Messages in this thread | | | Date | Mon, 30 May 2016 14:08:49 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/hweight: Get rid of the special calling convention |
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On Mon, May 30, 2016 at 12:56:27PM +0200, Borislav Petkov wrote: > From: Borislav Petkov <bp@suse.de> > > People complained about ARCH_HWEIGHT_CFLAGS and how it throws a wrench > into kcov, lto, etc, experimentations. > > Add asm versions for __sw_hweight{32,64}() and do explicit saving and > restoring of clobbered registers. This gets rid of the special calling > convention. We get to call those functions on !X86_FEATURE_POPCNT CPUs. > > We still need to hardcode POPCNT and register operands as some old gas > versions which we support, do not know about POPCNT. > > Btw, remove redundant REX prefix from 32-bit POPCNT because alternatives > can do padding now. > > Suggested-by: "H. Peter Anvin" <hpa@zytor.com> > Signed-off-by: Borislav Petkov <bp@suse.de> > Cc: Andy Lutomirski <luto@amacapital.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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