From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 873CF179FDD; Sun, 24 Mar 2024 23:41:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323667; cv=none; b=h20A/rPDCu+hwqG57eGUJPiYTPf7MQvo8NNHGNlOpYot0HxHwgWGHQz9LLZ+7blzfB5qa4p70Zs4hUbM8isvC5J2CfrXrGX1ja10Affx8PfLRz1Yd0CJDIW0a6dK5NlGJbA/KPG/9iTYoPMXMhFkK6FZoL0bWRhyPQ0T78h4BdY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323667; c=relaxed/simple; bh=bkgkY4MimmFGIFsqql8oT8WjKyOt0XojbbENl0nJP7w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p9PCOc30jlehk2aYaK+oPS4wfucVr8aCMP7D1Nv/chapIfCmXI/znIX3EsY70swzx9wqISlL6I1j/CGKT6jv/19UjTC5LSVJDA1Dfwjl9KKwx6n6xqGdWysmaSqbp9HsTK3MpF3GJo1VwowtpHLuwENznxGgV5TMTKa8bXY0/mE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OayZDEjj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OayZDEjj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1B79C43390; Sun, 24 Mar 2024 23:41:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711323666; bh=bkgkY4MimmFGIFsqql8oT8WjKyOt0XojbbENl0nJP7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OayZDEjjo9BnrNuEEhq3UF7iJxGjPVl8s7heX1wflSF/KHNuX+LoGah7MJ4psnmbS wopZGe2A1uGLfZod+qeb1CckK5DqBPC3D3kw3qNqeOQQhxP16qRmnpAfY4cHxUymFC F0Rm/B1Y41XHDlsvETGARrHr6m/kItginwl6uBmjDOc3HLlBaCLI4fi+1qSTqwcYJ4 dwPiNKrc7sgYSYtZdJArN+uEGdMGGSotaXbX6Q0q8rMscDumG1fkgwE/4QI+7/K26A zWNYTF8APlkNO+NM69FTaCxq72GERvXUGEuDqDunhMwUEZQLIw9k+A9DGV+Tt29cou pULmw1vBrxs/w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Hilber , Thomas Gleixner , John Stultz , Sasha Levin Subject: [PATCH 5.10 038/238] timekeeping: Fix cross-timestamp interpolation for non-x86 Date: Sun, 24 Mar 2024 19:37:06 -0400 Message-ID: <20240324234027.1354210-39-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324234027.1354210-1-sashal@kernel.org> References: <20240324234027.1354210-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Peter Hilber [ Upstream commit 14274d0bd31b4debf28284604589f596ad2e99f2 ] So far, get_device_system_crosststamp() unconditionally passes system_counterval.cycles to timekeeping_cycles_to_ns(). But when interpolating system time (do_interp == true), system_counterval.cycles is before tkr_mono.cycle_last, contrary to the timekeeping_cycles_to_ns() expectations. On x86, CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE will mitigate on interpolating, setting delta to 0. With delta == 0, xtstamp->sys_monoraw and xtstamp->sys_realtime are then set to the last update time, as implicitly expected by adjust_historical_crosststamp(). On other architectures, the resulting nonsense xtstamp->sys_monoraw and xtstamp->sys_realtime corrupt the xtstamp (ts) adjustment in adjust_historical_crosststamp(). Fix this by deriving xtstamp->sys_monoraw and xtstamp->sys_realtime from the last update time when interpolating, by using the local variable "cycles". The local variable already has the right value when interpolating, unlike system_counterval.cycles. Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices") Signed-off-by: Peter Hilber Signed-off-by: Thomas Gleixner Acked-by: John Stultz Link: https://lore.kernel.org/r/20231218073849.35294-4-peter.hilber@opensynergy.com Signed-off-by: Sasha Levin --- kernel/time/timekeeping.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 6f615db414769..629a07e6a0bfc 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1248,10 +1248,8 @@ int get_device_system_crosststamp(int (*get_time_fn) tk_core.timekeeper.offs_real); base_raw = tk->tkr_raw.base; - nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, - system_counterval.cycles); - nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, - system_counterval.cycles); + nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, cycles); + nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, cycles); } while (read_seqcount_retry(&tk_core.seq, seq)); xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real); -- 2.43.0