linux/arch
Luis R. Rodriguez cb32edf65b x86/mm/pat: Wrap pat_enabled into a function API
We use pat_enabled in x86-specific code to see if PAT is enabled
or not but we're granting full access to it even though readers
do not need to set it. If, for instance, we granted access to it
to modules later they then could override the variable
setting... no bueno.

This renames pat_enabled to a new static variable __pat_enabled.
Folks are redirected to use pat_enabled() now.

Code that sets this can only be internal to pat.c. Apart from
the early kernel parameter "nopat" to disable PAT, we also have
a few cases that disable it later and make use of a helper
pat_disable(). It is wrapped under an ifdef but since that code
cannot run unless PAT was enabled its not required to wrap it
with ifdefs, unwrap that. Likewise, since "nopat" doesn't really
change non-PAT systems just remove that ifdef as well.

Although we could add and use an early_param_off(), these
helpers don't use __read_mostly but we want to keep
__read_mostly for __pat_enabled as this is a hot path -- upon
boot, for instance, a simple guest may see ~4k accesses to
pat_enabled(). Since __read_mostly early boot params are not
that common we don't add a helper for them just yet.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430425520-22275-3-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1432628901-18044-13-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-27 14:41:01 +02:00
..
alpha alpha: forward declare struct pt_regs in processor.h 2015-04-17 09:03:53 -04:00
arc ARC: inline cache flush toggle helpers 2015-05-11 11:21:41 +05:30
arm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-05-22 15:44:50 -07:00
arm64 ARM: SoC fixes for 4.1-rc3 2015-05-16 15:33:25 -07:00
avr32 Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
blackfin blackfin updates for Linux 4.1 2015-04-24 07:58:07 -07:00
c6x C6X Fixes for v4.1 2015-04-16 18:48:55 -04:00
cris CRIS changes for 4.1 2015-04-26 13:31:05 -07:00
frv Devicetree updates for 4.1: 2015-04-24 08:46:18 -07:00
hexagon Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
ia64 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
m32r m32r: make flush_cpumask non-volatile. 2015-05-09 11:09:29 -07:00
m68k Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2015-04-20 10:12:29 -07:00
metag Metag architecture changes for v4.1 2015-04-24 07:56:50 -07:00
microblaze microblaze: use asm-generic for seccomp.h 2015-04-17 09:04:10 -04:00
mips MIPS: tlb-r4k: Fix PG_ELPA comment 2015-05-15 22:02:50 +02:00
mn10300 Devicetree updates for 4.1: 2015-04-24 08:46:18 -07:00
nios2 nios2 update for v4.1-rc1 2015-04-24 07:59:07 -07:00
openrisc Merge branch 'akpm' (patches from Andrew) 2015-04-15 16:39:15 -07:00
parisc parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures 2015-05-12 22:03:44 +02:00
powerpc This pull request includes a fix for two oopses, one on PPC 2015-05-21 20:15:16 -07:00
s390 Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2015-05-22 14:26:36 -07:00
score arch: Remove exec_domain from remaining archs 2015-04-12 21:03:30 +02:00
sh Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2015-04-24 09:49:37 -07:00
sparc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2015-04-21 23:21:34 -07:00
tile tile: properly use node_isset() on a nodemask_t 2015-04-28 10:36:45 -04:00
um Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
unicore32 Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
x86 x86/mm/pat: Wrap pat_enabled into a function API 2015-05-27 14:41:01 +02:00
xtensa Xtensa changes and fixes for 4.1 2015-04-17 15:32:30 -04:00
.gitignore
Kconfig powerpc updates for 4.1 2015-04-16 13:53:32 -05:00