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mm/nommu.c
45.8 KB
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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). * * See Documentation/nommu-mmap.txt * |
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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) 2007-2009 Paul Mundt <lethal@linux-sh.org> |
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*/ |
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#include <linux/module.h> |
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#include <linux/mm.h> #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/tracehook.h> |
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#include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/mount.h> #include <linux/personality.h> #include <linux/security.h> #include <linux/syscalls.h> #include <asm/uaccess.h> #include <asm/tlb.h> #include <asm/tlbflush.h> |
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#include "internal.h" static inline __attribute__((format(printf, 1, 2))) void no_printk(const char *fmt, ...) { } #if 0 #define kenter(FMT, ...) \ printk(KERN_DEBUG "==> %s("FMT") ", __func__, ##__VA_ARGS__) #define kleave(FMT, ...) \ printk(KERN_DEBUG "<== %s()"FMT" ", __func__, ##__VA_ARGS__) #define kdebug(FMT, ...) \ printk(KERN_DEBUG "xxx" FMT"yyy ", ##__VA_ARGS__) #else #define kenter(FMT, ...) \ no_printk(KERN_DEBUG "==> %s("FMT") ", __func__, ##__VA_ARGS__) #define kleave(FMT, ...) \ no_printk(KERN_DEBUG "<== %s()"FMT" ", __func__, ##__VA_ARGS__) #define kdebug(FMT, ...) \ no_printk(KERN_DEBUG FMT" ", ##__VA_ARGS__) #endif |
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#include "internal.h" |
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void *high_memory; struct page *mem_map; unsigned long max_mapnr; unsigned long num_physpages; |
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struct percpu_counter vm_committed_as; |
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int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ int sysctl_overcommit_ratio = 50; /* default is 50% */ int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; |
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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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|
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EXPORT_SYMBOL(mem_map); |
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EXPORT_SYMBOL(num_physpages); |
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|
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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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struct vm_operations_struct generic_file_vm_ops = { }; /* * Handle all mappings that got truncated by a "truncate()" * system call. * * NOTE! We have to be ready to update the memory sharing * between the file and the memory map for a potential last * incomplete page. Ugly, but necessary. */ int vmtruncate(struct inode *inode, loff_t offset) { struct address_space *mapping = inode->i_mapping; unsigned long limit; if (inode->i_size < offset) goto do_expand; i_size_write(inode, offset); truncate_inode_pages(mapping, offset); goto out_truncate; do_expand: limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; if (limit != RLIM_INFINITY && offset > limit) goto out_sig; if (offset > inode->i_sb->s_maxbytes) goto out; i_size_write(inode, offset); out_truncate: |
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if (inode->i_op->truncate) |
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inode->i_op->truncate(inode); return 0; out_sig: send_sig(SIGXFSZ, current, 0); out: return -EFBIG; } EXPORT_SYMBOL(vmtruncate); /* * 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 << compound_order(page); |
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} |
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int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int len, int flags, struct page **pages, struct vm_area_struct **vmas) |
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{ |
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struct vm_area_struct *vma; |
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unsigned long vm_flags; int i; |
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int write = !!(flags & GUP_FLAGS_WRITE); int force = !!(flags & GUP_FLAGS_FORCE); int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS); |
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/* calculate required read or write permissions. * - if 'force' is set, we only require the "MAY" flags. */ vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
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for (i = 0; i < len; i++) { |
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vma = find_vma(mm, start); |
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if (!vma) goto finish_or_fault; /* protect what we can, including chardevs */ if (vma->vm_flags & (VM_IO | VM_PFNMAP) || |
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(!ignore && !(vm_flags & vma->vm_flags))) |
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goto finish_or_fault; |
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|
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if (pages) { pages[i] = virt_to_page(start); if (pages[i]) page_cache_get(pages[i]); } if (vmas) |
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vmas[i] = vma; |
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start += PAGE_SIZE; } |
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return i; finish_or_fault: return i ? : -EFAULT; |
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} |
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/* * get a list of pages in an address range belonging to the specified process * and indicate the VMA that covers each page * - this is potentially dodgy as we may end incrementing the page count of a * slab page or a secondary page from a compound page * - don't permit access to VMAs that don't support it, such as I/O mappings */ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int len, int write, int force, struct page **pages, struct vm_area_struct **vmas) { int flags = 0; if (write) flags |= GUP_FLAGS_WRITE; if (force) flags |= GUP_FLAGS_FORCE; return __get_user_pages(tsk, mm, start, len, flags, pages, vmas); } |
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EXPORT_SYMBOL(get_user_pages); |
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DEFINE_RWLOCK(vmlist_lock); struct vm_struct *vmlist; |
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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, pgprot_t prot) |
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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_user(unsigned long size) { void *ret; ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); if (ret) { struct vm_area_struct *vma; down_write(¤t->mm->mmap_sem); vma = find_vma(current->mm, (unsigned long)ret); if (vma) vma->vm_flags |= VM_USERMAP; up_write(¤t->mm->mmap_sem); } return ret; } 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) { memcpy(buf, addr, count); return count; } long vwrite(char *buf, char *addr, unsigned long count) { /* Don't allow overflow */ if ((unsigned long) addr + count < count) count = -(unsigned long) addr; memcpy(addr, buf, count); return(count); } /* * vmalloc - allocate virtually continguos memory * * @size: allocation size * * Allocate enough pages to cover @size from the page level * allocator and map them into continguos kernel virtual space. * |
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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) { return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); } |
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EXPORT_SYMBOL(vmalloc); void *vmalloc_node(unsigned long size, int node) { return vmalloc(size); } EXPORT_SYMBOL(vmalloc_node); |
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#ifndef PAGE_KERNEL_EXEC # define PAGE_KERNEL_EXEC PAGE_KERNEL #endif /** * vmalloc_exec - allocate virtually contiguous, executable memory * @size: allocation size * * Kernel-internal function to allocate enough pages to cover @size * the page level allocator and map them into contiguous and * executable kernel virtual space. * * For tight control over page level allocator and protection flags * use __vmalloc() instead. */ void *vmalloc_exec(unsigned long size) { return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); } |
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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 * page level allocator and map them into continguos kernel virtual space. */ void *vmalloc_32(unsigned long size) { return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); } |
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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, pgprot_t prot) { 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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/* |
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* Implement a stub for vmalloc_sync_all() if the architecture chose not to * have one. */ void __attribute__((weak)) vmalloc_sync_all(void) { } |
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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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/* |
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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. */ return mm->brk = brk; } |
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/* * initialise the VMA and region record slabs */ void __init mmap_init(void) |
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{ |
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int ret; ret = percpu_counter_init(&vm_committed_as, 0); VM_BUG_ON(ret); |
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vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); |
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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(unlikely(last->vm_end <= last->vm_start)); BUG_ON(unlikely(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(unlikely(region->vm_end <= region->vm_start)); BUG_ON(unlikely(region->vm_top < region->vm_end)); BUG_ON(unlikely(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); kdebug("- free %lx", from); |
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atomic_long_dec(&mmap_pages_allocated); |
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if (page_count(page) != 1) |
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kdebug("free page %p: refcount not one: %d", page, page_count(page)); |
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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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kenter("%p{%d}", region, atomic_read(®ion->vm_usage)); |
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BUG_ON(!nommu_region_tree.rb_node); |
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if (atomic_dec_and_test(®ion->vm_usage)) { |
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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 */ if (region->vm_flags & VM_MAPPED_COPY) { kdebug("free series"); |
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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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|
598 599 600 601 |
* 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 |
3034097a5
|
602 |
*/ |
8feae1311
|
603 |
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4c
|
604 |
{ |
8feae1311
|
605 |
struct vm_area_struct *pvma, **pp; |
1da177e4c
|
606 |
struct address_space *mapping; |
8feae1311
|
607 608 609 610 611 612 613 614 |
struct rb_node **p, *parent; kenter(",%p", vma); BUG_ON(!vma->vm_region); mm->map_count++; vma->vm_mm = mm; |
1da177e4c
|
615 616 617 618 619 620 621 622 623 |
/* add the VMA to the mapping */ if (vma->vm_file) { mapping = vma->vm_file->f_mapping; flush_dcache_mmap_lock(mapping); vma_prio_tree_insert(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); } |
8feae1311
|
624 625 626 |
/* add the VMA to the tree */ parent = NULL; p = &mm->mm_rb.rb_node; |
1da177e4c
|
627 628 629 |
while (*p) { parent = *p; pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
8feae1311
|
630 631 632 |
/* 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
|
633 |
p = &(*p)->rb_left; |
8feae1311
|
634 |
else if (vma->vm_start > pvma->vm_start) |
1da177e4c
|
635 |
p = &(*p)->rb_right; |
8feae1311
|
636 637 638 639 640 641 642 643 644 645 |
else if (vma->vm_end < pvma->vm_end) p = &(*p)->rb_left; else if (vma->vm_end > pvma->vm_end) p = &(*p)->rb_right; else if (vma < pvma) p = &(*p)->rb_left; else if (vma > pvma) p = &(*p)->rb_right; else BUG(); |
1da177e4c
|
646 647 648 |
} rb_link_node(&vma->vm_rb, parent, p); |
8feae1311
|
649 650 651 652 653 654 655 656 657 658 659 660 661 662 |
rb_insert_color(&vma->vm_rb, &mm->mm_rb); /* add VMA to the VMA list also */ for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) { if (pvma->vm_start > vma->vm_start) break; if (pvma->vm_start < vma->vm_start) continue; if (pvma->vm_end < vma->vm_end) break; } vma->vm_next = *pp; *pp = vma; |
1da177e4c
|
663 |
} |
3034097a5
|
664 |
/* |
8feae1311
|
665 |
* delete a VMA from its owning mm_struct and address space |
3034097a5
|
666 |
*/ |
8feae1311
|
667 |
static void delete_vma_from_mm(struct vm_area_struct *vma) |
1da177e4c
|
668 |
{ |
8feae1311
|
669 |
struct vm_area_struct **pp; |
1da177e4c
|
670 |
struct address_space *mapping; |
8feae1311
|
671 672 673 674 675 676 677 |
struct mm_struct *mm = vma->vm_mm; kenter("%p", vma); mm->map_count--; if (mm->mmap_cache == vma) mm->mmap_cache = NULL; |
1da177e4c
|
678 679 680 681 682 683 684 685 686 |
/* remove the VMA from the mapping */ if (vma->vm_file) { mapping = vma->vm_file->f_mapping; flush_dcache_mmap_lock(mapping); vma_prio_tree_remove(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); } |
8feae1311
|
687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 |
/* remove from the MM's tree and list */ rb_erase(&vma->vm_rb, &mm->mm_rb); for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) { if (*pp == vma) { *pp = vma->vm_next; break; } } vma->vm_mm = NULL; } /* * destroy a VMA record */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { kenter("%p", vma); if (vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); if (vma->vm_file) { fput(vma->vm_file); if (vma->vm_flags & VM_EXECUTABLE) removed_exe_file_vma(mm); } 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; struct rb_node *n = mm->mm_rb.rb_node; /* check the cache first */ vma = mm->mmap_cache; if (vma && vma->vm_start <= addr && vma->vm_end > addr) return vma; /* trawl the tree (there may be multiple mappings in which addr * resides) */ for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { vma = rb_entry(n, struct vm_area_struct, vm_rb); if (vma->vm_start > addr) return NULL; if (vma->vm_end > addr) { mm->mmap_cache = 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; struct rb_node *n = mm->mm_rb.rb_node; unsigned long end = addr + len; /* check the cache first */ vma = mm->mmap_cache; if (vma && vma->vm_start == addr && vma->vm_end == end) return vma; /* trawl the tree (there may be multiple mappings in which addr * resides) */ for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { vma = rb_entry(n, struct vm_area_struct, vm_rb); if (vma->vm_start < addr) continue; if (vma->vm_start > addr) return NULL; if (vma->vm_end == end) { mm->mmap_cache = vma; return vma; } } return NULL; |
1da177e4c
|
796 797 798 799 800 801 802 803 804 805 806 807 808 809 |
} /* * 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
|
810 |
unsigned long capabilities, rlen; |
1da177e4c
|
811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 |
unsigned long reqprot = prot; int ret; /* do the simple checks first */ if (flags & MAP_FIXED || addr) { printk(KERN_DEBUG "%d: Can't do fixed-address/overlay mmap of RAM ", current->pid); return -EINVAL; } if ((flags & MAP_TYPE) != MAP_PRIVATE && (flags & MAP_TYPE) != MAP_SHARED) return -EINVAL; |
f81cff0d4
|
826 |
if (!len) |
1da177e4c
|
827 |
return -EINVAL; |
f81cff0d4
|
828 |
/* Careful about overflows.. */ |
8feae1311
|
829 830 |
rlen = PAGE_ALIGN(len); if (!rlen || rlen > TASK_SIZE) |
f81cff0d4
|
831 |
return -ENOMEM; |
1da177e4c
|
832 |
/* offset overflow? */ |
8feae1311
|
833 |
if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
f81cff0d4
|
834 |
return -EOVERFLOW; |
1da177e4c
|
835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 |
if (file) { /* validate file mapping requests */ struct address_space *mapping; /* files must support mmap */ if (!file->f_op || !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 */ mapping = file->f_mapping; if (!mapping) |
e9536ae72
|
850 |
mapping = file->f_path.dentry->d_inode->i_mapping; |
1da177e4c
|
851 852 853 854 855 856 857 858 |
capabilities = 0; if (mapping && mapping->backing_dev_info) capabilities = mapping->backing_dev_info->capabilities; if (!capabilities) { /* no explicit capabilities set, so assume some * defaults */ |
e9536ae72
|
859 |
switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
1da177e4c
|
860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 |
case S_IFREG: case S_IFBLK: capabilities = BDI_CAP_MAP_COPY; break; case S_IFCHR: capabilities = BDI_CAP_MAP_DIRECT | BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP; break; default: return -EINVAL; } } /* eliminate any capabilities that we can't support on this * device */ if (!file->f_op->get_unmapped_area) capabilities &= ~BDI_CAP_MAP_DIRECT; if (!file->f_op->read) capabilities &= ~BDI_CAP_MAP_COPY; if (flags & MAP_SHARED) { /* do checks for writing, appending and locking */ if ((prot & PROT_WRITE) && !(file->f_mode & FMODE_WRITE)) return -EACCES; |
e9536ae72
|
889 |
if (IS_APPEND(file->f_path.dentry->d_inode) && |
1da177e4c
|
890 891 |
(file->f_mode & FMODE_WRITE)) return -EACCES; |
e9536ae72
|
892 |
if (locks_verify_locked(file->f_path.dentry->d_inode)) |
1da177e4c
|
893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 |
return -EAGAIN; if (!(capabilities & BDI_CAP_MAP_DIRECT)) return -ENODEV; if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) ) { printk("MAP_SHARED not completely supported on !MMU "); return -EINVAL; } /* we mustn't privatise shared mappings */ capabilities &= ~BDI_CAP_MAP_COPY; } else { /* we're going to read the file into private memory we * allocate */ if (!(capabilities & BDI_CAP_MAP_COPY)) return -ENODEV; /* we don't permit a private writable mapping to be * shared with the backing device */ if (prot & PROT_WRITE) capabilities &= ~BDI_CAP_MAP_DIRECT; } /* handle executable mappings and implied executable * mappings */ |
e9536ae72
|
924 |
if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1da177e4c
|
925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 |
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 & BDI_CAP_EXEC_MAP) prot |= PROT_EXEC; } } else if ((prot & PROT_READ) && (prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP) ) { /* backing file is not executable, try to copy */ capabilities &= ~BDI_CAP_MAP_DIRECT; } } else { /* anonymous mappings are always memory backed and can be * privately mapped */ capabilities = BDI_CAP_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 */ |
ed0321895
|
956 |
ret = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1da177e4c
|
957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 |
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) | calc_vm_flag_bits(flags); vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; /* vm_flags |= mm->def_flags; */ if (!(capabilities & BDI_CAP_MAP_DIRECT)) { /* attempt to share read-only copies of mapped file chunks */ 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 */ if (flags & MAP_SHARED) vm_flags |= VM_MAYSHARE | VM_SHARED; else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0) vm_flags |= VM_MAYSHARE; } /* 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 */ |
fa8e26ccd
|
999 |
if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current)) |
1da177e4c
|
1000 1001 1002 1003 1004 1005 |
vm_flags &= ~VM_MAYSHARE; return vm_flags; } /* |
8feae1311
|
1006 1007 |
* set up a shared mapping on a file (the driver or filesystem provides and * pins the storage) |
1da177e4c
|
1008 |
*/ |
8feae1311
|
1009 |
static int do_mmap_shared_file(struct vm_area_struct *vma) |
1da177e4c
|
1010 1011 1012 1013 |
{ int ret; ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
dd8632a12
|
1014 1015 1016 1017 |
if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; return ret; } |
1da177e4c
|
1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 |
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 fall * through to making a private copy of the data and mapping * that if we can */ return -ENODEV; } /* * set up a private mapping or an anonymous shared mapping */ |
8feae1311
|
1031 1032 1033 |
static int do_mmap_private(struct vm_area_struct *vma, struct vm_region *region, unsigned long len) |
1da177e4c
|
1034 |
{ |
8feae1311
|
1035 1036 |
struct page *pages; unsigned long total, point, n, rlen; |
1da177e4c
|
1037 |
void *base; |
8feae1311
|
1038 |
int ret, order; |
1da177e4c
|
1039 1040 1041 1042 1043 1044 1045 |
/* 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 (vma->vm_file) { ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
dd8632a12
|
1046 |
if (ret == 0) { |
1da177e4c
|
1047 |
/* shouldn't return success if we're not sharing */ |
dd8632a12
|
1048 1049 1050 |
BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); vma->vm_region->vm_top = vma->vm_region->vm_end; return ret; |
1da177e4c
|
1051 |
} |
dd8632a12
|
1052 1053 |
if (ret != -ENOSYS) return ret; |
1da177e4c
|
1054 1055 1056 1057 1058 |
/* 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
|
1059 |
rlen = PAGE_ALIGN(len); |
1da177e4c
|
1060 1061 1062 1063 |
/* 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 */ |
8feae1311
|
1064 1065 1066 1067 1068 |
order = get_order(rlen); kdebug("alloc order %d for %lx", order, len); pages = alloc_pages(GFP_KERNEL, order); if (!pages) |
1da177e4c
|
1069 |
goto enomem; |
8feae1311
|
1070 |
total = 1 << order; |
33e5d7697
|
1071 |
atomic_long_add(total, &mmap_pages_allocated); |
8feae1311
|
1072 1073 |
point = rlen >> PAGE_SHIFT; |
dd8632a12
|
1074 1075 1076 1077 1078 1079 1080 1081 |
/* we allocated a power-of-2 sized page set, so we may want to trim off * the excess */ if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { while (total > point) { order = ilog2(total - point); n = 1 << order; kdebug("shave %lu/%lu @%lu", n, total - point, total); |
33e5d7697
|
1082 |
atomic_long_sub(n, &mmap_pages_allocated); |
dd8632a12
|
1083 1084 1085 1086 |
total -= n; set_page_refcounted(pages + total); __free_pages(pages + total, order); } |
8feae1311
|
1087 |
} |
8feae1311
|
1088 1089 |
for (point = 1; point < total; point++) set_page_refcounted(&pages[point]); |
1da177e4c
|
1090 |
|
8feae1311
|
1091 1092 1093 1094 |
base = page_address(pages); region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; region->vm_start = (unsigned long) base; region->vm_end = region->vm_start + rlen; |
dd8632a12
|
1095 |
region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
8feae1311
|
1096 1097 1098 |
vma->vm_start = region->vm_start; vma->vm_end = region->vm_start + len; |
1da177e4c
|
1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 |
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); |
8feae1311
|
1110 |
ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); |
1da177e4c
|
1111 1112 1113 1114 1115 1116 |
set_fs(old_fs); if (ret < 0) goto error_free; /* clear the last little bit */ |
8feae1311
|
1117 1118 |
if (ret < rlen) memset(base + ret, 0, rlen - ret); |
1da177e4c
|
1119 1120 1121 |
} else { /* if it's an anonymous mapping, then just clear it */ |
8feae1311
|
1122 |
memset(base, 0, rlen); |
1da177e4c
|
1123 1124 1125 1126 1127 |
} return 0; error_free: |
8feae1311
|
1128 1129 1130 |
free_page_series(region->vm_start, region->vm_end); region->vm_start = vma->vm_start = 0; region->vm_end = vma->vm_end = 0; |
dd8632a12
|
1131 |
region->vm_top = 0; |
1da177e4c
|
1132 1133 1134 |
return ret; enomem: |
05ae6fa31
|
1135 1136 1137 |
printk("Allocation of length %lu from process %d (%s) failed ", len, current->pid, current->comm); |
1da177e4c
|
1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 |
show_free_areas(); return -ENOMEM; } /* * handle mapping creation for uClinux */ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long pgoff) { |
8feae1311
|
1152 1153 |
struct vm_area_struct *vma; struct vm_region *region; |
1da177e4c
|
1154 |
struct rb_node *rb; |
8feae1311
|
1155 |
unsigned long capabilities, vm_flags, result; |
1da177e4c
|
1156 |
int ret; |
8feae1311
|
1157 |
kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
7cd94146c
|
1158 1159 |
if (!(flags & MAP_FIXED)) addr = round_hint_to_min(addr); |
1da177e4c
|
1160 1161 1162 1163 |
/* 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); |
8feae1311
|
1164 1165 |
if (ret < 0) { kleave(" = %d [val]", ret); |
1da177e4c
|
1166 |
return ret; |
8feae1311
|
1167 |
} |
1da177e4c
|
1168 1169 1170 1171 |
/* 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); |
8feae1311
|
1172 1173 1174 1175 1176 1177 1178 1179 |
/* 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; |
1da177e4c
|
1180 |
|
8feae1311
|
1181 1182 1183 1184 1185 1186 1187 |
atomic_set(®ion->vm_usage, 1); region->vm_flags = vm_flags; region->vm_pgoff = pgoff; INIT_LIST_HEAD(&vma->anon_vma_node); vma->vm_flags = vm_flags; vma->vm_pgoff = pgoff; |
1da177e4c
|
1188 |
|
8feae1311
|
1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 |
if (file) { region->vm_file = file; get_file(file); vma->vm_file = file; get_file(file); if (vm_flags & VM_EXECUTABLE) { added_exe_file_vma(current->mm); vma->vm_mm = current->mm; } } down_write(&nommu_region_sem); /* if we want to share, we need to check for regions created by other |
1da177e4c
|
1203 |
* mmap() calls that overlap with our proposed mapping |
8feae1311
|
1204 |
* - we can only share with a superset match on most regular files |
1da177e4c
|
1205 1206 1207 1208 1209 1210 |
* - 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
|
1211 1212 |
struct vm_region *pregion; unsigned long pglen, rpglen, pgend, rpgend, start; |
1da177e4c
|
1213 |
|
8feae1311
|
1214 1215 |
pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; pgend = pgoff + pglen; |
165b23927
|
1216 |
|
8feae1311
|
1217 1218 |
for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { pregion = rb_entry(rb, struct vm_region, vm_rb); |
1da177e4c
|
1219 |
|
8feae1311
|
1220 |
if (!(pregion->vm_flags & VM_MAYSHARE)) |
1da177e4c
|
1221 1222 1223 |
continue; /* search for overlapping mappings on the same file */ |
8feae1311
|
1224 1225 |
if (pregion->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode) |
1da177e4c
|
1226 |
continue; |
8feae1311
|
1227 |
if (pregion->vm_pgoff >= pgend) |
1da177e4c
|
1228 |
continue; |
8feae1311
|
1229 1230 1231 1232 |
rpglen = pregion->vm_end - pregion->vm_start; rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; rpgend = pregion->vm_pgoff + rpglen; if (pgoff >= rpgend) |
1da177e4c
|
1233 |
continue; |
8feae1311
|
1234 1235 1236 1237 1238 |
/* 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 */ |
1da177e4c
|
1239 1240 1241 1242 |
if (!(capabilities & BDI_CAP_MAP_DIRECT)) goto sharing_violation; continue; } |
8feae1311
|
1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 |
/* we've found a region we can share */ atomic_inc(&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) { kdebug("share copy"); vma->vm_flags |= VM_MAPPED_COPY; } else { kdebug("share mmap"); ret = do_mmap_shared_file(vma); if (ret < 0) { vma->vm_region = NULL; vma->vm_start = 0; vma->vm_end = 0; atomic_dec(&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; |
1da177e4c
|
1271 |
} |
1da177e4c
|
1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 |
/* 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 (file && file->f_op->get_unmapped_area) { addr = file->f_op->get_unmapped_area(file, addr, len, pgoff, flags); if (IS_ERR((void *) addr)) { ret = addr; if (ret != (unsigned long) -ENOSYS) |
8feae1311
|
1282 |
goto error_just_free; |
1da177e4c
|
1283 1284 1285 1286 1287 1288 |
/* the driver refused to tell us where to site * the mapping so we'll have to attempt to copy * it */ ret = (unsigned long) -ENODEV; if (!(capabilities & BDI_CAP_MAP_COPY)) |
8feae1311
|
1289 |
goto error_just_free; |
1da177e4c
|
1290 1291 |
capabilities &= ~BDI_CAP_MAP_DIRECT; |
8feae1311
|
1292 1293 1294 |
} else { vma->vm_start = region->vm_start = addr; vma->vm_end = region->vm_end = addr + len; |
1da177e4c
|
1295 1296 1297 |
} } } |
8feae1311
|
1298 |
vma->vm_region = region; |
1da177e4c
|
1299 1300 1301 |
/* set up the mapping */ if (file && vma->vm_flags & VM_SHARED) |
8feae1311
|
1302 |
ret = do_mmap_shared_file(vma); |
1da177e4c
|
1303 |
else |
8feae1311
|
1304 |
ret = do_mmap_private(vma, region, len); |
1da177e4c
|
1305 |
if (ret < 0) |
8feae1311
|
1306 1307 1308 |
goto error_put_region; add_nommu_region(region); |
1da177e4c
|
1309 1310 |
/* okay... we have a mapping; now we have to register it */ |
8feae1311
|
1311 |
result = vma->vm_start; |
1da177e4c
|
1312 |
|
1da177e4c
|
1313 |
current->mm->total_vm += len >> PAGE_SHIFT; |
8feae1311
|
1314 1315 |
share: add_vma_to_mm(current->mm, vma); |
1da177e4c
|
1316 |
|
8feae1311
|
1317 |
up_write(&nommu_region_sem); |
1da177e4c
|
1318 1319 |
if (prot & PROT_EXEC) |
8feae1311
|
1320 |
flush_icache_range(result, result + len); |
1da177e4c
|
1321 |
|
8feae1311
|
1322 1323 |
kleave(" = %lx", result); return result; |
1da177e4c
|
1324 |
|
8feae1311
|
1325 1326 |
error_put_region: __put_nommu_region(region); |
1da177e4c
|
1327 |
if (vma) { |
925d1c401
|
1328 |
if (vma->vm_file) { |
3fcd03e07
|
1329 |
fput(vma->vm_file); |
925d1c401
|
1330 1331 1332 |
if (vma->vm_flags & VM_EXECUTABLE) removed_exe_file_vma(vma->vm_mm); } |
8feae1311
|
1333 |
kmem_cache_free(vm_area_cachep, vma); |
1da177e4c
|
1334 |
} |
8feae1311
|
1335 |
kleave(" = %d [pr]", ret); |
1da177e4c
|
1336 |
return ret; |
8feae1311
|
1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 |
error_just_free: up_write(&nommu_region_sem); error: fput(region->vm_file); kmem_cache_free(vm_region_jar, region); fput(vma->vm_file); if (vma->vm_flags & VM_EXECUTABLE) removed_exe_file_vma(vma->vm_mm); kmem_cache_free(vm_area_cachep, vma); kleave(" = %d", ret); return ret; sharing_violation: up_write(&nommu_region_sem); printk(KERN_WARNING "Attempt to share mismatched mappings "); ret = -EINVAL; goto error; |
1da177e4c
|
1355 |
|
8feae1311
|
1356 1357 1358 1359 1360 |
error_getting_vma: kmem_cache_free(vm_region_jar, region); printk(KERN_WARNING "Allocation of vma for %lu byte allocation" " from process %d failed ", |
1da177e4c
|
1361 1362 1363 |
len, current->pid); show_free_areas(); return -ENOMEM; |
8feae1311
|
1364 1365 1366 1367 |
error_getting_region: printk(KERN_WARNING "Allocation of vm region for %lu byte allocation" " from process %d failed ", |
1da177e4c
|
1368 1369 1370 1371 |
len, current->pid); show_free_areas(); return -ENOMEM; } |
b50731732
|
1372 |
EXPORT_SYMBOL(do_mmap_pgoff); |
1da177e4c
|
1373 1374 |
/* |
8feae1311
|
1375 1376 |
* split a vma into two pieces at address 'addr', a new vma is allocated either * for the first part or the tail. |
1da177e4c
|
1377 |
*/ |
8feae1311
|
1378 1379 |
int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, int new_below) |
1da177e4c
|
1380 |
{ |
8feae1311
|
1381 1382 1383 |
struct vm_area_struct *new; struct vm_region *region; unsigned long npages; |
1da177e4c
|
1384 |
|
8feae1311
|
1385 |
kenter(""); |
1da177e4c
|
1386 |
|
8feae1311
|
1387 1388 1389 1390 1391 |
/* we're only permitted to split anonymous regions that have a single * owner */ if (vma->vm_file || atomic_read(&vma->vm_region->vm_usage) != 1) return -ENOMEM; |
1da177e4c
|
1392 |
|
8feae1311
|
1393 1394 |
if (mm->map_count >= sysctl_max_map_count) return -ENOMEM; |
1da177e4c
|
1395 |
|
8feae1311
|
1396 1397 1398 |
region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); if (!region) return -ENOMEM; |
1da177e4c
|
1399 |
|
8feae1311
|
1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 |
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) { |
dd8632a12
|
1414 |
region->vm_top = region->vm_end = new->vm_end = addr; |
8feae1311
|
1415 1416 1417 |
} else { region->vm_start = new->vm_start = addr; region->vm_pgoff = new->vm_pgoff += npages; |
1da177e4c
|
1418 |
} |
8feae1311
|
1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 |
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
|
1431 |
vma->vm_region->vm_top = addr; |
8feae1311
|
1432 1433 1434 1435 1436 1437 1438 |
} 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
|
1439 |
} |
3034097a5
|
1440 |
/* |
8feae1311
|
1441 1442 |
* shrink a VMA by removing the specified chunk from either the beginning or * the end |
3034097a5
|
1443 |
*/ |
8feae1311
|
1444 1445 1446 |
static int shrink_vma(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long from, unsigned long to) |
1da177e4c
|
1447 |
{ |
8feae1311
|
1448 |
struct vm_region *region; |
1da177e4c
|
1449 |
|
8feae1311
|
1450 |
kenter(""); |
1da177e4c
|
1451 |
|
8feae1311
|
1452 1453 1454 1455 1456 1457 1458 1459 |
/* 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
|
1460 |
|
8feae1311
|
1461 1462 1463 1464 1465 1466 |
/* cut the backing region down to size */ region = vma->vm_region; BUG_ON(atomic_read(®ion->vm_usage) != 1); down_write(&nommu_region_sem); delete_nommu_region(region); |
dd8632a12
|
1467 1468 1469 1470 |
if (from > region->vm_start) { to = region->vm_top; region->vm_top = region->vm_end = from; } else { |
8feae1311
|
1471 |
region->vm_start = to; |
dd8632a12
|
1472 |
} |
8feae1311
|
1473 1474 1475 1476 1477 1478 |
add_nommu_region(region); up_write(&nommu_region_sem); free_page_series(from, to); return 0; } |
1da177e4c
|
1479 |
|
8feae1311
|
1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 |
/* * 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; struct rb_node *rb; unsigned long end = start + len; int ret; |
1da177e4c
|
1491 |
|
8feae1311
|
1492 |
kenter(",%lx,%zx", start, len); |
1da177e4c
|
1493 |
|
8feae1311
|
1494 1495 |
if (len == 0) return -EINVAL; |
365e9c87a
|
1496 |
|
8feae1311
|
1497 1498 1499 |
/* find the first potentially overlapping VMA */ vma = find_vma(mm, start); if (!vma) { |
33e5d7697
|
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 |
static int limit = 0; if (limit < 5) { printk(KERN_WARNING "munmap of memory not mmapped by process %d" " (%s): 0x%lx-0x%lx ", current->pid, current->comm, start, start + len - 1); limit++; } |
8feae1311
|
1510 1511 |
return -EINVAL; } |
1da177e4c
|
1512 |
|
8feae1311
|
1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 |
/* we're allowed to split an anonymous VMA but not a file-backed one */ if (vma->vm_file) { do { if (start > vma->vm_start) { kleave(" = -EINVAL [miss]"); return -EINVAL; } if (end == vma->vm_end) goto erase_whole_vma; rb = rb_next(&vma->vm_rb); vma = rb_entry(rb, struct vm_area_struct, vm_rb); } while (rb); kleave(" = -EINVAL [split file]"); 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) { kleave(" = -EINVAL [superset]"); return -EINVAL; } if (start & ~PAGE_MASK) { kleave(" = -EINVAL [unaligned start]"); return -EINVAL; } if (end != vma->vm_end && end & ~PAGE_MASK) { kleave(" = -EINVAL [unaligned split]"); return -EINVAL; } if (start != vma->vm_start && end != vma->vm_end) { ret = split_vma(mm, vma, start, 1); if (ret < 0) { kleave(" = %d [split]", ret); return ret; } } return shrink_vma(mm, vma, start, end); } |
1da177e4c
|
1552 |
|
8feae1311
|
1553 1554 1555 1556 |
erase_whole_vma: delete_vma_from_mm(vma); delete_vma(mm, vma); kleave(" = 0"); |
1da177e4c
|
1557 1558 |
return 0; } |
b50731732
|
1559 |
EXPORT_SYMBOL(do_munmap); |
1da177e4c
|
1560 |
|
6a6160a7b
|
1561 |
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
3034097a5
|
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 |
{ int ret; struct mm_struct *mm = current->mm; down_write(&mm->mmap_sem); ret = do_munmap(mm, addr, len); up_write(&mm->mmap_sem); return ret; } /* |
8feae1311
|
1573 |
* release all the mappings made in a process's VM space |
3034097a5
|
1574 |
*/ |
8feae1311
|
1575 |
void exit_mmap(struct mm_struct *mm) |
1da177e4c
|
1576 |
{ |
8feae1311
|
1577 |
struct vm_area_struct *vma; |
1da177e4c
|
1578 |
|
8feae1311
|
1579 1580 |
if (!mm) return; |
1da177e4c
|
1581 |
|
8feae1311
|
1582 |
kenter(""); |
1da177e4c
|
1583 |
|
8feae1311
|
1584 |
mm->total_vm = 0; |
1da177e4c
|
1585 |
|
8feae1311
|
1586 1587 1588 1589 |
while ((vma = mm->mmap)) { mm->mmap = vma->vm_next; delete_vma_from_mm(vma); delete_vma(mm, vma); |
1da177e4c
|
1590 |
} |
8feae1311
|
1591 1592 |
kleave(""); |
1da177e4c
|
1593 |
} |
1da177e4c
|
1594 1595 1596 1597 1598 1599 |
unsigned long do_brk(unsigned long addr, unsigned long len) { return -ENOMEM; } /* |
6fa5f80bc
|
1600 1601 |
* expand (or shrink) an existing mapping, potentially moving it at the same * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
1da177e4c
|
1602 |
* |
6fa5f80bc
|
1603 |
* under NOMMU conditions, we only permit changing a mapping's size, and only |
8feae1311
|
1604 1605 |
* as long as it stays within the region allocated by do_mmap_private() and the * block is not shareable |
1da177e4c
|
1606 |
* |
6fa5f80bc
|
1607 |
* MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4c
|
1608 1609 1610 1611 1612 |
*/ unsigned long do_mremap(unsigned long addr, unsigned long old_len, unsigned long new_len, unsigned long flags, unsigned long new_addr) { |
6fa5f80bc
|
1613 |
struct vm_area_struct *vma; |
1da177e4c
|
1614 1615 |
/* insanity checks first */ |
8feae1311
|
1616 |
if (old_len == 0 || new_len == 0) |
1da177e4c
|
1617 |
return (unsigned long) -EINVAL; |
8feae1311
|
1618 1619 |
if (addr & ~PAGE_MASK) return -EINVAL; |
1da177e4c
|
1620 1621 |
if (flags & MREMAP_FIXED && new_addr != addr) return (unsigned long) -EINVAL; |
8feae1311
|
1622 |
vma = find_vma_exact(current->mm, addr, old_len); |
6fa5f80bc
|
1623 1624 |
if (!vma) return (unsigned long) -EINVAL; |
1da177e4c
|
1625 |
|
6fa5f80bc
|
1626 |
if (vma->vm_end != vma->vm_start + old_len) |
1da177e4c
|
1627 |
return (unsigned long) -EFAULT; |
6fa5f80bc
|
1628 |
if (vma->vm_flags & VM_MAYSHARE) |
1da177e4c
|
1629 |
return (unsigned long) -EPERM; |
8feae1311
|
1630 |
if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1da177e4c
|
1631 1632 1633 |
return (unsigned long) -ENOMEM; /* all checks complete - do it */ |
6fa5f80bc
|
1634 |
vma->vm_end = vma->vm_start + new_len; |
6fa5f80bc
|
1635 1636 |
return vma->vm_start; } |
b50731732
|
1637 |
EXPORT_SYMBOL(do_mremap); |
6fa5f80bc
|
1638 |
|
6a6160a7b
|
1639 1640 1641 |
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, unsigned long, new_len, unsigned long, flags, unsigned long, new_addr) |
6fa5f80bc
|
1642 1643 1644 1645 1646 1647 1648 |
{ 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; |
1da177e4c
|
1649 |
} |
6aab341e0
|
1650 |
struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd1
|
1651 |
unsigned int foll_flags) |
1da177e4c
|
1652 1653 1654 |
{ return NULL; } |
1da177e4c
|
1655 1656 1657 |
int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, unsigned long to, unsigned long size, pgprot_t prot) { |
66aa2b4b1
|
1658 1659 |
vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; return 0; |
1da177e4c
|
1660 |
} |
22c4af409
|
1661 |
EXPORT_SYMBOL(remap_pfn_range); |
1da177e4c
|
1662 |
|
f905bc447
|
1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 |
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
|
1677 1678 1679 1680 1681 1682 1683 1684 1685 |
void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) { } unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { return -ENOMEM; } |
1363c3cd8
|
1686 |
void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4c
|
1687 1688 |
{ } |
1da177e4c
|
1689 1690 1691 1692 1693 |
void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows) { } |
22c4af409
|
1694 |
EXPORT_SYMBOL(unmap_mapping_range); |
1da177e4c
|
1695 1696 |
/* |
d56e03cd2
|
1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 |
* ask for an unmapped area at which to create a mapping on a file */ unsigned long get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); get_area = current->mm->get_unmapped_area; if (file && file->f_op && file->f_op->get_unmapped_area) get_area = file->f_op->get_unmapped_area; if (!get_area) return -ENOSYS; return get_area(file, addr, len, pgoff, flags); } |
d56e03cd2
|
1715 1716 1717 |
EXPORT_SYMBOL(get_unmapped_area); /* |
1da177e4c
|
1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 |
* Check that a process has enough memory to allocate a new virtual * mapping. 0 means there is enough memory for the allocation to * succeed and -ENOMEM implies there is not. * * We currently support three overcommit policies, which are set via the * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting * * Strict overcommit modes added 2002 Feb 26 by Alan Cox. * Additional code 2002 Jul 20 by Robert Love. * * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. * * Note this is a helper function intended to be used by LSMs which * wish to use this logic. */ |
34b4e4aa3
|
1733 |
int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4c
|
1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 |
{ unsigned long free, allowed; vm_acct_memory(pages); /* * Sometimes we want to use more memory than we have */ if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) return 0; if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { unsigned long n; |
347ce434d
|
1747 |
free = global_page_state(NR_FILE_PAGES); |
1da177e4c
|
1748 1749 1750 1751 1752 1753 1754 1755 |
free += nr_swap_pages; /* * Any slabs which are created with the * SLAB_RECLAIM_ACCOUNT flag claim to have contents * which are reclaimable, under pressure. The dentry * cache and most inode caches should fall into this */ |
972d1a7b1
|
1756 |
free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4c
|
1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 |
/* * Leave the last 3% for root */ if (!cap_sys_admin) free -= free / 32; if (free > pages) return 0; /* * nr_free_pages() is very expensive on large systems, * only call if we're about to fail. */ n = nr_free_pages(); |
d5ddc79bc
|
1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 |
/* * Leave reserved pages. The pages are not for anonymous pages. */ if (n <= totalreserve_pages) goto error; else n -= totalreserve_pages; /* * Leave the last 3% for root */ |
1da177e4c
|
1784 1785 1786 1787 1788 1789 |
if (!cap_sys_admin) n -= n / 32; free += n; if (free > pages) return 0; |
d5ddc79bc
|
1790 1791 |
goto error; |
1da177e4c
|
1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 |
} allowed = totalram_pages * sysctl_overcommit_ratio / 100; /* * Leave the last 3% for root */ if (!cap_sys_admin) allowed -= allowed / 32; allowed += total_swap_pages; /* Don't let a single process grow too big: leave 3% of the size of this process for other processes */ |
731572d39
|
1804 1805 |
if (mm) allowed -= mm->total_vm / 32; |
1da177e4c
|
1806 |
|
00a62ce91
|
1807 |
if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4c
|
1808 |
return 0; |
00a62ce91
|
1809 |
|
d5ddc79bc
|
1810 |
error: |
1da177e4c
|
1811 1812 1813 1814 1815 1816 1817 1818 1819 |
vm_unacct_memory(pages); return -ENOMEM; } int in_gate_area_no_task(unsigned long addr) { return 0; } |
b0e15190e
|
1820 |
|
d0217ac04
|
1821 |
int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
b0e15190e
|
1822 1823 |
{ BUG(); |
d0217ac04
|
1824 |
return 0; |
b0e15190e
|
1825 |
} |
b50731732
|
1826 |
EXPORT_SYMBOL(filemap_fault); |
0ec76a110
|
1827 1828 1829 1830 1831 1832 1833 |
/* * 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) { |
0ec76a110
|
1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 |
struct vm_area_struct *vma; struct mm_struct *mm; if (addr + len < addr) return 0; mm = get_task_mm(tsk); if (!mm) return 0; down_read(&mm->mmap_sem); /* the access must start within one of the target process's mappings */ |
0159b141d
|
1847 1848 |
vma = find_vma(mm, addr); if (vma) { |
0ec76a110
|
1849 1850 1851 1852 1853 |
/* 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
|
1854 |
if (write && vma->vm_flags & VM_MAYWRITE) |
0ec76a110
|
1855 |
len -= copy_to_user((void *) addr, buf, len); |
d00c7b993
|
1856 |
else if (!write && vma->vm_flags & VM_MAYREAD) |
0ec76a110
|
1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 |
len -= copy_from_user(buf, (void *) addr, len); else len = 0; } else { len = 0; } up_read(&mm->mmap_sem); mmput(mm); return len; } |