From 871480933a1c28f8a9fed4c4d34d06c439a7a422 Mon Sep 17 00:00:00 2001
From: Srikant Patnaik
Date: Sun, 11 Jan 2015 12:28:04 +0530
Subject: Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
---
mm/filemap_xip.c | 480 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 480 insertions(+)
create mode 100644 mm/filemap_xip.c
(limited to 'mm/filemap_xip.c')
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
new file mode 100644
index 00000000..a4eb3113
--- /dev/null
+++ b/mm/filemap_xip.c
@@ -0,0 +1,480 @@
+/*
+ * linux/mm/filemap_xip.c
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Carsten Otte <cotte@de.ibm.com>
+ *
+ * derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/export.h>
+#include <linux/uio.h>
+#include <linux/rmap.h>
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+#include <linux/seqlock.h>
+#include <linux/mutex.h>
+#include <linux/gfp.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;
+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 mm_struct *mm;
+ struct prio_tree_iter iter;
+ unsigned long address;
+ pte_t *pte;
+ pte_t pteval;
+ spinlock_t *ptl;
+ struct page *page;
+ unsigned count;
+ int locked = 0;
+
+ count = read_seqcount_begin(&xip_sparse_seq);
+
+ page = __xip_sparse_page;
+ if (!page)
+ return;
+
+retry:
+ mutex_lock(&mapping->i_mmap_mutex);
+ vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
+ mm = vma->vm_mm;
+ 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_notify(vma, address, pte);
+ page_remove_rmap(page);
+ dec_mm_counter(mm, MM_FILEPAGES);
+ BUG_ON(pte_dirty(pteval));
+ pte_unmap_unlock(pte, ptl);
+ page_cache_release(page);
+ }
+ }
+ mutex_unlock(&mapping->i_mmap_mutex);
+
+ 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,
+};
+
+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_CAN_NONLINEAR | 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;
+
+ vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+ /* 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;
+
+ file_update_time(filp);
+
+ 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);
--
cgit