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Linus Torvalds 0a096f240a A reworked version of the opt-in L1D flush mechanism:
A stop gap for potential future speculation related hardware
   vulnerabilities and a mechanism for truly security paranoid
   applications.
 
   It allows a task to request that the L1D cache is flushed when the kernel
   switches to a different mm. This can be requested via prctl().
 
   Changes vs. the previous versions:
 
     - Get rid of the software flush fallback
 
     - Make the handling consistent with other mitigations
 
     - Kill the task when it ends up on a SMT enabled core which defeats the
       purpose of L1D flushing obviously
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Merge tag 'x86-cpu-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cache flush updates from Thomas Gleixner:
 "A reworked version of the opt-in L1D flush mechanism.

  This is a stop gap for potential future speculation related hardware
  vulnerabilities and a mechanism for truly security paranoid
  applications.

  It allows a task to request that the L1D cache is flushed when the
  kernel switches to a different mm. This can be requested via prctl().

  Changes vs the previous versions:

   - Get rid of the software flush fallback

   - Make the handling consistent with other mitigations

   - Kill the task when it ends up on a SMT enabled core which defeats
     the purpose of L1D flushing obviously"

* tag 'x86-cpu-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: Add L1D flushing Documentation
  x86, prctl: Hook L1D flushing in via prctl
  x86/mm: Prepare for opt-in based L1D flush in switch_mm()
  x86/process: Make room for TIF_SPEC_L1D_FLUSH
  sched: Add task_work callback for paranoid L1D flush
  x86/mm: Refactor cond_ibpb() to support other use cases
  x86/smp: Add a per-cpu view of SMT state
2021-08-30 15:00:33 -07:00
arch A reworked version of the opt-in L1D flush mechanism: 2021-08-30 15:00:33 -07:00
block Updates to the interrupt core and driver subsystems: 2021-08-30 14:38:37 -07:00
certs
crypto
Documentation A reworked version of the opt-in L1D flush mechanism: 2021-08-30 15:00:33 -07:00
drivers Updates to the interrupt core and driver subsystems: 2021-08-30 14:38:37 -07:00
fs Scheduler changes for v5.15 are: 2021-08-30 13:42:10 -07:00
include A reworked version of the opt-in L1D flush mechanism: 2021-08-30 15:00:33 -07:00
init Scheduler changes for v5.15 are: 2021-08-30 13:42:10 -07:00
ipc
kernel Updates to the interrupt core and driver subsystems: 2021-08-30 14:38:37 -07:00
lib Updates for locking and atomics: 2021-08-30 14:26:36 -07:00
LICENSES
mm SMP core updates: 2021-08-30 14:10:07 -07:00
net
samples
scripts
security A handful of EFI changes for this cycle: 2021-08-30 13:57:55 -07:00
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
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.