unimore/kernel-hacking-2024-linux-steffo
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Linux kernel modifications for the Kernel Hacking exam
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Ard Biesheuvel f24c4d4780 efi/capsule-loader: Reinstate virtual capsule mapping 
Commit:

  82c3768b8d ("efi/capsule-loader: Use a cached copy of the capsule header")

... refactored the capsule loading code that maps the capsule header,
to avoid having to map it several times.

However, as it turns out, the vmap() call we ended up removing did not
just map the header, but the entire capsule image, and dropping this
virtual mapping breaks capsules that are processed by the firmware
immediately (i.e., without a reboot).

Unfortunately, that change was part of a larger refactor that allowed
a quirk to be implemented for Quark, which has a non-standard memory
layout for capsules, and we have slightly painted ourselves into a
corner by allowing quirk code to mangle the capsule header and memory
layout.

So we need to fix this without breaking Quark. Fortunately, Quark does
not appear to care about the virtual mapping, and so we can simply
do a partial revert of commit:

  2a457fb31d ("efi/capsule-loader: Use page addresses rather than struct page pointers")

... and create a vmap() mapping of the entire capsule (including header)
based on the reinstated struct page array, unless running on Quark, in
which case we pass the capsule header copy as before.

Reported-by: Ge Song <ge.song@hxt-semitech.com>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Tested-by: Ge Song <ge.song@hxt-semitech.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 82c3768b8d ("efi/capsule-loader: Use a cached copy of the capsule header")
Link: http://lkml.kernel.org/r/20180102172110.17018-3-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-03 13:54:31 +01:00
arch efi/capsule-loader: Reinstate virtual capsule mapping 2018-01-03 13:54:31 +01:00
block block-throttle: avoid double charge 2017-12-20 11:10:17 -07:00
certs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-12-22 12:22:48 -08:00
Documentation Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 13:13:56 -08:00
drivers efi/capsule-loader: Reinstate virtual capsule mapping 2018-01-03 13:54:31 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Changes since last update: 2017-12-22 12:27:27 -08:00
include efi/capsule-loader: Reinstate virtual capsule mapping 2018-01-03 13:54:31 +01:00
init Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:27:19 -08:00
ipc Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:30:34 -08:00
lib Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:30:34 -08:00
mm Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-21 11:13:37 -08:00
net strparser: Call sock_owned_by_user_nocheck 2017-12-28 14:28:22 -05:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2017-12-03 13:08:30 -05:00
scripts Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-15 11:44:59 -08:00
security Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-29 17:02:49 -08:00
sound ALSA: hda - Fix missing COEF init for ALC225/295/299 2017-12-27 08:53:59 +01:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 11:47:24 -08:00
usr
virt KVM/ARM Fixes for v4.15, Round 2 2017-12-18 12:57:43 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
.mailmap Add Jason Gunthorpe as co-maintainer of the RDMA stack 2017-11-17 09:36:18 -08:00
COPYING
CREDITS
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig
MAINTAINERS Char/Misc fixes for 4.15-rc6 2017-12-31 10:52:51 -08:00
Makefile Linux 4.15-rc6 2017-12-31 14:47:43 -08:00
README

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.