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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /mm/nommu.c
downloadlinux-linaro-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'mm/nommu.c')
-rw-r--r--mm/nommu.c1180
1 files changed, 1180 insertions, 0 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
new file mode 100644
index 00000000000..b293ec1cc4e
--- /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;
+}