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48157aa392
The mini C runtime runs before relocations are processed, and so it cannot rely on statically initialized pointer variables. Add a check to ensure that such code does not get introduced by accident, by going over the relocations in each object, identifying the ones that operate on data sections that are part of the executable image, and raising an error if any relocations of type R_AARCH64_ABS64 exist. Note that such relocations are permitted in other places (e.g., debug sections) and will never occur in compiler generated code sections when using the small code model, so only check sections that have SHF_ALLOC set and SHF_EXECINSTR cleared. To accommodate cases where statically initialized symbol references are unavoidable, introduce a special case for ELF input data sections that have ".rodata.prel64" in their names, and in these cases, instead of rejecting any encountered ABS64 relocations, convert them into PREL64 relocations, which don't require any runtime fixups. Note that the code in question must still be modified to deal with this, as it needs to convert the 64-bit signed offsets into absolute addresses before use. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20240214122845.2033971-46-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 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.