x86/Kconfig: Rework CONFIG_X86_PAE dependency

Browse source

While looking at a Xen Kconfig dependency issue, I tried to understand the
exact dependencies for CONFIG_X86_PAE, which is selected by CONFIG_HIGHMEM64G
but can also be enabled manually.

Apparently the dependencies for CONFIG_HIGHMEM64G are strictly about CPUs
that do support PAE, but the actual feature can be incorrectly enabled on
older CPUs as well. The CONFIG_X86_CMPXCHG64 dependencies on the other hand
include X86_PAE because cmpxchg8b is requried for PAE to work.

Rework this for readability and correctness, using a positive list of CPUs
that support PAE in a new X86_HAVE_PAE symbol that can serve as a dependency
for both X86_PAE and HIGHMEM64G as well as simplify the X86_CMPXCHG64
dependency list.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231204084722.3789473-2-arnd@kernel.org

...

This commit is contained in:

Arnd Bergmann 2023-12-04 09:47:02 +01:00 • committed by Borislav Petkov (AMD)

parent 5225952d74

commit 88a2b4edda

2 changed files with 7 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

arch/x86/Kconfig

View file

6

arch/x86/Kconfig.cpu

View file