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efi/runtime-wrappers: Remove out of date comment regarding in_nmi() 

This code is long gone, so remove the comment as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
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/1454364428-494-6-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ard Biesheuvel 2016-02-01 22:06:59 +00:00 committed by Ingo Molnar
parent ca0e30dcaa
commit 774846defc
1 changed files with 0 additions and 26 deletions
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26
drivers/firmware/efi/runtime-wrappers.c
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@ -61,32 +61,6 @@
*/
static DEFINE_SPINLOCK(efi_runtime_lock);
/*
* Some runtime services calls can be reentrant under NMI, even if the table
* above says they are not. (source: UEFI Specification v2.4A)
*
* Table 32. Functions that may be called after Machine Check, INIT and NMI
* +----------------------------+------------------------------------------+
* | Function | Called after Machine Check, INIT and NMI |
* +----------------------------+------------------------------------------+
* | GetTime() | Yes, even if previously busy. |
* | GetVariable() | Yes, even if previously busy |
* | GetNextVariableName() | Yes, even if previously busy |
* | QueryVariableInfo() | Yes, even if previously busy |
* | SetVariable() | Yes, even if previously busy |
* | UpdateCapsule() | Yes, even if previously busy |
* | QueryCapsuleCapabilities() | Yes, even if previously busy |
* | ResetSystem() | Yes, even if previously busy |
* +----------------------------+------------------------------------------+
*
* In order to prevent deadlocks under NMI, the wrappers for these functions
* may only grab the efi_runtime_lock or rtc_lock spinlocks if !efi_in_nmi().
* However, not all of the services listed are reachable through NMI code paths,
* so the the special handling as suggested by the UEFI spec is only implemented
* for QueryVariableInfo() and SetVariable(), as these can be reached in NMI
* context through efi_pstore_write().
*/
/*
* As per commit ef68c8f87ed1 ("x86: Serialize EFI time accesses on rtc_lock"),
* the EFI specification requires that callers of the time related runtime