From 7028840552a220ac5efe51a4b554195cd954a912 Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 11 Mar 2025 18:37:09 +0000 Subject: [PATCH] x86/resctrl: Allow an architecture to disable pseudo lock 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 Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Tony Luck Reviewed-by: Reinette Chatre Reviewed-by: Fenghua Yu Reviewed-by: Babu Moger 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 Link: https://lore.kernel.org/r/20250311183715.16445-25-james.morse@arm.com --- 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 0e27ebd7e36a9..3cb3acdbc1071 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 4a06c37b9cf11..0c13b0befd8a9 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 725f223ea07be..8d35bb423aadd 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 a388ef66ef4ca..e59271515a463 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;