linux-kernel - Re: [PATCH 1/1] x86: Hyper-V: Mark the Hyper-V clocksource as being high resolution

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 4 Jul 2015 10:10:32 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	"K. Y. Srinivasan" <kys@...rosoft.com>
cc:	x86@...nel.org, gregkh@...uxfoundation.org,
	linux-kernel@...r.kernel.org, devel@...uxdriverproject.org,
	olaf@...fle.de, apw@...onical.com, jasowang@...hat.com,
	Vivek yadav <vyadav@...rosoft.com>
Subject: Re: [PATCH 1/1] x86: Hyper-V: Mark the Hyper-V clocksource as being
 high resolution

On Fri, 3 Jul 2015, K. Y. Srinivasan wrote:
> From: Vivek yadav <vyadav@...rosoft.com>
> 
> By design, alternative clock sources listed are based on the resolution of
> current clock source. Once you set a  high resolution clock,
> only high resolution sources are returned.
> Mark Hyper-V clock source as a high resolution clock source.
> 
> Signed-off-by: Vivek yadav <vyadav@...rosoft.com>
> Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
> ---
>  arch/x86/kernel/cpu/mshyperv.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 9b5d7b5..0e507a0 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -151,7 +151,8 @@ static struct clocksource hyperv_cs = {
>  	.rating		= 400, /* use this when running on Hyperv*/
>  	.read		= read_hv_clock,
>  	.mask		= CLOCKSOURCE_MASK(64),
> -	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> +	.flags		= CLOCK_SOURCE_IS_CONTINUOUS |
> +			  CLOCK_SOURCE_VALID_FOR_HRES,

No, this is wrong. The CLOCK_SOURCE_VALID_FOR_HRES flag is managed by
the core code and set when a clocksource fulfils the criteria.

The changelog above is not explaining what problem you are trying to
solve.

Thanks,

	tglx


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/