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Linus Torvalds d55564cfc2 x86: Make __put_user() generate an out-of-line call
Instead of inlining the stac/mov/clac sequence (which also requires
individual exception table entries and several asm instruction
alternatives entries), just generate "call __put_user_nocheck_X" for the
__put_user() cases, the same way we changed __get_user earlier.

Unlike the get_user() case, we didn't have the same nice infrastructure
to just generate the call with a single case, so this actually has to
change some of the infrastructure in order to do this.  But that only
cleans up the code further.

So now, instead of using a case statement for the sizes, we just do the
same thing we've done on the get_user() side for a long time: use the
size as an immediate constant to the asm, and generate the asm that way
directly.

In order to handle the special case of 64-bit data on a 32-bit kernel, I
needed to change the calling convention slightly: the data is passed in
%eax[:%edx], the pointer in %ecx, and the return value is also returned
in %ecx.  It used to be returned in %eax, but because of how %eax can
now be a double register input, we don't want mix that with a
single-register output.

The actual low-level asm is easier to handle: we'll just share the code
between the checking and non-checking case, with the non-checking case
jumping into the middle of the function.  That may sound a bit too
special, but this code is all very very special anyway, so...

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-12 16:57:57 -07:00
arch x86: Make __put_user() generate an out-of-line call 2020-10-12 16:57:57 -07:00
block Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
drivers Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
fs Merge branch 'compat.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:44:57 -07:00
include File locking fix for v5.10 2020-10-12 16:50:18 -07:00
init As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Merge branch 'work.quota-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:37:13 -07:00
lib Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
net Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
samples As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
scripts As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
security Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:35:51 -07:00
sound sound fixes for 5.9-rc7 2020-09-24 09:00:05 -07:00
tools Merge branch 'compat.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:44:57 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +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: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
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 As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
Makefile Linux 5.9 2020-10-11 14:15:50 -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.