linux-stable.git/include/linux/highmem.h, branch linux-2.6.20.y

[ARM] pass vma for flush_anon_page()

2007-01-08T19:49:54+00:00

Since get_user_pages() may be used with processes other than the
current process and calls flush_anon_page(), flush_anon_page() has to
cope in some way with non-current processes.

It may not be appropriate, or even desirable to flush a region of
virtual memory cache in the current process when that is different to
the process that we want the flush to occur for.

Therefore, pass the vma into flush_anon_page() so that the architecture
can work out whether the 'vmaddr' is for the current process or not.

Signed-off-by: Russell King

[PATCH] Pass vma argument to copy_user_highpage().

2006-12-13T17:27:08+00:00

To allow a more effective copy_user_highpage() on certain architectures,
a vma argument is added to the function and cow_user_page() allowing
the implementation of these functions to check for the VM_EXEC bit.

The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.

Signed-off-by: Atsushi Nemoto 
Signed-off-by: Ralf Baechle 
Signed-off-by: Linus Torvalds

[PATCH] Fix COW D-cache aliasing on fork

2006-12-13T17:27:07+00:00

Problem:

1. There is a process containing two thread (T1 and T2).  The
   thread T1 calls fork().  Then dup_mmap() function called on T1 context.

static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
	...
	flush_cache_mm(current->mm);
	...	/* A */
	(write-protect all Copy-On-Write pages)
	...	/* B */
	flush_tlb_mm(current->mm);
	...

2. When preemption happens between A and B (or on SMP kernel), the
   thread T2 can run and modify data on COW pages without page fault
   (modified data will stay in cache).

3. Some time after fork() completed, the thread T2 may cause a page
   fault by write-protect on a COW page.

4. Then data of the COW page will be copied to newly allocated
   physical page (copy_cow_page()).  It reads data via kernel mapping.
   The kernel mapping can have different 'color' with user space
   mapping of the thread T2 (dcache aliasing).  Therefore
   copy_cow_page() will copy stale data.  Then the modified data in
   cache will be lost.

In order to allow architecture code to deal with this problem allow
architecture code to override copy_user_highpage() by defining
__HAVE_ARCH_COPY_USER_HIGHPAGE in .

The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.

Signed-off-by: Atsushi Nemoto 
Signed-off-by: Ralf Baechle 
Signed-off-by: Linus Torvalds

[PATCH] mm: k{,um}map_atomic() vs in_atomic()

2006-12-07T16:39:21+00:00

Make kmap_atomic/kunmap_atomic denote a pagefault disabled scope.  All non
trivial implementations already do this anyway.

Signed-off-by: Peter Zijlstra 
Acked-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] reduce MAX_NR_ZONES: move HIGHMEM counters into highmem.c/.h

2006-09-26T15:48:46+00:00

Move totalhigh_pages and nr_free_highpages() into highmem.c/.h

Move the totalhigh_pages definition into highmem.c/.h.  Move the
nr_free_highpages function into highmem.c

[yoichi_yuasa@tripeaks.co.jp: build fix]
Signed-off-by: Christoph Lameter 
Signed-off-by: Yoichi Yuasa 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] update to the kernel kmap/kunmap API

2006-09-26T15:48:44+00:00

Give non-highmem architectures access to the kmap API for the purposes of
overriding (this is what the attached patch does).

The proposal is that we should now require all architectures with coherence
issues to manage data coherence via the kmap/kunmap API.  Thus driver
writers never have to write code like

    kmap(page)
    modify data in page
    flush_kernel_dcache_page(page)
    kunmap(page)

instead, kmap/kunmap will manage the coherence and driver (and filesystem)
writers don't need to worry about how to flush between kmap and kunmap.

For most architectures, the page only needs to be flushed if it was
actually written to *and* there are user mappings of it, so the best
implementation looks to be: clear the page dirty pte bit in the kernel page
tables on kmap and on kunmap, check page->mappings for user maps, and then
the dirty bit, and only flush if it both has user mappings and is dirty.

Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Don't include linux/config.h from anywhere else in include/

2006-04-26T11:56:16+00:00

Signed-off-by: David Woodhouse

[PATCH] Add flush_kernel_dcache_page() API

2006-03-26T16:56:53+00:00

We have a problem in a lot of emulated storage in that it takes a page from
get_user_pages() and does something like

kmap_atomic(page)
modify page
kunmap_atomic(page)

However, nothing has flushed the kernel cache view of the page before the
kunmap.  We need a lightweight API to do this, so this new API would
specifically be for flushing the kernel cache view of a user page which the
kernel has modified.  The driver would need to add
flush_kernel_dcache_page(page) before the final kunmap.

Signed-off-by: James Bottomley 
Cc: Russell King 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Add API for flushing Anon pages

2006-03-26T16:56:53+00:00

Currently, get_user_pages() returns fully coherent pages to the kernel for
anything other than anonymous pages.  This is a problem for things like
fuse and the SCSI generic ioctl SG_IO which can potentially wish to do DMA
to anonymous pages passed in by users.

The fix is to add a new memory management API: flush_anon_page() which
is used in get_user_pages() to make anonymous pages coherent.

Signed-off-by: James Bottomley 
Cc: Russell King 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kdump: Routines for copying dump pages

2005-06-25T23:24:53+00:00

This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.

Signed off by Hariprasad Nellitheertha 
Signed-off-by: Eric Biederman 
Signed-off-by: Vivek Goyal 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds