Mark Rutland 6e13b6b923 arm64: kaslr: split kaslr/module initialization
Currently kaslr_init() handles a mixture of detecting/announcing whether
KASLR is enabled, and randomizing the module region depending on whether
KASLR is enabled.

To make it easier to rework the module region initialization, split the
KASLR initialization into two steps:

* kaslr_init() determines whether KASLR should be enabled, and announces
  this choice, recording this to a new global boolean variable. This is
  called from setup_arch() just before the existing call to
  kaslr_requires_kpti() so that this will always provide the expected
  result.

* kaslr_module_init() randomizes the module region when required. This
  is called as a subsys_initcall, where we previously called
  kaslr_init().

As a bonus, moving the KASLR reporting earlier makes it easier to spot
and permits it to be logged via earlycon, making it easier to debug any
issues that could be triggered by KASLR.

Booting a v6.4-rc1 kernel with this patch applied, the log looks like:

| EFI stub: Booting Linux Kernel...
| EFI stub: Generating empty DTB
| EFI stub: Exiting boot services...
| [    0.000000] Booting Linux on physical CPU 0x0000000000 [0x000f0510]
| [    0.000000] Linux version 6.4.0-rc1-00006-g4763a8f8aeb3 (mark@lakrids) (aarch64-linux-gcc (GCC) 12.1.0, GNU ld (GNU Binutils) 2.38) #2 SMP PREEMPT Tue May  9 11:03:37 BST 2023
| [    0.000000] KASLR enabled
| [    0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '')
| [    0.000000] printk: bootconsole [pl11] enabled

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Will Deacon <will@kernel.org>
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230530110328.2213762-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-06-06 17:39:05 +01:00
2023-05-17 15:24:33 -07:00
2023-05-19 13:56:26 -04:00
2022-09-28 09:02:20 +02:00
2023-05-21 14:05:48 -07:00

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.
Description
No description provided
Readme 7.9 GiB
Languages
C 97.7%
Assembly 1.6%
Makefile 0.3%
Perl 0.1%