From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965140Ab2CMAe4 (ORCPT ); Mon, 12 Mar 2012 20:34:56 -0400 Received: from mail.windriver.com ([147.11.1.11]:48738 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965104Ab2CMAYf (ORCPT ); Mon, 12 Mar 2012 20:24:35 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Zachary Amsden , Marcelo Tosatti , Paul Gortmaker Subject: [34-longterm 168/196] x86: pvclock: Move scale_delta into common header Date: Mon, 12 Mar 2012 20:21:21 -0400 Message-Id: <1331598109-31424-123-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.3 In-Reply-To: <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> References: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zachary Amsden ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- commit 347bb4448c2155eb2310923ccaa4be5677649003 upstream. 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 Signed-off-by: Paul Gortmaker --- arch/x86/include/asm/pvclock.h | 38 ++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/pvclock.c | 3 ++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index daaacab..982aa32 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -12,4 +12,42 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall, 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 */ diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index b12fe8d..929047c 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -74,7 +74,8 @@ static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift) 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); } /* -- 1.7.9.3