| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| David Howells | 3304 | 48.54% | 34 | 13.08% |
| Alan Cox | 662 | 9.73% | 2 | 0.77% |
| Paul Mundt | 493 | 7.24% | 9 | 3.46% |
| Liam R. Howlett | 286 | 4.20% | 11 | 4.23% |
| Linus Torvalds (pre-git) | 181 | 2.66% | 22 | 8.46% |
| Matthew Wilcox | 167 | 2.45% | 2 | 0.77% |
| Linus Torvalds | 162 | 2.38% | 10 | 3.85% |
| Andrew Morton | 121 | 1.78% | 14 | 5.38% |
| Mike Frysinger | 111 | 1.63% | 3 | 1.15% |
| Christoph Hellwig | 78 | 1.15% | 9 | 3.46% |
| Andi Kleen | 65 | 0.95% | 2 | 0.77% |
| Andrew Shewmaker | 64 | 0.94% | 2 | 0.77% |
| David Hildenbrand | 58 | 0.85% | 2 | 0.77% |
| Al Viro | 56 | 0.82% | 10 | 3.85% |
| Bob Liu | 52 | 0.76% | 2 | 0.77% |
| Jie Zhang | 50 | 0.73% | 2 | 0.77% |
| Souptick Joarder | 49 | 0.72% | 2 | 0.77% |
| Bernd Schmidt | 49 | 0.72% | 2 | 0.77% |
| Heiko Carstens | 49 | 0.72% | 2 | 0.77% |
| Greg Ungerer | 47 | 0.69% | 7 | 2.69% |
| Lorenzo Stoakes | 35 | 0.51% | 10 | 3.85% |
| Chris Zankel | 33 | 0.48% | 1 | 0.38% |
| Kent Overstreet | 29 | 0.43% | 1 | 0.38% |
| Kirill A. Shutemov | 26 | 0.38% | 3 | 1.15% |
| Michel Lespinasse | 26 | 0.38% | 5 | 1.92% |
| Ralf Baechle | 25 | 0.37% | 1 | 0.38% |
| Suren Baghdasaryan | 23 | 0.34% | 1 | 0.38% |
| Andrii Nakryiko | 22 | 0.32% | 1 | 0.38% |
| Michal Hocko | 21 | 0.31% | 2 | 0.77% |
| JoonSoo Kim | 20 | 0.29% | 2 | 0.77% |
| Matt Helsley | 20 | 0.29% | 1 | 0.38% |
| Danilo Krummrich | 19 | 0.28% | 1 | 0.38% |
| Yang Ruirui | 19 | 0.28% | 1 | 0.38% |
| Arjan van de Ven | 19 | 0.28% | 1 | 0.38% |
| Motohiro Kosaki | 18 | 0.26% | 1 | 0.38% |
| Luke Yang | 17 | 0.25% | 2 | 0.77% |
| Nadia Yvette Chambers | 16 | 0.24% | 2 | 0.77% |
| Nicholas Piggin | 16 | 0.24% | 5 | 1.92% |
| Graff Yang | 16 | 0.24% | 1 | 0.38% |
| Andrea Arcangeli | 14 | 0.21% | 2 | 0.77% |
| Max Filippov | 14 | 0.21% | 1 | 0.38% |
| David Rientjes | 14 | 0.21% | 1 | 0.38% |
| Mike Rapoport | 13 | 0.19% | 2 | 0.77% |
| Jens Axboe | 12 | 0.18% | 1 | 0.38% |
| Dominik Brodowski | 12 | 0.18% | 1 | 0.38% |
| Hugh Dickins | 12 | 0.18% | 4 | 1.54% |
| Alexander Kuleshov | 12 | 0.18% | 1 | 0.38% |
| Mitchel Humpherys | 11 | 0.16% | 1 | 0.38% |
| Konstantin Khlebnikov | 10 | 0.15% | 2 | 0.77% |
| Roland McGrath | 9 | 0.13% | 1 | 0.38% |
| Ingo Molnar | 9 | 0.13% | 3 | 1.15% |
| Leon Romanovsky | 8 | 0.12% | 1 | 0.38% |
| Oleg Nesterov | 8 | 0.12% | 2 | 0.77% |
| Davidlohr Bueso A | 7 | 0.10% | 2 | 0.77% |
| Paul Gortmaker | 7 | 0.10% | 2 | 0.77% |
| Christoph Lameter | 7 | 0.10% | 2 | 0.77% |
| Pekka J Enberg | 7 | 0.10% | 1 | 0.38% |
| Chen Gang S | 6 | 0.09% | 2 | 0.77% |
| Kefeng Wang | 6 | 0.09% | 1 | 0.38% |
| Namhyung Kim | 6 | 0.09% | 5 | 1.92% |
| ZhangPeng | 6 | 0.09% | 1 | 0.38% |
| Arnd Bergmann | 5 | 0.07% | 1 | 0.38% |
| Catalin Marinas | 5 | 0.07% | 1 | 0.38% |
| Wolfgang Wander | 4 | 0.06% | 1 | 0.38% |
| Yu-cheng Yu | 4 | 0.06% | 1 | 0.38% |
| Linus Walleij | 4 | 0.06% | 1 | 0.38% |
| Geert Uytterhoeven | 4 | 0.06% | 1 | 0.38% |
| Andrey Ryabinin | 4 | 0.06% | 1 | 0.38% |
| Eric W. Biedermann | 4 | 0.06% | 1 | 0.38% |
| Tejun Heo | 4 | 0.06% | 2 | 0.77% |
| Masahiro Yamada | 3 | 0.04% | 1 | 0.38% |
| Gideon Israel Dsouza | 3 | 0.04% | 1 | 0.38% |
| Yoshinori Sato | 3 | 0.04% | 1 | 0.38% |
| Steven J. Magnani | 3 | 0.04% | 1 | 0.38% |
| Martin Schwidefsky | 2 | 0.03% | 1 | 0.38% |
| Vladimir Davydov | 2 | 0.03% | 1 | 0.38% |
| Gavin Lambert | 2 | 0.03% | 1 | 0.38% |
| Jan Kara | 2 | 0.03% | 1 | 0.38% |
| Dave Hansen | 2 | 0.03% | 1 | 0.38% |
| Clark Williams | 2 | 0.03% | 1 | 0.38% |
| Michael Hennerich | 2 | 0.03% | 1 | 0.38% |
| Alexey Dobriyan | 1 | 0.01% | 1 | 0.38% |
| Marek Szyprowski | 1 | 0.01% | 1 | 0.38% |
| Josef 'Jeff' Sipek | 1 | 0.01% | 1 | 0.38% |
| Stephen Kitt | 1 | 0.01% | 1 | 0.38% |
| Randy Dunlap | 1 | 0.01% | 1 | 0.38% |
| Thomas Gleixner | 1 | 0.01% | 1 | 0.38% |
| Robert P. J. Day | 1 | 0.01% | 1 | 0.38% |
| Hajime Tazaki | 1 | 0.01% | 1 | 0.38% |
| seokhoon.yoon | 1 | 0.01% | 1 | 0.38% |
| Total | 6807 | 260 |
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// 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/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 <linux/uio.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); } void vfree(const void *addr) { kfree(addr); } EXPORT_SYMBOL(vfree); void *__vmalloc_noprof(unsigned long size, gfp_t gfp_mask) { /* * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() * returns only a logical address. */ return kmalloc_noprof(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); } EXPORT_SYMBOL(__vmalloc_noprof); void *vrealloc_noprof(const void *p, size_t size, gfp_t flags) { return krealloc_noprof(p, size, (flags | __GFP_COMP) & ~__GFP_HIGHMEM); } void *__vmalloc_node_range_noprof(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_noprof(size, gfp_mask); } void *__vmalloc_node_noprof(unsigned long size, unsigned long align, gfp_t gfp_mask, int node, const void *caller) { return __vmalloc_noprof(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) vm_flags_set(vma, VM_USERMAP); mmap_write_unlock(current->mm); } return ret; } void *vmalloc_user_noprof(unsigned long size) { return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO); } EXPORT_SYMBOL(vmalloc_user_noprof); 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_iter(struct iov_iter *iter, const char *addr, size_t count) { /* Don't allow overflow */ if ((unsigned long) addr + count < count) count = -(unsigned long) addr; return copy_to_iter(addr, count, iter); } /* * 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_noprof(unsigned long size) { return __vmalloc_noprof(size, GFP_KERNEL); } EXPORT_SYMBOL(vmalloc_noprof); void *vmalloc_huge_noprof(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc_noprof); /* * 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_noprof(unsigned long size) { return __vmalloc_noprof(size, GFP_KERNEL | __GFP_ZERO); } EXPORT_SYMBOL(vzalloc_noprof); /** * 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_noprof(unsigned long size, int node) { return vmalloc_noprof(size); } EXPORT_SYMBOL(vmalloc_node_noprof); /** * 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_noprof(unsigned long size, int node) { return vzalloc_noprof(size); } EXPORT_SYMBOL(vzalloc_node_noprof); /** * 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_noprof(unsigned long size) { return __vmalloc_noprof(size, GFP_KERNEL); } EXPORT_SYMBOL(vmalloc_32_noprof); /** * 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_noprof(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_noprof(size); } EXPORT_SYMBOL(vmalloc_32_user_noprof); 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_insert_pages(struct vm_area_struct *vma, unsigned long addr, struct page **pages, unsigned long *num) { return -EINVAL; } EXPORT_SYMBOL(vm_insert_pages); 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); } static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm) { vma->vm_mm = mm; /* add the VMA to the mapping */ if (vma->vm_file) { struct address_space *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); } } static void cleanup_vma_from_mm(struct vm_area_struct *vma) { vma->vm_mm->map_count--; /* remove the VMA from the mapping */ if (vma->vm_file) { struct address_space *mapping; 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); } } /* * delete a VMA from its owning mm_struct and address space */ static int delete_vma_from_mm(struct vm_area_struct *vma) { VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start); vma_iter_config(&vmi, vma->vm_start, vma->vm_end); if (vma_iter_prealloc(&vmi, NULL)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); return -ENOMEM; } cleanup_vma_from_mm(vma); /* remove from the MM's tree and list */ vma_iter_clear(&vmi); return 0; } /* * destroy a VMA record */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region); vm_area_free(vma); } struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, unsigned long start_addr, unsigned long end_addr) { unsigned long index = start_addr; mmap_assert_locked(mm); return mt_find(&mm->mm_mt, &index, end_addr - 1); } EXPORT_SYMBOL(find_vma_intersection); /* * 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) { VMA_ITERATOR(vmi, mm, addr); return vma_iter_load(&vmi); } EXPORT_SYMBOL(find_vma); /* * At least xtensa ends up having protection faults even with no * MMU.. No stack expansion, at least. */ struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, unsigned long addr, struct pt_regs *regs) { struct vm_area_struct *vma; mmap_read_lock(mm); vma = vma_lookup(mm, addr); if (!vma) mmap_read_unlock(mm); return vma; } /* * expand a stack to a given address * - not supported under NOMMU conditions */ int expand_stack_locked(struct vm_area_struct *vma, unsigned long addr) { return -ENOMEM; } struct vm_area_struct *expand_stack(struct mm_struct *mm, unsigned long addr) { mmap_read_unlock(mm); return NULL; } /* * 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; VMA_ITERATOR(vmi, mm, addr); vma = vma_iter_load(&vmi); if (!vma) return NULL; if (vma->vm_start != addr) return NULL; if (vma->vm_end != end) return NULL; return vma; } /* * 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(file, flags); if (!file) { /* * MAP_ANONYMOUS. MAP_SHARED is mapped to MAP_PRIVATE, because * there is no fork(). */ vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; } else if (flags & MAP_PRIVATE) { /* MAP_PRIVATE file mapping */ if (capabilities & NOMMU_MAP_DIRECT) vm_flags |= (capabilities & NOMMU_VMFLAGS); else vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; if (!(prot & PROT_WRITE) && !current->ptrace) /* * R/O private file mapping which cannot be used to * modify memory, especially also not via active ptrace * (e.g., set breakpoints) or later by upgrading * permissions (no mprotect()). We can try overlaying * the file mapping, which will work e.g., on chardevs, * ramfs/tmpfs/shmfs and romfs/cramf. */ vm_flags |= VM_MAYOVERLAY; } else { /* MAP_SHARED file mapping: NOMMU_MAP_DIRECT is set. */ vm_flags |= VM_SHARED | VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS); } 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 = mmap_file(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_MAYOVERLAY will be set if * it may attempt to share, which will make is_nommu_shared_mapping() * happy. */ if (capabilities & NOMMU_MAP_DIRECT) { ret = mmap_file(vma->vm_file, vma); /* shouldn't return success if we're not sharing */ if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags))) ret = -ENOSYS; if (ret == 0) { 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); vm_flags_set(vma, VM_MAPPED_COPY); region->vm_flags = vma->vm_flags; 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_mem(); return -ENOMEM; } /* * handle mapping creation for uClinux */ unsigned long do_mmap(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate, struct list_head *uf) { struct vm_area_struct *vma; struct vm_region *region; struct rb_node *rb; unsigned long capabilities, result; int ret; VMA_ITERATOR(vmi, current->mm, 0); *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; vm_flags_init(vma, 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 (is_nommu_shared_mapping(vm_flags)) { 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 (!is_nommu_shared_mapping(pregion->vm_flags)) 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) vm_flags_set(vma, 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: BUG_ON(!vma->vm_region); vma_iter_config(&vmi, vma->vm_start, vma->vm_end); if (vma_iter_prealloc(&vmi, vma)) goto error_just_free; setup_vma_to_mm(vma, current->mm); current->mm->map_count++; /* add the VMA to the tree */ vma_iter_store(&vmi, 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: vma_iter_free(&vmi); 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_mem(); return -ENOMEM; error_getting_region: pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n", len, current->pid); show_mem(); 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. */ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long addr, int new_below) { struct vm_area_struct *new; struct vm_region *region; unsigned long npages; struct mm_struct *mm; /* we're only permitted to split anonymous regions (these should have * only a single usage on the region) */ if (vma->vm_file) return -ENOMEM; mm = vma->vm_mm; 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) goto err_vma_dup; /* 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; } vma_iter_config(vmi, new->vm_start, new->vm_end); if (vma_iter_prealloc(vmi, vma)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); goto err_vmi_preallocate; } if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); 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); setup_vma_to_mm(vma, mm); setup_vma_to_mm(new, mm); vma_iter_store(vmi, new); mm->map_count++; return 0; err_vmi_preallocate: vm_area_free(new); err_vma_dup: kmem_cache_free(vm_region_jar, region); return -ENOMEM; } /* * shrink a VMA by removing the specified chunk from either the beginning or * the end */ static int vmi_shrink_vma(struct vma_iterator *vmi, 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 */ if (from > vma->vm_start) { if (vma_iter_clear_gfp(vmi, from, vma->vm_end, GFP_KERNEL)) return -ENOMEM; vma->vm_end = from; } else { if (vma_iter_clear_gfp(vmi, vma->vm_start, to, GFP_KERNEL)) return -ENOMEM; vma->vm_start = to; } /* 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) { VMA_ITERATOR(vmi, mm, start); struct vm_area_struct *vma; unsigned long end; int ret = 0; len = PAGE_ALIGN(len); if (len == 0) return -EINVAL; end = start + len; /* find the first potentially overlapping VMA */ vma = vma_find(&vmi, end); 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_find(&vmi, end); } 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(&vmi, vma, start, 1); if (ret < 0) return ret; } return vmi_shrink_vma(&vmi, vma, start, end); } erase_whole_vma: if (delete_vma_from_mm(vma)) ret = -ENOMEM; else delete_vma(mm, vma); return ret; } 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) { VMA_ITERATOR(vmi, mm, 0); struct vm_area_struct *vma; if (!mm) return; mm->total_vm = 0; /* * Lock the mm to avoid assert complaining even though this is the only * user of the mm */ mmap_write_lock(mm); for_each_vma(vmi, vma) { cleanup_vma_from_mm(vma); delete_vma(mm, vma); cond_resched(); } __mt_destroy(&mm->mm_mt); mmap_write_unlock(mm); } /* * 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 (is_nommu_shared_mapping(vma->vm_flags)) 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; } 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; vm_flags_set(vma, 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); static 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 = K(global_zone_page_state(NR_FREE_PAGES)); 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 = K(global_zone_page_state(NR_FREE_PAGES)); sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); return 0; } subsys_initcall(init_admin_reserve);
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