string: factorize skip_spaces and export it to be generally available
[safe/jmp/linux-2.6] / mm / nommu.c
index 0c3e7d2..8687973 100644 (file)
@@ -33,6 +33,7 @@
 #include <asm/uaccess.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
 #include "internal.h"
 
 static inline __attribute__((format(printf, 1, 2)))
@@ -56,20 +57,19 @@ void no_printk(const char *fmt, ...)
        no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
 #endif
 
-#include "internal.h"
-
 void *high_memory;
 struct page *mem_map;
 unsigned long max_mapnr;
 unsigned long num_physpages;
-atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
+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% */
 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
-int sysctl_nr_trim_pages = 1; /* page trimming behaviour */
+int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
 int heap_stack_gap = 0;
 
-atomic_t mmap_pages_allocated;
+atomic_long_t mmap_pages_allocated;
 
 EXPORT_SYMBOL(mem_map);
 EXPORT_SYMBOL(num_physpages);
@@ -79,50 +79,10 @@ static struct kmem_cache *vm_region_jar;
 struct rb_root nommu_region_tree = RB_ROOT;
 DECLARE_RWSEM(nommu_region_sem);
 
-struct vm_operations_struct generic_file_vm_ops = {
+const 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->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.
  *
@@ -170,30 +130,29 @@ unsigned int kobjsize(const void *objp)
 }
 
 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                    unsigned long start, int len, int flags,
-               struct page **pages, struct vm_area_struct **vmas)
+                    unsigned long start, int nr_pages, unsigned int foll_flags,
+                    struct page **pages, struct vm_area_struct **vmas)
 {
        struct vm_area_struct *vma;
        unsigned long vm_flags;
        int i;
-       int write = !!(flags & GUP_FLAGS_WRITE);
-       int force = !!(flags & GUP_FLAGS_FORCE);
-       int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
 
        /* calculate required read or write permissions.
-        * - if 'force' is set, we only require the "MAY" flags.
+        * If FOLL_FORCE is set, we only require the "MAY" flags.
         */
-       vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
-       vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+       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 < len; i++) {
+       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) ||
-                   (!ignore && !(vm_flags & vma->vm_flags)))
+               if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+                   !(vm_flags & vma->vm_flags))
                        goto finish_or_fault;
 
                if (pages) {
@@ -212,7 +171,6 @@ 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
@@ -221,22 +179,41 @@ finish_or_fault:
  * - don't permit access to VMAs that don't support it, such as I/O mappings
  */
 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-       unsigned long start, int len, int write, int force,
+       unsigned long start, int nr_pages, int write, int force,
        struct page **pages, struct vm_area_struct **vmas)
 {
        int flags = 0;
 
        if (write)
-               flags |= GUP_FLAGS_WRITE;
+               flags |= FOLL_WRITE;
        if (force)
-               flags |= GUP_FLAGS_FORCE;
+               flags |= FOLL_FORCE;
 
-       return __get_user_pages(tsk, mm,
-                               start, len, flags,
-                               pages, vmas);
+       return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
 }
 EXPORT_SYMBOL(get_user_pages);
 
+/**
+ * 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);
+
 DEFINE_RWLOCK(vmlist_lock);
 struct vm_struct *vmlist;
 
@@ -463,12 +440,11 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
  */
 void __init mmap_init(void)
 {
-       vm_region_jar = kmem_cache_create("vm_region_jar",
-                                         sizeof(struct vm_region), 0,
-                                         SLAB_PANIC, NULL);
-       vm_area_cachep = kmem_cache_create("vm_area_struct",
-                                          sizeof(struct vm_area_struct), 0,
-                                          SLAB_PANIC, NULL);
+       int ret;
+
+       ret = percpu_counter_init(&vm_committed_as, 0);
+       VM_BUG_ON(ret);
+       vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
 }
 
 /*
@@ -486,27 +462,24 @@ static noinline void validate_nommu_regions(void)
                return;
 
        last = rb_entry(lastp, struct vm_region, vm_rb);
-       if (unlikely(last->vm_end <= last->vm_start))
-               BUG();
-       if (unlikely(last->vm_top < last->vm_end))
-               BUG();
+       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);
 
-               if (unlikely(region->vm_end <= region->vm_start))
-                       BUG();
-               if (unlikely(region->vm_top < region->vm_end))
-                       BUG();
-               if (unlikely(region->vm_start < last->vm_top))
-                       BUG();
+               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
-#define validate_nommu_regions() do {} while(0)
+static void validate_nommu_regions(void)
+{
+}
 #endif
 
 /*
@@ -519,8 +492,6 @@ static void add_nommu_region(struct vm_region *region)
 
        validate_nommu_regions();
 
-       BUG_ON(region->vm_start & ~PAGE_MASK);
-
        parent = NULL;
        p = &nommu_region_tree.rb_node;
        while (*p) {
@@ -563,16 +534,17 @@ static void free_page_series(unsigned long from, unsigned long to)
                struct page *page = virt_to_page(from);
 
                kdebug("- free %lx", from);
-               atomic_dec(&mmap_pages_allocated);
+               atomic_long_dec(&mmap_pages_allocated);
                if (page_count(page) != 1)
-                       kdebug("free page %p [%d]", page, page_count(page));
+                       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, which this releases
+ * - 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
  */
@@ -613,6 +585,22 @@ static void put_nommu_region(struct vm_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
@@ -631,6 +619,8 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
        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;
@@ -693,6 +683,8 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
 
        kenter("%p", vma);
 
+       protect_vma(vma, 0);
+
        mm->map_count--;
        if (mm->mmap_cache == vma)
                mm->mmap_cache = NULL;
@@ -834,7 +826,7 @@ static int validate_mmap_request(struct file *file,
        int ret;
 
        /* do the simple checks first */
-       if (flags & MAP_FIXED || addr) {
+       if (flags & MAP_FIXED) {
                printk(KERN_DEBUG
                       "%d: Can't do fixed-address/overlay mmap of RAM\n",
                       current->pid);
@@ -905,6 +897,10 @@ static int validate_mmap_request(struct file *file,
                if (!file->f_op->read)
                        capabilities &= ~BDI_CAP_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) &&
@@ -1038,7 +1034,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma)
        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 ret;
+               return 0;
        }
        if (ret != -ENOSYS)
                return ret;
@@ -1055,7 +1051,8 @@ static int do_mmap_shared_file(struct vm_area_struct *vma)
  */
 static int do_mmap_private(struct vm_area_struct *vma,
                           struct vm_region *region,
-                          unsigned long len)
+                          unsigned long len,
+                          unsigned long capabilities)
 {
        struct page *pages;
        unsigned long total, point, n, rlen;
@@ -1066,13 +1063,13 @@ static int do_mmap_private(struct vm_area_struct *vma,
         * shared mappings on devices or memory
         * - VM_MAYSHARE will be set if it may attempt to share
         */
-       if (vma->vm_file) {
+       if (capabilities & BDI_CAP_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 ret;
+                       return 0;
                }
                if (ret != -ENOSYS)
                        return ret;
@@ -1096,7 +1093,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
                goto enomem;
 
        total = 1 << order;
-       atomic_add(total, &mmap_pages_allocated);
+       atomic_long_add(total, &mmap_pages_allocated);
 
        point = rlen >> PAGE_SHIFT;
 
@@ -1107,7 +1104,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
                        order = ilog2(total - point);
                        n = 1 << order;
                        kdebug("shave %lu/%lu @%lu", n, total - point, total);
-                       atomic_sub(n, &mmap_pages_allocated);
+                       atomic_long_sub(n, &mmap_pages_allocated);
                        total -= n;
                        set_page_refcounted(pages + total);
                        __free_pages(pages + total, order);
@@ -1146,9 +1143,6 @@ static int do_mmap_private(struct vm_area_struct *vma,
                if (ret < rlen)
                        memset(base + ret, 0, rlen - ret);
 
-       } else {
-               /* if it's an anonymous mapping, then just clear it */
-               memset(base, 0, rlen);
        }
 
        return 0;
@@ -1161,8 +1155,8 @@ error_free:
        return ret;
 
 enomem:
-       printk("Allocation of length %lu from process %d failed\n",
-              len, current->pid);
+       printk("Allocation of length %lu from process %d (%s) failed\n",
+              len, current->pid, current->comm);
        show_free_areas();
        return -ENOMEM;
 }
@@ -1185,9 +1179,6 @@ unsigned long do_mmap_pgoff(struct file *file,
 
        kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
 
-       if (!(flags & MAP_FIXED))
-               addr = round_hint_to_min(addr);
-
        /* decide whether we should attempt the mapping, and if so what sort of
         * mapping */
        ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
@@ -1197,6 +1188,9 @@ unsigned long do_mmap_pgoff(struct file *file,
                return ret;
        }
 
+       /* we ignore the address hint */
+       addr = 0;
+
        /* 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);
@@ -1310,7 +1304,7 @@ unsigned long do_mmap_pgoff(struct file *file,
                 * - 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) {
+               if (capabilities & BDI_CAP_MAP_DIRECT) {
                        addr = file->f_op->get_unmapped_area(file, addr, len,
                                                             pgoff, flags);
                        if (IS_ERR((void *) addr)) {
@@ -1335,16 +1329,22 @@ unsigned long do_mmap_pgoff(struct file *file,
 
        vma->vm_region = region;
 
-       /* set up the mapping */
+       /* set up the mapping
+        * - the region is filled in if BDI_CAP_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);
+               ret = do_mmap_private(vma, region, len, capabilities);
        if (ret < 0)
-               goto error_put_region;
-
+               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;
 
@@ -1361,25 +1361,14 @@ share:
        kleave(" = %lx", result);
        return result;
 
-error_put_region:
-       __put_nommu_region(region);
-       if (vma) {
-               if (vma->vm_file) {
-                       fput(vma->vm_file);
-                       if (vma->vm_flags & VM_EXECUTABLE)
-                               removed_exe_file_vma(vma->vm_mm);
-               }
-               kmem_cache_free(vm_area_cachep, vma);
-       }
-       kleave(" = %d [pr]", ret);
-       return ret;
-
 error_just_free:
        up_write(&nommu_region_sem);
 error:
-       fput(region->vm_file);
+       if (region->vm_file)
+               fput(region->vm_file);
        kmem_cache_free(vm_region_jar, region);
-       fput(vma->vm_file);
+       if (vma->vm_file)
+               fput(vma->vm_file);
        if (vma->vm_flags & VM_EXECUTABLE)
                removed_exe_file_vma(vma->vm_mm);
        kmem_cache_free(vm_area_cachep, vma);
@@ -1536,10 +1525,15 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
        /* find the first potentially overlapping VMA */
        vma = find_vma(mm, start);
        if (!vma) {
-               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);
+               static int limit = 0;
+               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;
        }
 
@@ -1849,12 +1843,9 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
        if (mm)
                allowed -= mm->total_vm / 32;
 
-       /*
-        * cast `allowed' as a signed long because vm_committed_space
-        * sometimes has a negative value
-        */
-       if (atomic_long_read(&vm_committed_space) < (long)allowed)
+       if (percpu_counter_read_positive(&vm_committed_as) < allowed)
                return 0;
+
 error:
        vm_unacct_memory(pages);