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Currently, LPA2 kernel support implies support for up to 52 bits of
physical addressing, and this is reflected in global definitions such as
PHYS_MASK_SHIFT and MAX_PHYSMEM_BITS.
This is potentially problematic, given that LPA2 hardware support is
modeled as a CPU feature which can be overridden, and with LPA2 hardware
support turned off, attempting to map physical regions with address bits
[51:48] set (which may exist on LPA2 capable systems booting with
arm64.nolva) will result in corrupted mappings with a truncated output
address and bogus shareability attributes.
This means that the accepted physical address range in the mapping
routines should be at most 48 bits wide when LPA2 support is configured
but not enabled at runtime.
Fixes: 352b0395b5 ("arm64: Enable 52-bit virtual addressing for 4k and 16k granule configs")
Cc: stable@vger.kernel.org
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241212081841.2168124-9-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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 reStructuredText 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.