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Ard Biesheuvel d7c1901476 efi: Avoid cold plugged memory for placing the kernel
commit ba69e0750b upstream.

UEFI 2.11 introduced EFI_MEMORY_HOT_PLUGGABLE to annotate system memory
regions that are 'cold plugged' at boot, i.e., hot pluggable memory that
is available from early boot, and described as system RAM by the
firmware.

Existing loaders and EFI applications running in the boot context will
happily use this memory for allocating data structures that cannot be
freed or moved at runtime, and this prevents the memory from being
unplugged. Going forward, the new EFI_MEMORY_HOT_PLUGGABLE attribute
should be tested, and memory annotated as such should be avoided for
such allocations.

In the EFI stub, there are a couple of occurrences where, instead of the
high-level AllocatePages() UEFI boot service, a low-level code sequence
is used that traverses the EFI memory map and carves out the requested
number of pages from a free region. This is needed, e.g., for allocating
as low as possible, or for allocating pages at random.

While AllocatePages() should presumably avoid special purpose memory and
cold plugged regions, this manual approach needs to incorporate this
logic itself, in order to prevent the kernel itself from ending up in a
hot unpluggable region, preventing it from being unplugged.

So add the EFI_MEMORY_HOTPLUGGABLE macro definition, and check for it
where appropriate.

Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-02-21 13:50:04 +01:00
arch alpha: make stack 16-byte aligned (most cases) 2025-02-21 13:50:04 +01:00
block block: don't revert iter for -EIOCBQUEUED 2025-02-21 13:49:45 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: api - Add crypto_clone_tfm 2024-12-14 19:53:51 +01:00
Documentation kconfig: add warn-unknown-symbols sanity check 2025-02-21 13:49:24 +01:00
drivers
fs orangefs: fix a oob in orangefs_debug_write 2025-02-21 13:50:00 +01:00
include
init initramfs: avoid filename buffer overrun 2024-12-14 19:53:14 +01:00
io_uring io_uring/rw: commit provided buffer state on async 2025-02-21 13:49:53 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-14 19:54:06 +01:00
kernel cgroup: Remove steal time from usage_usec 2025-02-21 13:49:57 +01:00
lib maple_tree: simplify split calculation 2025-02-21 13:49:55 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: kmemleak: fix upper boundary check for physical address objects 2025-02-21 13:49:49 +01:00
net can: j1939: j1939_sk_send_loop(): fix unable to send messages with data length zero 2025-02-21 13:50:04 +01:00
rust rust: macros: provide correct provenance when constructing THIS_MODULE 2024-10-17 15:22:24 +02:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-02-21 13:49:03 +01:00
scripts kbuild: Move -Wenum-enum-conversion to W=2 2025-02-21 13:49:46 +01:00
security tomoyo: don't emit warning in tomoyo_write_control() 2025-02-21 13:49:31 +01:00
sound ASoC: Intel: bytcr_rt5640: Add DMI quirk for Vexia Edu Atla 10 tablet 5V 2025-02-21 13:50:00 +01:00
tools selftests: gpio: gpio-sim: Fix missing chip disablements 2025-02-21 13:50:00 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:46:21 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 dts files 2019-12-04 19:44:11 -08:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:21:15 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.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 MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 MAINTAINERS: add leah to 6.1 MAINTAINERS file 2024-05-17 11:56:16 +02:00
Makefile kbuild: switch from lz4c to lz4 for compression 2025-02-21 13:49:25 +01:00
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.