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=-9.8 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,URIBL_BLOCKED,USER_AGENT_GIT 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 66E5BC433E0 for ; Wed, 20 May 2020 01:23:45 +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 37FCA20756 for ; Wed, 20 May 2020 01:23:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="PJjhmgGM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 37FCA20756 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-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=u5dbj0aGeEWUbHxO/kLToj0Fb1/lwgNeTCuzmiVa7sU=; b=PJj hmgGMjV9WS6IdwnR/0RTDxpQw/cEBhyp1YnqwSUVxI3P5tjWNZB849Qf4jRqR9B0x2PiDWtKtaQo3 ux4tmVQyMsgsFin2J7OgQUJUQPgMhykDHP0xyVSCqf1UCWL9YDCIBbDqSCChN4ggnzkdZptBdzvu2 Dr4rdDXi3NtHbEmPdVsDRat0JLxwx7GfiDfKa502y3HZxd3lQSqsPGYjpScjRshPyNOAh37a6f8Xm REElQCI0byXs+0ducn8XpAciG3ZOYvyj79hLnOPLj9GJ3ZY6IWLyfDDO/76kMry3nrbM0WYT88uQQ MFYkY8HulGtnYxoim0XZAoaVkRvJFOw==; 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 1jbDSS-0000a4-T2; Wed, 20 May 2020 01:23:44 +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 1jbDSP-0000ZC-QO for linux-arm-kernel@lists.infradead.org; Wed, 20 May 2020 01:23:43 +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 9CE9A31B; Tue, 19 May 2020 18:23:39 -0700 (PDT) Received: from p8cg001049571a15.arm.com (unknown [10.163.75.101]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9F9473F68F; Tue, 19 May 2020 18:23:36 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64/cpufeature: Move BUG_ON() inside get_arm64_ftr_reg() Date: Wed, 20 May 2020 06:52:54 +0530 Message-Id: <1589937774-20479-1-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200519_182341_942334_7DA66771 X-CRM114-Status: GOOD ( 15.07 ) 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, Suzuki K Poulose , Catalin Marinas , Anshuman Khandual , linux-kernel@vger.kernel.org, Mark Brown , Will Deacon MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 BUG_ON() when the search fails in get_arm64_ftr_reg() rather than checking for return value and doing the same in some individual callers. But there are some callers that dont BUG_ON() upon search failure. It adds an argument 'failsafe' that provides required switch between callers based on whether they could proceed or not. 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 --- Applies on next-20200518 that has recent cpufeature changes from Will. arch/arm64/kernel/cpufeature.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index bc5048f152c1..62767cc540c3 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -557,7 +557,7 @@ static int search_cmp_ftr_reg(const void *id, const void *regp) * - NULL on failure. It is upto the caller to decide * the impact of a failure. */ -static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id) +static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id, bool failsafe) { const struct __ftr_reg_entry *ret; @@ -568,6 +568,13 @@ static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id) search_cmp_ftr_reg); if (ret) return ret->reg; + /* + * This can not really proceed when the search fails. + * Requesting for a non existent register search will + * also be an error in itself. Error out when not + * called with fail safe request. + */ + BUG_ON(!failsafe); return NULL; } @@ -630,9 +637,7 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) u64 valid_mask = 0; const struct arm64_ftr_bits *ftrp; - struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg); - - BUG_ON(!reg); + struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg, false); for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) { u64 ftr_mask = arm64_ftr_mask(ftrp); @@ -760,9 +765,8 @@ static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new) 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); + struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id, false); - BUG_ON(!regp); update_cpu_ftr_reg(regp, val); if ((boot & regp->strict_mask) == (val & regp->strict_mask)) return 0; @@ -774,10 +778,7 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot) 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; + struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id, false); for (ftrp = regp->ftr_bits; ftrp->width; ftrp++) { if (ftrp->shift == field) { @@ -959,10 +960,9 @@ void update_cpu_features(int cpu, u64 read_sanitised_ftr_reg(u32 id) { - struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id); + struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id, false); /* We shouldn't get a request for an unsupported register */ - BUG_ON(!regp); return regp->sys_val; } @@ -2565,7 +2565,7 @@ static int emulate_sys_reg(u32 id, u64 *valp) if (sys_reg_CRm(id) == 0) return emulate_id_reg(id, valp); - regp = get_arm64_ftr_reg(id); + regp = get_arm64_ftr_reg(id, true); if (regp) *valp = arm64_ftr_reg_user_value(regp); else -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel