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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E2B12C61DB9 for ; Tue, 25 Aug 2026 16:42:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=iR2QiG0Sai2JU3flZPc7oLIVw9Px1ZlLeFHfTecvox8=; b=vUKIE7E2VdemUjKLdLW3Gixq1D PT3T5mIu8EGWnb2zZJRz5mZ7qf04eTVHd/z5tLHS+NukF6iagU9PAAR0TtBlWrTakOgdLedEYK1FT IVOaqCLoJo+J558SnsuZMxoTWWcUZ54V4a9CeuMKb4AtuDXB6qwHZXfr5s2ckZaIZS1Bg+Mc6TO+i tmFhA0u7PMmHvI6CY0SetJa7clQUtzcrFkZg1iAeMwgc6y9/QcH/VZQeHKuQ0FwpeKzKUZbhM7bHp fuGFlHsaY97D5XKT8mlE0J9K6HvGJLhYJyuVc9LR1pS9zFzeE2IgNV8xcJ/LKRcRj6bUYGnKpePkn 9FtgT9ew==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wyuES-000000018Cw-0gnl; Tue, 25 Aug 2026 16:42:40 +0000 Received: from out-131.mta1.migadu.com ([2001:41d0:203:375::83] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wyuEK-0000000189x-0NkT for linux-arm-kernel@lists.infradead.org; Tue, 25 Aug 2026 16:42:35 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=zQU2cneHWYiXgdAM5Ki7+W+91fket5ATQUH8SgIxbj8=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787676150; v=1; x=1788280950; b=JeBT/yCId6Nw/f6FxMpE+FJ9DvG61j0vYhq4T1ddN5O92skKQ2/Xas5uIh6bqC2269YRGDIT OZupAdBGbry7mKjL8YWmjq/L8j1aqi+wyrtFmP1IbnYDhK5fj2ykyIQwdCLagtJvPMpmITRas3k KXFYvJXlgUbcfeqFrJybgelk= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: from claudy.local (2a01:4b00:ad36:1d00:3a05:25ff:fe33:35a9) by smtp.migadu.com with ESMTPS id eb5a6faaae912dd9; Tue, 25 Aug 2026 16:42:30 +0000 X-Mizu-Trace-ID: eb5a6faaae912dd9 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org Cc: Marc Zyngier , Oliver Upton , Mark Rutland , Suzuki K Poulose , Mark Brown , kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Fuad Tabba Subject: [PATCH v4 1/2] arm64: Apply overrides to CPU local capabilities Date: Tue, 25 Aug 2026 17:42:18 +0100 Message-Id: <20260825164219.3347229-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260825164219.3347229-1-fuad.tabba@linux.dev> References: <20260825164219.3347229-1-fuad.tabba@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260825_094232_272697_066BDA49 X-CRM114-Status: GOOD ( 13.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Suzuki K Poulose If an override has been applied, make sure we apply that for the secondary CPUs too, to limit the features. Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/all/afc5bd00-28ca-413b-b047-ee53589c285d@arm.com/ Cc: stable@vger.kernel.org [Fuad: whitespace and comment fixes] Signed-off-by: Fuad Tabba --- arch/arm64/kernel/cpufeature.c | 42 +++++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 9a22df0c5120f..88b15b5ef2f7f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1232,10 +1232,43 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) init_cpu_ftr_reg(SYS_GMID_EL1, info->reg_gmid); } +/* + * Sanitise the register fields to clamp the values to the overrides that + * have been applied. + */ +static u64 override_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 val) +{ + const struct arm64_ftr_bits *ftrp; + + if (!reg || !reg->override->mask) + return val; + + for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) { + u64 ftr_mask = arm64_ftr_mask(ftrp); + s64 ftr_val, ftr_ovr, ftr_safe; + + /* Skip the fields not overridden */ + if ((ftr_mask & reg->override->mask) != ftr_mask) + continue; + + ftr_val = arm64_ftr_value(ftrp, val); + ftr_ovr = arm64_ftr_value(ftrp, reg->override->val); + ftr_safe = arm64_ftr_safe_value(ftrp, ftr_ovr, ftr_val); + + if (ftr_safe != ftr_val) + val = arm64_ftr_set_value(ftrp, val, ftr_safe); + } + + return val; +} + static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new) { const struct arm64_ftr_bits *ftrp; + /* Apply the overrides */ + new = override_cpu_ftr_reg(reg, new); + for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) { s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val); s64 ftr_new = arm64_ftr_value(ftrp, new); @@ -1539,7 +1572,6 @@ EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg); */ u64 __read_sysreg_by_encoding(u32 sys_id) { - struct arm64_ftr_reg *regp; u64 val; switch (sys_id) { @@ -1592,13 +1624,7 @@ u64 __read_sysreg_by_encoding(u32 sys_id) return 0; } - regp = get_arm64_ftr_reg(sys_id); - if (regp) { - val &= ~regp->override->mask; - val |= (regp->override->val & regp->override->mask); - } - - return val; + return override_cpu_ftr_reg(get_arm64_ftr_reg(sys_id), val); } #include -- 2.39.5