efi/libstub/tpm: Initialize efi_physical_addr_t vars to zero for mixed mode
authorHans de Goede <hdegoede@redhat.com>
Fri, 22 Jun 2018 06:42:22 +0000 (08:42 +0200)
committerIngo Molnar <mingo@kernel.org>
Fri, 22 Jun 2018 08:58:27 +0000 (10:58 +0200)
commit52e1cf2d19c2e62e6a81b8de3f7320d033917dd5
tree46d7201877abba17fbab7678be9bb6c7ce214f19
parent1abd8a8f39cd9a2925149000056494523c85643a
efi/libstub/tpm: Initialize efi_physical_addr_t vars to zero for mixed mode

Commit:

  79832f0b5f71 ("efi/libstub/tpm: Initialize pointer variables to zero for mixed mode")

fixes a problem with the tpm code on mixed mode (64-bit kernel on 32-bit UEFI),
where 64-bit pointer variables are not fully initialized by the 32-bit EFI code.

A similar problem applies to the efi_physical_addr_t variables which
are written by the ->get_event_log() EFI call. Even though efi_physical_addr_t
is 64-bit everywhere, it seems that some 32-bit UEFI implementations only
fill in the lower 32 bits when passed a pointer to an efi_physical_addr_t
to fill.

This commit initializes these to 0 to, to ensure the upper 32 bits are
0 in mixed mode. This fixes recent kernels sometimes hanging during
early boot on mixed mode UEFI systems.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org> # v4.16+
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
Link: http://lkml.kernel.org/r/20180622064222.11633-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
drivers/firmware/efi/libstub/tpm.c