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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C756EC433DF for ; Tue, 26 May 2020 13:59:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 97F172087D for ; Tue, 26 May 2020 13:59:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="RQ4O9iK1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 97F172087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UweMin6fzs40ywTnNpr/oH2FLYshVwYwRvmCTbft1H4=; b=RQ4O9iK17RvqbjUZZHim2Qv0q SKisEqrsWtJWphzPT9x0YbcHB0UjfcvKQsas675tE+WmAKN7XGBkuIi0WUQdbReG1gyLMfOns/9fZ 2iCCnKPfjCpWCTFXcDYsDQkXGPqoO2vKPhG0HghJEPanoF+8yRxpfYN/0v8wIqsmNVwR0c00kZhF/ cIhTzLDSWgyO7LmCAmNPYmUERlFs1Lqq7kFKBjY2sPDz6ASqglE+jHejgcREcg4TlQk7kLPGQMXU8 GGHtNeCvngQebfVeIznrH0pI7xKz9/nVU/Sxcm3fsRcaQ0uhkprjbnXRLnyK8fCjE3OMbGNavoYKA TKrl/zcXA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jda7C-0007Rk-Gp; Tue, 26 May 2020 13:59:34 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jda79-0007Qx-0E for linux-arm-kernel@lists.infradead.org; Tue, 26 May 2020 13:59:32 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D719E1FB; Tue, 26 May 2020 06:59:27 -0700 (PDT) Received: from [10.37.8.5] (unknown [10.37.8.5]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 13CD43F6C4; Tue, 26 May 2020 06:59:25 -0700 (PDT) Subject: Re: [PATCH V2] arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() To: anshuman.khandual@arm.com, linux-arm-kernel@lists.infradead.org References: <1590500353-28082-1-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose Message-ID: <0726a5b9-fff6-a15c-e705-db7abd4b1abd@arm.com> Date: Tue, 26 May 2020 15:04:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1590500353-28082-1-git-send-email-anshuman.khandual@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200526_065931_085685_700D90A8 X-CRM114-Status: GOOD ( 21.09 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, catalin.marinas@arm.com, broonie@kernel.org, will@kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 05/26/2020 02:39 PM, Anshuman Khandual wrote: > There is no way to proceed when requested register could not be searched in > arm64_ftr_reg[]. Requesting for a non present register would be an error as > well. Hence lets just WARN_ON() when search fails in get_arm64_ftr_reg() > rather than checking for return value and doing a BUG_ON() instead in some > individual callers. But there are also caller instances that dont error out > when register search fails. Add a new helper get_arm64_ftr_reg_nowarn() for > such cases. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Suzuki K Poulose > Cc: Mark Brown > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > Changes in V2: > > - Added get_arm64_ftr_reg_nowarn() per Will > - read_sanitised_ftr_reg() returns 0 when register search fails per Catalin > > Changes in V1: (https://patchwork.kernel.org/patch/11559083/) > > arch/arm64/kernel/cpufeature.c | 42 +++++++++++++++++++++++----------- > 1 file changed, 29 insertions(+), 13 deletions(-) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index bc5048f152c1..f4555b9d145c 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -548,16 +548,16 @@ static int search_cmp_ftr_reg(const void *id, const void *regp) > } > ... > static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg, > s64 ftr_val) > { > @@ -632,8 +654,6 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) > const struct arm64_ftr_bits *ftrp; > struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg); > > - BUG_ON(!reg); > - > for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) { > u64 ftr_mask = arm64_ftr_mask(ftrp); > s64 ftr_new = arm64_ftr_value(ftrp, new); > @@ -762,7 +782,6 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot) > { > struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id); > > - BUG_ON(!regp); > update_cpu_ftr_reg(regp, val); > if ((boot & regp->strict_mask) == (val & regp->strict_mask)) > return 0; > @@ -776,9 +795,6 @@ static void relax_cpu_ftr_reg(u32 sys_id, int field) > const struct arm64_ftr_bits *ftrp; > struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id); > > - if (WARN_ON(!regp)) > - return; > - You need to return here, on !regp. Rest looks fine to me. Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel