--- /dev/null
+/*
+ * linux/mm/nommu.c
+ *
+ * Replacement code for mm functions to support CPU's that don't
+ * have any form of memory management unit (thus no virtual memory).
+ *
+ * See Documentation/nommu-mmap.txt
+ *
+ * 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/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/blkdev.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/sched/sysctl.h>
+#include <linux/printk.h>
+
+#include <asm/uaccess.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include "internal.h"
+
+#if 0
+#define kenter(FMT, ...) \
+ printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+ printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
+#else
+#define kenter(FMT, ...) \
+ no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+ no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
+#endif
+
+void *high_memory;
+EXPORT_SYMBOL(high_memory);
+struct page *mem_map;
+unsigned long max_mapnr;
+EXPORT_SYMBOL(max_mapnr);
+unsigned long highest_memmap_pfn;
+struct percpu_counter vm_committed_as;
+int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
+int sysctl_overcommit_ratio = 50; /* default is 50% */
+unsigned long sysctl_overcommit_kbytes __read_mostly;
+int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
+int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
+unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
+unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
+int heap_stack_gap = 0;
+
+atomic_long_t mmap_pages_allocated;
+
+/*
+ * The global memory commitment made in the system can be a metric
+ * that can be used to drive ballooning decisions when Linux is hosted
+ * as a guest. On Hyper-V, the host implements a policy engine for dynamically
+ * balancing memory across competing virtual machines that are hosted.
+ * Several metrics drive this policy engine including the guest reported
+ * memory commitment.
+ */
+unsigned long vm_memory_committed(void)
+{
+ return percpu_counter_read_positive(&vm_committed_as);
+}
+
+EXPORT_SYMBOL_GPL(vm_memory_committed);
+
+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 << compound_order(page);
+}
+
+long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ unsigned int foll_flags, struct page **pages,
+ struct vm_area_struct **vmas, int *nonblocking)
+{
+ struct vm_area_struct *vma;
+ unsigned long vm_flags;
+ int i;
+
+ /* calculate required read or write permissions.
+ * If FOLL_FORCE is set, we only require the "MAY" flags.
+ */
+ vm_flags = (foll_flags & FOLL_WRITE) ?
+ (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= (foll_flags & FOLL_FORCE) ?
+ (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+
+ for (i = 0; i < nr_pages; i++) {
+ vma = find_vma(mm, start);
+ if (!vma)
+ goto finish_or_fault;
+
+ /* protect what we can, including chardevs */
+ if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+ !(vm_flags & vma->vm_flags))
+ goto finish_or_fault;
+
+ if (pages) {
+ pages[i] = virt_to_page(start);
+ if (pages[i])
+ page_cache_get(pages[i]);
+ }
+ if (vmas)
+ vmas[i] = vma;
+ start = (start + PAGE_SIZE) & PAGE_MASK;
+ }
+
+ return i;
+
+finish_or_fault:
+ return i ? : -EFAULT;
+}
+
+/*
+ * get a list of pages in an address range belonging to the specified process
+ * and indicate the VMA that covers each page
+ * - this is potentially dodgy as we may end incrementing the page count of a
+ * slab page or a secondary page from a compound page
+ * - don't permit access to VMAs that don't support it, such as I/O mappings
+ */
+long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ struct vm_area_struct **vmas)
+{
+ int flags = 0;
+
+ if (write)
+ flags |= FOLL_WRITE;
+ if (force)
+ flags |= FOLL_FORCE;
+
+ return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
+ NULL);
+}
+EXPORT_SYMBOL(get_user_pages);
+
+long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ int *locked)
+{
+ return get_user_pages(tsk, mm, start, nr_pages, write, force,
+ pages, NULL);
+}
+EXPORT_SYMBOL(get_user_pages_locked);
+
+long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ unsigned int gup_flags)
+{
+ long ret;
+ down_read(&mm->mmap_sem);
+ ret = get_user_pages(tsk, mm, start, nr_pages, write, force,
+ pages, NULL);
+ up_read(&mm->mmap_sem);
+ return ret;
+}
+EXPORT_SYMBOL(__get_user_pages_unlocked);
+
+long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages)
+{
+ return __get_user_pages_unlocked(tsk, mm, start, nr_pages, write,
+ force, pages, 0);
+}
+EXPORT_SYMBOL(get_user_pages_unlocked);
+
+/**
+ * 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, pgprot_t prot)
+{
+ /*
+ * 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_user(unsigned long size)
+{
+ void *ret;
+
+ ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+ PAGE_KERNEL);
+ if (ret) {
+ struct vm_area_struct *vma;
+
+ down_write(¤t->mm->mmap_sem);
+ vma = find_vma(current->mm, (unsigned long)ret);
+ if (vma)
+ vma->vm_flags |= VM_USERMAP;
+ up_write(¤t->mm->mmap_sem);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(vmalloc_user);
+
+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;
+}
+
+long vwrite(char *buf, char *addr, unsigned long count)
+{
+ /* Don't allow overflow */
+ if ((unsigned long) addr + count < count)
+ count = -(unsigned long) addr;
+
+ memcpy(addr, buf, count);
+ return count;
+}
+
+/*
+ * vmalloc - allocate virtually continguos memory
+ *
+ * @size: allocation size
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into continguos kernel virtual space.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
+void *vmalloc(unsigned long size)
+{
+ return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
+}
+EXPORT_SYMBOL(vmalloc);
+
+/*
+ * vzalloc - allocate virtually continguos memory with zero fill
+ *
+ * @size: allocation size
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into continguos 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_HIGHMEM | __GFP_ZERO,
+ PAGE_KERNEL);
+}
+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);
+
+#ifndef PAGE_KERNEL_EXEC
+# define PAGE_KERNEL_EXEC PAGE_KERNEL
+#endif
+
+/**
+ * vmalloc_exec - allocate virtually contiguous, executable memory
+ * @size: allocation size
+ *
+ * Kernel-internal function to allocate enough pages to cover @size
+ * the page level allocator and map them into contiguous and
+ * executable kernel virtual space.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
+
+void *vmalloc_exec(unsigned long size)
+{
+ return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
+}
+
+/**
+ * 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 continguos kernel virtual space.
+ */
+void *vmalloc_32(unsigned long size)
+{
+ return __vmalloc(size, GFP_KERNEL, PAGE_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, pgprot_t prot)
+{
+ BUG();
+ return NULL;
+}
+EXPORT_SYMBOL(vm_map_ram);
+
+void vm_unmap_ram(const void *mem, unsigned int count)
+{
+ BUG();
+}
+EXPORT_SYMBOL(vm_unmap_ram);
+
+void vm_unmap_aliases(void)
+{
+}
+EXPORT_SYMBOL_GPL(vm_unmap_aliases);
+
+/*
+ * Implement a stub for vmalloc_sync_all() if the architecture chose not to
+ * have one.
+ */
+void __weak vmalloc_sync_all(void)
+{
+}
+
+/**
+ * alloc_vm_area - allocate a range of kernel address space
+ * @size: size of the area
+ *
+ * Returns: NULL on failure, vm_struct on success
+ *
+ * This function reserves a range of kernel address space, and
+ * allocates pagetables to map that range. No actual mappings
+ * are created. If the kernel address space is not shared
+ * between processes, it syncs the pagetable across all
+ * processes.
+ */
+struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
+{
+ BUG();
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(alloc_vm_area);
+
+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);
+
+/*
+ * 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_range(mm->brk, brk);
+ return mm->brk = brk;
+}
+
+/*
+ * initialise the VMA and region record slabs
+ */
+void __init mmap_init(void)
+{
+ int ret;
+
+ ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
+ VM_BUG_ON(ret);
+ vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
+}
+
+/*
+ * 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(unlikely(last->vm_end <= last->vm_start));
+ BUG_ON(unlikely(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(unlikely(region->vm_end <= region->vm_start));
+ BUG_ON(unlikely(region->vm_top < region->vm_end));
+ BUG_ON(unlikely(region->vm_start < last->vm_top));
+
+ lastp = p;
+ }
+}
+#else
+static void validate_nommu_regions(void)
+{
+}
+#endif
+
+/*
+ * add a region into the global tree
+ */
+static void add_nommu_region(struct vm_region *region)
+{
+ struct vm_region *pregion;
+ struct rb_node **p, *parent;
+
+ validate_nommu_regions();
+
+ parent = NULL;
+ p = &nommu_region_tree.rb_node;
+ while (*p) {
+ parent = *p;
+ pregion = rb_entry(parent, struct vm_region, vm_rb);
+ if (region->vm_start < pregion->vm_start)
+ p = &(*p)->rb_left;
+ else if (region->vm_start > pregion->vm_start)
+ p = &(*p)->rb_right;
+ else if (pregion == region)
+ return;
+ else
+ BUG();
+ }
+
+ rb_link_node(®ion->vm_rb, parent, p);
+ rb_insert_color(®ion->vm_rb, &nommu_region_tree);
+
+ validate_nommu_regions();
+}
+
+/*
+ * delete a region from the global tree
+ */
+static void delete_nommu_region(struct vm_region *region)
+{
+ BUG_ON(!nommu_region_tree.rb_node);
+
+ validate_nommu_regions();
+ rb_erase(®ion->vm_rb, &nommu_region_tree);
+ validate_nommu_regions();
+}
+
+/*
+ * free a contiguous series of pages
+ */
+static void free_page_series(unsigned long from, unsigned long to)
+{
+ for (; from < to; from += PAGE_SIZE) {
+ struct page *page = virt_to_page(from);
+
+ kdebug("- free %lx", from);
+ atomic_long_dec(&mmap_pages_allocated);
+ if (page_count(page) != 1)
+ kdebug("free page %p: refcount not one: %d",
+ page, page_count(page));
+ 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)
+{
+ kenter("%p{%d}", region, region->vm_usage);
+
+ 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) {
+ kdebug("free series");
+ free_page_series(region->vm_start, region->vm_top);
+ }
+ kmem_cache_free(vm_region_jar, region);
+ } else {
+ up_write(&nommu_region_sem);
+ }
+}
+
+/*
+ * release a reference to a region
+ */
+static void put_nommu_region(struct vm_region *region)
+{
+ down_write(&nommu_region_sem);
+ __put_nommu_region(region);
+}
+
+/*
+ * update protection on a vma
+ */
+static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
+{
+#ifdef CONFIG_MPU
+ struct mm_struct *mm = vma->vm_mm;
+ long start = vma->vm_start & PAGE_MASK;
+ while (start < vma->vm_end) {
+ protect_page(mm, start, flags);
+ start += PAGE_SIZE;
+ }
+ update_protections(mm);
+#endif
+}
+
+/*
+ * add a VMA into a process's mm_struct in the appropriate place in the list
+ * and tree and add to the address space's page tree also if not an anonymous
+ * page
+ * - should be called with mm->mmap_sem held writelocked
+ */
+static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+ struct vm_area_struct *pvma, *prev;
+ struct address_space *mapping;
+ struct rb_node **p, *parent, *rb_prev;
+
+ kenter(",%p", vma);
+
+ BUG_ON(!vma->vm_region);
+
+ mm->map_count++;
+ vma->vm_mm = mm;
+
+ protect_vma(vma, vma->vm_flags);
+
+ /* add the VMA to the mapping */
+ if (vma->vm_file) {
+ mapping = vma->vm_file->f_mapping;
+
+ i_mmap_lock_write(mapping);
+ flush_dcache_mmap_lock(mapping);
+ vma_interval_tree_insert(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+ i_mmap_unlock_write(mapping);
+ }
+
+ /* add the VMA to the tree */
+ parent = rb_prev = NULL;
+ p = &mm->mm_rb.rb_node;
+ while (*p) {
+ parent = *p;
+ pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
+
+ /* sort by: start addr, end addr, VMA struct addr in that order
+ * (the latter is necessary as we may get identical VMAs) */
+ if (vma->vm_start < pvma->vm_start)
+ p = &(*p)->rb_left;
+ else if (vma->vm_start > pvma->vm_start) {
+ rb_prev = parent;
+ p = &(*p)->rb_right;
+ } else if (vma->vm_end < pvma->vm_end)
+ p = &(*p)->rb_left;
+ else if (vma->vm_end > pvma->vm_end) {
+ rb_prev = parent;
+ p = &(*p)->rb_right;
+ } else if (vma < pvma)
+ p = &(*p)->rb_left;
+ else if (vma > pvma) {
+ rb_prev = parent;
+ p = &(*p)->rb_right;
+ } else
+ BUG();
+ }
+
+ rb_link_node(&vma->vm_rb, parent, p);
+ rb_insert_color(&vma->vm_rb, &mm->mm_rb);
+
+ /* add VMA to the VMA list also */
+ prev = NULL;
+ if (rb_prev)
+ prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
+
+ __vma_link_list(mm, vma, prev, parent);
+}
+
+/*
+ * delete a VMA from its owning mm_struct and address space
+ */
+static void delete_vma_from_mm(struct vm_area_struct *vma)
+{
+ int i;
+ struct address_space *mapping;
+ struct mm_struct *mm = vma->vm_mm;
+ struct task_struct *curr = current;
+
+ kenter("%p", vma);
+
+ protect_vma(vma, 0);
+
+ mm->map_count--;
+ for (i = 0; i < VMACACHE_SIZE; i++) {
+ /* if the vma is cached, invalidate the entire cache */
+ if (curr->vmacache[i] == vma) {
+ vmacache_invalidate(mm);
+ break;
+ }
+ }
+
+ /* remove the VMA from the mapping */
+ if (vma->vm_file) {
+ mapping = vma->vm_file->f_mapping;
+
+ i_mmap_lock_write(mapping);
+ flush_dcache_mmap_lock(mapping);
+ vma_interval_tree_remove(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+ i_mmap_unlock_write(mapping);
+ }
+
+ /* remove from the MM's tree and list */
+ rb_erase(&vma->vm_rb, &mm->mm_rb);
+
+ if (vma->vm_prev)
+ vma->vm_prev->vm_next = vma->vm_next;
+ else
+ mm->mmap = vma->vm_next;
+
+ if (vma->vm_next)
+ vma->vm_next->vm_prev = vma->vm_prev;
+}
+
+/*
+ * destroy a VMA record
+ */
+static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+ kenter("%p", vma);
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+ if (vma->vm_file)
+ fput(vma->vm_file);
+ put_nommu_region(vma->vm_region);
+ kmem_cache_free(vm_area_cachep, vma);
+}
+
+/*
+ * look up the first VMA in which addr resides, NULL if none
+ * - should be called with mm->mmap_sem at least held readlocked
+ */
+struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+{
+ struct vm_area_struct *vma;
+
+ /* check the cache first */
+ vma = vmacache_find(mm, addr);
+ if (likely(vma))
+ return vma;
+
+ /* trawl the list (there may be multiple mappings in which addr
+ * resides) */
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ if (vma->vm_start > addr)
+ return NULL;
+ if (vma->vm_end > addr) {
+ vmacache_update(addr, vma);
+ return vma;
+ }
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(find_vma);
+
+/*
+ * find a VMA
+ * - we don't extend stack VMAs under NOMMU conditions
+ */
+struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
+{
+ return find_vma(mm, addr);
+}
+
+/*
+ * expand a stack to a given address
+ * - not supported under NOMMU conditions
+ */
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+ return -ENOMEM;
+}
+
+/*
+ * look up the first VMA exactly that exactly matches addr
+ * - should be called with mm->mmap_sem at least held readlocked
+ */
+static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
+ unsigned long addr,
+ unsigned long len)
+{
+ struct vm_area_struct *vma;
+ unsigned long end = addr + len;
+
+ /* check the cache first */
+ vma = vmacache_find_exact(mm, addr, end);
+ if (vma)
+ return vma;
+
+ /* trawl the list (there may be multiple mappings in which addr
+ * resides) */
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ if (vma->vm_start < addr)
+ continue;
+ if (vma->vm_start > addr)
+ return NULL;
+ if (vma->vm_end == end) {
+ vmacache_update(addr, vma);
+ return vma;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * determine whether a mapping should be permitted and, if so, what sort of
+ * mapping we're capable of supporting
+ */
+static int validate_mmap_request(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long prot,
+ unsigned long flags,
+ unsigned long pgoff,
+ unsigned long *_capabilities)
+{
+ unsigned long capabilities, rlen;
+ int ret;
+
+ /* do the simple checks first */
+ if (flags & MAP_FIXED) {
+ printk(KERN_DEBUG
+ "%d: Can't do fixed-address/overlay mmap of RAM\n",
+ current->pid);
+ return -EINVAL;
+ }
+
+ if ((flags & MAP_TYPE) != MAP_PRIVATE &&
+ (flags & MAP_TYPE) != MAP_SHARED)
+ return -EINVAL;
+
+ if (!len)
+ return -EINVAL;
+
+ /* Careful about overflows.. */
+ rlen = PAGE_ALIGN(len);
+ if (!rlen || rlen > TASK_SIZE)
+ return -ENOMEM;
+
+ /* offset overflow? */
+ if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
+ return -EOVERFLOW;
+
+ if (file) {
+ /* files must support mmap */
+ if (!file->f_op->mmap)
+ return -ENODEV;
+
+ /* work out if what we've got could possibly be shared
+ * - we support chardevs that provide their own "memory"
+ * - we support files/blockdevs that are memory backed
+ */
+ if (file->f_op->mmap_capabilities) {
+ capabilities = file->f_op->mmap_capabilities(file);
+ } else {
+ /* no explicit capabilities set, so assume some
+ * defaults */
+ switch (file_inode(file)->i_mode & S_IFMT) {
+ case S_IFREG:
+ case S_IFBLK:
+ capabilities = NOMMU_MAP_COPY;
+ break;
+
+ case S_IFCHR:
+ capabilities =
+ NOMMU_MAP_DIRECT |
+ NOMMU_MAP_READ |
+ NOMMU_MAP_WRITE;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ }
+
+ /* eliminate any capabilities that we can't support on this
+ * device */
+ if (!file->f_op->get_unmapped_area)
+ capabilities &= ~NOMMU_MAP_DIRECT;
+ if (!(file->f_mode & FMODE_CAN_READ))
+ capabilities &= ~NOMMU_MAP_COPY;
+
+ /* The file shall have been opened with read permission. */
+ if (!(file->f_mode & FMODE_READ))
+ return -EACCES;
+
+ if (flags & MAP_SHARED) {
+ /* do checks for writing, appending and locking */
+ if ((prot & PROT_WRITE) &&
+ !(file->f_mode & FMODE_WRITE))
+ return -EACCES;
+
+ if (IS_APPEND(file_inode(file)) &&
+ (file->f_mode & FMODE_WRITE))
+ return -EACCES;
+
+ if (locks_verify_locked(file))
+ return -EAGAIN;
+
+ if (!(capabilities & NOMMU_MAP_DIRECT))
+ return -ENODEV;
+
+ /* we mustn't privatise shared mappings */
+ capabilities &= ~NOMMU_MAP_COPY;
+ } else {
+ /* we're going to read the file into private memory we
+ * allocate */
+ if (!(capabilities & NOMMU_MAP_COPY))
+ return -ENODEV;
+
+ /* we don't permit a private writable mapping to be
+ * shared with the backing device */
+ if (prot & PROT_WRITE)
+ capabilities &= ~NOMMU_MAP_DIRECT;
+ }
+
+ if (capabilities & NOMMU_MAP_DIRECT) {
+ if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
+ ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
+ ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
+ ) {
+ capabilities &= ~NOMMU_MAP_DIRECT;
+ if (flags & MAP_SHARED) {
+ printk(KERN_WARNING
+ "MAP_SHARED not completely supported on !MMU\n");
+ return -EINVAL;
+ }
+ }
+ }
+
+ /* handle executable mappings and implied executable
+ * mappings */
+ if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
+ 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) | calc_vm_flag_bits(flags);
+ /* vm_flags |= mm->def_flags; */
+
+ if (!(capabilities & NOMMU_MAP_DIRECT)) {
+ /* attempt to share read-only copies of mapped file chunks */
+ vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+ if (file && !(prot & PROT_WRITE))
+ vm_flags |= VM_MAYSHARE;
+ } else {
+ /* overlay a shareable mapping on the backing device or inode
+ * if possible - used for chardevs, ramfs/tmpfs/shmfs and
+ * romfs/cramfs */
+ vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS);
+ if (flags & MAP_SHARED)
+ vm_flags |= VM_SHARED;
+ }
+
+ /* refuse to let anyone share private mappings with this process if
+ * it's being traced - otherwise breakpoints set in it may interfere
+ * with another untraced process
+ */
+ if ((flags & MAP_PRIVATE) && current->ptrace)
+ vm_flags &= ~VM_MAYSHARE;
+
+ return vm_flags;
+}
+
+/*
+ * set up a shared mapping on a file (the driver or filesystem provides and
+ * pins the storage)
+ */
+static int do_mmap_shared_file(struct vm_area_struct *vma)
+{
+ int ret;
+
+ ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+ if (ret == 0) {
+ vma->vm_region->vm_top = vma->vm_region->vm_end;
+ return 0;
+ }
+ if (ret != -ENOSYS)
+ return ret;
+
+ /* getting -ENOSYS indicates that direct mmap isn't possible (as
+ * opposed to tried but failed) so we can only give a suitable error as
+ * it's not possible to make a private copy if MAP_SHARED was given */
+ return -ENODEV;
+}
+
+/*
+ * set up a private mapping or an anonymous shared mapping
+ */
+static int do_mmap_private(struct vm_area_struct *vma,
+ struct vm_region *region,
+ unsigned long len,
+ unsigned long capabilities)
+{
+ unsigned long total, point;
+ void *base;
+ int ret, order;
+
+ /* invoke the file's mapping function so that it can keep track of
+ * shared mappings on devices or memory
+ * - VM_MAYSHARE will be set if it may attempt to share
+ */
+ if (capabilities & NOMMU_MAP_DIRECT) {
+ ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+ if (ret == 0) {
+ /* shouldn't return success if we're not sharing */
+ BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
+ vma->vm_region->vm_top = vma->vm_region->vm_end;
+ return 0;
+ }
+ if (ret != -ENOSYS)
+ return ret;
+
+ /* getting an ENOSYS error indicates that direct mmap isn't
+ * possible (as opposed to tried but failed) so we'll try to
+ * make a private copy of the data and map that instead */
+ }
+
+
+ /* allocate some memory to hold the mapping
+ * - note that this may not return a page-aligned address if the object
+ * we're allocating is smaller than a page
+ */
+ order = get_order(len);
+ kdebug("alloc order %d for %lx", 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;
+ kdebug("try to alloc exact %lu pages", total);
+ }
+
+ base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
+ if (!base)
+ goto enomem;
+
+ atomic_long_add(total, &mmap_pages_allocated);
+
+ region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
+ region->vm_start = (unsigned long) base;
+ region->vm_end = region->vm_start + len;
+ region->vm_top = region->vm_start + (total << PAGE_SHIFT);
+
+ vma->vm_start = region->vm_start;
+ vma->vm_end = region->vm_start + len;
+
+ if (vma->vm_file) {
+ /* read the contents of a file into the copy */
+ mm_segment_t old_fs;
+ loff_t fpos;
+
+ fpos = vma->vm_pgoff;
+ fpos <<= PAGE_SHIFT;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ ret = __vfs_read(vma->vm_file, base, len, &fpos);
+ set_fs(old_fs);
+
+ if (ret < 0)
+ goto error_free;
+
+ /* clear the last little bit */
+ if (ret < len)
+ memset(base + ret, 0, len - ret);
+
+ }
+
+ return 0;
+
+error_free:
+ free_page_series(region->vm_start, region->vm_top);
+ region->vm_start = vma->vm_start = 0;
+ region->vm_end = vma->vm_end = 0;
+ region->vm_top = 0;
+ return ret;
+
+enomem:
+ pr_err("Allocation of length %lu from process %d (%s) failed\n",
+ len, current->pid, current->comm);
+ show_free_areas(0);
+ return -ENOMEM;
+}
+
+/*
+ * handle mapping creation for uClinux
+ */
+unsigned long do_mmap_pgoff(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long prot,
+ unsigned long flags,
+ unsigned long pgoff,
+ unsigned long *populate)
+{
+ struct vm_area_struct *vma;
+ struct vm_region *region;
+ struct rb_node *rb;
+ unsigned long capabilities, vm_flags, result;
+ int ret;
+
+ kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
+
+ *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) {
+ kleave(" = %d [val]", ret);
+ return ret;
+ }
+
+ /* we ignore the address hint */
+ addr = 0;
+ len = PAGE_ALIGN(len);
+
+ /* we've determined that we can make the mapping, now translate what we
+ * now know into VMA flags */
+ vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+
+ /* we're going to need to record the mapping */
+ region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
+ if (!region)
+ goto error_getting_region;
+
+ vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+ if (!vma)
+ goto error_getting_vma;
+
+ region->vm_usage = 1;
+ region->vm_flags = vm_flags;
+ region->vm_pgoff = pgoff;
+
+ INIT_LIST_HEAD(&vma->anon_vma_chain);
+ vma->vm_flags = vm_flags;
+ vma->vm_pgoff = pgoff;
+
+ if (file) {
+ region->vm_file = get_file(file);
+ vma->vm_file = get_file(file);
+ }
+
+ down_write(&nommu_region_sem);
+
+ /* if we want to share, we need to check for regions created by other
+ * mmap() calls that overlap with our proposed mapping
+ * - we can only share with a superset match on most regular files
+ * - shared mappings on character devices and memory backed files are
+ * permitted to overlap inexactly as far as we are concerned for in
+ * these cases, sharing is handled in the driver or filesystem rather
+ * than here
+ */
+ if (vm_flags & VM_MAYSHARE) {
+ struct vm_region *pregion;
+ unsigned long pglen, rpglen, pgend, rpgend, start;
+
+ pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ pgend = pgoff + pglen;
+
+ for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
+ pregion = rb_entry(rb, struct vm_region, vm_rb);
+
+ if (!(pregion->vm_flags & VM_MAYSHARE))
+ continue;
+
+ /* search for overlapping mappings on the same file */
+ if (file_inode(pregion->vm_file) !=
+ file_inode(file))
+ continue;
+
+ if (pregion->vm_pgoff >= pgend)
+ continue;
+
+ rpglen = pregion->vm_end - pregion->vm_start;
+ rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ rpgend = pregion->vm_pgoff + rpglen;
+ if (pgoff >= rpgend)
+ continue;
+
+ /* handle inexactly overlapping matches between
+ * mappings */
+ if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
+ !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
+ /* new mapping is not a subset of the region */
+ if (!(capabilities & NOMMU_MAP_DIRECT))
+ goto sharing_violation;
+ continue;
+ }
+
+ /* we've found a region we can share */
+ pregion->vm_usage++;
+ vma->vm_region = pregion;
+ start = pregion->vm_start;
+ start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
+ vma->vm_start = start;
+ vma->vm_end = start + len;
+
+ if (pregion->vm_flags & VM_MAPPED_COPY) {
+ kdebug("share copy");
+ vma->vm_flags |= VM_MAPPED_COPY;
+ } else {
+ kdebug("share mmap");
+ ret = do_mmap_shared_file(vma);
+ if (ret < 0) {
+ vma->vm_region = NULL;
+ vma->vm_start = 0;
+ vma->vm_end = 0;
+ pregion->vm_usage--;
+ pregion = NULL;
+ goto error_just_free;
+ }
+ }
+ fput(region->vm_file);
+ kmem_cache_free(vm_region_jar, region);
+ region = pregion;
+ result = start;
+ goto share;
+ }
+
+ /* obtain the address at which to make a shared mapping
+ * - this is the hook for quasi-memory character devices to
+ * tell us the location of a shared mapping
+ */
+ if (capabilities & NOMMU_MAP_DIRECT) {
+ addr = file->f_op->get_unmapped_area(file, addr, len,
+ pgoff, flags);
+ if (IS_ERR_VALUE(addr)) {
+ ret = addr;
+ if (ret != -ENOSYS)
+ goto error_just_free;
+
+ /* the driver refused to tell us where to site
+ * the mapping so we'll have to attempt to copy
+ * it */
+ ret = -ENODEV;
+ if (!(capabilities & NOMMU_MAP_COPY))
+ goto error_just_free;
+
+ capabilities &= ~NOMMU_MAP_DIRECT;
+ } else {
+ vma->vm_start = region->vm_start = addr;
+ vma->vm_end = region->vm_end = addr + len;
+ }
+ }
+ }
+
+ vma->vm_region = region;
+
+ /* set up the mapping
+ * - the region is filled in if NOMMU_MAP_DIRECT is still set
+ */
+ if (file && vma->vm_flags & VM_SHARED)
+ ret = do_mmap_shared_file(vma);
+ else
+ ret = do_mmap_private(vma, region, len, capabilities);
+ if (ret < 0)
+ goto error_just_free;
+ add_nommu_region(region);
+
+ /* clear anonymous mappings that don't ask for uninitialized data */
+ if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
+ memset((void *)region->vm_start, 0,
+ region->vm_end - region->vm_start);
+
+ /* okay... we have a mapping; now we have to register it */
+ result = vma->vm_start;
+
+ current->mm->total_vm += len >> PAGE_SHIFT;
+
+share:
+ add_vma_to_mm(current->mm, vma);
+
+ /* we flush the region from the icache only when the first executable
+ * mapping of it is made */
+ if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
+ flush_icache_range(region->vm_start, region->vm_end);
+ region->vm_icache_flushed = true;
+ }
+
+ up_write(&nommu_region_sem);
+
+ kleave(" = %lx", result);
+ return result;
+
+error_just_free:
+ up_write(&nommu_region_sem);
+error:
+ if (region->vm_file)
+ fput(region->vm_file);
+ kmem_cache_free(vm_region_jar, region);
+ if (vma->vm_file)
+ fput(vma->vm_file);
+ kmem_cache_free(vm_area_cachep, vma);
+ kleave(" = %d", ret);
+ return ret;
+
+sharing_violation:
+ up_write(&nommu_region_sem);
+ printk(KERN_WARNING "Attempt to share mismatched mappings\n");
+ ret = -EINVAL;
+ goto error;
+
+error_getting_vma:
+ kmem_cache_free(vm_region_jar, region);
+ printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
+ " from process %d failed\n",
+ len, current->pid);
+ show_free_areas(0);
+ return -ENOMEM;
+
+error_getting_region:
+ printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
+ " from process %d failed\n",
+ len, current->pid);
+ show_free_areas(0);
+ return -ENOMEM;
+}
+
+SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
+ unsigned long, prot, unsigned long, flags,
+ unsigned long, fd, unsigned long, pgoff)
+{
+ struct file *file = NULL;
+ unsigned long retval = -EBADF;
+
+ audit_mmap_fd(fd, flags);
+ if (!(flags & MAP_ANONYMOUS)) {
+ file = fget(fd);
+ if (!file)
+ goto out;
+ }
+
+ flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+
+ retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+
+ if (file)
+ fput(file);
+out:
+ return retval;
+}
+
+#ifdef __ARCH_WANT_SYS_OLD_MMAP
+struct mmap_arg_struct {
+ unsigned long addr;
+ unsigned long len;
+ unsigned long prot;
+ unsigned long flags;
+ unsigned long fd;
+ unsigned long offset;
+};
+
+SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
+{
+ struct mmap_arg_struct a;
+
+ if (copy_from_user(&a, arg, sizeof(a)))
+ return -EFAULT;
+ if (a.offset & ~PAGE_MASK)
+ return -EINVAL;
+
+ return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+ a.offset >> PAGE_SHIFT);
+}
+#endif /* __ARCH_WANT_SYS_OLD_MMAP */
+
+/*
+ * split a vma into two pieces at address 'addr', a new vma is allocated either
+ * for the first part or the tail.
+ */
+int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
+{
+ struct vm_area_struct *new;
+ struct vm_region *region;
+ unsigned long npages;
+
+ kenter("");
+
+ /* we're only permitted to split anonymous regions (these should have
+ * only a single usage on the region) */
+ if (vma->vm_file)
+ return -ENOMEM;
+
+ if (mm->map_count >= sysctl_max_map_count)
+ return -ENOMEM;
+
+ region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
+ if (!region)
+ return -ENOMEM;
+
+ new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+ if (!new) {
+ kmem_cache_free(vm_region_jar, region);
+ return -ENOMEM;
+ }
+
+ /* most fields are the same, copy all, and then fixup */
+ *new = *vma;
+ *region = *vma->vm_region;
+ new->vm_region = region;
+
+ npages = (addr - vma->vm_start) >> PAGE_SHIFT;
+
+ if (new_below) {
+ region->vm_top = region->vm_end = new->vm_end = addr;
+ } else {
+ region->vm_start = new->vm_start = addr;
+ region->vm_pgoff = new->vm_pgoff += npages;
+ }
+
+ if (new->vm_ops && new->vm_ops->open)
+ new->vm_ops->open(new);
+
+ delete_vma_from_mm(vma);
+ down_write(&nommu_region_sem);
+ delete_nommu_region(vma->vm_region);
+ if (new_below) {
+ vma->vm_region->vm_start = vma->vm_start = addr;
+ vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
+ } else {
+ vma->vm_region->vm_end = vma->vm_end = addr;
+ vma->vm_region->vm_top = addr;
+ }
+ add_nommu_region(vma->vm_region);
+ add_nommu_region(new->vm_region);
+ up_write(&nommu_region_sem);
+ add_vma_to_mm(mm, vma);
+ add_vma_to_mm(mm, new);
+ return 0;
+}
+
+/*
+ * shrink a VMA by removing the specified chunk from either the beginning or
+ * the end
+ */
+static int shrink_vma(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long from, unsigned long to)
+{
+ struct vm_region *region;
+
+ kenter("");
+
+ /* adjust the VMA's pointers, which may reposition it in the MM's tree
+ * and list */
+ delete_vma_from_mm(vma);
+ if (from > vma->vm_start)
+ vma->vm_end = from;
+ else
+ vma->vm_start = to;
+ add_vma_to_mm(mm, vma);
+
+ /* cut the backing region down to size */
+ region = vma->vm_region;
+ BUG_ON(region->vm_usage != 1);
+
+ down_write(&nommu_region_sem);
+ delete_nommu_region(region);
+ if (from > region->vm_start) {
+ to = region->vm_top;
+ region->vm_top = region->vm_end = from;
+ } else {
+ region->vm_start = to;
+ }
+ add_nommu_region(region);
+ up_write(&nommu_region_sem);
+
+ free_page_series(from, to);
+ return 0;
+}
+
+/*
+ * release a mapping
+ * - under NOMMU conditions the chunk to be unmapped must be backed by a single
+ * VMA, though it need not cover the whole VMA
+ */
+int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
+{
+ struct vm_area_struct *vma;
+ unsigned long end;
+ int ret;
+
+ kenter(",%lx,%zx", start, len);
+
+ 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) {
+ printk(KERN_WARNING
+ "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) {
+ kleave(" = -EINVAL [miss]");
+ return -EINVAL;
+ }
+ if (end == vma->vm_end)
+ goto erase_whole_vma;
+ vma = vma->vm_next;
+ } while (vma);
+ kleave(" = -EINVAL [split file]");
+ return -EINVAL;
+ } else {
+ /* the chunk must be a subset of the VMA found */
+ if (start == vma->vm_start && end == vma->vm_end)
+ goto erase_whole_vma;
+ if (start < vma->vm_start || end > vma->vm_end) {
+ kleave(" = -EINVAL [superset]");
+ return -EINVAL;
+ }
+ if (start & ~PAGE_MASK) {
+ kleave(" = -EINVAL [unaligned start]");
+ return -EINVAL;
+ }
+ if (end != vma->vm_end && end & ~PAGE_MASK) {
+ kleave(" = -EINVAL [unaligned split]");
+ return -EINVAL;
+ }
+ if (start != vma->vm_start && end != vma->vm_end) {
+ ret = split_vma(mm, vma, start, 1);
+ if (ret < 0) {
+ kleave(" = %d [split]", ret);
+ return ret;
+ }
+ }
+ return shrink_vma(mm, vma, start, end);
+ }
+
+erase_whole_vma:
+ delete_vma_from_mm(vma);
+ delete_vma(mm, vma);
+ kleave(" = 0");
+ return 0;
+}
+EXPORT_SYMBOL(do_munmap);
+
+int vm_munmap(unsigned long addr, size_t len)
+{
+ struct mm_struct *mm = current->mm;
+ int ret;
+
+ down_write(&mm->mmap_sem);
+ ret = do_munmap(mm, addr, len);
+ up_write(&mm->mmap_sem);
+ return ret;
+}
+EXPORT_SYMBOL(vm_munmap);
+
+SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
+{
+ return vm_munmap(addr, len);
+}
+
+/*
+ * release all the mappings made in a process's VM space
+ */
+void exit_mmap(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma;
+
+ if (!mm)
+ return;
+
+ kenter("");
+
+ mm->total_vm = 0;
+
+ while ((vma = mm->mmap)) {
+ mm->mmap = vma->vm_next;
+ delete_vma_from_mm(vma);
+ delete_vma(mm, vma);
+ cond_resched();
+ }
+
+ kleave("");
+}
+
+unsigned long 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 (addr & ~PAGE_MASK)
+ return -EINVAL;
+
+ if (flags & MREMAP_FIXED && new_addr != addr)
+ return (unsigned long) -EINVAL;
+
+ vma = find_vma_exact(current->mm, addr, old_len);
+ if (!vma)
+ return (unsigned long) -EINVAL;
+
+ if (vma->vm_end != vma->vm_start + old_len)
+ return (unsigned long) -EFAULT;
+
+ if (vma->vm_flags & VM_MAYSHARE)
+ return (unsigned long) -EPERM;
+
+ if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
+ return (unsigned long) -ENOMEM;
+
+ /* all checks complete - do it */
+ vma->vm_end = vma->vm_start + new_len;
+ return vma->vm_start;
+}
+
+SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
+ unsigned long, new_len, unsigned long, flags,
+ unsigned long, new_addr)
+{
+ unsigned long ret;
+
+ down_write(¤t->mm->mmap_sem);
+ ret = do_mremap(addr, old_len, new_len, flags, new_addr);
+ up_write(¤t->mm->mmap_sem);
+ return ret;
+}
+
+struct page *follow_page_mask(struct vm_area_struct *vma,
+ unsigned long address, unsigned int flags,
+ unsigned int *page_mask)
+{
+ *page_mask = 0;
+ return NULL;
+}
+
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+ if (addr != (pfn << PAGE_SHIFT))
+ return -EINVAL;
+
+ vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+ return 0;
+}
+EXPORT_SYMBOL(remap_pfn_range);
+
+int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
+{
+ unsigned long pfn = start >> PAGE_SHIFT;
+ unsigned long vm_len = vma->vm_end - vma->vm_start;
+
+ pfn += vma->vm_pgoff;
+ return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_iomap_memory);
+
+int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
+ unsigned long pgoff)
+{
+ unsigned int size = vma->vm_end - vma->vm_start;
+
+ if (!(vma->vm_flags & VM_USERMAP))
+ return -EINVAL;
+
+ vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
+ vma->vm_end = vma->vm_start + size;
+
+ return 0;
+}
+EXPORT_SYMBOL(remap_vmalloc_range);
+
+unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ return -ENOMEM;
+}
+
+void unmap_mapping_range(struct address_space *mapping,
+ loff_t const holebegin, loff_t const holelen,
+ int even_cows)
+{
+}
+EXPORT_SYMBOL(unmap_mapping_range);
+
+/*
+ * Check that a process has enough memory to allocate a new virtual
+ * mapping. 0 means there is enough memory for the allocation to
+ * succeed and -ENOMEM implies there is not.
+ *
+ * We currently support three overcommit policies, which are set via the
+ * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
+ *
+ * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
+ * Additional code 2002 Jul 20 by Robert Love.
+ *
+ * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
+ *
+ * Note this is a helper function intended to be used by LSMs which
+ * wish to use this logic.
+ */
+int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
+{
+ long free, allowed, reserve;
+
+ vm_acct_memory(pages);
+
+ /*
+ * Sometimes we want to use more memory than we have
+ */
+ if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
+ return 0;
+
+ if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
+ free = global_page_state(NR_FREE_PAGES);
+ free += global_page_state(NR_FILE_PAGES);
+
+ /*
+ * shmem pages shouldn't be counted as free in this
+ * case, they can't be purged, only swapped out, and
+ * that won't affect the overall amount of available
+ * memory in the system.
+ */
+ free -= global_page_state(NR_SHMEM);
+
+ free += get_nr_swap_pages();
+
+ /*
+ * Any slabs which are created with the
+ * SLAB_RECLAIM_ACCOUNT flag claim to have contents
+ * which are reclaimable, under pressure. The dentry
+ * cache and most inode caches should fall into this
+ */
+ free += global_page_state(NR_SLAB_RECLAIMABLE);
+
+ /*
+ * Leave reserved pages. The pages are not for anonymous pages.
+ */
+ if (free <= totalreserve_pages)
+ goto error;
+ else
+ free -= totalreserve_pages;
+
+ /*
+ * Reserve some for root
+ */
+ if (!cap_sys_admin)
+ free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
+
+ if (free > pages)
+ return 0;
+
+ goto error;
+ }
+
+ allowed = vm_commit_limit();
+ /*
+ * Reserve some 3% for root
+ */
+ if (!cap_sys_admin)
+ allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
+
+ /*
+ * Don't let a single process grow so big a user can't recover
+ */
+ if (mm) {
+ reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
+ allowed -= min_t(long, mm->total_vm / 32, reserve);
+ }
+
+ if (percpu_counter_read_positive(&vm_committed_as) < allowed)
+ return 0;
+
+error:
+ vm_unacct_memory(pages);
+
+ return -ENOMEM;
+}
+
+int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ BUG();
+ return 0;
+}
+EXPORT_SYMBOL(filemap_fault);
+
+void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ BUG();
+}
+EXPORT_SYMBOL(filemap_map_pages);
+
+static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long addr, void *buf, int len, int write)
+{
+ struct vm_area_struct *vma;
+
+ down_read(&mm->mmap_sem);
+
+ /* the access must start within one of the target process's mappings */
+ vma = find_vma(mm, addr);
+ if (vma) {
+ /* don't overrun this mapping */
+ if (addr + len >= vma->vm_end)
+ len = vma->vm_end - addr;
+
+ /* only read or write mappings where it is permitted */
+ if (write && vma->vm_flags & VM_MAYWRITE)
+ copy_to_user_page(vma, NULL, addr,
+ (void *) addr, buf, len);
+ else if (!write && vma->vm_flags & VM_MAYREAD)
+ copy_from_user_page(vma, NULL, addr,
+ buf, (void *) addr, len);
+ else
+ len = 0;
+ } else {
+ len = 0;
+ }
+
+ up_read(&mm->mmap_sem);
+
+ return len;
+}
+
+/**
+ * @access_remote_vm - access another process' address space
+ * @mm: the mm_struct of the target address space
+ * @addr: start address to access
+ * @buf: source or destination buffer
+ * @len: number of bytes to transfer
+ * @write: whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+ void *buf, int len, int write)
+{
+ return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
+/*
+ * Access another process' address space.
+ * - source/target buffer must be kernel space
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+ struct mm_struct *mm;
+
+ if (addr + len < addr)
+ return 0;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ len = __access_remote_vm(tsk, mm, addr, buf, len, write);
+
+ mmput(mm);
+ return len;
+}
+
+/**
+ * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
+ * @inode: The inode to check
+ * @size: The current filesize of the inode
+ * @newsize: The proposed filesize of the inode
+ *
+ * Check the shared mappings on an inode on behalf of a shrinking truncate to
+ * make sure that that any outstanding VMAs aren't broken and then shrink the
+ * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
+ * automatically grant mappings that are too large.
+ */
+int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
+ size_t newsize)
+{
+ struct vm_area_struct *vma;
+ struct vm_region *region;
+ pgoff_t low, high;
+ size_t r_size, r_top;
+
+ low = newsize >> PAGE_SHIFT;
+ high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ down_write(&nommu_region_sem);
+ i_mmap_lock_read(inode->i_mapping);
+
+ /* search for VMAs that fall within the dead zone */
+ vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
+ /* found one - only interested if it's shared out of the page
+ * cache */
+ if (vma->vm_flags & VM_SHARED) {
+ i_mmap_unlock_read(inode->i_mapping);
+ up_write(&nommu_region_sem);
+ return -ETXTBSY; /* not quite true, but near enough */
+ }
+ }
+
+ /* reduce any regions that overlap the dead zone - if in existence,
+ * these will be pointed to by VMAs that don't overlap the dead zone
+ *
+ * we don't check for any regions that start beyond the EOF as there
+ * shouldn't be any
+ */
+ vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
+ if (!(vma->vm_flags & VM_SHARED))
+ continue;
+
+ region = vma->vm_region;
+ r_size = region->vm_top - region->vm_start;
+ r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
+
+ if (r_top > newsize) {
+ region->vm_top -= r_top - newsize;
+ if (region->vm_end > region->vm_top)
+ region->vm_end = region->vm_top;
+ }
+ }
+
+ i_mmap_unlock_read(inode->i_mapping);
+ up_write(&nommu_region_sem);
+ return 0;
+}
+
+/*
+ * Initialise sysctl_user_reserve_kbytes.
+ *
+ * This is intended to prevent a user from starting a single memory hogging
+ * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
+ * mode.
+ *
+ * The default value is min(3% of free memory, 128MB)
+ * 128MB is enough to recover with sshd/login, bash, and top/kill.
+ */
+static int __meminit init_user_reserve(void)
+{
+ unsigned long free_kbytes;
+
+ free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+
+ sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
+ return 0;
+}
+module_init(init_user_reserve)
+
+/*
+ * Initialise sysctl_admin_reserve_kbytes.
+ *
+ * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
+ * to log in and kill a memory hogging process.
+ *
+ * Systems with more than 256MB will reserve 8MB, enough to recover
+ * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
+ * only reserve 3% of free pages by default.
+ */
+static int __meminit init_admin_reserve(void)
+{
+ unsigned long free_kbytes;
+
+ free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+
+ sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
+ return 0;
+}
+module_init(init_admin_reserve)
Code Review / kvmfornfv.git / blobdiff