x86/entry/64: Simplify reg restore code in the standard IRET paths

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The old code restored all the registers with movq instead of pop.

In theory, this was done because some CPUs have higher movq
throughput, but any gain there would be tiny and is almost certainly
outweighed by the higher text size.

This saves 96 bytes of text.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ad82520a207ccd851b04ba613f4f752b33ac05f7.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

...

This commit is contained in:

Andy Lutomirski 2017-11-02 00:59:01 -07:00 • committed by Ingo Molnar

parent 8a055d7f41

commit e872045bfd

2 changed files with 27 additions and 6 deletions

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21

arch/x86/entry/calling.h

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12

arch/x86/entry/entry_64.S

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