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,URIBL_BLOCKED, 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 0FF21C433E0 for ; Mon, 25 Jan 2021 10:53:56 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 8002222D04 for ; Mon, 25 Jan 2021 10:53:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8002222D04 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 19DD34B5B8; Mon, 25 Jan 2021 05:53:55 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lmuLOXt0tiMT; Mon, 25 Jan 2021 05:53:53 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B52EF4B5D8; Mon, 25 Jan 2021 05:53:53 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 94CE44B5BA for ; Mon, 25 Jan 2021 05:53:52 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Skqn9laLt82H for ; Mon, 25 Jan 2021 05:53:51 -0500 (EST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 586964B5B8 for ; Mon, 25 Jan 2021 05:53:51 -0500 (EST) 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 6C39822D50; Mon, 25 Jan 2021 10:53:50 +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 1l3zS6-009rDe-SV; Mon, 25 Jan 2021 10:50:35 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Subject: [PATCH v5 12/21] arm64: cpufeature: Add an early command-line cpufeature override facility Date: Mon, 25 Jan 2021 10:50:10 +0000 Message-Id: <20210125105019.2946057-13-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210125105019.2946057-1-maz@kernel.org> References: <20210125105019.2946057-1-maz@kernel.org> MIME-Version: 1.0 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 Cc: Prasad Sodagudi , Srinivas Ramana , Catalin Marinas , Ajay Patil , kernel-team@android.com, Will Deacon , Ard Biesheuvel X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu In order to be able to override CPU features at boot time, let's add a command line parser that matches options of the form "cpureg.feature=value", and store the corresponding value into the override val/mask pair. No features are currently defined, so no expected change in functionality. Signed-off-by: Marc Zyngier Acked-by: David Brazdil --- arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/head.S | 1 + arch/arm64/kernel/idreg-override.c | 130 +++++++++++++++++++++++++++++ 3 files changed, 132 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/kernel/idreg-override.c diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 86364ab6f13f..2262f0392857 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -17,7 +17,7 @@ obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ return_address.o cpuinfo.o cpu_errata.o \ cpufeature.o alternative.o cacheinfo.o \ smp.o smp_spin_table.o topology.o smccc-call.o \ - syscall.o proton-pack.o + syscall.o proton-pack.o idreg-override.o targets += efi-entry.o diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index d74e5f84042e..3243e3ae9bd8 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -435,6 +435,7 @@ SYM_FUNC_START_LOCAL(__primary_switched) mov x0, x21 // pass FDT address in x0 bl early_fdt_map // Try mapping the FDT early + bl init_feature_override bl switch_to_vhe #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) bl kasan_early_init diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c new file mode 100644 index 000000000000..2d184d6674fd --- /dev/null +++ b/arch/arm64/kernel/idreg-override.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Early cpufeature override framework + * + * Copyright (C) 2020 Google LLC + * Author: Marc Zyngier + */ + +#include +#include + +#include +#include + +struct ftr_set_desc { + const char *name; + struct arm64_ftr_override *override; + struct { + const char *name; + u8 shift; + } fields[]; +}; + +static const struct ftr_set_desc * const regs[] __initdata = { +}; + +static char *cmdline_contains_option(const char *cmdline, const char *option) +{ + char *str = strstr(cmdline, option); + + if ((str == cmdline || (str > cmdline && *(str - 1) == ' '))) + return str; + + return NULL; +} + +static int __init find_field(const char *cmdline, + const struct ftr_set_desc *reg, int f, u64 *v) +{ + char buf[256], *str; + size_t len; + + snprintf(buf, ARRAY_SIZE(buf), "%s.%s=", reg->name, reg->fields[f].name); + + str = cmdline_contains_option(cmdline, buf); + if (!str) + return -1; + + str += strlen(buf); + len = strcspn(str, " "); + len = min(len, ARRAY_SIZE(buf) - 1); + strncpy(buf, str, len); + buf[len] = 0; + + return kstrtou64(buf, 0, v); +} + +static void __init match_options(const char *cmdline) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(regs); i++) { + int f; + + if (!regs[i]->override) + continue; + + for (f = 0; regs[i]->fields[f].name; f++) { + u64 v; + + if (find_field(cmdline, regs[i], f, &v)) + continue; + + regs[i]->override->val |= (v & 0xf) << regs[i]->fields[f].shift; + regs[i]->override->mask |= 0xfUL << regs[i]->fields[f].shift; + } + } +} + +static __init void parse_cmdline(void) +{ + if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) { + const u8 *prop; + void *fdt; + int node; + + fdt = get_early_fdt_ptr(); + if (!fdt) + goto out; + + node = fdt_path_offset(fdt, "/chosen"); + if (node < 0) + goto out; + + prop = fdt_getprop(fdt, node, "bootargs", NULL); + if (!prop) + goto out; + + match_options(prop); + + if (!IS_ENABLED(CONFIG_CMDLINE_EXTEND)) + return; + } + +out: + match_options(CONFIG_CMDLINE); +} + +/* Keep checkers quiet */ +void init_feature_override(void); + +asmlinkage void __init init_feature_override(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(regs); i++) { + if (regs[i]->override) { + regs[i]->override->val = 0; + regs[i]->override->mask = 0; + } + } + + parse_cmdline(); + + for (i = 0; i < ARRAY_SIZE(regs); i++) { + if (regs[i]->override) + __flush_dcache_area(regs[i]->override, + sizeof(*regs[i]->override)); + } +} -- 2.29.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm