From patchwork Mon Feb 15 12:16:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hector Martin X-Patchwork-Id: 383042 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 515EBC433DB for ; Mon, 15 Feb 2021 12:19:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E25C64DAF for ; Mon, 15 Feb 2021 12:19:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230188AbhBOMTR (ORCPT ); Mon, 15 Feb 2021 07:19:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229996AbhBOMTF (ORCPT ); Mon, 15 Feb 2021 07:19:05 -0500 Received: from mail.marcansoft.com (marcansoft.com [IPv6:2a01:298:fe:f::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CE13C06178B; Mon, 15 Feb 2021 04:18:14 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: hector@marcansoft.com) by mail.marcansoft.com (Postfix) with ESMTPSA id D55664249E; Mon, 15 Feb 2021 12:18:08 +0000 (UTC) From: Hector Martin To: linux-arm-kernel@lists.infradead.org Cc: Hector Martin , Marc Zyngier , Rob Herring , Arnd Bergmann , Olof Johansson , Krzysztof Kozlowski , Mark Kettenis , Tony Lindgren , Mohamed Mediouni , Stan Skowronek , Alexander Graf , Will Deacon , Linus Walleij , Mark Rutland , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 07/25] arm64: cpufeature: Add a feature for FIQ support Date: Mon, 15 Feb 2021 21:16:55 +0900 Message-Id: <20210215121713.57687-8-marcan@marcan.st> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210215121713.57687-1-marcan@marcan.st> References: <20210215121713.57687-1-marcan@marcan.st> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Apple ARM SoCs (A11 and newer) have some interrupt sources hard-wired to the FIQ line. Introduce a cpufeature that can be used to enable FIQ handling via alternatives. This is currently enabled for all Apple CPUs. If/when support is implemented for older (pre-A11) iPhone/iPad SoCs which do not need FIQs, or if newer SoCs are released without the FIQ requirement, we can revisit the condition. Signed-off-by: Hector Martin --- arch/arm64/Kconfig | 11 +++++++++++ arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/kernel/cpufeature.c | 14 ++++++++++++++ 3 files changed, 27 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f39568b28ec1..fbc02af404b6 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1756,6 +1756,17 @@ config ARM64_DEBUG_PRIORITY_MASKING If unsure, say N endif +config ARM64_FIQ_SUPPORT + bool "Support for FIQ interrupts" + help + Adds support for handling FIQ interrupts as normal IRQs. + This is required on Apple platforms where some IRQ sources are + hardwired to the FIQ interrupt line. + + This option only affects platforms that require FIQ handling. + On all other platforms, unexpected FIQs will continue to + trigger a kernel panic. + config RELOCATABLE bool "Build a relocatable kernel image" if EXPERT select ARCH_HAS_RELR diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index b77d997b173b..c36d926ad801 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -66,7 +66,8 @@ #define ARM64_WORKAROUND_1508412 58 #define ARM64_HAS_LDAPR 59 #define ARM64_KVM_PROTECTED_MODE 60 +#define ARM64_NEEDS_FIQ 61 -#define ARM64_NCAPS 61 +#define ARM64_NCAPS 62 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index e99eddec0a46..9fde84beabf1 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1237,6 +1237,12 @@ static bool has_cache_idc(const struct arm64_cpu_capabilities *entry, return ctr & BIT(CTR_IDC_SHIFT); } +static bool needs_fiq(const struct arm64_cpu_capabilities *entry, int __unused) +{ + /* All supported Apple cores need this */ + return read_cpuid_implementor() == ARM_CPU_IMP_APPLE; +} + static void cpu_emulate_effective_ctr(const struct arm64_cpu_capabilities *__unused) { /* @@ -2154,6 +2160,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, .min_field_value = 1, }, +#ifdef CONFIG_ARM64_FIQ_SUPPORT + { + .desc = "FIQs", + .capability = ARM64_NEEDS_FIQ, + .type = ARM64_CPUCAP_BOOT_CPU_FEATURE, + .matches = needs_fiq, + }, +#endif {}, };