<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/kernel/power/power.h, branch linux-6.5.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2023-06-28T17:28:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-06-28T17:28:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6e17c6de3ddf3073741d9c91a796ee696914d8a0'/>
<id>6e17c6de3ddf3073741d9c91a796ee696914d8a0</id>
<content type='text'>
Pull mm updates from Andrew Morton:

 - Yosry Ahmed brought back some cgroup v1 stats in OOM logs

 - Yosry has also eliminated cgroup's atomic rstat flushing

 - Nhat Pham adds the new cachestat() syscall. It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability

 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning

 - Lorenzo Stoakes has done some maintanance work on the
   get_user_pages() interface

 - Liam Howlett continues with cleanups and maintenance work to the
   maple tree code. Peng Zhang also does some work on maple tree

 - Johannes Weiner has done some cleanup work on the compaction code

 - David Hildenbrand has contributed additional selftests for
   get_user_pages()

 - Thomas Gleixner has contributed some maintenance and optimization
   work for the vmalloc code

 - Baolin Wang has provided some compaction cleanups,

 - SeongJae Park continues maintenance work on the DAMON code

 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting

 - Christoph Hellwig has some cleanups for the filemap/directio code

 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the
   provided APIs rather than open-coding accesses

 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings

 - John Hubbard has a series of fixes to the MM selftesting code

 - ZhangPeng continues the folio conversion campaign

 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock

 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
   from 128 to 8

 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management

 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code

 - Vishal Moola also has done some folio conversion work

 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch

* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
  mm/hugetlb: remove hugetlb_set_page_subpool()
  mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
  hugetlb: revert use of page_cache_next_miss()
  Revert "page cache: fix page_cache_next/prev_miss off by one"
  mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
  mm: memcg: rename and document global_reclaim()
  mm: kill [add|del]_page_to_lru_list()
  mm: compaction: convert to use a folio in isolate_migratepages_block()
  mm: zswap: fix double invalidate with exclusive loads
  mm: remove unnecessary pagevec includes
  mm: remove references to pagevec
  mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
  mm: remove struct pagevec
  net: convert sunrpc from pagevec to folio_batch
  i915: convert i915_gpu_error to use a folio_batch
  pagevec: rename fbatch_count()
  mm: remove check_move_unevictable_pages()
  drm: convert drm_gem_put_pages() to use a folio_batch
  i915: convert shmem_sg_free_table() to use a folio_batch
  scatterlist: add sg_set_folio()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull mm updates from Andrew Morton:

 - Yosry Ahmed brought back some cgroup v1 stats in OOM logs

 - Yosry has also eliminated cgroup's atomic rstat flushing

 - Nhat Pham adds the new cachestat() syscall. It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability

 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning

 - Lorenzo Stoakes has done some maintanance work on the
   get_user_pages() interface

 - Liam Howlett continues with cleanups and maintenance work to the
   maple tree code. Peng Zhang also does some work on maple tree

 - Johannes Weiner has done some cleanup work on the compaction code

 - David Hildenbrand has contributed additional selftests for
   get_user_pages()

 - Thomas Gleixner has contributed some maintenance and optimization
   work for the vmalloc code

 - Baolin Wang has provided some compaction cleanups,

 - SeongJae Park continues maintenance work on the DAMON code

 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting

 - Christoph Hellwig has some cleanups for the filemap/directio code

 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the
   provided APIs rather than open-coding accesses

 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings

 - John Hubbard has a series of fixes to the MM selftesting code

 - ZhangPeng continues the folio conversion campaign

 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock

 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
   from 128 to 8

 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management

 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code

 - Vishal Moola also has done some folio conversion work

 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch

* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
  mm/hugetlb: remove hugetlb_set_page_subpool()
  mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
  hugetlb: revert use of page_cache_next_miss()
  Revert "page cache: fix page_cache_next/prev_miss off by one"
  mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
  mm: memcg: rename and document global_reclaim()
  mm: kill [add|del]_page_to_lru_list()
  mm: compaction: convert to use a folio in isolate_migratepages_block()
  mm: zswap: fix double invalidate with exclusive loads
  mm: remove unnecessary pagevec includes
  mm: remove references to pagevec
  mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
  mm: remove struct pagevec
  net: convert sunrpc from pagevec to folio_batch
  i915: convert i915_gpu_error to use a folio_batch
  pagevec: rename fbatch_count()
  mm: remove check_move_unevictable_pages()
  drm: convert drm_gem_put_pages() to use a folio_batch
  i915: convert shmem_sg_free_table() to use a folio_batch
  scatterlist: add sg_set_folio()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_cleanups_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-06-26T23:43:54+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-06-26T23:43:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=19300488c9d9c9ed539ab3f4f1bfc0050c9a4482'/>
<id>19300488c9d9c9ed539ab3f4f1bfc0050c9a4482</id>
<content type='text'>
Pull x86 cleanups from Dave Hansen:
 "As usual, these are all over the map. The biggest cluster is work from
  Arnd to eliminate -Wmissing-prototype warnings:

   - Address -Wmissing-prototype warnings

   - Remove repeated 'the' in comments

   - Remove unused current_untag_mask()

   - Document urgent tip branch timing

   - Clean up MSR kernel-doc notation

   - Clean up paravirt_ops doc

   - Update Srivatsa S. Bhat's maintained areas

   - Remove unused extern declaration acpi_copy_wakeup_routine()"

* tag 'x86_cleanups_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  x86/acpi: Remove unused extern declaration acpi_copy_wakeup_routine()
  Documentation: virt: Clean up paravirt_ops doc
  x86/mm: Remove unused current_untag_mask()
  x86/mm: Remove repeated word in comments
  x86/lib/msr: Clean up kernel-doc notation
  x86/platform: Avoid missing-prototype warnings for OLPC
  x86/mm: Add early_memremap_pgprot_adjust() prototype
  x86/usercopy: Include arch_wb_cache_pmem() declaration
  x86/vdso: Include vdso/processor.h
  x86/mce: Add copy_mc_fragile_handle_tail() prototype
  x86/fbdev: Include asm/fb.h as needed
  x86/hibernate: Declare global functions in suspend.h
  x86/entry: Add do_SYSENTER_32() prototype
  x86/quirks: Include linux/pnp.h for arch_pnpbios_disabled()
  x86/mm: Include asm/numa.h for set_highmem_pages_init()
  x86: Avoid missing-prototype warnings for doublefault code
  x86/fpu: Include asm/fpu/regset.h
  x86: Add dummy prototype for mk_early_pgtbl_32()
  x86/pci: Mark local functions as 'static'
  x86/ftrace: Move prepare_ftrace_return prototype to header
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 cleanups from Dave Hansen:
 "As usual, these are all over the map. The biggest cluster is work from
  Arnd to eliminate -Wmissing-prototype warnings:

   - Address -Wmissing-prototype warnings

   - Remove repeated 'the' in comments

   - Remove unused current_untag_mask()

   - Document urgent tip branch timing

   - Clean up MSR kernel-doc notation

   - Clean up paravirt_ops doc

   - Update Srivatsa S. Bhat's maintained areas

   - Remove unused extern declaration acpi_copy_wakeup_routine()"

* tag 'x86_cleanups_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  x86/acpi: Remove unused extern declaration acpi_copy_wakeup_routine()
  Documentation: virt: Clean up paravirt_ops doc
  x86/mm: Remove unused current_untag_mask()
  x86/mm: Remove repeated word in comments
  x86/lib/msr: Clean up kernel-doc notation
  x86/platform: Avoid missing-prototype warnings for OLPC
  x86/mm: Add early_memremap_pgprot_adjust() prototype
  x86/usercopy: Include arch_wb_cache_pmem() declaration
  x86/vdso: Include vdso/processor.h
  x86/mce: Add copy_mc_fragile_handle_tail() prototype
  x86/fbdev: Include asm/fb.h as needed
  x86/hibernate: Declare global functions in suspend.h
  x86/entry: Add do_SYSENTER_32() prototype
  x86/quirks: Include linux/pnp.h for arch_pnpbios_disabled()
  x86/mm: Include asm/numa.h for set_highmem_pages_init()
  x86: Avoid missing-prototype warnings for doublefault code
  x86/fpu: Include asm/fpu/regset.h
  x86: Add dummy prototype for mk_early_pgtbl_32()
  x86/pci: Mark local functions as 'static'
  x86/ftrace: Move prepare_ftrace_return prototype to header
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>block: use the holder as indication for exclusive opens</title>
<updated>2023-06-12T14:04:04+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2023-06-08T11:02:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2736e8eeb0ccdc71d1f4256c9c9a28f58cc43307'/>
<id>2736e8eeb0ccdc71d1f4256c9c9a28f58cc43307</id>
<content type='text'>
The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder.  Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Acked-by: Christian Brauner &lt;brauner@kernel.org&gt;
Acked-by: David Sterba &lt;dsterba@suse.com&gt;		[btrfs]
Acked-by: Jack Wang &lt;jinpu.wang@ionos.com&gt;		[rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder.  Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Acked-by: Christian Brauner &lt;brauner@kernel.org&gt;
Acked-by: David Sterba &lt;dsterba@suse.com&gt;		[btrfs]
Acked-by: Jack Wang &lt;jinpu.wang@ionos.com&gt;		[rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: page_alloc: move pm_* function into power</title>
<updated>2023-06-09T23:25:24+00:00</updated>
<author>
<name>Kefeng Wang</name>
<email>wangkefeng.wang@huawei.com</email>
</author>
<published>2023-05-16T06:38:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=07f44ac3c90c50a201307d3fe4dda120ee8394f5'/>
<id>07f44ac3c90c50a201307d3fe4dda120ee8394f5</id>
<content type='text'>
pm_restrict_gfp_mask()/pm_restore_gfp_mask() only used in power, let's
move them out of page_alloc.c.

Adding a general gfp_has_io_fs() function which return true if gfp with
both __GFP_IO and __GFP_FS flags, then use it inside of
pm_suspended_storage(), also the pm_suspended_storage() is moved into
suspend.h.

Link: https://lkml.kernel.org/r/20230516063821.121844-11-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Cc: Iurii Zaikin &lt;yzaikin@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Len Brown &lt;len.brown@intel.com&gt;
Cc: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Cc: Mike Rapoport (IBM) &lt;rppt@kernel.org&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Pavel Machek &lt;pavel@ucw.cz&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
pm_restrict_gfp_mask()/pm_restore_gfp_mask() only used in power, let's
move them out of page_alloc.c.

Adding a general gfp_has_io_fs() function which return true if gfp with
both __GFP_IO and __GFP_FS flags, then use it inside of
pm_suspended_storage(), also the pm_suspended_storage() is moved into
suspend.h.

Link: https://lkml.kernel.org/r/20230516063821.121844-11-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Cc: Iurii Zaikin &lt;yzaikin@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Len Brown &lt;len.brown@intel.com&gt;
Cc: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Cc: Mike Rapoport (IBM) &lt;rppt@kernel.org&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Pavel Machek &lt;pavel@ucw.cz&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: hibernate: remove the global snapshot_test variable</title>
<updated>2023-06-05T16:55:20+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2023-05-31T12:55:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d6545e687271ab27472eebff770f2de6a5f1a464'/>
<id>d6545e687271ab27472eebff770f2de6a5f1a464</id>
<content type='text'>
Passing call dependent variable in global variables is a huge
antipattern.  Fix it up.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Link: https://lore.kernel.org/r/20230531125535.676098-4-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Passing call dependent variable in global variables is a huge
antipattern.  Fix it up.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Link: https://lore.kernel.org/r/20230531125535.676098-4-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/hibernate: Declare global functions in suspend.h</title>
<updated>2023-05-18T18:56:18+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2023-05-16T19:35:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8a3e82d38674066f4cbed3588b78b0d9b8b15ed7'/>
<id>8a3e82d38674066f4cbed3588b78b0d9b8b15ed7</id>
<content type='text'>
Three functions that are defined in x86 specific code to override
generic __weak implementations cause a warning because of a missing
prototype:

arch/x86/power/cpu.c:298:5: error: no previous prototype for 'hibernate_resume_nonboot_cpu_disable' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:129:5: error: no previous prototype for 'arch_hibernation_header_restore' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:91:5: error: no previous prototype for 'arch_hibernation_header_save' [-Werror=missing-prototypes]

Move the declarations into a global header so it can be included
by any file defining one of these.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: Alexander Lobakin &lt;aleksander.lobakin@intel.com&gt;
Link: https://lore.kernel.org/all/20230516193549.544673-14-arnd%40kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Three functions that are defined in x86 specific code to override
generic __weak implementations cause a warning because of a missing
prototype:

arch/x86/power/cpu.c:298:5: error: no previous prototype for 'hibernate_resume_nonboot_cpu_disable' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:129:5: error: no previous prototype for 'arch_hibernation_header_restore' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:91:5: error: no previous prototype for 'arch_hibernation_header_save' [-Werror=missing-prototypes]

Move the declarations into a global header so it can be included
by any file defining one of these.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: Alexander Lobakin &lt;aleksander.lobakin@intel.com&gt;
Link: https://lore.kernel.org/all/20230516193549.544673-14-arnd%40kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: hibernate: Turn snapshot_test into global variable</title>
<updated>2023-04-27T17:00:28+00:00</updated>
<author>
<name>Chen Yu</name>
<email>yu.c.chen@intel.com</email>
</author>
<published>2023-04-14T12:10:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=08169a162f97819d3e5b4a342bb9cf5137787154'/>
<id>08169a162f97819d3e5b4a342bb9cf5137787154</id>
<content type='text'>
There is need to check snapshot_test and open block device
in different mode, so as to avoid the race condition.

No functional changes intended.

Suggested-by: Pavankumar Kondeti &lt;quic_pkondeti@quicinc.com&gt;
Signed-off-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is need to check snapshot_test and open block device
in different mode, so as to avoid the race condition.

No functional changes intended.

Suggested-by: Pavankumar Kondeti &lt;quic_pkondeti@quicinc.com&gt;
Signed-off-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: hibernate: Allow ACPI hardware signature to be honoured</title>
<updated>2021-12-08T15:06:10+00:00</updated>
<author>
<name>David Woodhouse</name>
<email>dwmw@amazon.co.uk</email>
</author>
<published>2021-11-08T16:09:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=74d9555580c48a04b2c3b742dfb0c80777aa0b26'/>
<id>74d9555580c48a04b2c3b742dfb0c80777aa0b26</id>
<content type='text'>
Theoretically, when the hardware signature in FACS changes, the OS
is supposed to gracefully decline to attempt to resume from S4:

 "If the signature has changed, OSPM will not restore the system
  context and can boot from scratch"

In practice, Windows doesn't do this and many laptop vendors do allow
the signature to change especially when docking/undocking, so it would
be a bad idea to simply comply with the specification by default in the
general case.

However, there are use cases where we do want the compliant behaviour
and we know it's safe. Specifically, when resuming virtual machines where
we know the hypervisor has changed sufficiently that resume will fail.
We really want to be able to *tell* the guest kernel not to try, so it
boots cleanly and doesn't just crash. This patch provides a way to opt
in to the spec-compliant behaviour on the command line.

A follow-up patch may do this automatically for certain "known good"
machines based on a DMI match, or perhaps just for all hypervisor
guests since there's no good reason a hypervisor would change the
hardware_signature that it exposes to guests *unless* it wants them
to obey the ACPI specification.

Signed-off-by: David Woodhouse &lt;dwmw@amazon.co.uk&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Theoretically, when the hardware signature in FACS changes, the OS
is supposed to gracefully decline to attempt to resume from S4:

 "If the signature has changed, OSPM will not restore the system
  context and can boot from scratch"

In practice, Windows doesn't do this and many laptop vendors do allow
the signature to change especially when docking/undocking, so it would
be a bad idea to simply comply with the specification by default in the
general case.

However, there are use cases where we do want the compliant behaviour
and we know it's safe. Specifically, when resuming virtual machines where
we know the hypervisor has changed sufficiently that resume will fail.
We really want to be able to *tell* the guest kernel not to try, so it
boots cleanly and doesn't just crash. This patch provides a way to opt
in to the spec-compliant behaviour on the command line.

A follow-up patch may do this automatically for certain "known good"
machines based on a DMI match, or perhaps just for all hypervisor
guests since there's no good reason a hypervisor would change the
hardware_signature that it exposes to guests *unless* it wants them
to obey the ACPI specification.

Signed-off-by: David Woodhouse &lt;dwmw@amazon.co.uk&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: sleep: Pause cpuidle later and resume it earlier during system transitions</title>
<updated>2021-10-26T13:52:07+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-10-22T16:07:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=23f62d7ab25bd1a7dbbb89cfcd429df7735855af'/>
<id>23f62d7ab25bd1a7dbbb89cfcd429df7735855af</id>
<content type='text'>
Commit 8651f97bd951 ("PM / cpuidle: System resume hang fix with
cpuidle") that introduced cpuidle pausing during system suspend
did that to work around a platform firmware issue causing systems
to hang during resume if CPUs were allowed to enter idle states
in the system suspend and resume code paths.

However, pausing cpuidle before the last phase of suspending
devices is the source of an otherwise arbitrary difference between
the suspend-to-idle path and other system suspend variants, so it is
cleaner to do that later, before taking secondary CPUs offline (it
is still safer to take secondary CPUs offline with cpuidle paused,
though).

Modify the code accordingly, but in order to avoid code duplication,
introduce new wrapper functions, pm_sleep_disable_secondary_cpus()
and pm_sleep_enable_secondary_cpus(), to combine cpuidle_pause()
and cpuidle_resume(), respectively, with the handling of secondary
CPUs during system-wide transitions to sleep states.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Tested-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 8651f97bd951 ("PM / cpuidle: System resume hang fix with
cpuidle") that introduced cpuidle pausing during system suspend
did that to work around a platform firmware issue causing systems
to hang during resume if CPUs were allowed to enter idle states
in the system suspend and resume code paths.

However, pausing cpuidle before the last phase of suspending
devices is the source of an otherwise arbitrary difference between
the suspend-to-idle path and other system suspend variants, so it is
cleaner to do that later, before taking secondary CPUs offline (it
is still safer to take secondary CPUs offline with cpuidle paused,
though).

Modify the code accordingly, but in order to avoid code duplication,
introduce new wrapper functions, pm_sleep_disable_secondary_cpus()
and pm_sleep_enable_secondary_cpus(), to combine cpuidle_pause()
and cpuidle_resume(), respectively, with the handling of secondary
CPUs during system-wide transitions to sleep states.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Tested-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kernel/power: allow hibernation with page_poison sanity checking</title>
<updated>2020-12-15T20:13:46+00:00</updated>
<author>
<name>Vlastimil Babka</name>
<email>vbabka@suse.cz</email>
</author>
<published>2020-12-15T03:13:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03b6c9a3e8805606c0bb4ad41855fac3bf85c3b9'/>
<id>03b6c9a3e8805606c0bb4ad41855fac3bf85c3b9</id>
<content type='text'>
Page poisoning used to be incompatible with hibernation, as the state of
poisoned pages was lost after resume, thus enabling CONFIG_HIBERNATION
forces CONFIG_PAGE_POISONING_NO_SANITY.  For the same reason, the
poisoning with zeroes variant CONFIG_PAGE_POISONING_ZERO used to disable
hibernation.  The latter restriction was removed by commit 1ad1410f632d
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f9e58 ("PM: hibernate: fix
crashes with init_on_free=1") by making sure free pages are cleared after
resume.

We can use the same mechanism to instead poison free pages with
PAGE_POISON after resume.  This covers both zero and 0xAA patterns.  Thus
we can remove the Kconfig restriction that disables page poison sanity
checking when hibernation is enabled.

Link: https://lkml.kernel.org/r/20201113104033.22907-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;	[hibernation]
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Laura Abbott &lt;labbott@kernel.org&gt;
Cc: Mateusz Nosek &lt;mateusznosek0@gmail.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Page poisoning used to be incompatible with hibernation, as the state of
poisoned pages was lost after resume, thus enabling CONFIG_HIBERNATION
forces CONFIG_PAGE_POISONING_NO_SANITY.  For the same reason, the
poisoning with zeroes variant CONFIG_PAGE_POISONING_ZERO used to disable
hibernation.  The latter restriction was removed by commit 1ad1410f632d
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f9e58 ("PM: hibernate: fix
crashes with init_on_free=1") by making sure free pages are cleared after
resume.

We can use the same mechanism to instead poison free pages with
PAGE_POISON after resume.  This covers both zero and 0xAA patterns.  Thus
we can remove the Kconfig restriction that disables page poison sanity
checking when hibernation is enabled.

Link: https://lkml.kernel.org/r/20201113104033.22907-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;	[hibernation]
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Laura Abbott &lt;labbott@kernel.org&gt;
Cc: Mateusz Nosek &lt;mateusznosek0@gmail.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
