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bf25266f83
The page table population code in map_range() uses a recursive algorithm to create the early mappings of the kernel, the DTB and the ID mapped text and data pages, and this fails to take into account that the way these page tables may be constructed is not precisely the same at each level. In particular, block mappings are not permitted at each level, and the code as it exists today might inadvertently create such a forbidden block mapping if it were used to map a region of the appropriate size and alignment. This never happens in practice, given the limited size of the assets being mapped by the early boot code. Nonetheless, it would be better if this code would behave correctly in all circumstances. So only permit block mappings at level 2, and page mappings at level 3, for any page size, and use table mappings exclusively at all other levels. This change should have no impact in practice, but it makes the code more robust. Cc: Anshuman Khandual <anshuman.khandual@arm.com> Reported-by: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://lore.kernel.org/r/20250311073043.96795-2-ardb+git@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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.