linux-stable.git/Documentation, branch v3.16.53

x86/kaiser: Check boottime cmdline params

2018-01-09T00:35:17+00:00

AMD (and possibly other vendors) are not affected by the leak
KAISER is protecting against.

Keep the "nopti" for traditional reasons and add pti=
like upstream.

Signed-off-by: Borislav Petkov 
Signed-off-by: Greg Kroah-Hartman 
Cc: Hugh Dickins 
Signed-off-by: Ben Hutchings

x86/kaiser: Rename and simplify X86_FEATURE_KAISER handling

2018-01-09T00:35:17+00:00

Concentrate it in arch/x86/mm/kaiser.c and use the upstream string "nopti".

Signed-off-by: Borislav Petkov 
Signed-off-by: Greg Kroah-Hartman 
Cc: Hugh Dickins 
Signed-off-by: Ben Hutchings

kaiser: add "nokaiser" boot option, using ALTERNATIVE

2018-01-09T00:35:15+00:00

Added "nokaiser" boot option: an early param like "noinvpcid".
Most places now check int kaiser_enabled (#defined 0 when not
CONFIG_KAISER) instead of #ifdef CONFIG_KAISER; but entry_64.S
and entry_64_compat.S are using the ALTERNATIVE technique, which
patches in the preferred instructions at runtime.  That technique
is tied to x86 cpu features, so X86_FEATURE_KAISER fabricated
("" in its comment so "kaiser" not magicked into /proc/cpuinfo).

Prior to "nokaiser", Kaiser #defined _PAGE_GLOBAL 0: revert that,
but be careful with both _PAGE_GLOBAL and CR4.PGE: setting them when
nokaiser like when !CONFIG_KAISER, but not setting either when kaiser -
neither matters on its own, but it's hard to be sure that _PAGE_GLOBAL
won't get set in some obscure corner, or something add PGE into CR4.
By omitting _PAGE_GLOBAL from __supported_pte_mask when kaiser_enabled,
all page table setup which uses pte_pfn() masks it out of the ptes.

It's slightly shameful that the same declaration versus definition of
kaiser_enabled appears in not one, not two, but in three header files
(asm/kaiser.h, asm/pgtable.h, asm/tlbflush.h).  I felt safer that way,
than with #including any of those in any of the others; and did not
feel it worth an asm/kaiser_enabled.h - kernel/cpu/common.c includes
them all, so we shall hear about it if they get out of synch.

Cleanups while in the area: removed the silly #ifdef CONFIG_KAISER
from kaiser.c; removed the unused native_get_normal_pgd(); removed
the spurious reg clutter from SWITCH_*_CR3 macro stubs; corrected some
comments.  But more interestingly, set CR4.PSE in secondary_startup_64:
the manual is clear that it does not matter whether it's 0 or 1 when
4-level-pts are enabled, but I was distracted to find cr4 different on
BSP and auxiliaries - BSP alone was adding PSE, in probe_page_size_mask().

(cherry picked from Change-Id: I8e5bec716944444359cbd19f6729311eff943e9a)

Signed-off-by: Hugh Dickins 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

x86/mm: Add the 'nopcid' boot option to turn off PCID

2018-01-09T00:35:12+00:00

commit 0790c9aad84901ca1bdc14746175549c8b5da215 upstream.
The parameter is only present on x86_64 systems to save a few bytes,
as PCID is always disabled on x86_32.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Nadav Amit 
Reviewed-by: Borislav Petkov 
Reviewed-by: Thomas Gleixner 
Cc: Andrew Morton 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Linus Torvalds 
Cc: Mel Gorman 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/8bbb2e65bcd249a5f18bfb8128b4689f08ac2b60.1498751203.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
[Hugh Dickins: Backported to 3.18:
 - Documentation/admin-guide/kernel-parameters.txt (not in this tree)
 - Documentation/kernel-parameters.txt (patched instead of that)
Signed-off-by: Hugh Dickins 
Signed-off-by: Ben Hutchings

x86/mm: Add a 'noinvpcid' boot option to turn off INVPCID

2018-01-09T00:35:08+00:00

commit d12a72b844a49d4162f24cefdab30bed3f86730e upstream.

This adds a chicken bit to turn off INVPCID in case something goes
wrong.  It's an early_param() because we do TLB flushes before we
parse __setup() parameters.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Borislav Petkov 
Cc: Andrew Morton 
Cc: Andrey Ryabinin 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Luis R. Rodriguez 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Toshi Kani 
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/f586317ed1bc2b87aee652267e515b90051af385.1454096309.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Cc: Hugh Dickins 
Signed-off-by: Ben Hutchings

x86/mm: New tunable for single vs full TLB flush

2018-01-09T00:35:06+00:00

commit 2d040a1ce903ca5d6e7c983621fb29c6883c4c48 upstream.

Most of the logic here is in the documentation file.  Please take
a look at it.

I know we've come full-circle here back to a tunable, but this
new one is *WAY* simpler.  I challenge anyone to describe in one
sentence how the old one worked.  Here's the way the new one
works:

	If we are flushing more pages than the ceiling, we use
	the full flush, otherwise we use per-page flushes.

Signed-off-by: Dave Hansen 
Link: http://lkml.kernel.org/r/20140731154101.12B52CAF@viggo.jf.intel.com
Acked-by: Rik van Riel 
Acked-by: Mel Gorman 
Signed-off-by: H. Peter Anvin 
Cc: Hugh Dickins 
Signed-off-by: Ben Hutchings

media: docs-rst: v4l: Fix sink compose selection target documentation

2017-11-26T13:50:14+00:00

commit 74dcb29a38e4419a8e4217caa7e35ccc1b31e5a4 upstream.

The rectangle which the sink compose rectangle is related to is documented
to be the source compose bounds rectangle. This is in obvious conflict with
the ground rule of the format propagation (from sink to source). The reason
behind this is that this was always supposed to be the sink compose bounds
rectangle. Fix it.

Fixes: 955f645aea04 ("[media] v4l: Add subdev selections documentation")

Signed-off-by: Sakari Ailus 
Acked-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings

MODULE_DEVICE_TABLE: fix some callsites

2017-11-11T13:33:42+00:00

commit 0f989f749b51ec1fd94bb5a42f8ad10c8b9f73cb upstream.

The patch "module: fix types of device tables aliases" newly requires that
invocations of

MODULE_DEVICE_TABLE(type, name);

come *after* the definition of `name'.  That is reasonable, but some
drivers weren't doing this.  Fix them.

Cc: James Bottomley 
Cc: Andrey Ryabinin 
Cc: David Miller 
Cc: Hans Verkuil 
Acked-by: Mauro Carvalho Chehab 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Ben Hutchings

cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags

2017-10-12T14:28:22+00:00

commit 2ad654bc5e2b211e92f66da1d819e47d79a866f0 upstream.

When we change cpuset.memory_spread_{page,slab}, cpuset will flip
PF_SPREAD_{PAGE,SLAB} bit of tsk->flags for each task in that cpuset.
This should be done using atomic bitops, but currently we don't,
which is broken.

Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happened
when one thread tried to clear PF_USED_MATH while at the same time another
thread tried to flip PF_SPREAD_PAGE/PF_SPREAD_SLAB. They both operate on
the same task.

Here's the full report:
https://lkml.org/lkml/2014/9/19/230

To fix this, we make PF_SPREAD_PAGE and PF_SPREAD_SLAB atomic flags.

v4:
- updated mm/slab.c. (Fengguang Wu)
- updated Documentation.

Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Miao Xie 
Cc: Kees Cook 
Fixes: 950592f7b991 ("cpusets: update tasks' page/slab spread flags in time")
Reported-by: Tetsuo Handa 
Signed-off-by: Zefan Li 
Signed-off-by: Tejun Heo 
Signed-off-by: Ben Hutchings

Documentation: DMA API: fix a typo in a function name

2017-10-12T14:27:44+00:00

commit 6a08d83e4324fcb23994dfd481acedf49e37cc06 upstream.

Correct the typo, the wrongly typed function does not exist.

Fixes: 6c9c6d6301287e ("dma-debug: New interfaces to debug dma mapping errors")
Signed-off-by: Wolfram Sang 
Signed-off-by: Jonathan Corbet 
Signed-off-by: Ben Hutchings