From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 69DBC266565 for ; Tue, 11 Mar 2025 18:41:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741718500; cv=none; b=DbkpX761iujhgtMSOz1ZZ4VS93Cnp+7f8wQaBdl+7jjwYXqSqNNEnPOz5FH/qscFzLgsL6l1OWb7lp3/Ejc+/y1pBeLQPfiNCo67A9QofrhgwPNDwVkGzRw55ITF2DC6mJJ+ZFMBYHRLQ3ikuXJtvlHoI+ePSb1IZNBtnRC3idg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741718500; c=relaxed/simple; bh=mssoB0ImMUQKadmQ5O3JX8EwHj5EcFbn72hByUTsbQI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=s7ExqxCfPSUrwslIlN3K4+AfwLXnIQWTLxbzzEcn/6f2pOYtj76zGNvAFPPpZYgw6N5Zln4yGixWH7/VReAKYM1Gg7P+vjZZDgwLbsWURibgujx1ke+rAdyvDt9eO4rwjfPXOOL02DPPkKwvuZILPRNJSUDUCHV0Qp7qC6MhUW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 12F881713; Tue, 11 Mar 2025 11:41:49 -0700 (PDT) Received: from merodach.members.linode.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8FF713F694; Tue, 11 Mar 2025 11:41:34 -0700 (PDT) From: James Morse To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , Babu Moger , James Morse , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, Shaopeng Tan , Babu Moger , Tony Luck Subject: [PATCH v8:for-boris 24/30] x86/resctrl: Allow an architecture to disable pseudo lock Date: Tue, 11 Mar 2025 18:37:09 +0000 Message-Id: <20250311183715.16445-25-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250311183715.16445-1-james.morse@arm.com> References: <20250311183715.16445-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Pseudo-lock relies on knowledge of the micro-architecture to disable prefetchers etc. On arm64 these controls are typically secure only, meaning linux can't access them. Arm's cache-lockdown feature works in a very different way. Resctrl's pseudo-lock isn't going to be used on arm64 platforms. Add a Kconfig symbol that can be selected by the architecture. This enables or disables building of the pseudo_lock.c file, and replaces the functions with stubs. An additional IS_ENABLED() check is needed in rdtgroup_mode_write() so that attempting to enable pseudo-lock reports an "Unknown or unsupported mode" to user-space via the last_cmd_status file. Signed-off-by: James Morse Tested-by: Carl Worth # arm64 Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Amit Singh Tomar # arm64 Tested-by: Shanker Donthineni # arm64 Tested-by: Babu Moger Reviewed-by: Shaopeng Tan Reviewed-by: Tony Luck Reviewed-by: Reinette Chatre Reviewed-by: Fenghua Yu --- Changes since v4: * "last_cmd file" -> "last_cmd_status file" Changes since v2: * Clarified the commit message as to where the error string is printed. Changes since v1: * [Commit message only] Typo fix: s/psuedo/pseudo/g --- arch/x86/Kconfig | 7 ++++ arch/x86/kernel/cpu/resctrl/Makefile | 5 +-- arch/x86/kernel/cpu/resctrl/internal.h | 49 +++++++++++++++++++++----- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 3 +- 4 files changed, 53 insertions(+), 11 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index be2c311f5118..1a89574a58f7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -505,6 +505,7 @@ config X86_CPU_RESCTRL depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) select KERNFS select PROC_CPU_RESCTRL if PROC_FS + select RESCTRL_FS_PSEUDO_LOCK help Enable x86 CPU resource control support. @@ -521,6 +522,12 @@ config X86_CPU_RESCTRL Say N if unsure. +config RESCTRL_FS_PSEUDO_LOCK + bool + help + Software mechanism to pin data in a cache portion using + micro-architecture specific knowledge. + config X86_FRED bool "Flexible Return and Event Delivery" depends on X86_64 diff --git a/arch/x86/kernel/cpu/resctrl/Makefile b/arch/x86/kernel/cpu/resctrl/Makefile index 4a06c37b9cf1..0c13b0befd8a 100644 --- a/arch/x86/kernel/cpu/resctrl/Makefile +++ b/arch/x86/kernel/cpu/resctrl/Makefile @@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -obj-$(CONFIG_X86_CPU_RESCTRL) += core.o rdtgroup.o monitor.o -obj-$(CONFIG_X86_CPU_RESCTRL) += ctrlmondata.o pseudo_lock.o +obj-$(CONFIG_X86_CPU_RESCTRL) += core.o rdtgroup.o monitor.o +obj-$(CONFIG_X86_CPU_RESCTRL) += ctrlmondata.o +obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK) += pseudo_lock.o CFLAGS_pseudo_lock.o = -I$(src) diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 725f223ea07b..8d35bb423aad 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -512,14 +512,6 @@ unsigned int rdtgroup_cbm_to_size(struct rdt_resource *r, struct rdt_ctrl_domain unsigned long cbm); enum rdtgrp_mode rdtgroup_mode_by_closid(int closid); int rdtgroup_tasks_assigned(struct rdtgroup *r); -int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp); -int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp); -bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_ctrl_domain *d, unsigned long cbm); -bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_ctrl_domain *d); -int rdt_pseudo_lock_init(void); -void rdt_pseudo_lock_release(void); -int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp); -void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp); struct rdt_ctrl_domain *get_ctrl_domain_from_cpu(int cpu, struct rdt_resource *r); struct rdt_mon_domain *get_mon_domain_from_cpu(int cpu, struct rdt_resource *r); int closids_supported(void); @@ -551,4 +543,45 @@ void resctrl_file_fflags_init(const char *config, unsigned long fflags); void rdt_staged_configs_clear(void); bool closid_allocated(unsigned int closid); int resctrl_find_cleanest_closid(void); + +#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK +int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp); +int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp); +bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_ctrl_domain *d, unsigned long cbm); +bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_ctrl_domain *d); +int rdt_pseudo_lock_init(void); +void rdt_pseudo_lock_release(void); +int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp); +void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp); +#else +static inline int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp) +{ + return -EOPNOTSUPP; +} + +static inline int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp) +{ + return -EOPNOTSUPP; +} + +static inline bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_ctrl_domain *d, unsigned long cbm) +{ + return false; +} + +static inline bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_ctrl_domain *d) +{ + return false; +} + +static inline int rdt_pseudo_lock_init(void) { return 0; } +static inline void rdt_pseudo_lock_release(void) { } +static inline int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp) +{ + return -EOPNOTSUPP; +} + +static inline void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp) { } +#endif /* CONFIG_RESCTRL_FS_PSEUDO_LOCK */ + #endif /* _ASM_X86_RESCTRL_INTERNAL_H */ diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index a388ef66ef4c..e59271515a46 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -1453,7 +1453,8 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, goto out; } rdtgrp->mode = RDT_MODE_EXCLUSIVE; - } else if (!strcmp(buf, "pseudo-locksetup")) { + } else if (IS_ENABLED(CONFIG_RESCTRL_FS_PSEUDO_LOCK) && + !strcmp(buf, "pseudo-locksetup")) { ret = rdtgroup_locksetup_enter(rdtgrp); if (ret) goto out; -- 2.39.5