*/
#include <linux/fs.h>
+#include <linux/backing-dev.h>
#include <linux/pagemap.h>
#include <linux/export.h>
#include <linux/uio.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
-/*
- * We do use our own empty page to avoid interference with other users
- * of ZERO_PAGE(), such as /dev/zero
- */
-static DEFINE_MUTEX(xip_sparse_mutex);
-static seqcount_t xip_sparse_seq = SEQCNT_ZERO(xip_sparse_seq);
-static struct page *__xip_sparse_page;
-
-/* called under xip_sparse_mutex */
-static struct page *xip_sparse_page(void)
-{
- if (!__xip_sparse_page) {
- struct page *page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
-
- if (page)
- __xip_sparse_page = page;
- }
- return __xip_sparse_page;
-}
-
-/*
- * This is a file read routine for execute in place files, and uses
- * the mapping->a_ops->get_xip_mem() function for the actual low-level
- * stuff.
- *
- * Note the struct file* is not used at all. It may be NULL.
- */
-static ssize_t
-do_xip_mapping_read(struct address_space *mapping,
- struct file_ra_state *_ra,
- struct file *filp,
- char __user *buf,
- size_t len,
- loff_t *ppos)
-{
- struct inode *inode = mapping->host;
- pgoff_t index, end_index;
- unsigned long offset;
- loff_t isize, pos;
- size_t copied = 0, error = 0;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- pos = *ppos;
- index = pos >> PAGE_CACHE_SHIFT;
- offset = pos & ~PAGE_CACHE_MASK;
-
- isize = i_size_read(inode);
- if (!isize)
- goto out;
-
- end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
- do {
- unsigned long nr, left;
- void *xip_mem;
- unsigned long xip_pfn;
- int zero = 0;
-
- /* nr is the maximum number of bytes to copy from this page */
- nr = PAGE_CACHE_SIZE;
- if (index >= end_index) {
- if (index > end_index)
- goto out;
- nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
- if (nr <= offset) {
- goto out;
- }
- }
- nr = nr - offset;
- if (nr > len - copied)
- nr = len - copied;
-
- error = mapping->a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(error)) {
- if (error == -ENODATA) {
- /* sparse */
- zero = 1;
- } else
- goto out;
- }
-
- /* If users can be writing to this page using arbitrary
- * virtual addresses, take care about potential aliasing
- * before reading the page on the kernel side.
- */
- if (mapping_writably_mapped(mapping))
- /* address based flush */ ;
-
- /*
- * Ok, we have the mem, so now we can copy it to user space...
- *
- * The actor routine returns how many bytes were actually used..
- * NOTE! This may not be the same as how much of a user buffer
- * we filled up (we may be padding etc), so we can only update
- * "pos" here (the actor routine has to update the user buffer
- * pointers and the remaining count).
- */
- if (!zero)
- left = __copy_to_user(buf+copied, xip_mem+offset, nr);
- else
- left = __clear_user(buf + copied, nr);
-
- if (left) {
- error = -EFAULT;
- goto out;
- }
-
- copied += (nr - left);
- offset += (nr - left);
- index += offset >> PAGE_CACHE_SHIFT;
- offset &= ~PAGE_CACHE_MASK;
- } while (copied < len);
-
-out:
- *ppos = pos + copied;
- if (filp)
- file_accessed(filp);
-
- return (copied ? copied : error);
-}
-
-ssize_t
-xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
-{
- if (!access_ok(VERIFY_WRITE, buf, len))
- return -EFAULT;
-
- return do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
- buf, len, ppos);
-}
-EXPORT_SYMBOL_GPL(xip_file_read);
-
-/*
- * __xip_unmap is invoked from xip_unmap and xip_write
- *
- * This function walks all vmas of the address_space and unmaps the
- * __xip_sparse_page when found at pgoff.
- */
-static void __xip_unmap(struct address_space * mapping, unsigned long pgoff)
-{
- struct vm_area_struct *vma;
- struct page *page;
- unsigned count;
- int locked = 0;
-
- count = read_seqcount_begin(&xip_sparse_seq);
-
- page = __xip_sparse_page;
- if (!page)
- return;
-
-retry:
- i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- pte_t *pte, pteval;
- spinlock_t *ptl;
- struct mm_struct *mm = vma->vm_mm;
- unsigned long address = vma->vm_start +
- ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
-
- BUG_ON(address < vma->vm_start || address >= vma->vm_end);
- pte = page_check_address(page, mm, address, &ptl, 1);
- if (pte) {
- /* Nuke the page table entry. */
- flush_cache_page(vma, address, pte_pfn(*pte));
- pteval = ptep_clear_flush(vma, address, pte);
- page_remove_rmap(page);
- dec_mm_counter(mm, MM_FILEPAGES);
- BUG_ON(pte_dirty(pteval));
- pte_unmap_unlock(pte, ptl);
- /* must invalidate_page _before_ freeing the page */
- mmu_notifier_invalidate_page(mm, address);
- page_cache_release(page);
- }
- }
- i_mmap_unlock_read(mapping);
-
- if (locked) {
- mutex_unlock(&xip_sparse_mutex);
- } else if (read_seqcount_retry(&xip_sparse_seq, count)) {
- mutex_lock(&xip_sparse_mutex);
- locked = 1;
- goto retry;
- }
-}
-
-/*
- * xip_fault() is invoked via the vma operations vector for a
- * mapped memory region to read in file data during a page fault.
- *
- * This function is derived from filemap_fault, but used for execute in place
- */
-static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- pgoff_t size;
- void *xip_mem;
- unsigned long xip_pfn;
- struct page *page;
- int error;
-
- /* XXX: are VM_FAULT_ codes OK? */
-again:
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (vmf->pgoff >= size)
- return VM_FAULT_SIGBUS;
-
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (likely(!error))
- goto found;
- if (error != -ENODATA)
- return VM_FAULT_OOM;
-
- /* sparse block */
- if ((vma->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
- (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) &&
- (!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
- int err;
-
- /* maybe shared writable, allocate new block */
- mutex_lock(&xip_sparse_mutex);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- if (error)
- return VM_FAULT_SIGBUS;
- /* unmap sparse mappings at pgoff from all other vmas */
- __xip_unmap(mapping, vmf->pgoff);
-
-found:
- err = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address,
- xip_pfn);
- if (err == -ENOMEM)
- return VM_FAULT_OOM;
- /*
- * err == -EBUSY is fine, we've raced against another thread
- * that faulted-in the same page
- */
- if (err != -EBUSY)
- BUG_ON(err);
- return VM_FAULT_NOPAGE;
- } else {
- int err, ret = VM_FAULT_OOM;
-
- mutex_lock(&xip_sparse_mutex);
- write_seqcount_begin(&xip_sparse_seq);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(!error)) {
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
- goto again;
- }
- if (error != -ENODATA)
- goto out;
- /* not shared and writable, use xip_sparse_page() */
- page = xip_sparse_page();
- if (!page)
- goto out;
- err = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
- page);
- if (err == -ENOMEM)
- goto out;
-
- ret = VM_FAULT_NOPAGE;
-out:
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
-
- return ret;
- }
-}
-
-static const struct vm_operations_struct xip_file_vm_ops = {
- .fault = xip_file_fault,
- .page_mkwrite = filemap_page_mkwrite,
- .remap_pages = generic_file_remap_pages,
-};
-
-int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
-{
- BUG_ON(!file->f_mapping->a_ops->get_xip_mem);
-
- file_accessed(file);
- vma->vm_ops = &xip_file_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_file_mmap);
-
-static ssize_t
-__xip_file_write(struct file *filp, const char __user *buf,
- size_t count, loff_t pos, loff_t *ppos)
-{
- struct address_space * mapping = filp->f_mapping;
- const struct address_space_operations *a_ops = mapping->a_ops;
- struct inode *inode = mapping->host;
- long status = 0;
- size_t bytes;
- ssize_t written = 0;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- do {
- unsigned long index;
- unsigned long offset;
- size_t copied;
- void *xip_mem;
- unsigned long xip_pfn;
-
- offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
- index = pos >> PAGE_CACHE_SHIFT;
- bytes = PAGE_CACHE_SIZE - offset;
- if (bytes > count)
- bytes = count;
-
- status = a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (status == -ENODATA) {
- /* we allocate a new page unmap it */
- mutex_lock(&xip_sparse_mutex);
- status = a_ops->get_xip_mem(mapping, index, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- if (!status)
- /* unmap page at pgoff from all other vmas */
- __xip_unmap(mapping, index);
- }
-
- if (status)
- break;
-
- copied = bytes -
- __copy_from_user_nocache(xip_mem + offset, buf, bytes);
-
- if (likely(copied > 0)) {
- status = copied;
-
- if (status >= 0) {
- written += status;
- count -= status;
- pos += status;
- buf += status;
- }
- }
- if (unlikely(copied != bytes))
- if (status >= 0)
- status = -EFAULT;
- if (status < 0)
- break;
- } while (count);
- *ppos = pos;
- /*
- * No need to use i_size_read() here, the i_size
- * cannot change under us because we hold i_mutex.
- */
- if (pos > inode->i_size) {
- i_size_write(inode, pos);
- mark_inode_dirty(inode);
- }
-
- return written ? written : status;
-}
-
-ssize_t
-xip_file_write(struct file *filp, const char __user *buf, size_t len,
- loff_t *ppos)
-{
- struct address_space *mapping = filp->f_mapping;
- struct inode *inode = mapping->host;
- size_t count;
- loff_t pos;
- ssize_t ret;
-
- mutex_lock(&inode->i_mutex);
-
- if (!access_ok(VERIFY_READ, buf, len)) {
- ret=-EFAULT;
- goto out_up;
- }
-
- pos = *ppos;
- count = len;
-
- /* We can write back this queue in page reclaim */
- current->backing_dev_info = mapping->backing_dev_info;
-
- ret = generic_write_checks(filp, &pos, &count, S_ISBLK(inode->i_mode));
- if (ret)
- goto out_backing;
- if (count == 0)
- goto out_backing;
-
- ret = file_remove_suid(filp);
- if (ret)
- goto out_backing;
-
- ret = file_update_time(filp);
- if (ret)
- goto out_backing;
-
- ret = __xip_file_write (filp, buf, count, pos, ppos);
-
- out_backing:
- current->backing_dev_info = NULL;
- out_up:
- mutex_unlock(&inode->i_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(xip_file_write);
-
-/*
- * truncate a page used for execute in place
- * functionality is analog to block_truncate_page but does use get_xip_mem
- * to get the page instead of page cache
- */
-int
-xip_truncate_page(struct address_space *mapping, loff_t from)
-{
- pgoff_t index = from >> PAGE_CACHE_SHIFT;
- unsigned offset = from & (PAGE_CACHE_SIZE-1);
- unsigned blocksize;
- unsigned length;
- void *xip_mem;
- unsigned long xip_pfn;
- int err;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- blocksize = 1 << mapping->host->i_blkbits;
- length = offset & (blocksize - 1);
-
- /* Block boundary? Nothing to do */
- if (!length)
- return 0;
-
- length = blocksize - length;
-
- err = mapping->a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(err)) {
- if (err == -ENODATA)
- /* Hole? No need to truncate */
- return 0;
- else
- return err;
- }
- memset(xip_mem + offset, 0, length);
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_truncate_page);
projects / linux-drm-fsl-dcu.git / blobdiff