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Juergen Gross 230ec83d42 x86/pat: Fix x86_has_pat_wp()
x86_has_pat_wp() is using a wrong test, as it relies on the normal
PAT configuration used by the kernel. In case the PAT MSR has been
setup by another entity (e.g. Xen hypervisor) it might return false
even if the PAT configuration is allowing WP mappings. This due to the
fact that when running as Xen PV guest the PAT MSR is setup by the
hypervisor and cannot be changed by the guest. This results in the WP
related entry to be at a different position when running as Xen PV
guest compared to the bare metal or fully virtualized case.

The correct way to test for WP support is:

1. Get the PTE protection bits needed to select WP mode by reading
   __cachemode2pte_tbl[_PAGE_CACHE_MODE_WP] (depending on the PAT MSR
   setting this might return protection bits for a stronger mode, e.g.
   UC-)
2. Translate those bits back into the real cache mode selected by those
   PTE bits by reading __pte2cachemode_tbl[__pte2cm_idx(prot)]
3. Test for the cache mode to be _PAGE_CACHE_MODE_WP

Fixes: f88a68facd ("x86/mm: Extend early_memremap() support with additional attrs")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.14
Link: https://lore.kernel.org/r/20220503132207.17234-1-jgross@suse.com
2022-07-13 12:44:04 +02:00
arch x86/pat: Fix x86_has_pat_wp() 2022-07-13 12:44:04 +02:00
block block: remove WARN_ON() from bd_link_disk_holder 2022-06-23 07:48:05 -06:00
certs Certs changes 2022-06-21 12:13:53 -05:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation overlayfs fixes for 5.19-rc7 2022-07-12 08:59:35 -07:00
drivers drm fixes for 5.19-rc6 (well rc5 but late). 2022-07-12 08:52:15 -07:00
fs overlayfs fixes for 5.19-rc7 2022-07-12 08:59:35 -07:00
include Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
lib ida: don't use BUG_ON() for debugging 2022-07-10 13:55:49 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: split huge PUD on wp_huge_pud fallback 2022-07-03 15:42:33 -07:00
net Networking fixes for 5.19-rc6, including fixes from bpf, netfilter, 2022-07-07 10:08:20 -07:00
samples Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
scripts Just when you thought that all the speculation bugs were addressed and 2022-07-11 18:15:25 -07:00
security x86/retbleed: Add fine grained Kconfig knobs 2022-06-29 17:43:41 +02:00
sound ALSA: cs46xx: Fix missing snd_card_free() call at probe error 2022-07-05 17:24:05 +02:00
tools Just when you thought that all the speculation bugs were addressed and 2022-07-11 18:15:25 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap cxl fixes for 5.19-rc6 2022-07-08 12:55:25 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS cxl fixes for 5.19-rc6 2022-07-08 12:55:25 -07:00
Makefile Linux 5.19-rc6 2022-07-10 14:40:51 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.