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  1. Jul 10, 2016
  3. Jul 09, 2016
  5. Jul 02, 2016
    • Rafael J. Wysocki's avatar
      PM / hibernate: Recycle safe pages after image restoration · 307c5971
      Rafael J. Wysocki authored 
      

One of the memory bitmaps used by the hibernation image restoration
code is freed after the image has been loaded.

That is not quite efficient, though, because the memory pages used
for building that bitmap are known to be safe (ie. they were not
used by the image kernel before hibernation) and the arch-specific
code finalizing the image restoration may need them.  In that case
it needs to allocate those pages again via the memory management
subsystem, check if they are really safe again by consulting the
other bitmaps and so on.

To avoid that, recycle those pages by putting them into the global
list of known safe pages so that they can be given to the arch code
right away when necessary.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      307c5971
    • Rafael J. Wysocki's avatar
      PM / hibernate: Simplify mark_unsafe_pages() · 6dbecfd3
      Rafael J. Wysocki authored 
      

Rework mark_unsafe_pages() to use a simpler method of clearing
all bits in free_pages_map and to set the bits for the "unsafe"
pages (ie. pages that were used by the image kernel before
hibernation) with the help of duplicate_memory_bitmap().

For this purpose, move the pfn_valid() check from mark_unsafe_pages()
to unpack_orig_pfns() where the "unsafe" pages are discovered.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      6dbecfd3
    • Rafael J. Wysocki's avatar
      PM / hibernate: Do not free preallocated safe pages during image restore · 9c744481
      Rafael J. Wysocki authored 
      

The core image restoration code preallocates some safe pages
(ie. pages that weren't used by the image kernel before hibernation)
for future use before allocating the bulk of memory for loading the
image data.  Those safe pages are then freed so they can be allocated
again (with the memory management subsystem's help).  That's done to
ensure that there will be enough safe pages for temporary data
structures needed during image restoration.

However, it is not really necessary to free those pages after they
have been allocated.  They can be added to the (global) list of
safe pages right away and then picked up from there when needed
without freeing.

That reduces the overhead related to using safe pages, especially
in the arch-specific code, so modify the code accordingly.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      9c744481
    • Roger Lu's avatar
      PM / suspend: show workqueue state in suspend flow · 7b776af6
      Roger Lu authored 
      

If freezable workqueue aborts suspend flow, show
workqueue state for debug purpose.

Signed-off-by: default avatarRoger Lu <roger.lu@mediatek.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      7b776af6
  7. Jul 01, 2016
    • Rafael J. Wysocki's avatar
      x86/power/64: Fix kernel text mapping corruption during image restoration · 65c0554b
      Rafael J. Wysocki authored 
      Logan Gunthorpe reports that hibernation stopped working reliably for
him after commit ab76f7b4 (x86/mm: Set NX on gap between __ex_table
and rodata).

That turns out to be a consequence of a long-standing issue with the
64-bit image restoration code on x86, which is that the temporary
page tables set up by it to avoid page tables corruption when the
last bits of the image kernel's memory contents are copied into
their original page frames re-use the boot kernel's text mapping,
but that mapping may very well get corrupted just like any other
part of the page tables.  Of course, if that happens, the final
jump to the image kernel's entry point will go to nowhere.

The exact reason why commit ab76f7b4 matters here is that it
sometimes causes a PMD of a large page to be split into PTEs
that are allocated dynamically and get corrupted during image
restoration as described above.

To fix that issue note that the code copying the last bits of the
image kernel's memory contents to the page frames occupied by them
previoulsy doesn't use the kernel text mapping, because it runs from
a special page covered by the identity mapping set up for that code
from scratch.  Hence, the kernel text mapping is only needed before
that code starts to run and then it will only be used just for the
final jump to the image kernel's entry point.

Accordingly, the temporary page tables set up in swsusp_arch_resume()
on x86-64 need to contain the kernel text mapping too.  That mapping
is only going to be used for the final jump to the image kernel, so
it only needs to cover the image kernel's entry point, because the
first thing the image kernel does after getting control back is to
switch over to its own original page tables.  Moreover, the virtual
address of the image kernel's entry point in that mapping has to be
the same as the one mapped by the image kernel's page tables.

With that in mind, modify the x86-64's arch_hibernation_header_save()
and arch_hibernation_header_restore() routines to pass the physical
address of the image kernel's entry point (in addition to its virtual
address) to the boot kernel (a small piece of assembly code involved
in passing the entry point's virtual address to the image kernel is
not necessary any more after that, so drop it).  Update RESTORE_MAGIC
too to reflect the image header format change.

Next, in set_up_temporary_mappings(), use the physical and virtual
addresses of the image kernel's entry point passed in the image
header to set up a minimum kernel text mapping (using memory pages
that won't be overwritten by the image kernel's memory contents) that
will map those addresses to each other as appropriate.

This makes the concern about the possible corruption of the original
boot kernel text mapping go away and if the the minimum kernel text
mapping used for the final jump marks the image kernel's entry point
memory as executable, the jump to it is guaraneed to succeed.

Fixes: ab76f7b4 (x86/mm: Set NX on gap between __ex_table and rodata)
Link: http://marc.info/?l=linux-pm&m=146372852823760&w=2


Reported-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reported-and-tested-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      65c0554b
  9. Jun 28, 2016
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  13. Jun 25, 2016