[PATCH v2 0/2] efi: Follow-up fixes for EFI runtime stack

Ard Biesheuvel ardb at kernel.org
Wed Jan 4 09:44:31 PST 2023


Commit ff7a167961d1b ("arm64: efi: Execute runtime services from a
dedicated stack") introduced a dedicated stack for EFI runtime services,
in an attempt to make the execution of EFI runtime services more robust,
given that they execute at the same privilege level as the kernel.

However, this stack needs to be declared to the stacktrace machinery,
which is careful not to walk the stack when it leads into memory regions
that are not known to be allocated for stack use.

Also, given that the ACPI code may invoke the low-level EFI runtime call
wrapper without using the dedicated kernel thread and workqueue, we
should take this into account when trying to gracefully handle
synchronous exceptions.

Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Lee Jones <lee at kernel.org>

Ard Biesheuvel (2):
  arm64: efi: Avoid workqueue to check whether EFI runtime is live
  arm64: efi: Account for the EFI runtime stack in stack unwinder

 arch/arm64/include/asm/efi.h        | 10 ++++++++++
 arch/arm64/include/asm/stacktrace.h | 15 +++++++++++++++
 arch/arm64/kernel/efi.c             |  3 ++-
 arch/arm64/kernel/stacktrace.c      | 12 ++++++++++++
 4 files changed, 39 insertions(+), 1 deletion(-)

-- 
2.39.0




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