remote_vm(struct mm_struct *mm, unsigned long addr, |
6347e8d5b
|
1624 |
void *buf, int len, unsigned int gup_flags) |
f55f199b7
|
1625 |
{ |
d3f5ffcac
|
1626 |
return __access_remote_vm(mm, addr, buf, len, gup_flags); |
f55f199b7
|
1627 1628 1629 1630 1631 1632 |
} /* * Access another process' address space. * - source/target buffer must be kernel space */ |
f307ab6dc
|
1633 1634 |
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, unsigned int gup_flags) |
f55f199b7
|
1635 1636 1637 1638 1639 1640 1641 1642 1643 |
{ struct mm_struct *mm; if (addr + len < addr) return 0; mm = get_task_mm(tsk); if (!mm) return 0; |
d3f5ffcac
|
1644 |
len = __access_remote_vm(mm, addr, buf, len, gup_flags); |
f55f199b7
|
1645 |
|
0ec76a110
|
1646 1647 1648 |
mmput(mm); return len; } |
fcd35857d
|
1649 |
EXPORT_SYMBOL_GPL(access_process_vm); |
7e6608724
|
1650 1651 1652 1653 1654 1655 1656 1657 |
/** * 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 |
c08b342c2
|
1658 1659 |
* make sure that any outstanding VMAs aren't broken and then shrink the * vm_regions that extend beyond so that do_mmap() doesn't |
7e6608724
|
1660 1661 1662 1663 1664 1665 |
* 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; |
7e6608724
|
1666 1667 1668 1669 1670 1671 1672 1673 |
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); |
1acf2e040
|
1674 |
i_mmap_lock_read(inode->i_mapping); |
7e6608724
|
1675 1676 |
/* search for VMAs that fall within the dead zone */ |
6b2dbba8b
|
1677 |
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) { |
7e6608724
|
1678 1679 1680 |
/* found one - only interested if it's shared out of the page * cache */ if (vma->vm_flags & VM_SHARED) { |
1acf2e040
|
1681 |
i_mmap_unlock_read(inode->i_mapping); |
7e6608724
|
1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 |
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 */ |
1acf2e040
|
1693 |
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) { |
7e6608724
|
1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 |
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; } } |
1acf2e040
|
1707 |
i_mmap_unlock_read(inode->i_mapping); |
7e6608724
|
1708 1709 1710 |
up_write(&nommu_region_sem); return 0; } |
c9b1d0981
|
1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 |
/* * 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; |
c41f012ad
|
1725 |
free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
c9b1d0981
|
1726 1727 1728 1729 |
sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); return 0; } |
a4bc6fc79
|
1730 |
subsys_initcall(init_user_reserve); |
4eeab4f55
|
1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 |
/* * 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; |
c41f012ad
|
1745 |
free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
4eeab4f55
|
1746 1747 1748 1749 |
sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); return 0; } |
a4bc6fc79
|
1750 |
subsys_initcall(init_admin_reserve); |