#include <linux/module.h>
#include <linux/delayacct.h>
#include <linux/init.h>
+#include <linux/writeback.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
return retval;
}
-/*
+/**
+ * vm_insert_page - insert single page into user vma
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @page: source kernel page
+ *
* This allows drivers to insert individual pages they've allocated
* into a user vma.
*
return 0;
}
-/* Note: this is only safe if the mm semaphore is held when called. */
+/**
+ * remap_pfn_range - remap kernel memory to userspace
+ * @vma: user vma to map to
+ * @addr: target user address to start at
+ * @pfn: physical address of kernel memory
+ * @size: size of map area
+ * @prot: page protection flags for this mapping
+ *
+ * Note: this is only safe if the mm semaphore is held when called.
+ */
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t prot)
{
goto gotten;
/*
- * Only catch write-faults on shared writable pages, read-only
- * shared pages can get COWed by get_user_pages(.write=1, .force=1).
+ * Take out anonymous pages first, anonymous shared vmas are
+ * not dirty accountable.
*/
- if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
+ if (PageAnon(old_page)) {
+ if (!TestSetPageLocked(old_page)) {
+ reuse = can_share_swap_page(old_page);
+ unlock_page(old_page);
+ }
+ } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
+ /*
+ * Only catch write-faults on shared writable pages,
+ * read-only shared pages can get COWed by
+ * get_user_pages(.write=1, .force=1).
+ */
if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
/*
* Notify the address space that the page is about to
dirty_page = old_page;
get_page(dirty_page);
reuse = 1;
- } else if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
- reuse = can_share_swap_page(old_page);
- unlock_page(old_page);
}
if (reuse) {
entry = mk_pte(new_page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
lazy_mmu_prot_update(entry);
- ptep_establish(vma, address, page_table, entry);
+ /*
+ * Clear the pte entry and flush it first, before updating the
+ * pte with the new entry. This will avoid a race condition
+ * seen in the presence of one thread doing SMC and another
+ * thread doing COW.
+ */
+ ptep_clear_flush(vma, address, page_table);
+ set_pte_at(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
lru_cache_add_active(new_page);
page_add_new_anon_rmap(new_page, vma, address);
unlock:
pte_unmap_unlock(page_table, ptl);
if (dirty_page) {
- set_page_dirty(dirty_page);
+ set_page_dirty_balance(dirty_page);
put_page(dirty_page);
}
return ret;
}
EXPORT_SYMBOL(unmap_mapping_range);
-/*
- * Handle all mappings that got truncated by a "truncate()"
- * system call.
+/**
+ * vmtruncate - unmap mappings "freed" by truncate() syscall
+ * @inode: inode of the file used
+ * @offset: file offset to start truncating
*
* NOTE! We have to be ready to update the memory sharing
* between the file and the memory map for a potential last
}
EXPORT_UNUSED_SYMBOL(vmtruncate_range); /* June 2006 */
-/*
+/**
+ * swapin_readahead - swap in pages in hope we need them soon
+ * @entry: swap entry of this memory
+ * @addr: address to start
+ * @vma: user vma this addresses belong to
+ *
* Primitive swap readahead code. We simply read an aligned block of
* (1 << page_cluster) entries in the swap area. This method is chosen
* because it doesn't cost us any seek time. We also make sure to queue
- * the 'original' request together with the readahead ones...
+ * the 'original' request together with the readahead ones...
*
* This has been extended to use the NUMA policies from the mm triggering
* the readahead.
unlock:
pte_unmap_unlock(page_table, ptl);
if (dirty_page) {
- set_page_dirty(dirty_page);
+ set_page_dirty_balance(dirty_page);
put_page(dirty_page);
}
return ret;
return VM_FAULT_OOM;
}
+/*
+ * do_no_pfn() tries to create a new page mapping for a page without
+ * a struct_page backing it
+ *
+ * As this is called only for pages that do not currently exist, we
+ * do not need to flush old virtual caches or the TLB.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ *
+ * It is expected that the ->nopfn handler always returns the same pfn
+ * for a given virtual mapping.
+ *
+ * Mark this `noinline' to prevent it from bloating the main pagefault code.
+ */
+static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *page_table, pmd_t *pmd,
+ int write_access)
+{
+ spinlock_t *ptl;
+ pte_t entry;
+ unsigned long pfn;
+ int ret = VM_FAULT_MINOR;
+
+ pte_unmap(page_table);
+ BUG_ON(!(vma->vm_flags & VM_PFNMAP));
+ BUG_ON(is_cow_mapping(vma->vm_flags));
+
+ pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
+ if (pfn == NOPFN_OOM)
+ return VM_FAULT_OOM;
+ if (pfn == NOPFN_SIGBUS)
+ return VM_FAULT_SIGBUS;
+
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+
+ /* Only go through if we didn't race with anybody else... */
+ if (pte_none(*page_table)) {
+ entry = pfn_pte(pfn, vma->vm_page_prot);
+ if (write_access)
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ set_pte_at(mm, address, page_table, entry);
+ }
+ pte_unmap_unlock(page_table, ptl);
+ return ret;
+}
+
/*
* Fault of a previously existing named mapping. Repopulate the pte
* from the encoded file_pte if possible. This enables swappable
old_entry = entry = *pte;
if (!pte_present(entry)) {
if (pte_none(entry)) {
- if (!vma->vm_ops || !vma->vm_ops->nopage)
- return do_anonymous_page(mm, vma, address,
- pte, pmd, write_access);
- return do_no_page(mm, vma, address,
- pte, pmd, write_access);
+ if (vma->vm_ops) {
+ if (vma->vm_ops->nopage)
+ return do_no_page(mm, vma, address,
+ pte, pmd,
+ write_access);
+ if (unlikely(vma->vm_ops->nopfn))
+ return do_no_pfn(mm, vma, address, pte,
+ pmd, write_access);
+ }
+ return do_anonymous_page(mm, vma, address,
+ pte, pmd, write_access);
}
if (pte_file(entry))
return do_file_page(mm, vma, address,
}
#endif /* __HAVE_ARCH_GATE_AREA */
+
+/*
+ * Access another process' address space.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ struct page *page;
+ void *old_buf = buf;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ down_read(&mm->mmap_sem);
+ /* ignore errors, just check how much was sucessfully transfered */
+ while (len) {
+ int bytes, ret, offset;
+ void *maddr;
+
+ ret = get_user_pages(tsk, mm, addr, 1,
+ write, 1, &page, &vma);
+ if (ret <= 0)
+ break;
+
+ bytes = len;
+ offset = addr & (PAGE_SIZE-1);
+ if (bytes > PAGE_SIZE-offset)
+ bytes = PAGE_SIZE-offset;
+
+ maddr = kmap(page);
+ if (write) {
+ copy_to_user_page(vma, page, addr,
+ maddr + offset, buf, bytes);
+ set_page_dirty_lock(page);
+ } else {
+ copy_from_user_page(vma, page, addr,
+ buf, maddr + offset, bytes);
+ }
+ kunmap(page);
+ page_cache_release(page);
+ len -= bytes;
+ buf += bytes;
+ addr += bytes;
+ }
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+
+ return buf - old_buf;
+}
projects / linux-2.6-microblaze.git / blobdiff