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Thomas Gleixner 08ded2cd18 x86/fpu: Get rid of the FNSAVE optimization
The FNSAVE support requires conditionals in quite some call paths because
FNSAVE reinitializes the FPU hardware. If the save has to preserve the FPU
register state then the caller has to conditionally restore it from memory
when FNSAVE is in use.

This also requires a conditional in context switch because the restore
avoidance optimization cannot work with FNSAVE. As this only affects 20+
years old CPUs there is really no reason to keep this optimization
effective for FNSAVE. It's about time to not optimize for antiques anymore.

Just unconditionally FRSTOR the save content to the registers and clean up
the conditionals all over the place.

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.617369268@linutronix.de
2021-06-23 18:29:41 +02:00
Documentation Merge x86/urgent into x86/fpu 2021-06-23 17:43:38 +02:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch x86/fpu: Get rid of the FNSAVE optimization 2021-06-23 18:29:41 +02:00
block block-5.13-2021-05-22 2021-05-22 07:40:34 -10:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto async_xor: check src_offs is not NULL before updating it 2021-06-10 19:40:14 -07:00
drivers A single fix for GICv3 to not take an interrupt in an NMI context. 2021-06-20 09:38:14 -07:00
fs for-5.13-rc6-tag 2021-06-18 16:39:03 -07:00
include Merge x86/urgent into x86/fpu 2021-06-23 17:43:38 +02:00
init pid: take a reference when initializing `cad_pid` 2021-06-05 08:58:11 -07:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-22 15:09:07 -10:00
kernel - A single fix to restore fairness between control groups with equal priority 2021-06-20 09:44:52 -07:00
lib lib: crc64: fix kernel-doc warning 2021-06-05 08:58:12 -07:00
mm mm/sparse: fix check_usemap_section_nr warnings 2021-06-16 09:24:43 -07:00
net Networking fixes for 5.13-rc7, including fixes from wireless, bpf, 2021-06-18 18:55:29 -07:00
samples VFIO fixes for v5.13-rc5 2021-06-03 11:52:24 -07:00
scripts recordmcount: Correct st_shndx handling 2021-06-18 09:09:17 -04:00
security trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
sound sound fixes for 5.13-rc6 2021-06-11 10:47:10 -07:00
tools Merge x86/urgent into x86/fpu 2021-06-23 17:43:38 +02:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: VMX: update vcpu posted-interrupt descriptor when assigning device 2021-05-27 07:58:23 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +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 .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: use private address for Michel Lespinasse 2021-06-05 08:58:12 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
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 Networking fixes for 5.13-rc7, including fixes from wireless, bpf, 2021-06-18 18:55:29 -07:00
Makefile Linux 5.13-rc7 2021-06-20 15:03:15 -07:00
README

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.