| /* |
| * 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). |
| * |
| * 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/smp_lock.h> |
| #include <linux/highmem.h> |
| #include <linux/pagemap.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| #include <linux/blkdev.h> |
| #include <linux/backing-dev.h> |
| |
| #include <asm/pgalloc.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; /* default is heuristic overcommit */ |
| int sysctl_overcommit_ratio = 50; /* default is 50% */ |
| |
| int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; |
| EXPORT_SYMBOL(sysctl_max_map_count); |
| |
| /* |
| * 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->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; |
| } |
| |
| /* |
| * 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); |
| } |
| |
| rwlock_t vmlist_lock = RW_LOCK_UNLOCKED; |
| 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); |
| } |
| |
| 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->end_code || 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 mm_tblock_struct *tblock; |
| |
| printk("Process blocks %d:", current->pid); |
| |
| for (tblock = ¤t->mm->context.tblock; tblock; tblock = tblock->next) { |
| printk(" %p: %p", tblock, tblock->rblock); |
| if (tblock->rblock) |
| printk(" (%d @%p #%d)", kobjsize(tblock->rblock->kblock), tblock->rblock->kblock, tblock->rblock->refcount); |
| printk(tblock->next ? " ->" : ".\n"); |
| } |
| } |
| #endif /* DEBUG */ |
| |
| unsigned long do_mmap_pgoff( |
| struct file * file, |
| unsigned long addr, |
| unsigned long len, |
| unsigned long prot, |
| unsigned long flags, |
| unsigned long pgoff) |
| { |
| void * result; |
| struct mm_tblock_struct * tblock; |
| unsigned int vm_flags; |
| |
| /* |
| * Get the !CONFIG_MMU specific checks done first |
| */ |
| if ((flags & MAP_SHARED) && (prot & PROT_WRITE) && (file)) { |
| printk("MAP_SHARED not supported (cannot write mappings to disk)\n"); |
| return -EINVAL; |
| } |
| |
| if ((prot & PROT_WRITE) && (flags & MAP_PRIVATE)) { |
| printk("Private writable mappings not supported\n"); |
| return -EINVAL; |
| } |
| |
| /* |
| * now all the standard checks |
| */ |
| if (file && (!file->f_op || !file->f_op->mmap)) |
| return -ENODEV; |
| |
| if (PAGE_ALIGN(len) == 0) |
| return addr; |
| |
| if (len > TASK_SIZE) |
| return -EINVAL; |
| |
| /* offset overflow? */ |
| if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| return -EINVAL; |
| |
| /* 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; |
| |
| /* |
| * determine the object being mapped and call the appropriate |
| * specific mapper. |
| */ |
| if (file) { |
| struct vm_area_struct vma; |
| int error; |
| |
| if (!file->f_op) |
| return -ENODEV; |
| |
| vma.vm_start = addr; |
| vma.vm_end = addr + len; |
| vma.vm_flags = vm_flags; |
| vma.vm_pgoff = pgoff; |
| |
| #ifdef MAGIC_ROM_PTR |
| /* First, try simpler routine designed to give us a ROM pointer. */ |
| |
| if (file->f_op->romptr && !(prot & PROT_WRITE)) { |
| error = file->f_op->romptr(file, &vma); |
| #ifdef DEBUG |
| printk("romptr mmap returned %d, start 0x%.8x\n", error, |
| vma.vm_start); |
| #endif |
| if (!error) |
| return vma.vm_start; |
| else if (error != -ENOSYS) |
| return 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) { |
| error = file->f_op->mmap(file, &vma); |
| |
| #ifdef DEBUG |
| printk("f_op->mmap() returned %d/%lx\n", error, vma.vm_start); |
| #endif |
| if (!error) |
| return vma.vm_start; |
| else if (error != -ENOSYS) |
| return error; |
| } else |
| return -ENODEV; /* No mapping operations defined */ |
| |
| /* An ENOSYS error indicates that mmap isn't possible (as opposed to |
| tried but failed) so we'll fall through to the copy. */ |
| } |
| |
| tblock = (struct mm_tblock_struct *) |
| kmalloc(sizeof(struct mm_tblock_struct), GFP_KERNEL); |
| if (!tblock) { |
| printk("Allocation of tblock for %lu byte allocation from process %d failed\n", len, current->pid); |
| show_free_areas(); |
| return -ENOMEM; |
| } |
| |
| tblock->rblock = (struct mm_rblock_struct *) |
| kmalloc(sizeof(struct mm_rblock_struct), GFP_KERNEL); |
| |
| if (!tblock->rblock) { |
| printk("Allocation of rblock for %lu byte allocation from process %d failed\n", len, current->pid); |
| show_free_areas(); |
| kfree(tblock); |
| return -ENOMEM; |
| } |
| |
| result = kmalloc(len, GFP_KERNEL); |
| if (!result) { |
| printk("Allocation of length %lu from process %d failed\n", len, |
| current->pid); |
| show_free_areas(); |
| kfree(tblock->rblock); |
| kfree(tblock); |
| return -ENOMEM; |
| } |
| |
| tblock->rblock->refcount = 1; |
| tblock->rblock->kblock = result; |
| tblock->rblock->size = len; |
| |
| realalloc += kobjsize(result); |
| askedalloc += 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) { |
| int error; |
| mm_segment_t old_fs = get_fs(); |
| set_fs(KERNEL_DS); |
| error = file->f_op->read(file, (char *) result, len, &file->f_pos); |
| set_fs(old_fs); |
| if (error < 0) { |
| kfree(result); |
| kfree(tblock->rblock); |
| kfree(tblock); |
| return error; |
| } |
| if (error < len) |
| memset(result+error, '\0', len-error); |
| } else { |
| memset(result, '\0', len); |
| } |
| |
| realalloc += kobjsize(tblock); |
| askedalloc += sizeof(struct mm_tblock_struct); |
| |
| realalloc += kobjsize(tblock->rblock); |
| askedalloc += sizeof(struct mm_rblock_struct); |
| |
| tblock->next = current->mm->context.tblock.next; |
| current->mm->context.tblock.next = tblock; |
| |
| #ifdef DEBUG |
| printk("do_mmap:\n"); |
| show_process_blocks(); |
| #endif |
| |
| return (unsigned long)result; |
| } |
| |
| int do_munmap(struct mm_struct * mm, unsigned long addr, size_t len) |
| { |
| struct mm_tblock_struct * tblock, *tmp; |
| |
| #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 |
| |
| tmp = &mm->context.tblock; /* dummy head */ |
| while ((tblock=tmp->next) && tblock->rblock && |
| tblock->rblock->kblock != (void*)addr) |
| tmp = tblock; |
| |
| if (!tblock) { |
| printk("munmap of non-mmaped memory by process %d (%s): %p\n", |
| current->pid, current->comm, (void*)addr); |
| return -EINVAL; |
| } |
| if (tblock->rblock) { |
| if (!--tblock->rblock->refcount) { |
| if (tblock->rblock->kblock) { |
| realalloc -= kobjsize(tblock->rblock->kblock); |
| askedalloc -= tblock->rblock->size; |
| kfree(tblock->rblock->kblock); |
| } |
| |
| realalloc -= kobjsize(tblock->rblock); |
| askedalloc -= sizeof(struct mm_rblock_struct); |
| kfree(tblock->rblock); |
| } |
| } |
| tmp->next = tblock->next; |
| realalloc -= kobjsize(tblock); |
| askedalloc -= sizeof(struct mm_tblock_struct); |
| kfree(tblock); |
| |
| #ifdef DEBUG |
| show_process_blocks(); |
| #endif |
| |
| return 0; |
| } |
| |
| /* Release all mmaps. */ |
| void exit_mmap(struct mm_struct * mm) |
| { |
| struct mm_tblock_struct *tmp; |
| |
| if (!mm) |
| return; |
| |
| #ifdef DEBUG |
| printk("Exit_mmap:\n"); |
| #endif |
| |
| while((tmp = mm->context.tblock.next)) { |
| if (tmp->rblock) { |
| if (!--tmp->rblock->refcount) { |
| if (tmp->rblock->kblock) { |
| realalloc -= kobjsize(tmp->rblock->kblock); |
| askedalloc -= tmp->rblock->size; |
| kfree(tmp->rblock->kblock); |
| } |
| realalloc -= kobjsize(tmp->rblock); |
| askedalloc -= sizeof(struct mm_rblock_struct); |
| kfree(tmp->rblock); |
| } |
| tmp->rblock = 0; |
| } |
| mm->context.tblock.next = tmp->next; |
| realalloc -= kobjsize(tmp); |
| askedalloc -= sizeof(struct mm_tblock_struct); |
| 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; |
| } |
| |
| struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) |
| { |
| return NULL; |
| } |
| |
| 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_page_range(struct vm_area_struct *vma, unsigned long from, |
| unsigned long to, unsigned long size, pgprot_t prot) |
| { |
| return -EPERM; |
| } |
| |
| unsigned long get_unmapped_area(struct file *file, unsigned long addr, |
| unsigned long len, unsigned long pgoff, unsigned long flags) |
| { |
| return -ENOMEM; |
| } |
| |
| void swap_unplug_io_fn(struct backing_dev_info *) |
| { |
| } |