| /* |
| * 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; |
| } |
| |
| /* |
| * Combine the mmap "prot" and "flags" argument into one "vm_flags" used |
| * internally. Essentially, translate the "PROT_xxx" and "MAP_xxx" bits |
| * into "VM_xxx". |
| */ |
| static inline unsigned long calc_vm_flags(unsigned long prot, unsigned long flags) |
| { |
| #define _trans(x,bit1,bit2) \ |
| ((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0) |
| |
| unsigned long prot_bits, flag_bits; |
| prot_bits = |
| _trans(prot, PROT_READ, VM_READ) | |
| _trans(prot, PROT_WRITE, VM_WRITE) | |
| _trans(prot, PROT_EXEC, VM_EXEC); |
| flag_bits = |
| _trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) | |
| _trans(flags, MAP_DENYWRITE, VM_DENYWRITE) | |
| _trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE); |
| return prot_bits | flag_bits; |
| #undef _trans |
| } |
| |
| #ifdef DEBUG |
| static void show_process_blocks(void) |
| { |
| struct vm_list_struct *vml; |
| |
| printk("Process blocks %d:", current->pid); |
| |
| for (vml = ¤t->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); |
| } |
| |
| /* |
| * 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 int vm_flags; |
| void *result; |
| int ret, membacked; |
| |
| /* 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 (PAGE_ALIGN(len) == 0) |
| return addr; |
| |
| if (len > TASK_SIZE) |
| return -EINVAL; |
| |
| /* offset overflow? */ |
| if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| return -EINVAL; |
| |
| /* validate file mapping requests */ |
| membacked = 0; |
| if (file) { |
| /* files must support mmap */ |
| if (!file->f_op || !file->f_op->mmap) |
| return -ENODEV; |
| |
| if ((prot & PROT_EXEC) && |
| (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)) |
| return -EPERM; |
| |
| /* 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 (S_ISCHR(file->f_dentry->d_inode->i_mode)) { |
| membacked = 1; |
| } |
| else { |
| struct address_space *mapping = file->f_mapping; |
| if (!mapping) |
| mapping = file->f_dentry->d_inode->i_mapping; |
| if (mapping && mapping->backing_dev_info) |
| membacked = mapping->backing_dev_info->memory_backed; |
| } |
| |
| 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 (!membacked) { |
| printk("MAP_SHARED not completely supported on !MMU\n"); |
| return -EINVAL; |
| } |
| |
| /* we require greater support from the driver or |
| * filesystem - we ask it to tell us what memory to |
| * use */ |
| if (!file->f_op->get_unmapped_area) |
| return -ENODEV; |
| } |
| else { |
| /* we read private files into memory we allocate */ |
| if (!file->f_op->read) |
| return -ENODEV; |
| } |
| } |
| |
| /* handle PROT_EXEC implication by PROT_READ */ |
| if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
| if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))) |
| prot |= PROT_EXEC; |
| |
| /* do simple checking here so the lower-level routines won't have |
| * to. we assume access permissions have been handled by the open |
| * of the memory object, so we don't do any here. |
| */ |
| vm_flags = calc_vm_flags(prot,flags) /* | mm->def_flags */ |
| | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| |
| if (!membacked) { |
| /* share any file segment that's mapped read-only */ |
| if (((flags & MAP_PRIVATE) && !(prot & PROT_WRITE) && file) || |
| ((flags & MAP_SHARED) && !(prot & PROT_WRITE) && file)) |
| vm_flags |= VM_MAYSHARE; |
| |
| /* refuse to let anyone share files with this process if it's being traced - |
| * otherwise breakpoints set in it may interfere with another untraced process |
| */ |
| if (current->ptrace & PT_PTRACED) |
| vm_flags &= ~(VM_SHARED | VM_MAYSHARE); |
| } |
| else { |
| /* permit sharing of character devices and ramfs files at any time for |
| * anything other than a privately writable mapping |
| */ |
| if (!(flags & MAP_PRIVATE) || !(prot & PROT_WRITE)) { |
| vm_flags |= VM_MAYSHARE; |
| if (flags & MAP_SHARED) |
| vm_flags |= VM_SHARED; |
| } |
| } |
| |
| /* allow the security API to have its say */ |
| ret = security_file_mmap(file, prot, flags); |
| if (ret) |
| return ret; |
| |
| /* 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 search for VMAs created by another |
| * mmap() call 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) >> PAGE_SHIFT; |
| if (pgoff >= vma->vm_pgoff + vmpglen) |
| continue; |
| |
| /* handle inexact matches between mappings */ |
| if (vmpglen != pglen || vma->vm_pgoff != pgoff) { |
| if (!membacked) |
| 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 to map to. we verify (or select) it and ensure |
| * that it represents a valid section of the address space |
| * - this is the hook for quasi-memory character devices |
| */ |
| 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) |
| ret = (unsigned long) -ENODEV; |
| goto error; |
| } |
| } |
| |
| /* 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; |
| |
| /* determine the object being mapped and call the appropriate specific |
| * mapper. |
| */ |
| if (file) { |
| #ifdef MAGIC_ROM_PTR |
| /* First, try simpler routine designed to give us a ROM pointer. */ |
| if (file->f_op->romptr && !(prot & PROT_WRITE)) { |
| ret = file->f_op->romptr(file, vma); |
| #ifdef DEBUG |
| printk("romptr mmap returned %d (st=%lx)\n", |
| ret, vma->vm_start); |
| #endif |
| result = (void *) vma->vm_start; |
| if (!ret) |
| goto done; |
| else if (ret != -ENOSYS) |
| goto error; |
| } else |
| #endif /* MAGIC_ROM_PTR */ |
| /* Then try full mmap routine, which might return a RAM |
| * pointer, or do something truly complicated |
| */ |
| if (file->f_op->mmap) { |
| ret = file->f_op->mmap(file, vma); |
| |
| #ifdef DEBUG |
| printk("f_op->mmap() returned %d (st=%lx)\n", |
| ret, vma->vm_start); |
| #endif |
| result = (void *) vma->vm_start; |
| if (!ret) |
| goto done; |
| else if (ret != -ENOSYS) |
| goto error; |
| } else { |
| ret = -ENODEV; /* No mapping operations defined */ |
| goto error; |
| } |
| |
| /* An ENOSYS error indicates that mmap isn't possible (as |
| * opposed to tried but failed) so we'll fall through to the |
| * copy. */ |
| } |
| |
| /* 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 |
| */ |
| ret = -ENOMEM; |
| result = kmalloc(len, GFP_KERNEL); |
| if (!result) { |
| printk("Allocation of length %lu from process %d failed\n", |
| len, current->pid); |
| show_free_areas(); |
| goto error; |
| } |
| |
| vma->vm_start = (unsigned long) result; |
| vma->vm_end = vma->vm_start + len; |
| |
| #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 (file) { |
| mm_segment_t old_fs = get_fs(); |
| loff_t fpos; |
| |
| fpos = pgoff; |
| fpos <<= PAGE_SHIFT; |
| |
| set_fs(KERNEL_DS); |
| ret = file->f_op->read(file, (char *) result, len, &fpos); |
| set_fs(old_fs); |
| |
| if (ret < 0) |
| goto error2; |
| if (ret < len) |
| memset(result + ret, 0, len - ret); |
| } else { |
| memset(result, 0, len); |
| } |
| |
| if (prot & PROT_EXEC) |
| flush_icache_range((unsigned long) result, (unsigned long) result + len); |
| |
| done: |
| if (!(vma->vm_flags & VM_SHARED)) { |
| 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); |
| |
| #ifdef DEBUG |
| printk("do_mmap:\n"); |
| show_process_blocks(); |
| #endif |
| |
| return (unsigned long) result; |
| |
| error2: |
| kfree(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_IO | VM_SHARED)) && vma->vm_start) { |
| 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 MAGIC_ROM_PTR |
| /* For efficiency's sake, if the pointer is obviously in ROM, |
| don't bother walking the lists to free it */ |
| if (is_in_rom(addr)) |
| return 0; |
| #endif |
| |
| #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(void) |
| { |
| struct task_struct *tsk = current; |
| |
| if (likely(tsk->mm)) { |
| if (tsk->mm->hiwater_rss < tsk->mm->rss) |
| tsk->mm->hiwater_rss = tsk->mm->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; |
| } |
| |