Commit-ID: 2a5d76a4fc6469ea9dd6f02fcd4dad3a129bc1c0 Gitweb: https://git.kernel.org/tip/2a5d76a4fc6469ea9dd6f02fcd4dad3a129bc1c0 Author: Reinette Chatre <reinette.cha...@intel.com> AuthorDate: Fri, 22 Jun 2018 15:42:13 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Sat, 23 Jun 2018 13:03:46 +0200
x86/intel_rdt: Utilities to restrict/restore access to specific files In support of Cache Pseudo-Locking we need to restrict access to specific resctrl files to protect the state of a resource group used for pseudo-locking from being changed in unsupported ways. Introduce two utilities that can be used to either restrict or restore the access to all files irrelevant to cache pseudo-locking when pseudo-locking in progress for the resource group. At this time introduce a new source file, intel_rdt_pseudo_lock.c, that will contain most of the code related to cache pseudo-locking. Temporarily mark these new functions as unused to silence compile warnings until they are used. Signed-off-by: Reinette Chatre <reinette.cha...@intel.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: fenghua...@intel.com Cc: tony.l...@intel.com Cc: vikas.shiva...@linux.intel.com Cc: gavin.hind...@intel.com Cc: jithu.jos...@intel.com Cc: dave.han...@intel.com Cc: h...@zytor.com Link: https://lkml.kernel.org/r/ab6319d1244366be3f9b7f9fba1c3da4810a274b.1529706536.git.reinette.cha...@intel.com --- arch/x86/kernel/cpu/Makefile | 3 +- arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c | 113 ++++++++++++++++++++++++++++ 2 files changed, 115 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 7a40196967cb..c4e02555563a 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -35,7 +35,8 @@ obj-$(CONFIG_CPU_SUP_CENTAUR) += centaur.o obj-$(CONFIG_CPU_SUP_TRANSMETA_32) += transmeta.o obj-$(CONFIG_CPU_SUP_UMC_32) += umc.o -obj-$(CONFIG_INTEL_RDT) += intel_rdt.o intel_rdt_rdtgroup.o intel_rdt_monitor.o intel_rdt_ctrlmondata.o +obj-$(CONFIG_INTEL_RDT) += intel_rdt.o intel_rdt_rdtgroup.o intel_rdt_monitor.o +obj-$(CONFIG_INTEL_RDT) += intel_rdt_ctrlmondata.o intel_rdt_pseudo_lock.o obj-$(CONFIG_X86_MCE) += mcheck/ obj-$(CONFIG_MTRR) += mtrr/ diff --git a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c new file mode 100644 index 000000000000..dc79b3090ac5 --- /dev/null +++ b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Resource Director Technology (RDT) + * + * Pseudo-locking support built on top of Cache Allocation Technology (CAT) + * + * Copyright (C) 2018 Intel Corporation + * + * Author: Reinette Chatre <reinette.cha...@intel.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include "intel_rdt.h" + +/** + * rdtgroup_locksetup_user_restrict - Restrict user access to group + * @rdtgrp: resource group needing access restricted + * + * A resource group used for cache pseudo-locking cannot have cpus or tasks + * assigned to it. This is communicated to the user by restricting access + * to all the files that can be used to make such changes. + * + * Permissions restored with rdtgroup_locksetup_user_restore() + * + * Return: 0 on success, <0 on failure. If a failure occurs during the + * restriction of access an attempt will be made to restore permissions but + * the state of the mode of these files will be uncertain when a failure + * occurs. + */ +static int __attribute__ ((unused)) +rdtgroup_locksetup_user_restrict(struct rdtgroup *rdtgrp) +{ + int ret; + + ret = rdtgroup_kn_mode_restrict(rdtgrp, "tasks"); + if (ret) + return ret; + + ret = rdtgroup_kn_mode_restrict(rdtgrp, "cpus"); + if (ret) + goto err_tasks; + + ret = rdtgroup_kn_mode_restrict(rdtgrp, "cpus_list"); + if (ret) + goto err_cpus; + + if (rdt_mon_capable) { + ret = rdtgroup_kn_mode_restrict(rdtgrp, "mon_groups"); + if (ret) + goto err_cpus_list; + } + + ret = 0; + goto out; + +err_cpus_list: + rdtgroup_kn_mode_restore(rdtgrp, "cpus_list"); +err_cpus: + rdtgroup_kn_mode_restore(rdtgrp, "cpus"); +err_tasks: + rdtgroup_kn_mode_restore(rdtgrp, "tasks"); +out: + return ret; +} + +/** + * rdtgroup_locksetup_user_restore - Restore user access to group + * @rdtgrp: resource group needing access restored + * + * Restore all file access previously removed using + * rdtgroup_locksetup_user_restrict() + * + * Return: 0 on success, <0 on failure. If a failure occurs during the + * restoration of access an attempt will be made to restrict permissions + * again but the state of the mode of these files will be uncertain when + * a failure occurs. + */ +static int __attribute__ ((unused)) +rdtgroup_locksetup_user_restore(struct rdtgroup *rdtgrp) +{ + int ret; + + ret = rdtgroup_kn_mode_restore(rdtgrp, "tasks"); + if (ret) + return ret; + + ret = rdtgroup_kn_mode_restore(rdtgrp, "cpus"); + if (ret) + goto err_tasks; + + ret = rdtgroup_kn_mode_restore(rdtgrp, "cpus_list"); + if (ret) + goto err_cpus; + + if (rdt_mon_capable) { + ret = rdtgroup_kn_mode_restore(rdtgrp, "mon_groups"); + if (ret) + goto err_cpus_list; + } + + ret = 0; + goto out; + +err_cpus_list: + rdtgroup_kn_mode_restrict(rdtgrp, "cpus_list"); +err_cpus: + rdtgroup_kn_mode_restrict(rdtgrp, "cpus"); +err_tasks: + rdtgroup_kn_mode_restrict(rdtgrp, "tasks"); +out: + return ret; +}
