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Commit:0d95981438("x86: efi/random: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table") causes the drivers/efi/libstub/random.c code to get used on x86 for the first time. But this code was not written with EFI mixed mode in mind (running a 64 bit kernel on 32 bit EFI firmware), this causes the kernel to crash during early boot when running in mixed mode. The problem is that in mixed mode pointers are 64 bit, but when running on a 32 bit firmware, EFI calls which return a pointer value by reference only fill the lower 32 bits of the passed pointer, leaving the upper 32 bits uninitialized which leads to crashes. This commit fixes this by initializing pointers which are passed by reference to EFI calls to NULL before passing them, so that the upper 32 bits are initialized to 0. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes:0d95981438("x86: efi/random: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table") Link: https://lkml.kernel.org/r/20191224132909.102540-3-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@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.