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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 7404FC433E0 for ; Mon, 11 Jan 2021 13:30:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D8C2221F1 for ; Mon, 11 Jan 2021 13:30:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732188AbhAKN3z (ORCPT ); Mon, 11 Jan 2021 08:29:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:42420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732761AbhAKN3p (ORCPT ); Mon, 11 Jan 2021 08:29:45 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1307C223E8; Mon, 11 Jan 2021 13:28:29 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kyxFD-006gPD-CK; Mon, 11 Jan 2021 13:28:27 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Mark Rutland , David Brazdil , Alexandru Elisei , Ard Biesheuvel , Jing Zhang , Ajay Patil , Prasad Sodagudi , Srinivas Ramana , James Morse , Julien Thierry , Suzuki K Poulose , kernel-team@android.com Subject: [PATCH v3 09/21] arm64: cpufeature: Add global feature override facility Date: Mon, 11 Jan 2021 13:27:59 +0000 Message-Id: <20210111132811.2455113-10-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210111132811.2455113-1-maz@kernel.org> References: <20210111132811.2455113-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, dbrazdil@google.com, alexandru.elisei@arm.com, ardb@kernel.org, jingzhangos@google.com, pajay@qti.qualcomm.com, psodagud@codeaurora.org, sramana@codeaurora.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a facility to globally override a feature, no matter what the HW says. Yes, this is dangerous. Nothing uses this yet, so we are pretty safe. For now. Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/cpufeature.h | 2 ++ arch/arm64/kernel/cpufeature.c | 26 +++++++++++++++++++++----- 2 files changed, 23 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 9a555809b89c..465d2cb63bfc 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -75,6 +75,8 @@ struct arm64_ftr_reg { u64 sys_val; u64 user_val; const struct arm64_ftr_bits *ftr_bits; + u64 *override_val; + u64 *override_mask; }; extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index e99eddec0a46..492321054bd5 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -544,13 +544,17 @@ static const struct arm64_ftr_bits ftr_raz[] = { ARM64_FTR_END, }; -#define ARM64_FTR_REG(id, table) { \ - .sys_id = id, \ - .reg = &(struct arm64_ftr_reg){ \ - .name = #id, \ - .ftr_bits = &((table)[0]), \ +#define ARM64_FTR_REG_OVERRIDE(id, table, v, m) { \ + .sys_id = id, \ + .reg = &(struct arm64_ftr_reg){ \ + .name = #id, \ + .ftr_bits = &((table)[0]), \ + .override_val = v, \ + .override_mask = m, \ }} +#define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL) + static const struct __ftr_reg_entry { u32 sys_id; struct arm64_ftr_reg *reg; @@ -786,6 +790,18 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) val &= valid_mask; + if (reg->override_mask && reg->override_val) { + u64 override = val; + override &= ~*reg->override_mask; + override |= (*reg->override_val & *reg->override_mask); + + if (val != override) + pr_warn("%s: forced from %016llx to %016llx\n", + reg->name, val, override); + + val = override; + } + reg->sys_val = val; reg->strict_mask = strict_mask; reg->user_mask = user_mask; -- 2.29.2