1 files changed, 1180 insertions, 0 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
new file mode 100644
index 000000000000..b293ec1cc4e6
--- /dev/null
+++ b/mm/nommu.c
@@ -0,0 +1,1180 @@
+/*
+ *  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) 2004-2005 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>
+ */
+
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/swap.h>
+#include <linux/file.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/ptrace.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/mount.h>
+#include <linux/personality.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+
+#include <asm/uaccess.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+void *high_memory;
+struct page *mem_map;
+unsigned long max_mapnr;
+unsigned long num_physpages;
+unsigned long askedalloc, realalloc;
+atomic_t vm_committed_space = ATOMIC_INIT(0);
+int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
+int sysctl_overcommit_ratio = 50; /* default is 50% */
+int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
+int heap_stack_gap = 0;
+
+EXPORT_SYMBOL(mem_map);
+EXPORT_SYMBOL(sysctl_max_map_count);
+EXPORT_SYMBOL(sysctl_overcommit_memory);
+EXPORT_SYMBOL(sysctl_overcommit_ratio);
+EXPORT_SYMBOL(vm_committed_space);
+EXPORT_SYMBOL(__vm_enough_memory);
+
+/* list of shareable VMAs */
+struct rb_root nommu_vma_tree = RB_ROOT;
+DECLARE_RWSEM(nommu_vma_sem);
+
+struct vm_operations_struct generic_file_vm_ops = {
+};
+
+/*
+ * Handle all mappings that got truncated by a "truncate()"
+ * system call.
+ *
+ * NOTE! We have to be ready to update the memory sharing
+ * between the file and the memory map for a potential last
+ * incomplete page.  Ugly, but necessary.
+ */
+int vmtruncate(struct inode *inode, loff_t offset)
+{
+        struct address_space *mapping = inode->i_mapping;
+        unsigned long limit;
+
+        if (inode->i_size < offset)
+                goto do_expand;
+        i_size_write(inode, offset);
+
+        truncate_inode_pages(mapping, offset);
+        goto out_truncate;
+
+do_expand:
+        limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+        if (limit != RLIM_INFINITY && offset > limit)
+                goto out_sig;
+        if (offset > inode->i_sb->s_maxbytes)
+                goto out;
+        i_size_write(inode, offset);
+
+out_truncate:
+        if (inode->i_op && inode->i_op->truncate)
+                inode->i_op->truncate(inode);
+        return 0;
+out_sig:
+        send_sig(SIGXFSZ, current, 0);
+out:
+        return -EFBIG;
+}
+
+EXPORT_SYMBOL(vmtruncate);
+
+/*
+ * Return the total memory allocated for this pointer, not
+ * just what the caller asked for.
+ *
+ * Doesn't have to be accurate, i.e. may have races.
+ */
+unsigned int kobjsize(const void *objp)
+{
+        struct page *page;
+
+        if (!objp || !((page = virt_to_page(objp))))
+                return 0;
+
+        if (PageSlab(page))
+                return ksize(objp);
+
+        BUG_ON(page->index < 0);
+        BUG_ON(page->index >= MAX_ORDER);
+
+        return (PAGE_SIZE << page->index);
+}
+
+/*
+ * The nommu dodgy version :-)
+ */
+int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+        unsigned long start, int len, int write, int force,
+        struct page **pages, struct vm_area_struct **vmas)
+{
+        int i;
+        static struct vm_area_struct dummy_vma;
+
+        for (i = 0; i < len; i++) {
+                if (pages) {
+                        pages[i] = virt_to_page(start);
+                        if (pages[i])
+                                page_cache_get(pages[i]);
+                }
+                if (vmas)
+                        vmas[i] = &dummy_vma;
+                start += PAGE_SIZE;
+        }
+        return(i);
+}
+
+DEFINE_RWLOCK(vmlist_lock);
+struct vm_struct *vmlist;
+
+void vfree(void *addr)
+{
+        kfree(addr);
+}
+
+void *__vmalloc(unsigned long size, int gfp_mask, pgprot_t prot)
+{
+        /*
+         * kmalloc doesn't like __GFP_HIGHMEM for some reason
+         */
+        return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
+}
+
+struct page * vmalloc_to_page(void *addr)
+{
+        return virt_to_page(addr);
+}
+
+unsigned long vmalloc_to_pfn(void *addr)
+{
+        return page_to_pfn(virt_to_page(addr));
+}
+
+
+long vread(char *buf, char *addr, unsigned long count)
+{
+        memcpy(buf, addr, count);
+        return count;
+}
+
+long vwrite(char *buf, char *addr, unsigned long count)
+{
+        /* Don't allow overflow */
+        if ((unsigned long) addr + count < count)
+                count = -(unsigned long) addr;
+
+        memcpy(addr, buf, count);
+        return(count);
+}
+
+/*
+ *      vmalloc  -  allocate virtually continguos memory
+ *
+ *      @size:          allocation size
+ *
+ *      Allocate enough pages to cover @size from the page level
+ *      allocator and map them into continguos kernel virtual space.
+ *
+ *      For tight cotrol over page level allocator and protection flags
+ *      use __vmalloc() instead.
+ */
+void *vmalloc(unsigned long size)
+{
+       return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
+}
+
+/*
+ *      vmalloc_32  -  allocate virtually continguos 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);
+}
+
+void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
+{
+        BUG();
+        return NULL;
+}
+
+void vunmap(void *addr)
+{
+        BUG();
+}
+
+/*
+ *  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.
+ */
+asmlinkage unsigned long sys_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.
+         */
+        return mm->brk = brk;
+}
+
+#ifdef DEBUG
+static void show_process_blocks(void)
+{
+        struct vm_list_struct *vml;
+
+        printk("Process blocks %d:", current->pid);
+
+        for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
+                printk(" %p: %p", vml, vml->vma);
+                if (vml->vma)
+                        printk(" (%d @%lx #%d)",
+                               kobjsize((void *) vml->vma->vm_start),
+                               vml->vma->vm_start,
+                               atomic_read(&vml->vma->vm_usage));
+                printk(vml->next ? " ->" : ".\n");
+        }
+}
+#endif /* DEBUG */
+
+static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
+{
+        struct vm_area_struct *vma;
+        struct rb_node *n = nommu_vma_tree.rb_node;
+
+        while (n) {
+                vma = rb_entry(n, struct vm_area_struct, vm_rb);
+
+                if (start < vma->vm_start)
+                        n = n->rb_left;
+                else if (start > vma->vm_start)
+                        n = n->rb_right;
+                else
+                        return vma;
+        }
+
+        return NULL;
+}
+
+static void add_nommu_vma(struct vm_area_struct *vma)
+{
+        struct vm_area_struct *pvma;
+        struct address_space *mapping;
+        struct rb_node **p = &nommu_vma_tree.rb_node;
+        struct rb_node *parent = NULL;
+
+        /* add the VMA to the mapping */
+        if (vma->vm_file) {
+                mapping = vma->vm_file->f_mapping;
+
+                flush_dcache_mmap_lock(mapping);
+                vma_prio_tree_insert(vma, &mapping->i_mmap);
+                flush_dcache_mmap_unlock(mapping);
+        }
+
+        /* add the VMA to the master list */
+        while (*p) {
+                parent = *p;
+                pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
+
+                if (vma->vm_start < pvma->vm_start) {
+                        p = &(*p)->rb_left;
+                }
+                else if (vma->vm_start > pvma->vm_start) {
+                        p = &(*p)->rb_right;
+                }
+                else {
+                        /* mappings are at the same address - this can only
+                         * happen for shared-mem chardevs and shared file
+                         * mappings backed by ramfs/tmpfs */
+                        BUG_ON(!(pvma->vm_flags & VM_SHARED));
+
+                        if (vma < pvma)
+                                p = &(*p)->rb_left;
+                        else if (vma > pvma)
+                                p = &(*p)->rb_right;
+                        else
+                                BUG();
+                }
+        }
+
+        rb_link_node(&vma->vm_rb, parent, p);
+        rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
+}
+
+static void delete_nommu_vma(struct vm_area_struct *vma)
+{
+        struct address_space *mapping;
+
+        /* remove the VMA from the mapping */
+        if (vma->vm_file) {
+                mapping = vma->vm_file->f_mapping;
+
+                flush_dcache_mmap_lock(mapping);
+                vma_prio_tree_remove(vma, &mapping->i_mmap);
+                flush_dcache_mmap_unlock(mapping);
+        }
+
+        /* remove from the master list */
+        rb_erase(&vma->vm_rb, &nommu_vma_tree);
+}
+
+/*
+ * 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;
+        unsigned long reqprot = prot;
+        int ret;
+
+        /* do the simple checks first */
+        if (flags & MAP_FIXED || addr) {
+                printk(KERN_DEBUG
+                       "%d: Can't do fixed-address/overlay mmap of RAM\n",
+                       current->pid);
+                return -EINVAL;
+        }
+
+        if ((flags & MAP_TYPE) != MAP_PRIVATE &&
+            (flags & MAP_TYPE) != MAP_SHARED)
+                return -EINVAL;
+
+        if (PAGE_ALIGN(len) == 0)
+                return addr;
+
+        if (len > TASK_SIZE)
+                return -EINVAL;
+
+        /* offset overflow? */
+        if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
+                return -EINVAL;
+
+        if (file) {
+                /* validate file mapping requests */
+                struct address_space *mapping;
+
+                /* files must support mmap */
+                if (!file->f_op || !file->f_op->mmap)
+                        return -ENODEV;
+
+                /* work out if what we've got could possibly be shared
+                 * - we support chardevs that provide their own "memory"
+                 * - we support files/blockdevs that are memory backed
+                 */
+                mapping = file->f_mapping;
+                if (!mapping)
+                        mapping = file->f_dentry->d_inode->i_mapping;
+
+                capabilities = 0;
+                if (mapping && mapping->backing_dev_info)
+                        capabilities = mapping->backing_dev_info->capabilities;
+
+                if (!capabilities) {
+                        /* no explicit capabilities set, so assume some
+                         * defaults */
+                        switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
+                        case S_IFREG:
+                        case S_IFBLK:
+                                capabilities = BDI_CAP_MAP_COPY;
+                                break;
+
+                        case S_IFCHR:
+                                capabilities =
+                                        BDI_CAP_MAP_DIRECT |
+                                        BDI_CAP_READ_MAP |
+                                        BDI_CAP_WRITE_MAP;
+                                break;
+
+                        default:
+                                return -EINVAL;
+                        }
+                }
+
+                /* eliminate any capabilities that we can't support on this
+                 * device */
+                if (!file->f_op->get_unmapped_area)
+                        capabilities &= ~BDI_CAP_MAP_DIRECT;
+                if (!file->f_op->read)
+                        capabilities &= ~BDI_CAP_MAP_COPY;
+
+                if (flags & MAP_SHARED) {
+                        /* do checks for writing, appending and locking */
+                        if ((prot & PROT_WRITE) &&
+                            !(file->f_mode & FMODE_WRITE))
+                                return -EACCES;
+
+                        if (IS_APPEND(file->f_dentry->d_inode) &&
+                            (file->f_mode & FMODE_WRITE))
+                                return -EACCES;
+
+                        if (locks_verify_locked(file->f_dentry->d_inode))
+                                return -EAGAIN;
+
+                        if (!(capabilities & BDI_CAP_MAP_DIRECT))
+                                return -ENODEV;
+
+                        if (((prot & PROT_READ)  && !(capabilities & BDI_CAP_READ_MAP))  ||
+                            ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
+                            ((prot & PROT_EXEC)  && !(capabilities & BDI_CAP_EXEC_MAP))
+                            ) {
+                                printk("MAP_SHARED not completely supported on !MMU\n");
+                                return -EINVAL;
+                        }
+
+                        /* we mustn't privatise shared mappings */
+                        capabilities &= ~BDI_CAP_MAP_COPY;
+                }
+                else {
+                        /* we're going to read the file into private memory we
+                         * allocate */
+                        if (!(capabilities & BDI_CAP_MAP_COPY))
+                                return -ENODEV;
+
+                        /* we don't permit a private writable mapping to be
+                         * shared with the backing device */
+                        if (prot & PROT_WRITE)
+                                capabilities &= ~BDI_CAP_MAP_DIRECT;
+                }
+
+                /* handle executable mappings and implied executable
+                 * mappings */
+                if (file->f_vfsmnt->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 & BDI_CAP_EXEC_MAP)
+                                        prot |= PROT_EXEC;
+                        }
+                }
+                else if ((prot & PROT_READ) &&
+                         (prot & PROT_EXEC) &&
+                         !(capabilities & BDI_CAP_EXEC_MAP)
+                         ) {
+                        /* backing file is not executable, try to copy */
+                        capabilities &= ~BDI_CAP_MAP_DIRECT;
+                }
+        }
+        else {
+                /* anonymous mappings are always memory backed and can be
+                 * privately mapped
+                 */
+                capabilities = BDI_CAP_MAP_COPY;
+
+                /* handle PROT_EXEC implication by PROT_READ */
+                if ((prot & PROT_READ) &&
+                    (current->personality & READ_IMPLIES_EXEC))
+                        prot |= PROT_EXEC;
+        }
+
+        /* allow the security API to have its say */
+        ret = security_file_mmap(file, reqprot, prot, flags);
+        if (ret < 0)
+                return ret;
+
+        /* looks okay */
+        *_capabilities = capabilities;
+        return 0;
+}
+
+/*
+ * we've determined that we can make the mapping, now translate what we
+ * now know into VMA flags
+ */
+static unsigned long determine_vm_flags(struct file *file,
+                                        unsigned long prot,
+                                        unsigned long flags,
+                                        unsigned long capabilities)
+{
+        unsigned long vm_flags;
+
+        vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
+        vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+        /* vm_flags |= mm->def_flags; */
+
+        if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
+                /* attempt to share read-only copies of mapped file chunks */
+                if (file && !(prot & PROT_WRITE))
+                        vm_flags |= VM_MAYSHARE;
+        }
+        else {
+                /* overlay a shareable mapping on the backing device or inode
+                 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
+                 * romfs/cramfs */
+                if (flags & MAP_SHARED)
+                        vm_flags |= VM_MAYSHARE | VM_SHARED;
+                else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
+                        vm_flags |= VM_MAYSHARE;
+        }
+
+        /* refuse to let anyone share private mappings with this process if
+         * it's being traced - otherwise breakpoints set in it may interfere
+         * with another untraced process
+         */
+        if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
+                vm_flags &= ~VM_MAYSHARE;
+
+        return vm_flags;
+}
+
+/*
+ * set up a shared mapping on a file
+ */
+static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
+{
+        int ret;
+
+        ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+        if (ret != -ENOSYS)
+                return ret;
+
+        /* getting an ENOSYS error indicates that direct mmap isn't
+         * possible (as opposed to tried but failed) so we'll fall
+         * through to making a private copy of the data and mapping
+         * that if we can */
+        return -ENODEV;
+}
+
+/*
+ * set up a private mapping or an anonymous shared mapping
+ */
+static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
+{
+        void *base;
+        int ret;
+
+        /* invoke the file's mapping function so that it can keep track of
+         * shared mappings on devices or memory
+         * - VM_MAYSHARE will be set if it may attempt to share
+         */
+        if (vma->vm_file) {
+                ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+                if (ret != -ENOSYS) {
+                        /* shouldn't return success if we're not sharing */
+                        BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
+                        return ret; /* success or a real error */
+                }
+
+                /* 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
+         */
+        base = kmalloc(len, GFP_KERNEL);
+        if (!base)
+                goto enomem;
+
+        vma->vm_start = (unsigned long) base;
+        vma->vm_end = vma->vm_start + len;
+        vma->vm_flags |= VM_MAPPED_COPY;
+
+#ifdef WARN_ON_SLACK
+        if (len + WARN_ON_SLACK <= kobjsize(result))
+                printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
+                       len, current->pid, kobjsize(result) - len);
+#endif
+
+        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 = vma->vm_file->f_op->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);
+
+        } else {
+                /* if it's an anonymous mapping, then just clear it */
+                memset(base, 0, len);
+        }
+
+        return 0;
+
+error_free:
+        kfree(base);
+        vma->vm_start = 0;
+        return ret;
+
+enomem:
+        printk("Allocation of length %lu from process %d failed\n",
+               len, current->pid);
+        show_free_areas();
+        return -ENOMEM;
+}
+
+/*
+ * handle mapping creation for uClinux
+ */
+unsigned long do_mmap_pgoff(struct file *file,
+                            unsigned long addr,
+                            unsigned long len,
+                            unsigned long prot,
+                            unsigned long flags,
+                            unsigned long pgoff)
+{
+        struct vm_list_struct *vml = NULL;
+        struct vm_area_struct *vma = NULL;
+        struct rb_node *rb;
+        unsigned long capabilities, vm_flags;
+        void *result;
+        int ret;
+
+        /* 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'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 if it works */
+        vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
+        if (!vml)
+                goto error_getting_vml;
+        memset(vml, 0, sizeof(*vml));
+
+        down_write(&nommu_vma_sem);
+
+        /* if we want to share, we need to check for VMAs created by other
+         * mmap() calls that overlap with our proposed mapping
+         * - we can only share with an exact 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) {
+                unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+                unsigned long vmpglen;
+
+                for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
+                        vma = rb_entry(rb, struct vm_area_struct, vm_rb);
+
+                        if (!(vma->vm_flags & VM_MAYSHARE))
+                                continue;
+
+                        /* search for overlapping mappings on the same file */
+                        if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
+                                continue;
+
+                        if (vma->vm_pgoff >= pgoff + pglen)
+                                continue;
+
+                        vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
+                        vmpglen >>= PAGE_SHIFT;
+                        if (pgoff >= vma->vm_pgoff + vmpglen)
+                                continue;
+
+                        /* handle inexactly overlapping matches between mappings */
+                        if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
+                                if (!(capabilities & BDI_CAP_MAP_DIRECT))
+                                        goto sharing_violation;
+                                continue;
+                        }
+
+                        /* we've found a VMA we can share */
+                        atomic_inc(&vma->vm_usage);
+
+                        vml->vma = vma;
+                        result = (void *) vma->vm_start;
+                        goto shared;
+                }
+
+                vma = NULL;
+
+                /* obtain the address at which to make a shared mapping
+                 * - this is the hook for quasi-memory character devices to
+                 *   tell us the location of a shared mapping
+                 */
+                if (file && file->f_op->get_unmapped_area) {
+                        addr = file->f_op->get_unmapped_area(file, addr, len,
+                                                             pgoff, flags);
+                        if (IS_ERR((void *) addr)) {
+                                ret = addr;
+                                if (ret != (unsigned long) -ENOSYS)
+                                        goto error;
+
+                                /* the driver refused to tell us where to site
+                                 * the mapping so we'll have to attempt to copy
+                                 * it */
+                                ret = (unsigned long) -ENODEV;
+                                if (!(capabilities & BDI_CAP_MAP_COPY))
+                                        goto error;
+
+                                capabilities &= ~BDI_CAP_MAP_DIRECT;
+                        }
+                }
+        }
+
+        /* we're going to need a VMA struct as well */
+        vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+        if (!vma)
+                goto error_getting_vma;
+
+        memset(vma, 0, sizeof(*vma));
+        INIT_LIST_HEAD(&vma->anon_vma_node);
+        atomic_set(&vma->vm_usage, 1);
+        if (file)
+                get_file(file);
+        vma->vm_file    = file;
+        vma->vm_flags   = vm_flags;
+        vma->vm_start   = addr;
+        vma->vm_end     = addr + len;
+        vma->vm_pgoff   = pgoff;
+
+        vml->vma = vma;
+
+        /* set up the mapping */
+        if (file && vma->vm_flags & VM_SHARED)
+                ret = do_mmap_shared_file(vma, len);
+        else
+                ret = do_mmap_private(vma, len);
+        if (ret < 0)
+                goto error;
+
+        /* okay... we have a mapping; now we have to register it */
+        result = (void *) vma->vm_start;
+
+        if (vma->vm_flags & VM_MAPPED_COPY) {
+                realalloc += kobjsize(result);
+                askedalloc += len;
+        }
+
+        realalloc += kobjsize(vma);
+        askedalloc += sizeof(*vma);
+
+        current->mm->total_vm += len >> PAGE_SHIFT;
+
+        add_nommu_vma(vma);
+
+ shared:
+        realalloc += kobjsize(vml);
+        askedalloc += sizeof(*vml);
+
+        vml->next = current->mm->context.vmlist;
+        current->mm->context.vmlist = vml;
+
+        up_write(&nommu_vma_sem);
+
+        if (prot & PROT_EXEC)
+                flush_icache_range((unsigned long) result,
+                                   (unsigned long) result + len);
+
+#ifdef DEBUG
+        printk("do_mmap:\n");
+        show_process_blocks();
+#endif
+
+        return (unsigned long) result;
+
+ error:
+        up_write(&nommu_vma_sem);
+        kfree(vml);
+        if (vma) {
+                fput(vma->vm_file);
+                kfree(vma);
+        }
+        return ret;
+
+ sharing_violation:
+        up_write(&nommu_vma_sem);
+        printk("Attempt to share mismatched mappings\n");
+        kfree(vml);
+        return -EINVAL;
+
+ error_getting_vma:
+        up_write(&nommu_vma_sem);
+        kfree(vml);
+        printk("Allocation of vml for %lu byte allocation from process %d failed\n",
+               len, current->pid);
+        show_free_areas();
+        return -ENOMEM;
+
+ error_getting_vml:
+        printk("Allocation of vml for %lu byte allocation from process %d failed\n",
+               len, current->pid);
+        show_free_areas();
+        return -ENOMEM;
+}
+
+/*
+ * handle mapping disposal for uClinux
+ */
+static void put_vma(struct vm_area_struct *vma)
+{
+        if (vma) {
+                down_write(&nommu_vma_sem);
+
+                if (atomic_dec_and_test(&vma->vm_usage)) {
+                        delete_nommu_vma(vma);
+
+                        if (vma->vm_ops && vma->vm_ops->close)
+                                vma->vm_ops->close(vma);
+
+                        /* IO memory and memory shared directly out of the pagecache from
+                         * ramfs/tmpfs mustn't be released here */
+                        if (vma->vm_flags & VM_MAPPED_COPY) {
+                                realalloc -= kobjsize((void *) vma->vm_start);
+                                askedalloc -= vma->vm_end - vma->vm_start;
+                                kfree((void *) vma->vm_start);
+                        }
+
+                        realalloc -= kobjsize(vma);
+                        askedalloc -= sizeof(*vma);
+
+                        if (vma->vm_file)
+                                fput(vma->vm_file);
+                        kfree(vma);
+                }
+
+                up_write(&nommu_vma_sem);
+        }
+}
+
+int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
+{
+        struct vm_list_struct *vml, **parent;
+        unsigned long end = addr + len;
+
+#ifdef DEBUG
+        printk("do_munmap:\n");
+#endif
+
+        for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
+                if ((*parent)->vma->vm_start == addr &&
+                    (*parent)->vma->vm_end == end)
+                        goto found;
+
+        printk("munmap of non-mmaped memory by process %d (%s): %p\n",
+               current->pid, current->comm, (void *) addr);
+        return -EINVAL;
+
+ found:
+        vml = *parent;
+
+        put_vma(vml->vma);
+
+        *parent = vml->next;
+        realalloc -= kobjsize(vml);
+        askedalloc -= sizeof(*vml);
+        kfree(vml);
+        mm->total_vm -= len >> PAGE_SHIFT;
+
+#ifdef DEBUG
+        show_process_blocks();
+#endif
+
+        return 0;
+}
+
+/* Release all mmaps. */
+void exit_mmap(struct mm_struct * mm)
+{
+        struct vm_list_struct *tmp;
+
+        if (mm) {
+#ifdef DEBUG
+                printk("Exit_mmap:\n");
+#endif
+
+                mm->total_vm = 0;
+
+                while ((tmp = mm->context.vmlist)) {
+                        mm->context.vmlist = tmp->next;
+                        put_vma(tmp->vma);
+
+                        realalloc -= kobjsize(tmp);
+                        askedalloc -= sizeof(*tmp);
+                        kfree(tmp);
+                }
+
+#ifdef DEBUG
+                show_process_blocks();
+#endif
+        }
+}
+
+asmlinkage long sys_munmap(unsigned long addr, size_t len)
+{
+        int ret;
+        struct mm_struct *mm = current->mm;
+
+        down_write(&mm->mmap_sem);
+        ret = do_munmap(mm, addr, len);
+        up_write(&mm->mmap_sem);
+        return ret;
+}
+
+unsigned long do_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)
+ *
+ * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
+ * This option implies MREMAP_MAYMOVE.
+ *
+ * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
+ * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
+ */
+unsigned long do_mremap(unsigned long addr,
+                        unsigned long old_len, unsigned long new_len,
+                        unsigned long flags, unsigned long new_addr)
+{
+        struct vm_list_struct *vml = NULL;
+
+        /* insanity checks first */
+        if (new_len == 0)
+                return (unsigned long) -EINVAL;
+
+        if (flags & MREMAP_FIXED && new_addr != addr)
+                return (unsigned long) -EINVAL;
+
+        for (vml = current->mm->context.vmlist; vml; vml = vml->next)
+                if (vml->vma->vm_start == addr)
+                        goto found;
+
+        return (unsigned long) -EINVAL;
+
+ found:
+        if (vml->vma->vm_end != vml->vma->vm_start + old_len)
+                return (unsigned long) -EFAULT;
+
+        if (vml->vma->vm_flags & VM_MAYSHARE)
+                return (unsigned long) -EPERM;
+
+        if (new_len > kobjsize((void *) addr))
+                return (unsigned long) -ENOMEM;
+
+        /* all checks complete - do it */
+        vml->vma->vm_end = vml->vma->vm_start + new_len;
+
+        askedalloc -= old_len;
+        askedalloc += new_len;
+
+        return vml->vma->vm_start;
+}
+
+/*
+ * Look up the first VMA which satisfies  addr < vm_end,  NULL if none
+ */
+struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+{
+        struct vm_list_struct *vml;
+
+        for (vml = mm->context.vmlist; vml; vml = vml->next)
+                if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
+                        return vml->vma;
+
+        return NULL;
+}
+
+EXPORT_SYMBOL(find_vma);
+
+struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write)
+{
+        return NULL;
+}
+
+struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
+{
+        return NULL;
+}
+
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
+                unsigned long to, unsigned long size, pgprot_t prot)
+{
+        return -EPERM;
+}
+
+void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
+{
+}
+
+unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+        return -ENOMEM;
+}
+
+void arch_unmap_area(struct vm_area_struct *area)
+{
+}
+
+void update_mem_hiwater(struct task_struct *tsk)
+{
+        unsigned long rss = get_mm_counter(tsk->mm, rss);
+
+        if (likely(tsk->mm)) {
+                if (tsk->mm->hiwater_rss < rss)
+                        tsk->mm->hiwater_rss = rss;
+                if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
+                        tsk->mm->hiwater_vm = tsk->mm->total_vm;
+        }
+}
+
+void unmap_mapping_range(struct address_space *mapping,
+                         loff_t const holebegin, loff_t const holelen,
+                         int even_cows)
+{
+}
+
+/*
+ * 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(long pages, int cap_sys_admin)
+{
+        unsigned long free, allowed;
+
+        vm_acct_memory(pages);
+
+        /*
+         * Sometimes we want to use more memory than we have
+         */
+        if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
+                return 0;
+
+        if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
+                unsigned long n;
+
+                free = get_page_cache_size();
+                free += nr_swap_pages;
+
+                /*
+                 * Any slabs which are created with the
+                 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
+                 * which are reclaimable, under pressure.  The dentry
+                 * cache and most inode caches should fall into this
+                 */
+                free += atomic_read(&slab_reclaim_pages);
+
+                /*
+                 * Leave the last 3% for root
+                 */
+                if (!cap_sys_admin)
+                        free -= free / 32;
+
+                if (free > pages)
+                        return 0;
+
+                /*
+                 * nr_free_pages() is very expensive on large systems,
+                 * only call if we're about to fail.
+                 */
+                n = nr_free_pages();
+                if (!cap_sys_admin)
+                        n -= n / 32;
+                free += n;
+
+                if (free > pages)
+                        return 0;
+                vm_unacct_memory(pages);
+                return -ENOMEM;
+        }
+
+        allowed = totalram_pages * sysctl_overcommit_ratio / 100;
+        /*
+         * Leave the last 3% for root
+         */
+        if (!cap_sys_admin)
+                allowed -= allowed / 32;
+        allowed += total_swap_pages;
+
+        /* Don't let a single process grow too big:
+           leave 3% of the size of this process for other processes */
+        allowed -= current->mm->total_vm / 32;
+
+        if (atomic_read(&vm_committed_space) < allowed)
+                return 0;
+
+        vm_unacct_memory(pages);
+
+        return -ENOMEM;
+}
+
+int in_gate_area_no_task(unsigned long addr)
+{
+        return 0;
+}