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Linus Torvalds 1dbc0a9515 x86: mm: remove 'sign' games from LAM untagged_addr*() macros
The intent of the sign games was to not modify kernel addresses when
untagging them.  However, that had two issues:

 (a) it didn't actually work as intended, since the mask was calculated
     as 'addr >> 63' on an _unsigned_ address. So instead of getting a
     mask of all ones for kernel addresses, you just got '1'.

 (b) untagging a kernel address isn't actually a valid operation anyway.

Now, (a) had originally been true for both 'untagged_addr()' and the
remote version of it, but had accidentally been fixed for the regular
version of untagged_addr() by commit e0bddc19ba ("x86/mm: Reduce
untagged_addr() overhead for systems without LAM").  That one rewrote
the shift to be part of the alternative asm code, and in the process
changed the unsigned shift into a signed 'sar' instruction.

And while it is true that we don't want to turn what looks like a kernel
address into a user address by masking off the high bit, that doesn't
need these sign masking games - all it needs is that the mm context
'untag_mask' value has the high bit set.

Which it always does.

So simplify the code by just removing the superfluous (and in the case
of untagged_addr_remote(), still buggy) sign bit games in the address
masking.

Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-05-03 10:37:22 -07:00
arch x86: mm: remove 'sign' games from LAM untagged_addr*() macros 2023-05-03 10:37:22 -07:00
block Driver core changes for 6.4-rc1 2023-04-27 11:53:57 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto modules-6.4-rc1 2023-04-27 16:36:55 -07:00
Documentation Pin control bulk changes for the v6.4 kernel: 2023-05-02 15:40:41 -07:00
drivers Pin control bulk changes for the v6.4 kernel: 2023-05-02 15:40:41 -07:00
fs afs: Avoid endless loop if file is larger than expected 2023-05-02 17:23:50 +01:00
include VFIO updates for v6.4-rc1 2023-05-02 11:56:43 -07:00
init Objtool changes for v6.4: 2023-04-28 14:02:54 -07:00
io_uring Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel IOMMU Updates for Linux 6.4 2023-04-30 13:00:38 -07:00
lib s390 updates for the 6.4 merge window 2023-04-30 11:43:31 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm x86-64: make access_ok() independent of LAM 2023-05-03 10:37:22 -07:00
net NFSD 6.4 Release Notes 2023-04-29 11:04:14 -07:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples Rust changes for v6.4 2023-04-30 11:20:22 -07:00
scripts Kbuild updates for v6.4 2023-04-30 11:32:53 -07:00
security integrity-v6.4 2023-04-29 10:11:32 -07:00
sound Mainly singleton patches all over the place. Series of note are: 2023-04-27 19:57:00 -07:00
tools s390: 2023-05-01 12:06:20 -07:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt s390: 2023-05-01 12:06:20 -07:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap Mainly singleton patches all over the place. Series of note are: 2023-04-27 19:57:00 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Char/Misc drivers for 6.4-rc1 2023-04-27 12:07:50 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Pin control bulk changes for the v6.4 kernel: 2023-05-02 15:40:41 -07:00
Makefile Kbuild updates for v6.4 2023-04-30 11:32:53 -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.