From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932579Ab1EFA0W (ORCPT ); Thu, 5 May 2011 20:26:22 -0400 Received: from kroah.org ([198.145.64.141]:37423 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932538Ab1EFA0N (ORCPT ); Thu, 5 May 2011 20:26:13 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Thu May 5 17:22:19 2011 Message-Id: <20110506002219.104537530@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Thu, 05 May 2011 17:22:06 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, greg@kroah.com Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "Serge E. Hallyn" , Zachary Amsden , Marcelo Tosatti , avi@redhat.com Subject: [141/143] x86: pvclock: Move scale_delta into common header In-Reply-To: <20110506002311.GA15354@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Zachary Amsden (cherry-picked from commit 347bb4448c2155eb2310923ccaa4be5677649003) The scale_delta function for shift / multiply with 31-bit precision moves to a common header so it can be used by both kernel and kvm module. Signed-off-by: Zachary Amsden Signed-off-by: Marcelo Tosatti BugLink: http://bugs.launchpad.net/bugs/714335 Signed-off-by: Serge E. Hallyn Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/pvclock.h | 38 ++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/pvclock.c | 3 ++- 2 files changed, 40 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -12,4 +12,42 @@ void pvclock_read_wallclock(struct pvclo struct timespec *ts); void pvclock_resume(void); +/* + * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, + * yielding a 64-bit result. + */ +static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) +{ + u64 product; +#ifdef __i386__ + u32 tmp1, tmp2; +#endif + + if (shift < 0) + delta >>= -shift; + else + delta <<= shift; + +#ifdef __i386__ + __asm__ ( + "mul %5 ; " + "mov %4,%%eax ; " + "mov %%edx,%4 ; " + "mul %5 ; " + "xor %5,%5 ; " + "add %4,%%eax ; " + "adc %5,%%edx ; " + : "=A" (product), "=r" (tmp1), "=r" (tmp2) + : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); +#elif defined(__x86_64__) + __asm__ ( + "mul %%rdx ; shrd $32,%%rdx,%%rax" + : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) ); +#else +#error implement me! +#endif + + return product; +} + #endif /* _ASM_X86_PVCLOCK_H */ --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -74,7 +74,8 @@ static inline u64 scale_delta(u64 delta, static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow) { u64 delta = native_read_tsc() - shadow->tsc_timestamp; - return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); + return pvclock_scale_delta(delta, shadow->tsc_to_nsec_mul, + shadow->tsc_shift); } /*