]> git.karo-electronics.de Git - karo-tx-linux.git/commit
efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Wed, 17 Feb 2016 12:35:55 +0000 (12:35 +0000)
committerIngo Molnar <mingo@kernel.org>
Mon, 22 Feb 2016 07:26:25 +0000 (08:26 +0100)
commitfe3244945c47161e2486412d6412c87ba279305d
tree55d5091c13d9f4bcd91684936986e376891c6512
parent662b1d890c593673964758fe5b6f22067bffba7a
efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled

The UEFI spec allows Runtime Services to be invoked with interrupts
enabled. The only reason we were disabling interrupts was to prevent
recursive calls into the services on the same CPU, which will lead to
deadlock. However, the only context where such invocations may occur
legally is from efi-pstore via efivars, and that code has been updated
to call a non-blocking alternative when invoked from a non-interruptible
context.

So instead, update the ordinary, blocking UEFI Runtime Services wrappers
to execute with interrupts enabled. This aims to prevent excessive interrupt
latencies on uniprocessor platforms with slow variable stores.

Note that other OSes such as Windows call UEFI Runtime Services with
interrupts enabled as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
drivers/firmware/efi/runtime-wrappers.c