From nobody Fri Dec 19 07:40:46 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9041A16C694 for ; Fri, 14 Jun 2024 15:02:26 +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=1718377348; cv=none; b=XBjo46xxOilktnYmVmbBOs7cHXfJESDrgFlAyDBSZW3au8K3vOskftfpq9E0Kyhj+wFRxaqxjr9QKoqKHhU9GGfpg7h6C2zIEBHMl0s+weBS8qvPqONk/xzYvZsa0D29cnfBqepGju7SL4Mutcf3uK8vYo7zCNiBzgnIw/xcrtM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718377348; c=relaxed/simple; bh=yNTqRUghwPe/l6stpzmt1jPff8/o0A6JI+W5WOoy8jc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Cihe3xS6ICuENaO9BpKBAlKofdJu3xfoyoUshEkE5fdIcRV4pFc53uIHRrcGy/haLjphnDbUEKt+XCajmZyJEsKgcokmhXfT7J1wHbdZaxrgr38H8t6rqQ+s8O+Ust4Lb+XyYgN0rySn2eCaiBGAuyzXyrg8bKrhE1L7EJvAzd0= 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 80D2A1AC1; Fri, 14 Jun 2024 08:02:50 -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 CED123F5A1; Fri, 14 Jun 2024 08:02:22 -0700 (PDT) From: James Morse To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , 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 , Shaopeng Tan Subject: [PATCH v3 23/38] x86/resctrl: Allow an architecture to disable pseudo lock Date: Fri, 14 Jun 2024 15:00:18 +0000 Message-Id: <20240614150033.10454-24-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20240614150033.10454-1-james.morse@arm.com> References: <20240614150033.10454-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" 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 file. Signed-off-by: James Morse Tested-by: Peter Newman Tested-by: Shaopeng Tan --- 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 | 48 +++++++++++++++++++++----- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 3 +- 4 files changed, 52 insertions(+), 11 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1d7122a1883e..446984277b45 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -492,6 +492,7 @@ 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. =20 @@ -508,6 +509,12 @@ config X86_CPU_RESCTRL =20 Say N if unsure. =20 +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/res= ctrl/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-$(CONFIG_X86_CPU_RESCTRL) +=3D core.o rdtgroup.o monitor.o -obj-$(CONFIG_X86_CPU_RESCTRL) +=3D ctrlmondata.o pseudo_lock.o +obj-$(CONFIG_X86_CPU_RESCTRL) +=3D core.o rdtgroup.o monitor.o +obj-$(CONFIG_X86_CPU_RESCTRL) +=3D ctrlmondata.o +obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK) +=3D pseudo_lock.o CFLAGS_pseudo_lock.o =3D -I$(src) diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/r= esctrl/internal.h index 85a5c6e83fad..1c2132e67df3 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -491,14 +491,6 @@ unsigned int rdtgroup_cbm_to_size(struct rdt_resource = *r, struct rdt_domain *d, 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_domain *d, unsigned lo= ng cbm); -bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_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_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r); int closids_supported(void); void closid_free(int closid); @@ -531,4 +523,44 @@ void rdt_staged_configs_clear(void); bool closid_allocated(unsigned int closid); int resctrl_find_cleanest_closid(void); =20 +#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_domain *d, unsigned lo= ng cbm); +bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_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_domain *= d, unsigned long cbm) +{ + return false; +} + +static inline bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_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/r= esctrl/rdtgroup.c index 0446d30db4da..7957edcfc97d 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -1450,7 +1450,8 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open= _file *of, goto out; } rdtgrp->mode =3D RDT_MODE_EXCLUSIVE; - } else if (!strcmp(buf, "pseudo-locksetup")) { + } else if (IS_ENABLED(CONFIG_RESCTRL_FS_PSEUDO_LOCK) && + !strcmp(buf, "pseudo-locksetup")) { ret =3D rdtgroup_locksetup_enter(rdtgrp); if (ret) goto out; --=20 2.39.2