| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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/admin-guide/mm/nommu-mmap.rst |
| * |
| * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com> |
| * 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> |
| * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/export.h> |
| #include <linux/mm.h> |
| #include <linux/sched/mm.h> |
| #include <linux/vmacache.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> |
| #include <linux/backing-dev.h> |
| #include <linux/compiler.h> |
| #include <linux/mount.h> |
| #include <linux/personality.h> |
| #include <linux/security.h> |
| #include <linux/syscalls.h> |
| #include <linux/audit.h> |
| #include <linux/printk.h> |
| |
| #include <linux/uaccess.h> |
| #include <asm/tlb.h> |
| #include <asm/tlbflush.h> |
| #include <asm/mmu_context.h> |
| #include "internal.h" |
| |
| void *high_memory; |
| EXPORT_SYMBOL(high_memory); |
| struct page *mem_map; |
| unsigned long max_mapnr; |
| EXPORT_SYMBOL(max_mapnr); |
| unsigned long highest_memmap_pfn; |
| int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; |
| int heap_stack_gap = 0; |
| |
| atomic_long_t mmap_pages_allocated; |
| |
| EXPORT_SYMBOL(mem_map); |
| |
| /* 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); |
| |
| const struct vm_operations_struct generic_file_vm_ops = { |
| }; |
| |
| /* |
| * 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; |
| |
| /* |
| * If the object we have should not have ksize performed on it, |
| * return size of 0 |
| */ |
| if (!objp || !virt_addr_valid(objp)) |
| return 0; |
| |
| page = virt_to_head_page(objp); |
| |
| /* |
| * If the allocator sets PageSlab, we know the pointer came from |
| * kmalloc(). |
| */ |
| if (PageSlab(page)) |
| return ksize(objp); |
| |
| /* |
| * 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; |
| } |
| |
| /* |
| * The ksize() function is only guaranteed to work for pointers |
| * returned by kmalloc(). So handle arbitrary pointers here. |
| */ |
| return page_size(page); |
| } |
| |
| /** |
| * 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); |
| |
| LIST_HEAD(vmap_area_list); |
| |
| void vfree(const void *addr) |
| { |
| kfree(addr); |
| } |
| EXPORT_SYMBOL(vfree); |
| |
| void *__vmalloc(unsigned long size, gfp_t gfp_mask) |
| { |
| /* |
| * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() |
| * returns only a logical address. |
| */ |
| return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
| } |
| EXPORT_SYMBOL(__vmalloc); |
| |
| 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); |
| } |
| |
| void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, |
| int node, const void *caller) |
| { |
| return __vmalloc(size, gfp_mask); |
| } |
| |
| static void *__vmalloc_user_flags(unsigned long size, gfp_t flags) |
| { |
| void *ret; |
| |
| ret = __vmalloc(size, flags); |
| if (ret) { |
| struct vm_area_struct *vma; |
| |
| mmap_write_lock(current->mm); |
| vma = find_vma(current->mm, (unsigned long)ret); |
| if (vma) |
| vma->vm_flags |= VM_USERMAP; |
| mmap_write_unlock(current->mm); |
| } |
| |
| return ret; |
| } |
| |
| void *vmalloc_user(unsigned long size) |
| { |
| return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO); |
| } |
| EXPORT_SYMBOL(vmalloc_user); |
| |
| struct page *vmalloc_to_page(const void *addr) |
| { |
| return virt_to_page(addr); |
| } |
| EXPORT_SYMBOL(vmalloc_to_page); |
| |
| unsigned long vmalloc_to_pfn(const void *addr) |
| { |
| return page_to_pfn(virt_to_page(addr)); |
| } |
| EXPORT_SYMBOL(vmalloc_to_pfn); |
| |
| long vread(char *buf, char *addr, unsigned long count) |
| { |
| /* Don't allow overflow */ |
| if ((unsigned long) buf + count < count) |
| count = -(unsigned long) buf; |
| |
| memcpy(buf, addr, count); |
| return count; |
| } |
| |
| /* |
| * vmalloc - allocate virtually contiguous memory |
| * |
| * @size: allocation size |
| * |
| * 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. |
| */ |
| void *vmalloc(unsigned long size) |
| { |
| return __vmalloc(size, GFP_KERNEL); |
| } |
| EXPORT_SYMBOL(vmalloc); |
| |
| void *vmalloc_huge(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc); |
| |
| /* |
| * vzalloc - allocate virtually contiguous memory with zero fill |
| * |
| * @size: allocation size |
| * |
| * 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(unsigned long size) |
| { |
| return __vmalloc(size, GFP_KERNEL | __GFP_ZERO); |
| } |
| 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. |
| */ |
| void *vmalloc_node(unsigned long size, int node) |
| { |
| return vmalloc(size); |
| } |
| EXPORT_SYMBOL(vmalloc_node); |
| |
| /** |
| * 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); |
| |
| /** |
| * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) |
| * @size: allocation size |
| * |
| * Allocate enough 32bit PA addressable pages to cover @size from the |
| * page level allocator and map them into contiguous kernel virtual space. |
| */ |
| void *vmalloc_32(unsigned long size) |
| { |
| return __vmalloc(size, GFP_KERNEL); |
| } |
| 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. |
| * |
| * VM_USERMAP is set on the corresponding VMA so that subsequent calls to |
| * remap_vmalloc_range() are permissible. |
| */ |
| void *vmalloc_32_user(unsigned long size) |
| { |
| /* |
| * 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); |
| } |
| EXPORT_SYMBOL(vmalloc_32_user); |
| |
| void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) |
| { |
| BUG(); |
| return NULL; |
| } |
| EXPORT_SYMBOL(vmap); |
| |
| void vunmap(const void *addr) |
| { |
| BUG(); |
| } |
| EXPORT_SYMBOL(vunmap); |
| |
| void *vm_map_ram(struct page **pages, unsigned int count, int node) |
| { |
| 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); |
| |
| void free_vm_area(struct vm_struct *area) |
| { |
| BUG(); |
| } |
| EXPORT_SYMBOL_GPL(free_vm_area); |
| |
| int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
| struct page *page) |
| { |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(vm_insert_page); |
| |
| 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); |
| |
| /* |
| * 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. |
| */ |
| SYSCALL_DEFINE1(brk, unsigned long, brk) |
| { |
| 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. |
| */ |
| flush_icache_user_range(mm->brk, brk); |
| return mm->brk = brk; |
| } |
| |
| /* |
| * initialise the percpu counter for VM and region record slabs |
| */ |
| void __init mmap_init(void) |
| { |
| int ret; |
| |
| ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); |
| VM_BUG_ON(ret); |
| vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT); |
| } |
| |
| /* |
| * validate the region tree |
| * - the caller must hold the region lock |
| */ |
| #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
| static noinline void validate_nommu_regions(void) |
| { |
| struct vm_region *region, *last; |
| struct rb_node *p, *lastp; |
| |
| lastp = rb_first(&nommu_region_tree); |
| if (!lastp) |
| return; |
| |
| last = rb_entry(lastp, struct vm_region, vm_rb); |
| BUG_ON(last->vm_end <= last->vm_start); |
| BUG_ON(last->vm_top < last->vm_end); |
| |
| while ((p = rb_next(lastp))) { |
| region = rb_entry(p, struct vm_region, vm_rb); |
| last = rb_entry(lastp, struct vm_region, vm_rb); |
| |
| BUG_ON(region->vm_end <= region->vm_start); |
| BUG_ON(region->vm_top < region->vm_end); |
| BUG_ON(region->vm_start < last->vm_top); |
| |
| lastp = p; |
| } |
| } |
| #else |
| static void validate_nommu_regions(void) |
| { |
| } |
| #endif |
| |
| /* |
| * add a region into the global tree |
| */ |
| static void add_nommu_region(struct vm_region *region) |
| { |
| struct vm_region *pregion; |
| struct rb_node **p, *parent; |
| |
| validate_nommu_regions(); |
| |
| parent = NULL; |
| p = &nommu_region_tree.rb_node; |
| while (*p) { |
| parent = *p; |
| pregion = rb_entry(parent, struct vm_region, vm_rb); |
| if (region->vm_start < pregion->vm_start) |
| p = &(*p)->rb_left; |
| else if (region->vm_start > pregion->vm_start) |
| p = &(*p)->rb_right; |
| else if (pregion == region) |
| return; |
| else |
| BUG(); |
| } |
| |
| rb_link_node(®ion->vm_rb, parent, p); |
| rb_insert_color(®ion->vm_rb, &nommu_region_tree); |
| |
| validate_nommu_regions(); |
| } |
| |
| /* |
| * delete a region from the global tree |
| */ |
| static void delete_nommu_region(struct vm_region *region) |
| { |
| BUG_ON(!nommu_region_tree.rb_node); |
| |
| validate_nommu_regions(); |
| rb_erase(®ion->vm_rb, &nommu_region_tree); |
| validate_nommu_regions(); |
| } |
| |
| /* |
| * free a contiguous series of pages |
| */ |
| static void free_page_series(unsigned long from, unsigned long to) |
| { |
| for (; from < to; from += PAGE_SIZE) { |
| struct page *page = virt_to_page((void *)from); |
| |
| atomic_long_dec(&mmap_pages_allocated); |
| put_page(page); |
| } |
| } |
| |
| /* |
| * release a reference to a region |
| * - the caller must hold the region semaphore for writing, which this releases |
| * - the region may not have been added to the tree yet, in which case vm_top |
| * will equal vm_start |
| */ |
| static void __put_nommu_region(struct vm_region *region) |
| __releases(nommu_region_sem) |
| { |
| BUG_ON(!nommu_region_tree.rb_node); |
| |
| if (--region->vm_usage == 0) { |
| if (region->vm_top > region->vm_start) |
| delete_nommu_region(region); |
| up_write(&nommu_region_sem); |
| |
| if (region->vm_file) |
| fput(region->vm_file); |
| |
| /* IO memory and memory shared directly out of the pagecache |
| * from ramfs/tmpfs mustn't be released here */ |
| if (region->vm_flags & VM_MAPPED_COPY) |
| free_page_series(region->vm_start, region->vm_top); |
| kmem_cache_free(vm_region_jar, region); |
| } else { |
| up_write(&nommu_region_sem); |
| } |
| } |
| |
| /* |
| * release a reference to a region |
| */ |
| static void put_nommu_region(struct vm_region *region) |
| { |
| down_write(&nommu_region_sem); |
| __put_nommu_region(region); |
| } |
| |
| void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas) |
| { |
| mas_set_range(mas, vma->vm_start, vma->vm_end - 1); |
| mas_store_prealloc(mas, vma); |
| } |
| |
| void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas) |
| { |
| mas->index = vma->vm_start; |
| mas->last = vma->vm_end - 1; |
| mas_store_prealloc(mas, NULL); |
| } |
| |
| /* |
| * 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_lock held writelocked |
| */ |
| static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
| { |
| struct vm_area_struct *pvma, *prev; |
| struct address_space *mapping; |
| struct rb_node **p, *parent, *rb_prev; |
| |
| BUG_ON(!vma->vm_region); |
| |
| mm->map_count++; |
| vma->vm_mm = mm; |
| |
| /* add the VMA to the mapping */ |
| if (vma->vm_file) { |
| mapping = vma->vm_file->f_mapping; |
| |
| i_mmap_lock_write(mapping); |
| flush_dcache_mmap_lock(mapping); |
| vma_interval_tree_insert(vma, &mapping->i_mmap); |
| flush_dcache_mmap_unlock(mapping); |
| i_mmap_unlock_write(mapping); |
| } |
| |
| /* add the VMA to the tree */ |
| parent = rb_prev = NULL; |
| p = &mm->mm_rb.rb_node; |
| while (*p) { |
| parent = *p; |
| pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
| |
| /* sort by: start addr, end addr, VMA struct addr in that order |
| * (the latter is necessary as we may get identical VMAs) */ |
| if (vma->vm_start < pvma->vm_start) |
| p = &(*p)->rb_left; |
| else if (vma->vm_start > pvma->vm_start) { |
| rb_prev = parent; |
| p = &(*p)->rb_right; |
| } else if (vma->vm_end < pvma->vm_end) |
| p = &(*p)->rb_left; |
| else if (vma->vm_end > pvma->vm_end) { |
| rb_prev = parent; |
| p = &(*p)->rb_right; |
| } else if (vma < pvma) |
| p = &(*p)->rb_left; |
| else if (vma > pvma) { |
| rb_prev = parent; |
| p = &(*p)->rb_right; |
| } else |
| BUG(); |
| } |
| |
| rb_link_node(&vma->vm_rb, parent, p); |
| rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
| |
| /* add VMA to the VMA list also */ |
| prev = NULL; |
| if (rb_prev) |
| prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
| |
| __vma_link_list(mm, vma, prev); |
| } |
| |
| /* |
| * delete a VMA from its owning mm_struct and address space |
| */ |
| static void delete_vma_from_mm(struct vm_area_struct *vma) |
| { |
| int i; |
| struct address_space *mapping; |
| struct mm_struct *mm = vma->vm_mm; |
| struct task_struct *curr = current; |
| |
| mm->map_count--; |
| for (i = 0; i < VMACACHE_SIZE; i++) { |
| /* if the vma is cached, invalidate the entire cache */ |
| if (curr->vmacache.vmas[i] == vma) { |
| vmacache_invalidate(mm); |
| break; |
| } |
| } |
| |
| /* remove the VMA from the mapping */ |
| if (vma->vm_file) { |
| mapping = vma->vm_file->f_mapping; |
| |
| i_mmap_lock_write(mapping); |
| flush_dcache_mmap_lock(mapping); |
| vma_interval_tree_remove(vma, &mapping->i_mmap); |
| flush_dcache_mmap_unlock(mapping); |
| i_mmap_unlock_write(mapping); |
| } |
| |
| /* remove from the MM's tree and list */ |
| rb_erase(&vma->vm_rb, &mm->mm_rb); |
| |
| __vma_unlink_list(mm, vma); |
| } |
| |
| /* |
| * destroy a VMA record |
| */ |
| static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) |
| { |
| if (vma->vm_ops && vma->vm_ops->close) |
| vma->vm_ops->close(vma); |
| if (vma->vm_file) |
| fput(vma->vm_file); |
| put_nommu_region(vma->vm_region); |
| vm_area_free(vma); |
| } |
| |
| /* |
| * look up the first VMA in which addr resides, NULL if none |
| * - should be called with mm->mmap_lock at least held readlocked |
| */ |
| struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
| { |
| struct vm_area_struct *vma; |
| |
| /* check the cache first */ |
| vma = vmacache_find(mm, addr); |
| if (likely(vma)) |
| return vma; |
| |
| /* trawl the list (there may be multiple mappings in which addr |
| * resides) */ |
| for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| if (vma->vm_start > addr) |
| return NULL; |
| if (vma->vm_end > addr) { |
| vmacache_update(addr, vma); |
| return vma; |
| } |
| } |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL(find_vma); |
| |
| /* |
| * find a VMA |
| * - we don't extend stack VMAs under NOMMU conditions |
| */ |
| struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) |
| { |
| return find_vma(mm, addr); |
| } |
| |
| /* |
| * expand a stack to a given address |
| * - not supported under NOMMU conditions |
| */ |
| int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| { |
| return -ENOMEM; |
| } |
| |
| /* |
| * look up the first VMA exactly that exactly matches addr |
| * - should be called with mm->mmap_lock at least held readlocked |
| */ |
| static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, |
| unsigned long addr, |
| unsigned long len) |
| { |
| struct vm_area_struct *vma; |
| unsigned long end = addr + len; |
| |
| /* check the cache first */ |
| vma = vmacache_find_exact(mm, addr, end); |
| if (vma) |
| return vma; |
| |
| /* trawl the list (there may be multiple mappings in which addr |
| * resides) */ |
| for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| if (vma->vm_start < addr) |
| continue; |
| if (vma->vm_start > addr) |
| return NULL; |
| if (vma->vm_end == end) { |
| vmacache_update(addr, vma); |
| return vma; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * determine whether a mapping should be permitted and, if so, what sort of |
| * mapping we're capable of supporting |
| */ |
| static int validate_mmap_request(struct file *file, |
| unsigned long addr, |
| unsigned long len, |
| unsigned long prot, |
| unsigned long flags, |
| unsigned long pgoff, |
| unsigned long *_capabilities) |
| { |
| unsigned long capabilities, rlen; |
| int ret; |
| |
| /* do the simple checks first */ |
| if (flags & MAP_FIXED) |
| return -EINVAL; |
| |
| if ((flags & MAP_TYPE) != MAP_PRIVATE && |
| (flags & MAP_TYPE) != MAP_SHARED) |
| return -EINVAL; |
| |
| if (!len) |
| return -EINVAL; |
| |
| /* Careful about overflows.. */ |
| rlen = PAGE_ALIGN(len); |
| if (!rlen || rlen > TASK_SIZE) |
| return -ENOMEM; |
| |
| /* offset overflow? */ |
| if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
| return -EOVERFLOW; |
| |
| if (file) { |
| /* files must support mmap */ |
| if (!file->f_op->mmap) |
| return -ENODEV; |
| |
| /* work out if what we've got could possibly be shared |
| * - we support chardevs that provide their own "memory" |
| * - we support files/blockdevs that are memory backed |
| */ |
| if (file->f_op->mmap_capabilities) { |
| capabilities = file->f_op->mmap_capabilities(file); |
| } else { |
| /* no explicit capabilities set, so assume some |
| * defaults */ |
| switch (file_inode(file)->i_mode & S_IFMT) { |
| case S_IFREG: |
| case S_IFBLK: |
| capabilities = NOMMU_MAP_COPY; |
| break; |
| |
| case S_IFCHR: |
| capabilities = |
| NOMMU_MAP_DIRECT | |
| NOMMU_MAP_READ | |
| NOMMU_MAP_WRITE; |
| break; |
| |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| /* eliminate any capabilities that we can't support on this |
| * device */ |
| if (!file->f_op->get_unmapped_area) |
| capabilities &= ~NOMMU_MAP_DIRECT; |
| if (!(file->f_mode & FMODE_CAN_READ)) |
| capabilities &= ~NOMMU_MAP_COPY; |
| |
| /* The file shall have been opened with read permission. */ |
| if (!(file->f_mode & FMODE_READ)) |
| return -EACCES; |
| |
| if (flags & MAP_SHARED) { |
| /* do checks for writing, appending and locking */ |
| if ((prot & PROT_WRITE) && |
| !(file->f_mode & FMODE_WRITE)) |
| return -EACCES; |
| |
| if (IS_APPEND(file_inode(file)) && |
| (file->f_mode & FMODE_WRITE)) |
| return -EACCES; |
| |
| if (!(capabilities & NOMMU_MAP_DIRECT)) |
| return -ENODEV; |
| |
| /* we mustn't privatise shared mappings */ |
| capabilities &= ~NOMMU_MAP_COPY; |
| } else { |
| /* we're going to read the file into private memory we |
| * allocate */ |
| if (!(capabilities & NOMMU_MAP_COPY)) |
| return -ENODEV; |
| |
| /* we don't permit a private writable mapping to be |
| * shared with the backing device */ |
| if (prot & PROT_WRITE) |
| capabilities &= ~NOMMU_MAP_DIRECT; |
| } |
| |
| if (capabilities & NOMMU_MAP_DIRECT) { |
| if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) || |
| ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) || |
| ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC)) |
| ) { |
| capabilities &= ~NOMMU_MAP_DIRECT; |
| if (flags & MAP_SHARED) { |
| pr_warn("MAP_SHARED not completely supported on !MMU\n"); |
| return -EINVAL; |
| } |
| } |
| } |
| |
| /* handle executable mappings and implied executable |
| * mappings */ |
| if (path_noexec(&file->f_path)) { |
| if (prot & PROT_EXEC) |
| return -EPERM; |
| } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
| /* handle implication of PROT_EXEC by PROT_READ */ |
| if (current->personality & READ_IMPLIES_EXEC) { |
| if (capabilities & NOMMU_MAP_EXEC) |
| prot |= PROT_EXEC; |
| } |
| } else if ((prot & PROT_READ) && |
| (prot & PROT_EXEC) && |
| !(capabilities & NOMMU_MAP_EXEC) |
| ) { |
| /* backing file is not executable, try to copy */ |
| capabilities &= ~NOMMU_MAP_DIRECT; |
| } |
| } else { |
| /* anonymous mappings are always memory backed and can be |
| * privately mapped |
| */ |
| capabilities = NOMMU_MAP_COPY; |
| |
| /* handle PROT_EXEC implication by PROT_READ */ |
| if ((prot & PROT_READ) && |
| (current->personality & READ_IMPLIES_EXEC)) |
| prot |= PROT_EXEC; |
| } |
| |
| /* allow the security API to have its say */ |
| ret = security_mmap_addr(addr); |
| if (ret < 0) |
| return ret; |
| |
| /* looks okay */ |
| *_capabilities = capabilities; |
| return 0; |
| } |
| |
| /* |
| * we've determined that we can make the mapping, now translate what we |
| * now know into VMA flags |
| */ |
| static unsigned long determine_vm_flags(struct file *file, |
| unsigned long prot, |
| unsigned long flags, |
| unsigned long capabilities) |
| { |
| unsigned long vm_flags; |
| |
| vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); |
| /* vm_flags |= mm->def_flags; */ |
| |
| if (!(capabilities & NOMMU_MAP_DIRECT)) { |
| /* attempt to share read-only copies of mapped file chunks */ |
| vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| if (file && !(prot & PROT_WRITE)) |
| vm_flags |= VM_MAYSHARE; |
| } else { |
| /* overlay a shareable mapping on the backing device or inode |
| * if possible - used for chardevs, ramfs/tmpfs/shmfs and |
| * romfs/cramfs */ |
| vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS); |
| if (flags & MAP_SHARED) |
| vm_flags |= VM_SHARED; |
| } |
| |
| /* refuse to let anyone share private mappings with this process if |
| * it's being traced - otherwise breakpoints set in it may interfere |
| * with another untraced process |
| */ |
| if ((flags & MAP_PRIVATE) && current->ptrace) |
| vm_flags &= ~VM_MAYSHARE; |
| |
| return vm_flags; |
| } |
| |
| /* |
| * set up a shared mapping on a file (the driver or filesystem provides and |
| * pins the storage) |
| */ |
| static int do_mmap_shared_file(struct vm_area_struct *vma) |
| { |
| int ret; |
| |
| ret = call_mmap(vma->vm_file, vma); |
| if (ret == 0) { |
| vma->vm_region->vm_top = vma->vm_region->vm_end; |
| return 0; |
| } |
| if (ret != -ENOSYS) |
| return ret; |
| |
| /* getting -ENOSYS indicates that direct mmap isn't possible (as |
| * opposed to tried but failed) so we can only give a suitable error as |
| * it's not possible to make a private copy if MAP_SHARED was given */ |
| return -ENODEV; |
| } |
| |
| /* |
| * set up a private mapping or an anonymous shared mapping |
| */ |
| static int do_mmap_private(struct vm_area_struct *vma, |
| struct vm_region *region, |
| unsigned long len, |
| unsigned long capabilities) |
| { |
| unsigned long total, point; |
| void *base; |
| int ret, order; |
| |
| /* invoke the file's mapping function so that it can keep track of |
| * shared mappings on devices or memory |
| * - VM_MAYSHARE will be set if it may attempt to share |
| */ |
| if (capabilities & NOMMU_MAP_DIRECT) { |
| ret = call_mmap(vma->vm_file, vma); |
| if (ret == 0) { |
| /* shouldn't return success if we're not sharing */ |
| BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
| vma->vm_region->vm_top = vma->vm_region->vm_end; |
| return 0; |
| } |
| if (ret != -ENOSYS) |
| return ret; |
| |
| /* getting an ENOSYS error indicates that direct mmap isn't |
| * possible (as opposed to tried but failed) so we'll try to |
| * make a private copy of the data and map that instead */ |
| } |
| |
| |
| /* allocate some memory to hold the mapping |
| * - note that this may not return a page-aligned address if the object |
| * we're allocating is smaller than a page |
| */ |
| order = get_order(len); |
| total = 1 << order; |
| point = len >> PAGE_SHIFT; |
| |
| /* we don't want to allocate a power-of-2 sized page set */ |
| if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) |
| total = point; |
| |
| base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL); |
| if (!base) |
| goto enomem; |
| |
| atomic_long_add(total, &mmap_pages_allocated); |
| |
| region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; |
| region->vm_start = (unsigned long) base; |
| region->vm_end = region->vm_start + len; |
| region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
| |
| vma->vm_start = region->vm_start; |
| vma->vm_end = region->vm_start + len; |
| |
| if (vma->vm_file) { |
| /* read the contents of a file into the copy */ |
| loff_t fpos; |
| |
| fpos = vma->vm_pgoff; |
| fpos <<= PAGE_SHIFT; |
| |
| ret = kernel_read(vma->vm_file, base, len, &fpos); |
| if (ret < 0) |
| goto error_free; |
| |
| /* clear the last little bit */ |
| if (ret < len) |
| memset(base + ret, 0, len - ret); |
| |
| } else { |
| vma_set_anonymous(vma); |
| } |
| |
| return 0; |
| |
| error_free: |
| free_page_series(region->vm_start, region->vm_top); |
| region->vm_start = vma->vm_start = 0; |
| region->vm_end = vma->vm_end = 0; |
| region->vm_top = 0; |
| return ret; |
| |
| enomem: |
| pr_err("Allocation of length %lu from process %d (%s) failed\n", |
| len, current->pid, current->comm); |
| show_free_areas(0, NULL); |
| return -ENOMEM; |
| } |
| |
| /* |
| * handle mapping creation for uClinux |
| */ |
| unsigned long do_mmap(struct file *file, |
| unsigned long addr, |
| unsigned long len, |
| unsigned long prot, |
| unsigned long flags, |
| unsigned long pgoff, |
| unsigned long *populate, |
| struct list_head *uf) |
| { |
| struct vm_area_struct *vma; |
| struct vm_region *region; |
| struct rb_node *rb; |
| vm_flags_t vm_flags; |
| unsigned long capabilities, result; |
| int ret; |
| |
| *populate = 0; |
| |
| /* decide whether we should attempt the mapping, and if so what sort of |
| * mapping */ |
| ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
| &capabilities); |
| if (ret < 0) |
| return ret; |
| |
| /* we ignore the address hint */ |
| addr = 0; |
| len = PAGE_ALIGN(len); |
| |
| /* we've determined that we can make the mapping, now translate what we |
| * now know into VMA flags */ |
| vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
| |
| /* we're going to need to record the mapping */ |
| region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); |
| if (!region) |
| goto error_getting_region; |
| |
| vma = vm_area_alloc(current->mm); |
| if (!vma) |
| goto error_getting_vma; |
| |
| region->vm_usage = 1; |
| region->vm_flags = vm_flags; |
| region->vm_pgoff = pgoff; |
| |
| vma->vm_flags = vm_flags; |
| vma->vm_pgoff = pgoff; |
| |
| if (file) { |
| region->vm_file = get_file(file); |
| vma->vm_file = get_file(file); |
| } |
| |
| down_write(&nommu_region_sem); |
| |
| /* if we want to share, we need to check for regions created by other |
| * mmap() calls that overlap with our proposed mapping |
| * - we can only share with a superset match on most regular files |
| * - shared mappings on character devices and memory backed files are |
| * permitted to overlap inexactly as far as we are concerned for in |
| * these cases, sharing is handled in the driver or filesystem rather |
| * than here |
| */ |
| if (vm_flags & VM_MAYSHARE) { |
| struct vm_region *pregion; |
| unsigned long pglen, rpglen, pgend, rpgend, start; |
| |
| pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| pgend = pgoff + pglen; |
| |
| for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
| pregion = rb_entry(rb, struct vm_region, vm_rb); |
| |
| if (!(pregion->vm_flags & VM_MAYSHARE)) |
| continue; |
| |
| /* search for overlapping mappings on the same file */ |
| if (file_inode(pregion->vm_file) != |
| file_inode(file)) |
| continue; |
| |
| if (pregion->vm_pgoff >= pgend) |
| continue; |
| |
| rpglen = pregion->vm_end - pregion->vm_start; |
| rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| rpgend = pregion->vm_pgoff + rpglen; |
| if (pgoff >= rpgend) |
| continue; |
| |
| /* handle inexactly overlapping matches between |
| * mappings */ |
| if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && |
| !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { |
| /* new mapping is not a subset of the region */ |
| if (!(capabilities & NOMMU_MAP_DIRECT)) |
| goto sharing_violation; |
| continue; |
| } |
| |
| /* we've found a region we can share */ |
| pregion->vm_usage++; |
| vma->vm_region = pregion; |
| start = pregion->vm_start; |
| start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; |
| vma->vm_start = start; |
| vma->vm_end = start + len; |
| |
| if (pregion->vm_flags & VM_MAPPED_COPY) |
| vma->vm_flags |= VM_MAPPED_COPY; |
| else { |
| ret = do_mmap_shared_file(vma); |
| if (ret < 0) { |
| vma->vm_region = NULL; |
| vma->vm_start = 0; |
| vma->vm_end = 0; |
| pregion->vm_usage--; |
| pregion = NULL; |
| goto error_just_free; |
| } |
| } |
| fput(region->vm_file); |
| kmem_cache_free(vm_region_jar, region); |
| region = pregion; |
| result = start; |
| goto share; |
| } |
| |
| /* obtain the address at which to make a shared mapping |
| * - this is the hook for quasi-memory character devices to |
| * tell us the location of a shared mapping |
| */ |
| if (capabilities & NOMMU_MAP_DIRECT) { |
| addr = file->f_op->get_unmapped_area(file, addr, len, |
| pgoff, flags); |
| if (IS_ERR_VALUE(addr)) { |
| ret = addr; |
| if (ret != -ENOSYS) |
| goto error_just_free; |
| |
| /* the driver refused to tell us where to site |
| * the mapping so we'll have to attempt to copy |
| * it */ |
| ret = -ENODEV; |
| if (!(capabilities & NOMMU_MAP_COPY)) |
| goto error_just_free; |
| |
| capabilities &= ~NOMMU_MAP_DIRECT; |
| } else { |
| vma->vm_start = region->vm_start = addr; |
| vma->vm_end = region->vm_end = addr + len; |
| } |
| } |
| } |
| |
| vma->vm_region = region; |
| |
| /* set up the mapping |
| * - the region is filled in if NOMMU_MAP_DIRECT is still set |
| */ |
| if (file && vma->vm_flags & VM_SHARED) |
| ret = do_mmap_shared_file(vma); |
| else |
| ret = do_mmap_private(vma, region, len, capabilities); |
| if (ret < 0) |
| goto error_just_free; |
| add_nommu_region(region); |
| |
| /* clear anonymous mappings that don't ask for uninitialized data */ |
| if (!vma->vm_file && |
| (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) || |
| !(flags & MAP_UNINITIALIZED))) |
| memset((void *)region->vm_start, 0, |
| region->vm_end - region->vm_start); |
| |
| /* okay... we have a mapping; now we have to register it */ |
| result = vma->vm_start; |
| |
| current->mm->total_vm += len >> PAGE_SHIFT; |
| |
| share: |
| add_vma_to_mm(current->mm, vma); |
| |
| /* we flush the region from the icache only when the first executable |
| * mapping of it is made */ |
| if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { |
| flush_icache_user_range(region->vm_start, region->vm_end); |
| region->vm_icache_flushed = true; |
| } |
| |
| up_write(&nommu_region_sem); |
| |
| return result; |
| |
| error_just_free: |
| up_write(&nommu_region_sem); |
| error: |
| if (region->vm_file) |
| fput(region->vm_file); |
| kmem_cache_free(vm_region_jar, region); |
| if (vma->vm_file) |
| fput(vma->vm_file); |
| vm_area_free(vma); |
| return ret; |
| |
| sharing_violation: |
| up_write(&nommu_region_sem); |
| pr_warn("Attempt to share mismatched mappings\n"); |
| ret = -EINVAL; |
| goto error; |
| |
| error_getting_vma: |
| kmem_cache_free(vm_region_jar, region); |
| pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n", |
| len, current->pid); |
| show_free_areas(0, NULL); |
| return -ENOMEM; |
| |
| error_getting_region: |
| pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n", |
| len, current->pid); |
| show_free_areas(0, NULL); |
| return -ENOMEM; |
| } |
| |
| unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, |
| unsigned long prot, unsigned long flags, |
| unsigned long fd, unsigned long pgoff) |
| { |
| struct file *file = NULL; |
| unsigned long retval = -EBADF; |
| |
| audit_mmap_fd(fd, flags); |
| if (!(flags & MAP_ANONYMOUS)) { |
| file = fget(fd); |
| if (!file) |
| goto out; |
| } |
| |
| retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
| |
| if (file) |
| fput(file); |
| out: |
| return retval; |
| } |
| |
| 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); |
| } |
| |
| #ifdef __ARCH_WANT_SYS_OLD_MMAP |
| struct mmap_arg_struct { |
| unsigned long addr; |
| unsigned long len; |
| unsigned long prot; |
| unsigned long flags; |
| unsigned long fd; |
| unsigned long offset; |
| }; |
| |
| SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
| { |
| struct mmap_arg_struct a; |
| |
| if (copy_from_user(&a, arg, sizeof(a))) |
| return -EFAULT; |
| if (offset_in_page(a.offset)) |
| return -EINVAL; |
| |
| return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
| a.offset >> PAGE_SHIFT); |
| } |
| #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
| |
| /* |
| * split a vma into two pieces at address 'addr', a new vma is allocated either |
| * for the first part or the tail. |
| */ |
| int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long addr, int new_below) |
| { |
| struct vm_area_struct *new; |
| struct vm_region *region; |
| unsigned long npages; |
| |
| /* we're only permitted to split anonymous regions (these should have |
| * only a single usage on the region) */ |
| if (vma->vm_file) |
| return -ENOMEM; |
| |
| if (mm->map_count >= sysctl_max_map_count) |
| return -ENOMEM; |
| |
| region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
| if (!region) |
| return -ENOMEM; |
| |
| new = vm_area_dup(vma); |
| if (!new) { |
| kmem_cache_free(vm_region_jar, region); |
| return -ENOMEM; |
| } |
| |
| /* most fields are the same, copy all, and then fixup */ |
| *region = *vma->vm_region; |
| new->vm_region = region; |
| |
| npages = (addr - vma->vm_start) >> PAGE_SHIFT; |
| |
| if (new_below) { |
| region->vm_top = region->vm_end = new->vm_end = addr; |
| } else { |
| region->vm_start = new->vm_start = addr; |
| region->vm_pgoff = new->vm_pgoff += npages; |
| } |
| |
| if (new->vm_ops && new->vm_ops->open) |
| new->vm_ops->open(new); |
| |
| delete_vma_from_mm(vma); |
| down_write(&nommu_region_sem); |
| delete_nommu_region(vma->vm_region); |
| if (new_below) { |
| vma->vm_region->vm_start = vma->vm_start = addr; |
| vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; |
| } else { |
| vma->vm_region->vm_end = vma->vm_end = addr; |
| vma->vm_region->vm_top = addr; |
| } |
| add_nommu_region(vma->vm_region); |
| add_nommu_region(new->vm_region); |
| up_write(&nommu_region_sem); |
| add_vma_to_mm(mm, vma); |
| add_vma_to_mm(mm, new); |
| return 0; |
| } |
| |
| /* |
| * shrink a VMA by removing the specified chunk from either the beginning or |
| * the end |
| */ |
| static int shrink_vma(struct mm_struct *mm, |
| struct vm_area_struct *vma, |
| unsigned long from, unsigned long to) |
| { |
| struct vm_region *region; |
| |
| /* adjust the VMA's pointers, which may reposition it in the MM's tree |
| * and list */ |
| delete_vma_from_mm(vma); |
| if (from > vma->vm_start) |
| vma->vm_end = from; |
| else |
| vma->vm_start = to; |
| add_vma_to_mm(mm, vma); |
| |
| /* cut the backing region down to size */ |
| region = vma->vm_region; |
| BUG_ON(region->vm_usage != 1); |
| |
| down_write(&nommu_region_sem); |
| delete_nommu_region(region); |
| if (from > region->vm_start) { |
| to = region->vm_top; |
| region->vm_top = region->vm_end = from; |
| } else { |
| region->vm_start = to; |
| } |
| add_nommu_region(region); |
| up_write(&nommu_region_sem); |
| |
| free_page_series(from, to); |
| return 0; |
| } |
| |
| /* |
| * release a mapping |
| * - under NOMMU conditions the chunk to be unmapped must be backed by a single |
| * VMA, though it need not cover the whole VMA |
| */ |
| int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf) |
| { |
| struct vm_area_struct *vma; |
| unsigned long end; |
| int ret; |
| |
| len = PAGE_ALIGN(len); |
| if (len == 0) |
| return -EINVAL; |
| |
| end = start + len; |
| |
| /* find the first potentially overlapping VMA */ |
| vma = find_vma(mm, start); |
| if (!vma) { |
| static int limit; |
| if (limit < 5) { |
| pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n", |
| current->pid, current->comm, |
| start, start + len - 1); |
| limit++; |
| } |
| return -EINVAL; |
| } |
| |
| /* we're allowed to split an anonymous VMA but not a file-backed one */ |
| if (vma->vm_file) { |
| do { |
| if (start > vma->vm_start) |
| return -EINVAL; |
| if (end == vma->vm_end) |
| goto erase_whole_vma; |
| vma = vma->vm_next; |
| } while (vma); |
| return -EINVAL; |
| } else { |
| /* the chunk must be a subset of the VMA found */ |
| if (start == vma->vm_start && end == vma->vm_end) |
| goto erase_whole_vma; |
| if (start < vma->vm_start || end > vma->vm_end) |
| return -EINVAL; |
| if (offset_in_page(start)) |
| return -EINVAL; |
| if (end != vma->vm_end && offset_in_page(end)) |
| return -EINVAL; |
| if (start != vma->vm_start && end != vma->vm_end) { |
| ret = split_vma(mm, vma, start, 1); |
| if (ret < 0) |
| return ret; |
| } |
| return shrink_vma(mm, vma, start, end); |
| } |
| |
| erase_whole_vma: |
| delete_vma_from_mm(vma); |
| delete_vma(mm, vma); |
| return 0; |
| } |
| |
| int vm_munmap(unsigned long addr, size_t len) |
| { |
| struct mm_struct *mm = current->mm; |
| int ret; |
| |
| mmap_write_lock(mm); |
| ret = do_munmap(mm, addr, len, NULL); |
| mmap_write_unlock(mm); |
| return ret; |
| } |
| EXPORT_SYMBOL(vm_munmap); |
| |
| SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
| { |
| return vm_munmap(addr, len); |
| } |
| |
| /* |
| * release all the mappings made in a process's VM space |
| */ |
| void exit_mmap(struct mm_struct *mm) |
| { |
| struct vm_area_struct *vma; |
| |
| if (!mm) |
| return; |
| |
| mm->total_vm = 0; |
| |
| while ((vma = mm->mmap)) { |
| mm->mmap = vma->vm_next; |
| delete_vma_from_mm(vma); |
| delete_vma(mm, vma); |
| cond_resched(); |
| } |
| } |
| |
| int vm_brk(unsigned long addr, unsigned long len) |
| { |
| return -ENOMEM; |
| } |
| |
| /* |
| * expand (or shrink) an existing mapping, potentially moving it at the same |
| * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
| * |
| * under NOMMU conditions, we only permit changing a mapping's size, and only |
| * as long as it stays within the region allocated by do_mmap_private() and the |
| * block is not shareable |
| * |
| * MREMAP_FIXED is not supported under NOMMU conditions |
| */ |
| static unsigned long do_mremap(unsigned long addr, |
| unsigned long old_len, unsigned long new_len, |
| unsigned long flags, unsigned long new_addr) |
| { |
| struct vm_area_struct *vma; |
| |
| /* insanity checks first */ |
| old_len = PAGE_ALIGN(old_len); |
| new_len = PAGE_ALIGN(new_len); |
| if (old_len == 0 || new_len == 0) |
| return (unsigned long) -EINVAL; |
| |
| if (offset_in_page(addr)) |
| return -EINVAL; |
| |
| if (flags & MREMAP_FIXED && new_addr != addr) |
| return (unsigned long) -EINVAL; |
| |
| vma = find_vma_exact(current->mm, addr, old_len); |
| if (!vma) |
| return (unsigned long) -EINVAL; |
| |
| if (vma->vm_end != vma->vm_start + old_len) |
| return (unsigned long) -EFAULT; |
| |
| if (vma->vm_flags & VM_MAYSHARE) |
| return (unsigned long) -EPERM; |
| |
| if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
| return (unsigned long) -ENOMEM; |
| |
| /* all checks complete - do it */ |
| vma->vm_end = vma->vm_start + new_len; |
| return vma->vm_start; |
| } |
| |
| SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
| unsigned long, new_len, unsigned long, flags, |
| unsigned long, new_addr) |
| { |
| unsigned long ret; |
| |
| mmap_write_lock(current->mm); |
| ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
| mmap_write_unlock(current->mm); |
| return ret; |
| } |
| |
| struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
| unsigned int foll_flags) |
| { |
| return NULL; |
| } |
| |
| int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
| unsigned long pfn, unsigned long size, pgprot_t prot) |
| { |
| if (addr != (pfn << PAGE_SHIFT)) |
| return -EINVAL; |
| |
| vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
| return 0; |
| } |
| EXPORT_SYMBOL(remap_pfn_range); |
| |
| int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) |
| { |
| unsigned long pfn = start >> PAGE_SHIFT; |
| unsigned long vm_len = vma->vm_end - vma->vm_start; |
| |
| pfn += vma->vm_pgoff; |
| return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); |
| } |
| EXPORT_SYMBOL(vm_iomap_memory); |
| |
| int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
| unsigned long pgoff) |
| { |
| unsigned int size = vma->vm_end - vma->vm_start; |
| |
| if (!(vma->vm_flags & VM_USERMAP)) |
| return -EINVAL; |
| |
| vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); |
| vma->vm_end = vma->vm_start + size; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(remap_vmalloc_range); |
| |
| vm_fault_t filemap_fault(struct vm_fault *vmf) |
| { |
| BUG(); |
| return 0; |
| } |
| EXPORT_SYMBOL(filemap_fault); |
| |
| vm_fault_t filemap_map_pages(struct vm_fault *vmf, |
| pgoff_t start_pgoff, pgoff_t end_pgoff) |
| { |
| BUG(); |
| return 0; |
| } |
| EXPORT_SYMBOL(filemap_map_pages); |
| |
| int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, |
| int len, unsigned int gup_flags) |
| { |
| struct vm_area_struct *vma; |
| int write = gup_flags & FOLL_WRITE; |
| |
| if (mmap_read_lock_killable(mm)) |
| return 0; |
| |
| /* the access must start within one of the target process's mappings */ |
| vma = find_vma(mm, addr); |
| if (vma) { |
| /* don't overrun this mapping */ |
| if (addr + len >= vma->vm_end) |
| len = vma->vm_end - addr; |
| |
| /* only read or write mappings where it is permitted */ |
| if (write && vma->vm_flags & VM_MAYWRITE) |
| copy_to_user_page(vma, NULL, addr, |
| (void *) addr, buf, len); |
| else if (!write && vma->vm_flags & VM_MAYREAD) |
| copy_from_user_page(vma, NULL, addr, |
| buf, (void *) addr, len); |
| else |
| len = 0; |
| } else { |
| len = 0; |
| } |
| |
| mmap_read_unlock(mm); |
| |
| return len; |
| } |
| |
| /** |
| * access_remote_vm - access another process' address space |
| * @mm: the mm_struct of the target address space |
| * @addr: start address to access |
| * @buf: source or destination buffer |
| * @len: number of bytes to transfer |
| * @gup_flags: flags modifying lookup behaviour |
| * |
| * The caller must hold a reference on @mm. |
| */ |
| int access_remote_vm(struct mm_struct *mm, unsigned long addr, |
| void *buf, int len, unsigned int gup_flags) |
| { |
| return __access_remote_vm(mm, addr, buf, len, gup_flags); |
| } |
| |
| /* |
| * 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, |
| unsigned int gup_flags) |
| { |
| struct mm_struct *mm; |
| |
| if (addr + len < addr) |
| return 0; |
| |
| mm = get_task_mm(tsk); |
| if (!mm) |
| return 0; |
| |
| len = __access_remote_vm(mm, addr, buf, len, gup_flags); |
| |
| mmput(mm); |
| return len; |
| } |
| EXPORT_SYMBOL_GPL(access_process_vm); |
| |
| /** |
| * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode |
| * @inode: The inode to check |
| * @size: The current filesize of the inode |
| * @newsize: The proposed filesize of the inode |
| * |
| * Check the shared mappings on an inode on behalf of a shrinking truncate to |
| * make sure that any outstanding VMAs aren't broken and then shrink the |
| * vm_regions that extend beyond so that do_mmap() doesn't |
| * automatically grant mappings that are too large. |
| */ |
| int nommu_shrink_inode_mappings(struct inode *inode, size_t size, |
| size_t newsize) |
| { |
| struct vm_area_struct *vma; |
| struct vm_region *region; |
| pgoff_t low, high; |
| size_t r_size, r_top; |
| |
| low = newsize >> PAGE_SHIFT; |
| high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| |
| down_write(&nommu_region_sem); |
| i_mmap_lock_read(inode->i_mapping); |
| |
| /* search for VMAs that fall within the dead zone */ |
| vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) { |
| /* found one - only interested if it's shared out of the page |
| * cache */ |
| if (vma->vm_flags & VM_SHARED) { |
| i_mmap_unlock_read(inode->i_mapping); |
| up_write(&nommu_region_sem); |
| return -ETXTBSY; /* not quite true, but near enough */ |
| } |
| } |
| |
| /* reduce any regions that overlap the dead zone - if in existence, |
| * these will be pointed to by VMAs that don't overlap the dead zone |
| * |
| * we don't check for any regions that start beyond the EOF as there |
| * shouldn't be any |
| */ |
| vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) { |
| if (!(vma->vm_flags & VM_SHARED)) |
| continue; |
| |
| region = vma->vm_region; |
| r_size = region->vm_top - region->vm_start; |
| r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; |
| |
| if (r_top > newsize) { |
| region->vm_top -= r_top - newsize; |
| if (region->vm_end > region->vm_top) |
| region->vm_end = region->vm_top; |
| } |
| } |
| |
| i_mmap_unlock_read(inode->i_mapping); |
| up_write(&nommu_region_sem); |
| return 0; |
| } |
| |
| /* |
| * Initialise sysctl_user_reserve_kbytes. |
| * |
| * This is intended to prevent a user from starting a single memory hogging |
| * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER |
| * mode. |
| * |
| * The default value is min(3% of free memory, 128MB) |
| * 128MB is enough to recover with sshd/login, bash, and top/kill. |
| */ |
| static int __meminit init_user_reserve(void) |
| { |
| unsigned long free_kbytes; |
| |
| free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
| |
| sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); |
| return 0; |
| } |
| subsys_initcall(init_user_reserve); |
| |
| /* |
| * Initialise sysctl_admin_reserve_kbytes. |
| * |
| * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin |
| * to log in and kill a memory hogging process. |
| * |
| * Systems with more than 256MB will reserve 8MB, enough to recover |
| * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will |
| * only reserve 3% of free pages by default. |
| */ |
| static int __meminit init_admin_reserve(void) |
| { |
| unsigned long free_kbytes; |
| |
| free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
| |
| sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); |
| return 0; |
| } |
| subsys_initcall(init_admin_reserve); |