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Hans de Goede authored
Commit: 0d959814 ("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: 0d959814 ("x86: efi/random: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table") Link: https://lkml.kernel.org/r/20191224132909.102540-3-ardb@kernel.orgSigned-off-by:
Ingo Molnar <mingo@kernel.org>
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