From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 508DFC43334 for ; Mon, 13 Jun 2022 10:15:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236222AbiFMKP5 (ORCPT ); Mon, 13 Jun 2022 06:15:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241652AbiFMKPe (ORCPT ); Mon, 13 Jun 2022 06:15:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85B27DEC2; Mon, 13 Jun 2022 03:14:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E846761499; Mon, 13 Jun 2022 10:14:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05F8FC34114; Mon, 13 Jun 2022 10:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655115286; bh=TnYwbZQiMyo0m5WbMSZ2DeELNzqTxDai2ASvjnjnB1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gPWLs0DsVGVif01Cmrhn+kv9ap4ZOyNkrmuM0jSNqoKYClVGRZhShdUuIwjf59I5s M91WuiDLDqw0iNlUDoyrJdd3tW7YS2OCWjZ82Rgq8FluLUC9I2AkPkBnVvb99kONWy WL4jMMvSn10ylT7odqJ5QA/PKAy4Pz/07B5HGL5U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Arnd Bergmann , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Guenter Roeck , "Jason A. Donenfeld" , Sasha Levin Subject: [PATCH 4.9 021/167] openrisc: start CPU timer early in boot Date: Mon, 13 Jun 2022 12:08:15 +0200 Message-Id: <20220613094845.830124695@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094840.720778945@linuxfoundation.org> References: <20220613094840.720778945@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason A. Donenfeld [ Upstream commit 516dd4aacd67a0f27da94f3fe63fe0f4dbab6e2b ] In order to measure the boot process, the timer should be switched on as early in boot as possible. As well, the commit defines the get_cycles macro, like the previous patches in this series, so that generic code is aware that it's implemented by the platform, as is done on other archs. Cc: Thomas Gleixner Cc: Arnd Bergmann Cc: Jonas Bonn Cc: Stefan Kristiansson Acked-by: Stafford Horne Reported-by: Guenter Roeck Signed-off-by: Jason A. Donenfeld Signed-off-by: Sasha Levin --- arch/openrisc/include/asm/timex.h | 1 + arch/openrisc/kernel/head.S | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/arch/openrisc/include/asm/timex.h b/arch/openrisc/include/asm/timex.h index 9935cad1b9b9..34d015bf0462 100644 --- a/arch/openrisc/include/asm/timex.h +++ b/arch/openrisc/include/asm/timex.h @@ -27,6 +27,7 @@ static inline cycles_t get_cycles(void) { return mfspr(SPR_TTCR); } +#define get_cycles get_cycles /* This isn't really used any more */ #define CLOCK_TICK_RATE 1000 diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index 98dd6860bc0b..0b6be5b3522b 100644 --- a/arch/openrisc/kernel/head.S +++ b/arch/openrisc/kernel/head.S @@ -452,6 +452,15 @@ _start: l.ori r3,r0,0x1 l.mtspr r0,r3,SPR_SR + /* + * Start the TTCR as early as possible, so that the RNG can make use of + * measurements of boot time from the earliest opportunity. Especially + * important is that the TTCR does not return zero by the time we reach + * rand_initialize(). + */ + l.movhi r3,hi(SPR_TTMR_CR) + l.mtspr r0,r3,SPR_TTMR + CLEAR_GPR(r1) CLEAR_GPR(r2) CLEAR_GPR(r3) -- 2.35.1