linux-toradex.git/mm/dmapool.c, branch v5.12-rc5

mm/dmapool: use might_alloc()

2021-02-26T17:41:01+00:00

Now that my little helper has landed, use it more.  On top of the existing
check this also uses lockdep through the fs_reclaim annotations.

Link: https://lkml.kernel.org/r/20210113135009.3606813-1-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/dmapool.c: replace hard coded function name with func

2020-10-14T01:38:32+00:00

No need to hard code function name when __func__ can be used.

While here, replace specifiers for special types like dma_addr_t.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Andrew Morton 
Cc: Matthew Wilcox 
Link: http://lkml.kernel.org/r/20200814135055.24898-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds

mm/dmapool.c: replace open-coded list_for_each_entry_safe()

2020-10-14T01:38:32+00:00

There is a place in the code where open-coded version of
list_for_each_entry_safe() is used.  Replace that with the standard macro.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Andrew Morton 
Cc: Matthew Wilcox 
Link: http://lkml.kernel.org/r/20200814135055.24898-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds

mm/dmapool.c: micro-optimisation remove unnecessary branch

2020-04-07T17:43:42+00:00

Previously there was a check if 'size' is aligned to 'align' and if not
then it was aligned.  This check was expensive as both branch and division
are expensive instructions in most architectures.  'ALIGN' function on
already aligned value will not change it, and as it is cheaper than branch
+ division it can be executed all the time and branch can be removed.

Signed-off-by: Mateusz Nosek 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds

mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options

2019-07-12T18:05:46+00:00

Patch series "add init_on_alloc/init_on_free boot options", v10.

Provide init_on_alloc and init_on_free boot options.

These are aimed at preventing possible information leaks and making the
control-flow bugs that depend on uninitialized values more deterministic.

Enabling either of the options guarantees that the memory returned by the
page allocator and SL[AU]B is initialized with zeroes.  SLOB allocator
isn't supported at the moment, as its emulation of kmem caches complicates
handling of SLAB_TYPESAFE_BY_RCU caches correctly.

Enabling init_on_free also guarantees that pages and heap objects are
initialized right after they're freed, so it won't be possible to access
stale data by using a dangling pointer.

As suggested by Michal Hocko, right now we don't let the heap users to
disable initialization for certain allocations.  There's not enough
evidence that doing so can speed up real-life cases, and introducing ways
to opt-out may result in things going out of control.

This patch (of 2):

The new options are needed to prevent possible information leaks and make
control-flow bugs that depend on uninitialized values more deterministic.

This is expected to be on-by-default on Android and Chrome OS.  And it
gives the opportunity for anyone else to use it under distros too via the
boot args.  (The init_on_free feature is regularly requested by folks
where memory forensics is included in their threat models.)

init_on_alloc=1 makes the kernel initialize newly allocated pages and heap
objects with zeroes.  Initialization is done at allocation time at the
places where checks for __GFP_ZERO are performed.

init_on_free=1 makes the kernel initialize freed pages and heap objects
with zeroes upon their deletion.  This helps to ensure sensitive data
doesn't leak via use-after-free accesses.

Both init_on_alloc=1 and init_on_free=1 guarantee that the allocator
returns zeroed memory.  The two exceptions are slab caches with
constructors and SLAB_TYPESAFE_BY_RCU flag.  Those are never
zero-initialized to preserve their semantics.

Both init_on_alloc and init_on_free default to zero, but those defaults
can be overridden with CONFIG_INIT_ON_ALLOC_DEFAULT_ON and
CONFIG_INIT_ON_FREE_DEFAULT_ON.

If either SLUB poisoning or page poisoning is enabled, those options take
precedence over init_on_alloc and init_on_free: initialization is only
applied to unpoisoned allocations.

Slowdown for the new features compared to init_on_free=0, init_on_alloc=0:

hackbench, init_on_free=1:  +7.62% sys time (st.err 0.74%)
hackbench, init_on_alloc=1: +7.75% sys time (st.err 2.14%)

Linux build with -j12, init_on_free=1:  +8.38% wall time (st.err 0.39%)
Linux build with -j12, init_on_free=1:  +24.42% sys time (st.err 0.52%)
Linux build with -j12, init_on_alloc=1: -0.13% wall time (st.err 0.42%)
Linux build with -j12, init_on_alloc=1: +0.57% sys time (st.err 0.40%)

The slowdown for init_on_free=0, init_on_alloc=0 compared to the baseline
is within the standard error.

The new features are also going to pave the way for hardware memory
tagging (e.g.  arm64's MTE), which will require both on_alloc and on_free
hooks to set the tags for heap objects.  With MTE, tagging will have the
same cost as memory initialization.

Although init_on_free is rather costly, there are paranoid use-cases where
in-memory data lifetime is desired to be minimized.  There are various
arguments for/against the realism of the associated threat models, but
given that we'll need the infrastructure for MTE anyway, and there are
people who want wipe-on-free behavior no matter what the performance cost,
it seems reasonable to include it in this series.

[glider@google.com: v8]
  Link: http://lkml.kernel.org/r/20190626121943.131390-2-glider@google.com
[glider@google.com: v9]
  Link: http://lkml.kernel.org/r/20190627130316.254309-2-glider@google.com
[glider@google.com: v10]
  Link: http://lkml.kernel.org/r/20190628093131.199499-2-glider@google.com
Link: http://lkml.kernel.org/r/20190617151050.92663-2-glider@google.com
Signed-off-by: Alexander Potapenko 
Acked-by: Kees Cook 
Acked-by: Michal Hocko 		[page and dmapool parts
Acked-by: James Morris ]
Cc: Christoph Lameter 
Cc: Masahiro Yamada 
Cc: "Serge E. Hallyn" 
Cc: Nick Desaulniers 
Cc: Kostya Serebryany 
Cc: Dmitry Vyukov 
Cc: Sandeep Patil 
Cc: Laura Abbott 
Cc: Randy Dunlap 
Cc: Jann Horn 
Cc: Mark Rutland 
Cc: Marco Elver 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 403

2019-06-05T15:37:13+00:00

Based on 1 normalized pattern(s):

  this software may be redistributed and or modified under the terms
  of the gnu general public license gpl version 2 as published by the
  free software foundation

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Armijn Hemel 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190112.039124428@linutronix.de
Signed-off-by: Greg Kroah-Hartman

docs/core-api/mm: fix return value descriptions in mm/

2019-03-06T05:07:20+00:00

Many kernel-doc comments in mm/ have the return value descriptions
either misformatted or omitted at all which makes kernel-doc script
unhappy:

$ make V=1 htmldocs
...
./mm/util.c:36: info: Scanning doc for kstrdup
./mm/util.c:41: warning: No description found for return value of 'kstrdup'
./mm/util.c:57: info: Scanning doc for kstrdup_const
./mm/util.c:66: warning: No description found for return value of 'kstrdup_const'
./mm/util.c:75: info: Scanning doc for kstrndup
./mm/util.c:83: warning: No description found for return value of 'kstrndup'
...

Fixing the formatting and adding the missing return value descriptions
eliminates ~100 such warnings.

Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport 
Reviewed-by: Andrew Morton 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use octal not symbolic permissions

2018-06-14T22:55:25+00:00

mm/*.c files use symbolic and octal styles for permissions.

Using octal and not symbolic permissions is preferred by many as more
readable.

https://lkml.org/lkml/2016/8/2/1945

Prefer the direct use of octal for permissions.

Done using
$ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c
and some typing.

Before:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
44
After:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
86

Miscellanea:

o Whitespace neatening around these conversions.

Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.com
Signed-off-by: Joe Perches 
Acked-by: David Rientjes 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/vsprintf.c: remove %Z support

2017-02-28T02:43:47+00:00

Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement.  Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: cleanups for printing phys_addr_t and dma_addr_t

2017-02-25T01:46:56+00:00

cleanup rest of dma_addr_t and phys_addr_t type casting in mm
use %pad for dma_addr_t
use %pa for phys_addr_t

Link: http://lkml.kernel.org/r/1486618489-13912-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds