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  1. Mar 14, 2021
    • Mike Rapoport's avatar
      mm/page_alloc.c: refactor initialization of struct page for holes in memory layout · 0740a50b
      Mike Rapoport authored 
      There could be struct pages that are not backed by actual physical memory.
This can happen when the actual memory bank is not a multiple of
SECTION_SIZE or when an architecture does not register memory holes
reserved by the firmware as memblock.memory.

Such pages are currently initialized using init_unavailable_mem() function
that iterates through PFNs in holes in memblock.memory and if there is a
struct page corresponding to a PFN, the fields of this page are set to
default values and it is marked as Reserved.

init_unavailable_mem() does not take into account zone and node the page
belongs to and sets both zone and node links in struct page to zero.

Before commit 73a6e474 ("mm: memmap_init: iterate over memblock
regions rather that check each PFN") the holes inside a zone were
re-initialized during memmap_init() and got their zone/node links right.
However, after that commit nothing updates the struct pages representing
such holes.

On a system that has firmware reserved holes in a zone above ZONE_DMA, for
instance in a configuration below:

	# grep -A1 E820 /proc/iomem
	7a17b000-7a216fff : Unknown E820 type
	7a217000-7bffffff : System RAM

unset zone link in struct page will trigger

	VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);

in set_pfnblock_flags_mask() when called with a struct page from a range
other than E820_TYPE_RAM because there are pages in the range of
ZONE_DMA32 but the unset zone link in struct page makes them appear as a
part of ZONE_DMA.

Interleave initialization of the unavailable pages with the normal
initialization of memory map, so that zone and node information will be
properly set on struct pages that are not backed by the actual memory.

With this change the pages for holes inside a zone will get proper
zone/node links and the pages that are not spanned by any node will get
links to the adjacent zone/node.  The holes between nodes will be
prepended to the zone/node above the hole and the trailing pages in the
last section that will be appended to the zone/node below.

[akpm@linux-foundation.org: don't initialize static to zero, use %llu for u64]

Link: https://lkml.kernel.org/r/20210225224351.7356-2-rppt@kernel.org


Fixes: 73a6e474 ("mm: memmap_init: iterate over memblock regions rather that check each PFN")
Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Reported-by: default avatarQian Cai <cai@lca.pw>
Reported-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Reviewed-by: default avatarBaoquan He <bhe@redhat.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Łukasz Majczak <lma@semihalf.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Sarvela, Tomi P" <tomi.p.sarvela@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0740a50b
    • Masahiro Yamada's avatar
      init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM · ea29b20a
      Masahiro Yamada authored 
      I read the commit log of the following two:

- bc083a64 ("init/Kconfig: make COMPILE_TEST depend on !UML")
- 334ef6ed ("init/Kconfig: make COMPILE_TEST depend on !S390")

Both are talking about HAS_IOMEM dependency missing in many drivers.

So, 'depends on HAS_IOMEM' seems the direct, sensible solution to me.

This does not change the behavior of UML. UML still cannot enable
COMPILE_TEST because it does not provide HAS_IOMEM.

The current dependency for S390 is too strong. Under the condition of
CONFIG_PCI=y, S390 provides HAS_IOMEM, hence can enable COMPILE_TEST.

I also removed the meaningless 'default n'.

Link: https://lkml.kernel.org/r/20210224140809.1067582-1-masahiroy@kernel.org


Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KP Singh <kpsingh@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ea29b20a
    • Arnd Bergmann's avatar
      stop_machine: mark helpers __always_inline · cbf78d85
      Arnd Bergmann authored 
      With clang-13, some functions only get partially inlined, with a
specialized version referring to a global variable.  This triggers a
harmless build-time check for the intel-rng driver:

WARNING: modpost: drivers/char/hw_random/intel-rng.o(.text+0xe): Section mismatch in reference from the function stop_machine() to the function .init.text:intel_rng_hw_init()
The function stop_machine() references
the function __init intel_rng_hw_init().
This is often because stop_machine lacks a __init
annotation or the annotation of intel_rng_hw_init is wrong.

In this instance, an easy workaround is to force the stop_machine()
function to be inline, along with related interfaces that did not show the
same behavior at the moment, but theoretically could.

The combination of the two patches listed below triggers the behavior in
clang-13, but individually these commits are correct.

Link: https://lkml.kernel.org/r/20210225130153.1956990-1-arnd@kernel.org


Fixes: fe5595c0 ("stop_machine: Provide stop_machine_cpuslocked()")
Fixes: ee527cd3 ("Use stop_machine_run in the Intel RNG driver")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cbf78d85
    • Arnd Bergmann's avatar
      memblock: fix section mismatch warning · 34dc2efb
      Arnd Bergmann authored 
      The inlining logic in clang-13 is rewritten to often not inline some
functions that were inlined by all earlier compilers.

In case of the memblock interfaces, this exposed a harmless bug of a
missing __init annotation:

WARNING: modpost: vmlinux.o(.text+0x507c0a): Section mismatch in reference from the function memblock_bottom_up() to the variable .meminit.data:memblock
The function memblock_bottom_up() references
the variable __meminitdata memblock.
This is often because memblock_bottom_up lacks a __meminitdata
annotation or the annotation of memblock is wrong.

Interestingly, these annotations were present originally, but got removed
with the explanation that the __init annotation prevents the function from
getting inlined.  I checked this again and found that while this is the
case with clang, gcc (version 7 through 10, did not test others) does
inline the functions regardless.

As the previous change was apparently intended to help the clang builds,
reverting it to help the newer clang versions seems appropriate as well.
gcc builds don't seem to care either way.

Link: https://lkml.kernel.org/r/20210225133808.2188581-1-arnd@kernel.org


Fixes: 5bdba520 ("mm: memblock: drop __init from memblock functions to make it inline")
Reference: 2cfb3665 ("include/linux/memblock.h: add __init to memblock_set_bottom_up()")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Faiyaz Mohammed <faiyazm@codeaurora.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Aslan Bakirov <aslan@fb.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      34dc2efb
  3. Mar 12, 2021
  5. Mar 11, 2021