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

Message ID 20230104174433.1259428-1-ardb@kernel.org (mailing list archive)
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Series efi: Follow-up fixes for EFI runtime stack | expand

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Ard Biesheuvel Jan. 4, 2023, 5:44 p.m. UTC 
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@arm.com>
Cc: Lee Jones <lee@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(-)