linux-stable.git/mm/memory.c, branch linux-2.6.20.y

[PATCH] i386 vDSO: use VM_ALWAYSDUMP

2007-01-26T21:50:58+00:00

This patch fixes core dumps to include the vDSO vma, which is left out now.
It removes the special-case core writing macros, which were not doing the
right thing for the vDSO vma anyway.  Instead, it uses VM_ALWAYSDUMP in the
vma; there is no need for the fixmap page to be installed.  It handles the
CONFIG_COMPAT_VDSO case by making elf_core_dump use the fake vma from
get_gate_vma after real vmas in the same way the /proc/PID/maps code does.

This changes core dumps so they no longer include the non-PT_LOAD phdrs from
the vDSO.  I made the change to add them in the first place, but in turned out
that nothing ever wanted them there since the advent of NT_AUXV.  It's cleaner
to leave them out, and just let the phdrs inside the vDSO image speak for
themselves.

Signed-off-by: Roland McGrath 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Fix gate_vma.vm_flags

2007-01-26T21:50:58+00:00

This patch fixes the initialization of gate_vma.vm_flags and
gate_vma.vm_page_prot to reflect reality.  This makes the "[vdso]" line in
/proc/PID/maps correctly show r-xp instead of ---p, when gate_vma is used
(CONFIG_COMPAT_VDSO on i386).

Signed-off-by: Roland McGrath 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[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] mm: more rmap debugging

2006-12-22T16:55:49+00:00

Add more debugging in the rmap code in an attempt to locate to source of
the occasional "mapcount went negative" assertions.

Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[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] read_zero_pagealigned() locking fix

2006-12-10T17:55:39+00:00

Ramiro Voicu hits the BUG_ON(!pte_none(*pte)) in zeromap_pte_range: kernel
bugzilla 7645.  Right: read_zero_pagealigned uses down_read of mmap_sem,
but another thread's racing read of /dev/zero, or a normal fault, can
easily set that pte again, in between zap_page_range and zeromap_page_range
getting there.  It's been wrong ever since 2.4.3.

The simple fix is to use down_write instead, but that would serialize reads
of /dev/zero more than at present: perhaps some app would be badly
affected.  So instead let zeromap_page_range return the error instead of
BUG_ON, and read_zero_pagealigned break to the slower clear_user loop in
that case - there's no need to optimize for it.

Use -EEXIST for when a pte is found: BUG_ON in mmap_zero (the other user of
zeromap_page_range), though it really isn't interesting there.  And since
mmap_zero wants -EAGAIN for out-of-memory, the zeromaps better return that
than -ENOMEM.

Signed-off-by: Hugh Dickins 
Cc: Ramiro Voicu: 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols

2006-12-07T16:39:44+00:00

In time for 2.6.20, we can get rid of this junk.

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

[PATCH] grab swap token reordered

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

Make sure the contention for the token happens _before_ any read-in and
kicks the swap-token algo only when the VM is under pressure.

Signed-off-by: Ashwin Chaugule 
Cc: Rik van Riel 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: D-cache aliasing issue in cow_user_page

2006-10-20T17:26:43+00:00

--=-=-=

 from mm/memory.c:
  1434  static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
  1435  {
  1436          /*
  1437           * If the source page was a PFN mapping, we don't have
  1438           * a "struct page" for it. We do a best-effort copy by
  1439           * just copying from the original user address. If that
  1440           * fails, we just zero-fill it. Live with it.
  1441           */
  1442          if (unlikely(!src)) {
  1443                  void *kaddr = kmap_atomic(dst, KM_USER0);
  1444                  void __user *uaddr = (void __user *)(va & PAGE_MASK);
  1445
  1446                  /*
  1447                   * This really shouldn't fail, because the page is there
  1448                   * in the page tables. But it might just be unreadable,
  1449                   * in which case we just give up and fill the result with
  1450                   * zeroes.
  1451                   */
  1452                  if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
  1453                          memset(kaddr, 0, PAGE_SIZE);
  1454                  kunmap_atomic(kaddr, KM_USER0);
  #### D-cache have to be flushed here.
  #### It seems it is just forgotten.

  1455                  return;
  1456
  1457          }
  1458          copy_user_highpage(dst, src, va);
  #### Ok here. flush_dcache_page() called from this func if arch need it
  1459  }

Following is the patch  fix this issue:

Signed-off-by: Dmitriy Monakhov 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] page fault retry with NOPAGE_REFAULT

2006-10-06T15:53:40+00:00

Add a way for a no_page() handler to request a retry of the faulting
instruction.  It goes back to userland on page faults and just tries again
in get_user_pages().  I added a cond_resched() in the loop in that later
case.

The problem I have with signal and spufs is an actual bug affecting apps and I
don't see other ways of fixing it.

In addition, we are having issues with infiniband and 64k pages (related to
the way the hypervisor deals with some HV cards) that will require us to muck
around with the MMU from within the IB driver's no_page() (it's a pSeries
specific driver) and return to the caller the same way using NOPAGE_REFAULT.

And to add to this, the graphics folks have been following a new approach of
memory management that involves transparently swapping objects between video
ram and main meory.  To do that, they need installing PTEs from a no_page()
handler as well and that also requires returning with NOPAGE_REFAULT.

(For the later, they are currently using io_remap_pfn_range to install one PTE
from no_page() which is a bit racy, we need to add a check for the PTE having
already been installed afer taking the lock, but that's ok, they are only at
the proof-of-concept stage.  I'll send a patch adding a "clean" function to do
that, we can use that from spufs too and get rid of the sparsemem hacks we do
to create struct page for SPEs.  Basically, that provides a generic solution
for being able to have no_page() map hardware devices, which is something that
I think sound driver folks have been asking for some time too).

All of these things depend on having the NOPAGE_REFAULT exit path from
no_page() handlers.

Signed-off-by: Benjamin Herrenchmidt 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds