Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v1 20/31] x86/resctrl: Allow an architecture to disable pseudo lock | Date | Thu, 21 Mar 2024 16:50:55 +0000 |
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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 psuedo_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.
Signed-off-by: James Morse <james.morse@arm.com> --- 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 7aed87cbf386..e071e564452e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -481,6 +481,7 @@ 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. @@ -506,6 +507,12 @@ config X86_FRED ring transitions and exception/interrupt handling if the system supports. +config RESCTRL_FS_PSEUDO_LOCK + bool + help + Software mechanism to pin data in a cache portion using + micro-architecture specific knowledge. + if X86_32 config X86_BIGSMP bool "Support for big SMP systems with more than 8 CPUs" 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 238b81d3f64a..d6db15839dc4 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -489,14 +489,6 @@ 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 long 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); @@ -529,4 +521,44 @@ 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_domain *d, unsigned long 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/resctrl/rdtgroup.c index 56a0bfdc11f7..9275d6f8a74e 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -1452,7 +1452,8 @@ 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; -- 2.39.2
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