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Filename Latest commit message Latest commit date
Thomas Gleixner 7652ac9201 x86/asm: Move native_write_cr0/4() out of line
The pinning of sensitive CR0 and CR4 bits caused a boot crash when loading
the kvm_intel module on a kernel compiled with CONFIG_PARAVIRT=n.

The reason is that the static key which controls the pinning is marked RO
after init. The kvm_intel module contains a CR4 write which requires to
update the static key entry list. That obviously does not work when the key
is in a RO section.

With CONFIG_PARAVIRT enabled this does not happen because the CR4 write
uses the paravirt indirection and the actual write function is built in.

As the key is intended to be immutable after init, move
native_write_cr0/4() out of line.

While at it consolidate the update of the cr4 shadow variable and store the
value right away when the pinning is initialized on a booting CPU. No point
in reading it back 20 instructions later. This allows to confine the static
key and the pinning variable to cpu/common and allows to mark them static.

Fixes: 8dbec27a24 ("x86/asm: Pin sensitive CR0 bits")
Fixes: 873d50d58f ("x86/asm: Pin sensitive CR4 bits")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Xi Ruoyao <xry111@mengyan1223.wang>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Xi Ruoyao <xry111@mengyan1223.wang>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907102140340.1758@nanos.tec.linutronix.de
2019-07-10 22:15:05 +02:00
arch x86/asm: Move native_write_cr0/4() out of line 2019-07-10 22:15:05 +02:00
block blk-mq: fix up placement of debugfs directory of queue files 2019-07-06 10:07:38 -06:00
certs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-05 13:31:19 +09:00
Documentation Merge branch 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 18:28:44 -07:00
drivers Merge branch 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 18:28:44 -07:00
fs Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 17:28:57 -07:00
include Merge branch 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 18:28:44 -07:00
init Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:39:53 -07:00
ipc
kernel Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:39:53 -07:00
lib Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:39:53 -07:00
LICENSES
mm arm64 updates for 5.3: 2019-07-08 09:54:55 -07:00
net Two more quick bugfixes for nfsd, fixing a regression causing mount 2019-07-05 19:00:37 -07:00
samples Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:39:53 -07:00
scripts Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:12:03 -07:00
security Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:12:03 -07:00
sound sound fixes for 5.2 2019-07-05 02:03:50 +09:00
tools Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 15:45:14 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 11:59:59 -07:00
Makefile Linux 5.2 2019-07-07 15:41:56 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.