netdev - Re: [PATCH net] net/mlx5: Dynamic cyclecounter shift calculation for PTP free running clock

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]

Message-ID: <20230824084048.GD3523530@kernel.org>
Date: Thu, 24 Aug 2023 10:40:48 +0200
From: Simon Horman <horms@...nel.org>
To: Rahul Rameshbabu <rrameshbabu@...dia.com>
Cc: netdev@...r.kernel.org, Saeed Mahameed <saeed@...nel.org>,
	Jakub Kicinski <kuba@...nel.org>,
	Richard Cochran <richardcochran@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Paolo Abeni <pabeni@...hat.com>, Vadim Fedorenko <vadfed@...a.com>,
	Kenneth Klette Jonassen <kenneth.jonassen@...dgetech.tv>
Subject: Re: [PATCH net] net/mlx5: Dynamic cyclecounter shift calculation for
 PTP free running clock

On Mon, Aug 21, 2023 at 04:05:54PM -0700, Rahul Rameshbabu wrote:
> Use a dynamic calculation to determine the shift value for the internal
> timer cyclecounter that will lead to the highest precision frequency
> adjustments. Previously used a constant for the shift value assuming all
> devices supported by the driver had a nominal frequency of 1GHz. However,
> there are devices that operate at different frequencies. The previous shift
> value constant would break the PHC functionality for those devices.
> 
> Reported-by: Vadim Fedorenko <vadim.fedorenko@...ux.dev>
> Closes: https://lore.kernel.org/netdev/20230815151507.3028503-1-vadfed@meta.com/
> Fixes: 6a4010927562 ("net/mlx5: Update cyclecounter shift value to improve ptp free running mode precision")
> Signed-off-by: Rahul Rameshbabu <rrameshbabu@...dia.com>
> Tested-by: Vadim Fedorenko <vadim.fedorenko@...ux.dev>

Reviewed-by: Simon Horman <horms@...nel.org>