diff options
Diffstat (limited to 'mm/nommu.c')
| -rw-r--r-- | mm/nommu.c | 1180 |
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 = ¤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); +} + +/* + * 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; +} |