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There is no need for head_32.S and head_64.S both declaring a copy of the global 'image_offset' variable, so drop those and make the extern C declaration the definition. When image_offset is moved to the .c file, it needs to be placed particularly in the .data section because it lands by default in the .bss section which is cleared too late, in .Lrelocated, before the first access to it and thus garbage gets read, leading to SEV guests exploding in early boot. This happens only when the SEV guest kernel is loaded through grub. If supplied with qemu's -kernel command line option, that memory is always cleared upfront by qemu and all is fine there. [ bp: Expand commit message with SEV aspect. ] Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20221122161017.2426828-8-ardb@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 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.