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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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.chatre@intel.com>
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/cacheinfo.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/debugfs.h>
 #include <linux/kthread.h>
 #include <linux/mman.h>
 #include <linux/perf_event.h>
 #include <linux/pm_qos.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 
 #include <asm/cacheflush.h>
 #include <asm/intel-family.h>
 #include <asm/resctrl.h>
 #include <asm/perf_event.h>
 
 #include "../../events/perf_event.h" /* For X86_CONFIG() */
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
 #include "pseudo_lock_event.h"
 
 /*
  * The bits needed to disable hardware prefetching varies based on the
  * platform. During initialization we will discover which bits to use.
  */
 static u64 prefetch_disable_bits;
 
 /*
  * Major number assigned to and shared by all devices exposing
  * pseudo-locked regions.
  */
 static unsigned int pseudo_lock_major;
 static unsigned long pseudo_lock_minor_avail = GENMASK(MINORBITS, 0);
 static struct class *pseudo_lock_class;
 
 /**
  * get_prefetch_disable_bits - prefetch disable bits of supported platforms
  * @void: It takes no parameters.
  *
  * Capture the list of platforms that have been validated to support
  * pseudo-locking. This includes testing to ensure pseudo-locked regions
  * with low cache miss rates can be created under variety of load conditions
  * as well as that these pseudo-locked regions can maintain their low cache
  * miss rates under variety of load conditions for significant lengths of time.
  *
  * After a platform has been validated to support pseudo-locking its
  * hardware prefetch disable bits are included here as they are documented
  * in the SDM.
  *
  * When adding a platform here also add support for its cache events to
  * measure_cycles_perf_fn()
  *
  * Return:
  * If platform is supported, the bits to disable hardware prefetchers, 0
  * if platform is not supported.
  */
 static u64 get_prefetch_disable_bits(void)
 {
     if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
         boot_cpu_data.x86 != 6)
         return 0;
 
     switch (boot_cpu_data.x86_model) {
     case INTEL_FAM6_BROADWELL_X:
         /*
          * SDM defines bits of MSR_MISC_FEATURE_CONTROL register
          * as:
          * 0    L2 Hardware Prefetcher Disable (R/W)
          * 1    L2 Adjacent Cache Line Prefetcher Disable (R/W)
          * 2    DCU Hardware Prefetcher Disable (R/W)
          * 3    DCU IP Prefetcher Disable (R/W)
          * 63:4 Reserved
          */
         return 0xF;
     case INTEL_FAM6_ATOM_GOLDMONT:
     case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
         /*
          * SDM defines bits of MSR_MISC_FEATURE_CONTROL register
          * as:
          * 0     L2 Hardware Prefetcher Disable (R/W)
          * 1     Reserved
          * 2     DCU Hardware Prefetcher Disable (R/W)
          * 63:3  Reserved
          */
         return 0x5;
     }
 
     return 0;
 }
 
 /**
  * pseudo_lock_minor_get - Obtain available minor number
  * @minor: Pointer to where new minor number will be stored
  *
  * A bitmask is used to track available minor numbers. Here the next free
  * minor number is marked as unavailable and returned.
  *
  * Return: 0 on success, <0 on failure.
  */
 static int pseudo_lock_minor_get(unsigned int *minor)
 {
     unsigned long first_bit;
 
     first_bit = find_first_bit(&pseudo_lock_minor_avail, MINORBITS);
 
     if (first_bit == MINORBITS)
         return -ENOSPC;
 
     __clear_bit(first_bit, &pseudo_lock_minor_avail);
     *minor = first_bit;
 
     return 0;
 }
 
 /**
  * pseudo_lock_minor_release - Return minor number to available
  * @minor: The minor number made available
  */
 static void pseudo_lock_minor_release(unsigned int minor)
 {
     __set_bit(minor, &pseudo_lock_minor_avail);
 }
 
 /**
  * region_find_by_minor - Locate a pseudo-lock region by inode minor number
  * @minor: The minor number of the device representing pseudo-locked region
  *
  * When the character device is accessed we need to determine which
  * pseudo-locked region it belongs to. This is done by matching the minor
  * number of the device to the pseudo-locked region it belongs.
  *
  * Minor numbers are assigned at the time a pseudo-locked region is associated
  * with a cache instance.
  *
  * Return: On success return pointer to resource group owning the pseudo-locked
  *         region, NULL on failure.
  */
 static struct rdtgroup *region_find_by_minor(unsigned int minor)
 {
     struct rdtgroup *rdtgrp, *rdtgrp_match = NULL;
 
     list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
         if (rdtgrp->plr && rdtgrp->plr->minor == minor) {
             rdtgrp_match = rdtgrp;
             break;
         }
     }
     return rdtgrp_match;
 }
 
 /**
  * struct pseudo_lock_pm_req - A power management QoS request list entry
  * @list:   Entry within the @pm_reqs list for a pseudo-locked region
  * @req:    PM QoS request
  */
 struct pseudo_lock_pm_req {
     struct list_head list;
     struct dev_pm_qos_request req;
 };
 
 static void pseudo_lock_cstates_relax(struct pseudo_lock_region *plr)
 {
     struct pseudo_lock_pm_req *pm_req, *next;
 
     list_for_each_entry_safe(pm_req, next, &plr->pm_reqs, list) {
         dev_pm_qos_remove_request(&pm_req->req);
         list_del(&pm_req->list);
         kfree(pm_req);
     }
 }
 
 /**
  * pseudo_lock_cstates_constrain - Restrict cores from entering C6
  * @plr: Pseudo-locked region
  *
  * To prevent the cache from being affected by power management entering
  * C6 has to be avoided. This is accomplished by requesting a latency
  * requirement lower than lowest C6 exit latency of all supported
  * platforms as found in the cpuidle state tables in the intel_idle driver.
  * At this time it is possible to do so with a single latency requirement
  * for all supported platforms.
  *
  * Since Goldmont is supported, which is affected by X86_BUG_MONITOR,
  * the ACPI latencies need to be considered while keeping in mind that C2
  * may be set to map to deeper sleep states. In this case the latency
  * requirement needs to prevent entering C2 also.
  *
  * Return: 0 on success, <0 on failure
  */
 static int pseudo_lock_cstates_constrain(struct pseudo_lock_region *plr)
 {
     struct pseudo_lock_pm_req *pm_req;
     int cpu;
     int ret;
 
     for_each_cpu(cpu, &plr->d->cpu_mask) {
         pm_req = kzalloc(sizeof(*pm_req), GFP_KERNEL);
         if (!pm_req) {
             rdt_last_cmd_puts("Failure to allocate memory for PM QoS\n");
             ret = -ENOMEM;
             goto out_err;
         }
         ret = dev_pm_qos_add_request(get_cpu_device(cpu),
                          &pm_req->req,
                          DEV_PM_QOS_RESUME_LATENCY,
                          30);
         if (ret < 0) {
             rdt_last_cmd_printf("Failed to add latency req CPU%d\n",
                         cpu);
             kfree(pm_req);
             ret = -1;
             goto out_err;
         }
         list_add(&pm_req->list, &plr->pm_reqs);
     }
 
     return 0;
 
 out_err:
     pseudo_lock_cstates_relax(plr);
     return ret;
 }
 
 /**
  * pseudo_lock_region_clear - Reset pseudo-lock region data
  * @plr: pseudo-lock region
  *
  * All content of the pseudo-locked region is reset - any memory allocated
  * freed.
  *
  * Return: void
  */
 static void pseudo_lock_region_clear(struct pseudo_lock_region *plr)
 {
     plr->size = 0;
     plr->line_size = 0;
     kfree(plr->kmem);
     plr->kmem = NULL;
     plr->s = NULL;
     if (plr->d)
         plr->d->plr = NULL;
     plr->d = NULL;
     plr->cbm = 0;
     plr->debugfs_dir = NULL;
 }
 
 /**
  * pseudo_lock_region_init - Initialize pseudo-lock region information
  * @plr: pseudo-lock region
  *
  * Called after user provided a schemata to be pseudo-locked. From the
  * schemata the &struct pseudo_lock_region is on entry already initialized
  * with the resource, domain, and capacity bitmask. Here the information
  * required for pseudo-locking is deduced from this data and &struct
  * pseudo_lock_region initialized further. This information includes:
  * - size in bytes of the region to be pseudo-locked
  * - cache line size to know the stride with which data needs to be accessed
  *   to be pseudo-locked
  * - a cpu associated with the cache instance on which the pseudo-locking
  *   flow can be executed
  *
  * Return: 0 on success, <0 on failure. Descriptive error will be written
  * to last_cmd_status buffer.
  */
 static int pseudo_lock_region_init(struct pseudo_lock_region *plr)
 {
     struct cpu_cacheinfo *ci;
     int ret;
     int i;
 
     /* Pick the first cpu we find that is associated with the cache. */
     plr->cpu = cpumask_first(&plr->d->cpu_mask);
 
     if (!cpu_online(plr->cpu)) {
         rdt_last_cmd_printf("CPU %u associated with cache not online\n",
                     plr->cpu);
         ret = -ENODEV;
         goto out_region;
     }
 
     ci = get_cpu_cacheinfo(plr->cpu);
 
     plr->size = rdtgroup_cbm_to_size(plr->s->res, plr->d, plr->cbm);
 
     for (i = 0; i < ci->num_leaves; i++) {
         if (ci->info_list[i].level == plr->s->res->cache_level) {
             plr->line_size = ci->info_list[i].coherency_line_size;
             return 0;
         }
     }
 
     ret = -1;
     rdt_last_cmd_puts("Unable to determine cache line size\n");
 out_region:
     pseudo_lock_region_clear(plr);
     return ret;
 }
 
 /**
  * pseudo_lock_init - Initialize a pseudo-lock region
  * @rdtgrp: resource group to which new pseudo-locked region will belong
  *
  * A pseudo-locked region is associated with a resource group. When this
  * association is created the pseudo-locked region is initialized. The
  * details of the pseudo-locked region are not known at this time so only
  * allocation is done and association established.
  *
  * Return: 0 on success, <0 on failure
  */
 static int pseudo_lock_init(struct rdtgroup *rdtgrp)
 {
     struct pseudo_lock_region *plr;
 
     plr = kzalloc(sizeof(*plr), GFP_KERNEL);
     if (!plr)
         return -ENOMEM;
 
     init_waitqueue_head(&plr->lock_thread_wq);
     INIT_LIST_HEAD(&plr->pm_reqs);
     rdtgrp->plr = plr;
     return 0;
 }
 
 /**
  * pseudo_lock_region_alloc - Allocate kernel memory that will be pseudo-locked
  * @plr: pseudo-lock region
  *
  * Initialize the details required to set up the pseudo-locked region and
  * allocate the contiguous memory that will be pseudo-locked to the cache.
  *
  * Return: 0 on success, <0 on failure.  Descriptive error will be written
  * to last_cmd_status buffer.
  */
 static int pseudo_lock_region_alloc(struct pseudo_lock_region *plr)
 {
     int ret;
 
     ret = pseudo_lock_region_init(plr);
     if (ret < 0)
         return ret;
 
     /*
      * We do not yet support contiguous regions larger than
      * KMALLOC_MAX_SIZE.
      */
     if (plr->size > KMALLOC_MAX_SIZE) {
         rdt_last_cmd_puts("Requested region exceeds maximum size\n");
         ret = -E2BIG;
         goto out_region;
     }
 
     plr->kmem = kzalloc(plr->size, GFP_KERNEL);
     if (!plr->kmem) {
         rdt_last_cmd_puts("Unable to allocate memory\n");
         ret = -ENOMEM;
         goto out_region;
     }
 
     ret = 0;
     goto out;
 out_region:
     pseudo_lock_region_clear(plr);
 out:
     return ret;
 }
 
 /**
  * pseudo_lock_free - Free a pseudo-locked region
  * @rdtgrp: resource group to which pseudo-locked region belonged
  *
  * The pseudo-locked region's resources have already been released, or not
  * yet created at this point. Now it can be freed and disassociated from the
  * resource group.
  *
  * Return: void
  */
 static void pseudo_lock_free(struct rdtgroup *rdtgrp)
 {
     pseudo_lock_region_clear(rdtgrp->plr);
     kfree(rdtgrp->plr);
     rdtgrp->plr = NULL;
 }
 
 /**
  * pseudo_lock_fn - Load kernel memory into cache
  * @_rdtgrp: resource group to which pseudo-lock region belongs
  *
  * This is the core pseudo-locking flow.
  *
  * First we ensure that the kernel memory cannot be found in the cache.
  * Then, while taking care that there will be as little interference as
  * possible, the memory to be loaded is accessed while core is running
  * with class of service set to the bitmask of the pseudo-locked region.
  * After this is complete no future CAT allocations will be allowed to
  * overlap with this bitmask.
  *
  * Local register variables are utilized to ensure that the memory region
  * to be locked is the only memory access made during the critical locking
  * loop.
  *
  * Return: 0. Waiter on waitqueue will be woken on completion.
  */
 static int pseudo_lock_fn(void *_rdtgrp)
 {
     struct rdtgroup *rdtgrp = _rdtgrp;
     struct pseudo_lock_region *plr = rdtgrp->plr;
     u32 rmid_p, closid_p;
     unsigned long i;
 #ifdef CONFIG_KASAN
     /*
      * The registers used for local register variables are also used
      * when KASAN is active. When KASAN is active we use a regular
      * variable to ensure we always use a valid pointer, but the cost
      * is that this variable will enter the cache through evicting the
      * memory we are trying to lock into the cache. Thus expect lower
      * pseudo-locking success rate when KASAN is active.
      */
     unsigned int line_size;
     unsigned int size;
     void *mem_r;
 #else
     register unsigned int line_size asm("esi");
     register unsigned int size asm("edi");
     register void *mem_r asm(_ASM_BX);
 #endif /* CONFIG_KASAN */
 
     /*
      * Make sure none of the allocated memory is cached. If it is we
      * will get a cache hit in below loop from outside of pseudo-locked
      * region.
      * wbinvd (as opposed to clflush/clflushopt) is required to
      * increase likelihood that allocated cache portion will be filled
      * with associated memory.
      */
     native_wbinvd();
 
     /*
      * Always called with interrupts enabled. By disabling interrupts
      * ensure that we will not be preempted during this critical section.
      */
     local_irq_disable();
 
     /*
      * Call wrmsr and rdmsr as directly as possible to avoid tracing
      * clobbering local register variables or affecting cache accesses.
      *
      * Disable the hardware prefetcher so that when the end of the memory
      * being pseudo-locked is reached the hardware will not read beyond
      * the buffer and evict pseudo-locked memory read earlier from the
      * cache.
      */
     __wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0);
     closid_p = this_cpu_read(pqr_state.cur_closid);
     rmid_p = this_cpu_read(pqr_state.cur_rmid);
     mem_r = plr->kmem;
     size = plr->size;
     line_size = plr->line_size;
     /*
      * Critical section begin: start by writing the closid associated
      * with the capacity bitmask of the cache region being
      * pseudo-locked followed by reading of kernel memory to load it
      * into the cache.
      */
     __wrmsr(IA32_PQR_ASSOC, rmid_p, rdtgrp->closid);
     /*
      * Cache was flushed earlier. Now access kernel memory to read it
      * into cache region associated with just activated plr->closid.
      * Loop over data twice:
      * - In first loop the cache region is shared with the page walker
      *   as it populates the paging structure caches (including TLB).
      * - In the second loop the paging structure caches are used and
      *   cache region is populated with the memory being referenced.
      */
     for (i = 0; i < size; i += PAGE_SIZE) {
         /*
          * Add a barrier to prevent speculative execution of this
          * loop reading beyond the end of the buffer.
          */
         rmb();
         asm volatile("mov (%0,%1,1), %%eax\n\t"
             :
             : "r" (mem_r), "r" (i)
             : "%eax", "memory");
     }
     for (i = 0; i < size; i += line_size) {
         /*
          * Add a barrier to prevent speculative execution of this
          * loop reading beyond the end of the buffer.
          */
         rmb();
         asm volatile("mov (%0,%1,1), %%eax\n\t"
             :
             : "r" (mem_r), "r" (i)
             : "%eax", "memory");
     }
     /*
      * Critical section end: restore closid with capacity bitmask that
      * does not overlap with pseudo-locked region.
      */
     __wrmsr(IA32_PQR_ASSOC, rmid_p, closid_p);
 
     /* Re-enable the hardware prefetcher(s) */
     wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0);
     local_irq_enable();
 
     plr->thread_done = 1;
     wake_up_interruptible(&plr->lock_thread_wq);
     return 0;
 }
 
 /**
  * rdtgroup_monitor_in_progress - Test if monitoring in progress
  * @rdtgrp: resource group being queried
  *
  * Return: 1 if monitor groups have been created for this resource
  * group, 0 otherwise.
  */
 static int rdtgroup_monitor_in_progress(struct rdtgroup *rdtgrp)
 {
     return !list_empty(&rdtgrp->mon.crdtgrp_list);
 }
 
 /**
  * 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 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", 0777);
 err_cpus:
     rdtgroup_kn_mode_restore(rdtgrp, "cpus", 0777);
 err_tasks:
     rdtgroup_kn_mode_restore(rdtgrp, "tasks", 0777);
 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 rdtgroup_locksetup_user_restore(struct rdtgroup *rdtgrp)
 {
     int ret;
 
     ret = rdtgroup_kn_mode_restore(rdtgrp, "tasks", 0777);
     if (ret)
         return ret;
 
     ret = rdtgroup_kn_mode_restore(rdtgrp, "cpus", 0777);
     if (ret)
         goto err_tasks;
 
     ret = rdtgroup_kn_mode_restore(rdtgrp, "cpus_list", 0777);
     if (ret)
         goto err_cpus;
 
     if (rdt_mon_capable) {
         ret = rdtgroup_kn_mode_restore(rdtgrp, "mon_groups", 0777);
         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;
 }
 
 /**
  * rdtgroup_locksetup_enter - Resource group enters locksetup mode
  * @rdtgrp: resource group requested to enter locksetup mode
  *
  * A resource group enters locksetup mode to reflect that it would be used
  * to represent a pseudo-locked region and is in the process of being set
  * up to do so. A resource group used for a pseudo-locked region would
  * lose the closid associated with it so we cannot allow it to have any
  * tasks or cpus assigned nor permit tasks or cpus to be assigned in the
  * future. Monitoring of a pseudo-locked region is not allowed either.
  *
  * The above and more restrictions on a pseudo-locked region are checked
  * for and enforced before the resource group enters the locksetup mode.
  *
  * Returns: 0 if the resource group successfully entered locksetup mode, <0
  * on failure. On failure the last_cmd_status buffer is updated with text to
  * communicate details of failure to the user.
  */
 int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp)
 {
     int ret;
 
     /*
      * The default resource group can neither be removed nor lose the
      * default closid associated with it.
      */
     if (rdtgrp == &rdtgroup_default) {
         rdt_last_cmd_puts("Cannot pseudo-lock default group\n");
         return -EINVAL;
     }
 
     /*
      * Cache Pseudo-locking not supported when CDP is enabled.
      *
      * Some things to consider if you would like to enable this
      * support (using L3 CDP as example):
      * - When CDP is enabled two separate resources are exposed,
      *   L3DATA and L3CODE, but they are actually on the same cache.
      *   The implication for pseudo-locking is that if a
      *   pseudo-locked region is created on a domain of one
      *   resource (eg. L3CODE), then a pseudo-locked region cannot
      *   be created on that same domain of the other resource
      *   (eg. L3DATA). This is because the creation of a
      *   pseudo-locked region involves a call to wbinvd that will
      *   affect all cache allocations on particular domain.
      * - Considering the previous, it may be possible to only
      *   expose one of the CDP resources to pseudo-locking and
      *   hide the other. For example, we could consider to only
      *   expose L3DATA and since the L3 cache is unified it is
      *   still possible to place instructions there are execute it.
      * - If only one region is exposed to pseudo-locking we should
      *   still keep in mind that availability of a portion of cache
      *   for pseudo-locking should take into account both resources.
      *   Similarly, if a pseudo-locked region is created in one
      *   resource, the portion of cache used by it should be made
      *   unavailable to all future allocations from both resources.
      */
     if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3) ||
         resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2)) {
         rdt_last_cmd_puts("CDP enabled\n");
         return -EINVAL;
     }
 
     /*
      * Not knowing the bits to disable prefetching implies that this
      * platform does not support Cache Pseudo-Locking.
      */
     prefetch_disable_bits = get_prefetch_disable_bits();
     if (prefetch_disable_bits == 0) {
         rdt_last_cmd_puts("Pseudo-locking not supported\n");
         return -EINVAL;
     }
 
     if (rdtgroup_monitor_in_progress(rdtgrp)) {
         rdt_last_cmd_puts("Monitoring in progress\n");
         return -EINVAL;
     }
 
     if (rdtgroup_tasks_assigned(rdtgrp)) {
         rdt_last_cmd_puts("Tasks assigned to resource group\n");
         return -EINVAL;
     }
 
     if (!cpumask_empty(&rdtgrp->cpu_mask)) {
         rdt_last_cmd_puts("CPUs assigned to resource group\n");
         return -EINVAL;
     }
 
     if (rdtgroup_locksetup_user_restrict(rdtgrp)) {
         rdt_last_cmd_puts("Unable to modify resctrl permissions\n");
         return -EIO;
     }
 
     ret = pseudo_lock_init(rdtgrp);
     if (ret) {
         rdt_last_cmd_puts("Unable to init pseudo-lock region\n");
         goto out_release;
     }
 
     /*
      * If this system is capable of monitoring a rmid would have been
      * allocated when the control group was created. This is not needed
      * anymore when this group would be used for pseudo-locking. This
      * is safe to call on platforms not capable of monitoring.
      */
     free_rmid(rdtgrp->mon.rmid);
 
     ret = 0;
     goto out;
 
 out_release:
     rdtgroup_locksetup_user_restore(rdtgrp);
 out:
     return ret;
 }
 
 /**
  * rdtgroup_locksetup_exit - resource group exist locksetup mode
  * @rdtgrp: resource group
  *
  * When a resource group exits locksetup mode the earlier restrictions are
  * lifted.
  *
  * Return: 0 on success, <0 on failure
  */
 int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp)
 {
     int ret;
 
     if (rdt_mon_capable) {
         ret = alloc_rmid();
         if (ret < 0) {
             rdt_last_cmd_puts("Out of RMIDs\n");
             return ret;
         }
         rdtgrp->mon.rmid = ret;
     }
 
     ret = rdtgroup_locksetup_user_restore(rdtgrp);
     if (ret) {
         free_rmid(rdtgrp->mon.rmid);
         return ret;
     }
 
     pseudo_lock_free(rdtgrp);
     return 0;
 }
 
 /**
  * rdtgroup_cbm_overlaps_pseudo_locked - Test if CBM or portion is pseudo-locked
  * @d: RDT domain
  * @cbm: CBM to test
  *
  * @d represents a cache instance and @cbm a capacity bitmask that is
  * considered for it. Determine if @cbm overlaps with any existing
  * pseudo-locked region on @d.
  *
  * @cbm is unsigned long, even if only 32 bits are used, to make the
  * bitmap functions work correctly.
  *
  * Return: true if @cbm overlaps with pseudo-locked region on @d, false
  * otherwise.
  */
 bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, unsigned long cbm)
 {
     unsigned int cbm_len;
     unsigned long cbm_b;
 
     if (d->plr) {
         cbm_len = d->plr->s->res->cache.cbm_len;
         cbm_b = d->plr->cbm;
         if (bitmap_intersects(&cbm, &cbm_b, cbm_len))
             return true;
     }
     return false;
 }
 
 /**
  * rdtgroup_pseudo_locked_in_hierarchy - Pseudo-locked region in cache hierarchy
  * @d: RDT domain under test
  *
  * The setup of a pseudo-locked region affects all cache instances within
  * the hierarchy of the region. It is thus essential to know if any
  * pseudo-locked regions exist within a cache hierarchy to prevent any
  * attempts to create new pseudo-locked regions in the same hierarchy.
  *
  * Return: true if a pseudo-locked region exists in the hierarchy of @d or
  *         if it is not possible to test due to memory allocation issue,
  *         false otherwise.
  */
 bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d)
 {
     cpumask_var_t cpu_with_psl;
     struct rdt_resource *r;
     struct rdt_domain *d_i;
     bool ret = false;
 
     if (!zalloc_cpumask_var(&cpu_with_psl, GFP_KERNEL))
         return true;
 
     /*
      * First determine which cpus have pseudo-locked regions
      * associated with them.
      */
     for_each_alloc_enabled_rdt_resource(r) {
         list_for_each_entry(d_i, &r->domains, list) {
             if (d_i->plr)
                 cpumask_or(cpu_with_psl, cpu_with_psl,
                        &d_i->cpu_mask);
         }
     }
 
     /*
      * Next test if new pseudo-locked region would intersect with
      * existing region.
      */
     if (cpumask_intersects(&d->cpu_mask, cpu_with_psl))
         ret = true;
 
     free_cpumask_var(cpu_with_psl);
     return ret;
 }
 
 /**
  * measure_cycles_lat_fn - Measure cycle latency to read pseudo-locked memory
  * @_plr: pseudo-lock region to measure
  *
  * There is no deterministic way to test if a memory region is cached. One
  * way is to measure how long it takes to read the memory, the speed of
  * access is a good way to learn how close to the cpu the data was. Even
  * more, if the prefetcher is disabled and the memory is read at a stride
  * of half the cache line, then a cache miss will be easy to spot since the
  * read of the first half would be significantly slower than the read of
  * the second half.
  *
  * Return: 0. Waiter on waitqueue will be woken on completion.
  */
 static int measure_cycles_lat_fn(void *_plr)
 {
     struct pseudo_lock_region *plr = _plr;
     unsigned long i;
     u64 start, end;
     void *mem_r;
 
     local_irq_disable();
     /*
      * Disable hardware prefetchers.
      */
     wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0);
     mem_r = READ_ONCE(plr->kmem);
     /*
      * Dummy execute of the time measurement to load the needed
      * instructions into the L1 instruction cache.
      */
     start = rdtsc_ordered();
     for (i = 0; i < plr->size; i += 32) {
         start = rdtsc_ordered();
         asm volatile("mov (%0,%1,1), %%eax\n\t"
                  :
                  : "r" (mem_r), "r" (i)
                  : "%eax", "memory");
         end = rdtsc_ordered();
         trace_pseudo_lock_mem_latency((u32)(end - start));
     }
     wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0);
     local_irq_enable();
     plr->thread_done = 1;
     wake_up_interruptible(&plr->lock_thread_wq);
     return 0;
 }
 
 /*
  * Create a perf_event_attr for the hit and miss perf events that will
  * be used during the performance measurement. A perf_event maintains
  * a pointer to its perf_event_attr so a unique attribute structure is
  * created for each perf_event.
  *
  * The actual configuration of the event is set right before use in order
  * to use the X86_CONFIG macro.
  */
 static struct perf_event_attr perf_miss_attr = {
     .type       = PERF_TYPE_RAW,
     .size       = sizeof(struct perf_event_attr),
     .pinned     = 1,
     .disabled   = 0,
     .exclude_user   = 1,
 };
 
 static struct perf_event_attr perf_hit_attr = {
     .type       = PERF_TYPE_RAW,
     .size       = sizeof(struct perf_event_attr),
     .pinned     = 1,
     .disabled   = 0,
     .exclude_user   = 1,
 };
 
 struct residency_counts {
     u64 miss_before, hits_before;
     u64 miss_after,  hits_after;
 };
 
 static int measure_residency_fn(struct perf_event_attr *miss_attr,
                 struct perf_event_attr *hit_attr,
                 struct pseudo_lock_region *plr,
                 struct residency_counts *counts)
 {
     u64 hits_before = 0, hits_after = 0, miss_before = 0, miss_after = 0;
     struct perf_event *miss_event, *hit_event;
     int hit_pmcnum, miss_pmcnum;
     unsigned int line_size;
     unsigned int size;
     unsigned long i;
     void *mem_r;
     u64 tmp;
 
     miss_event = perf_event_create_kernel_counter(miss_attr, plr->cpu,
                               NULL, NULL, NULL);
     if (IS_ERR(miss_event))
         goto out;
 
     hit_event = perf_event_create_kernel_counter(hit_attr, plr->cpu,
                              NULL, NULL, NULL);
     if (IS_ERR(hit_event))
         goto out_miss;
 
     local_irq_disable();
     /*
      * Check any possible error state of events used by performing
      * one local read.
      */
     if (perf_event_read_local(miss_event, &tmp, NULL, NULL)) {
         local_irq_enable();
         goto out_hit;
     }
     if (perf_event_read_local(hit_event, &tmp, NULL, NULL)) {
         local_irq_enable();
         goto out_hit;
     }
 
     /*
      * Disable hardware prefetchers.
      */
     wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0);
 
     /* Initialize rest of local variables */
     /*
      * Performance event has been validated right before this with
      * interrupts disabled - it is thus safe to read the counter index.
      */
     miss_pmcnum = x86_perf_rdpmc_index(miss_event);
     hit_pmcnum = x86_perf_rdpmc_index(hit_event);
     line_size = READ_ONCE(plr->line_size);
     mem_r = READ_ONCE(plr->kmem);
     size = READ_ONCE(plr->size);
 
     /*
      * Read counter variables twice - first to load the instructions
      * used in L1 cache, second to capture accurate value that does not
      * include cache misses incurred because of instruction loads.
      */
     rdpmcl(hit_pmcnum, hits_before);
     rdpmcl(miss_pmcnum, miss_before);
     /*
      * From SDM: Performing back-to-back fast reads are not guaranteed
      * to be monotonic.
      * Use LFENCE to ensure all previous instructions are retired
      * before proceeding.
      */
     rmb();
     rdpmcl(hit_pmcnum, hits_before);
     rdpmcl(miss_pmcnum, miss_before);
     /*
      * Use LFENCE to ensure all previous instructions are retired
      * before proceeding.
      */
     rmb();
     for (i = 0; i < size; i += line_size) {
         /*
          * Add a barrier to prevent speculative execution of this
          * loop reading beyond the end of the buffer.
          */
         rmb();
         asm volatile("mov (%0,%1,1), %%eax\n\t"
                  :
                  : "r" (mem_r), "r" (i)
                  : "%eax", "memory");
     }
     /*
      * Use LFENCE to ensure all previous instructions are retired
      * before proceeding.
      */
     rmb();
     rdpmcl(hit_pmcnum, hits_after);
     rdpmcl(miss_pmcnum, miss_after);
     /*
      * Use LFENCE to ensure all previous instructions are retired
      * before proceeding.
      */
     rmb();
     /* Re-enable hardware prefetchers */
     wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0);
     local_irq_enable();
 out_hit:
     perf_event_release_kernel(hit_event);
 out_miss:
     perf_event_release_kernel(miss_event);
 out:
     /*
      * All counts will be zero on failure.
      */
     counts->miss_before = miss_before;
     counts->hits_before = hits_before;
     counts->miss_after  = miss_after;
     counts->hits_after  = hits_after;
     return 0;
 }
 
 static int measure_l2_residency(void *_plr)
 {
     struct pseudo_lock_region *plr = _plr;
     struct residency_counts counts = {0};
 
     /*
      * Non-architectural event for the Goldmont Microarchitecture
      * from Intel x86 Architecture Software Developer Manual (SDM):
      * MEM_LOAD_UOPS_RETIRED D1H (event number)
      * Umask values:
      *     L2_HIT   02H
      *     L2_MISS  10H
      */
     switch (boot_cpu_data.x86_model) {
     case INTEL_FAM6_ATOM_GOLDMONT:
     case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
         perf_miss_attr.config = X86_CONFIG(.event = 0xd1,
                            .umask = 0x10);
         perf_hit_attr.config = X86_CONFIG(.event = 0xd1,
                           .umask = 0x2);
         break;
     default:
         goto out;
     }
 
     measure_residency_fn(&perf_miss_attr, &perf_hit_attr, plr, &counts);
     /*
      * If a failure prevented the measurements from succeeding
      * tracepoints will still be written and all counts will be zero.
      */
     trace_pseudo_lock_l2(counts.hits_after - counts.hits_before,
                  counts.miss_after - counts.miss_before);
 out:
     plr->thread_done = 1;
     wake_up_interruptible(&plr->lock_thread_wq);
     return 0;
 }
 
 static int measure_l3_residency(void *_plr)
 {
     struct pseudo_lock_region *plr = _plr;
     struct residency_counts counts = {0};
 
     /*
      * On Broadwell Microarchitecture the MEM_LOAD_UOPS_RETIRED event
      * has two "no fix" errata associated with it: BDM35 and BDM100. On
      * this platform the following events are used instead:
      * LONGEST_LAT_CACHE 2EH (Documented in SDM)
      *       REFERENCE 4FH
      *       MISS      41H
      */
 
     switch (boot_cpu_data.x86_model) {
     case INTEL_FAM6_BROADWELL_X:
         /* On BDW the hit event counts references, not hits */
         perf_hit_attr.config = X86_CONFIG(.event = 0x2e,
                           .umask = 0x4f);
         perf_miss_attr.config = X86_CONFIG(.event = 0x2e,
                            .umask = 0x41);
         break;
     default:
         goto out;
     }
 
     measure_residency_fn(&perf_miss_attr, &perf_hit_attr, plr, &counts);
     /*
      * If a failure prevented the measurements from succeeding
      * tracepoints will still be written and all counts will be zero.
      */
 
     counts.miss_after -= counts.miss_before;
     if (boot_cpu_data.x86_model == INTEL_FAM6_BROADWELL_X) {
         /*
          * On BDW references and misses are counted, need to adjust.
          * Sometimes the "hits" counter is a bit more than the
          * references, for example, x references but x + 1 hits.
          * To not report invalid hit values in this case we treat
          * that as misses equal to references.
          */
         /* First compute the number of cache references measured */
         counts.hits_after -= counts.hits_before;
         /* Next convert references to cache hits */
         counts.hits_after -= min(counts.miss_after, counts.hits_after);
     } else {
         counts.hits_after -= counts.hits_before;
     }
 
     trace_pseudo_lock_l3(counts.hits_after, counts.miss_after);
 out:
     plr->thread_done = 1;
     wake_up_interruptible(&plr->lock_thread_wq);
     return 0;
 }
 
 /**
  * pseudo_lock_measure_cycles - Trigger latency measure to pseudo-locked region
  * @rdtgrp: Resource group to which the pseudo-locked region belongs.
  * @sel: Selector of which measurement to perform on a pseudo-locked region.
  *
  * The measurement of latency to access a pseudo-locked region should be
  * done from a cpu that is associated with that pseudo-locked region.
  * Determine which cpu is associated with this region and start a thread on
  * that cpu to perform the measurement, wait for that thread to complete.
  *
  * Return: 0 on success, <0 on failure
  */
 static int pseudo_lock_measure_cycles(struct rdtgroup *rdtgrp, int sel)
 {
     struct pseudo_lock_region *plr = rdtgrp->plr;
     struct task_struct *thread;
     unsigned int cpu;
     int ret = -1;
 
     cpus_read_lock();
     mutex_lock(&rdtgroup_mutex);
 
     if (rdtgrp->flags & RDT_DELETED) {
         ret = -ENODEV;
         goto out;
     }
 
     if (!plr->d) {
         ret = -ENODEV;
         goto out;
     }
 
     plr->thread_done = 0;
     cpu = cpumask_first(&plr->d->cpu_mask);
     if (!cpu_online(cpu)) {
         ret = -ENODEV;
         goto out;
     }
 
     plr->cpu = cpu;
 
     if (sel == 1)
         thread = kthread_create_on_node(measure_cycles_lat_fn, plr,
                         cpu_to_node(cpu),
                         "pseudo_lock_measure/%u",
                         cpu);
     else if (sel == 2)
         thread = kthread_create_on_node(measure_l2_residency, plr,
                         cpu_to_node(cpu),
                         "pseudo_lock_measure/%u",
                         cpu);
     else if (sel == 3)
         thread = kthread_create_on_node(measure_l3_residency, plr,
                         cpu_to_node(cpu),
                         "pseudo_lock_measure/%u",
                         cpu);
     else
         goto out;
 
     if (IS_ERR(thread)) {
         ret = PTR_ERR(thread);
         goto out;
     }
     kthread_bind(thread, cpu);
     wake_up_process(thread);
 
     ret = wait_event_interruptible(plr->lock_thread_wq,
                        plr->thread_done == 1);
     if (ret < 0)
         goto out;
 
     ret = 0;
 
 out:
     mutex_unlock(&rdtgroup_mutex);
     cpus_read_unlock();
     return ret;
 }
 
 static ssize_t pseudo_lock_measure_trigger(struct file *file,
                        const char __user *user_buf,
                        size_t count, loff_t *ppos)
 {
     struct rdtgroup *rdtgrp = file->private_data;
     size_t buf_size;
     char buf[32];
     int ret;
     int sel;
 
     buf_size = min(count, (sizeof(buf) - 1));
     if (copy_from_user(buf, user_buf, buf_size))
         return -EFAULT;
 
     buf[buf_size] = '\0';
     ret = kstrtoint(buf, 10, &sel);
     if (ret == 0) {
         if (sel != 1 && sel != 2 && sel != 3)
             return -EINVAL;
         ret = debugfs_file_get(file->f_path.dentry);
         if (ret)
             return ret;
         ret = pseudo_lock_measure_cycles(rdtgrp, sel);
         if (ret == 0)
             ret = count;
         debugfs_file_put(file->f_path.dentry);
     }
 
     return ret;
 }
 
 static const struct file_operations pseudo_measure_fops = {
     .write = pseudo_lock_measure_trigger,
     .open = simple_open,
     .llseek = default_llseek,
 };
 
 /**
  * rdtgroup_pseudo_lock_create - Create a pseudo-locked region
  * @rdtgrp: resource group to which pseudo-lock region belongs
  *
  * Called when a resource group in the pseudo-locksetup mode receives a
  * valid schemata that should be pseudo-locked. Since the resource group is
  * in pseudo-locksetup mode the &struct pseudo_lock_region has already been
  * allocated and initialized with the essential information. If a failure
  * occurs the resource group remains in the pseudo-locksetup mode with the
  * &struct pseudo_lock_region associated with it, but cleared from all
  * information and ready for the user to re-attempt pseudo-locking by
  * writing the schemata again.
  *
  * Return: 0 if the pseudo-locked region was successfully pseudo-locked, <0
  * on failure. Descriptive error will be written to last_cmd_status buffer.
  */
 int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp)
 {
     struct pseudo_lock_region *plr = rdtgrp->plr;
     struct task_struct *thread;
     unsigned int new_minor;
     struct device *dev;
     int ret;
 
     ret = pseudo_lock_region_alloc(plr);
     if (ret < 0)
         return ret;
 
     ret = pseudo_lock_cstates_constrain(plr);
     if (ret < 0) {
         ret = -EINVAL;
         goto out_region;
     }
 
     plr->thread_done = 0;
 
     thread = kthread_create_on_node(pseudo_lock_fn, rdtgrp,
                     cpu_to_node(plr->cpu),
                     "pseudo_lock/%u", plr->cpu);
     if (IS_ERR(thread)) {
         ret = PTR_ERR(thread);
         rdt_last_cmd_printf("Locking thread returned error %d\n", ret);
         goto out_cstates;
     }
 
     kthread_bind(thread, plr->cpu);
     wake_up_process(thread);
 
     ret = wait_event_interruptible(plr->lock_thread_wq,
                        plr->thread_done == 1);
     if (ret < 0) {
         /*
          * If the thread does not get on the CPU for whatever
          * reason and the process which sets up the region is
          * interrupted then this will leave the thread in runnable
          * state and once it gets on the CPU it will dereference
          * the cleared, but not freed, plr struct resulting in an
          * empty pseudo-locking loop.
          */
         rdt_last_cmd_puts("Locking thread interrupted\n");
         goto out_cstates;
     }
 
     ret = pseudo_lock_minor_get(&new_minor);
     if (ret < 0) {
         rdt_last_cmd_puts("Unable to obtain a new minor number\n");
         goto out_cstates;
     }
 
     /*
      * Unlock access but do not release the reference. The
      * pseudo-locked region will still be here on return.
      *
      * The mutex has to be released temporarily to avoid a potential
      * deadlock with the mm->mmap_lock which is obtained in the
      * device_create() and debugfs_create_dir() callpath below as well as
      * before the mmap() callback is called.
      */
     mutex_unlock(&rdtgroup_mutex);
 
     if (!IS_ERR_OR_NULL(debugfs_resctrl)) {
         plr->debugfs_dir = debugfs_create_dir(rdtgrp->kn->name,
                               debugfs_resctrl);
         if (!IS_ERR_OR_NULL(plr->debugfs_dir))
             debugfs_create_file("pseudo_lock_measure", 0200,
                         plr->debugfs_dir, rdtgrp,
                         &pseudo_measure_fops);
     }
 
     dev = device_create(pseudo_lock_class, NULL,
                 MKDEV(pseudo_lock_major, new_minor),
                 rdtgrp, "%s", rdtgrp->kn->name);
 
     mutex_lock(&rdtgroup_mutex);
 
     if (IS_ERR(dev)) {
         ret = PTR_ERR(dev);
         rdt_last_cmd_printf("Failed to create character device: %d\n",
                     ret);
         goto out_debugfs;
     }
 
     /* We released the mutex - check if group was removed while we did so */
     if (rdtgrp->flags & RDT_DELETED) {
         ret = -ENODEV;
         goto out_device;
     }
 
     plr->minor = new_minor;
 
     rdtgrp->mode = RDT_MODE_PSEUDO_LOCKED;
     closid_free(rdtgrp->closid);
     rdtgroup_kn_mode_restore(rdtgrp, "cpus", 0444);
     rdtgroup_kn_mode_restore(rdtgrp, "cpus_list", 0444);
 
     ret = 0;
     goto out;
 
 out_device:
     device_destroy(pseudo_lock_class, MKDEV(pseudo_lock_major, new_minor));
 out_debugfs:
     debugfs_remove_recursive(plr->debugfs_dir);
     pseudo_lock_minor_release(new_minor);
 out_cstates:
     pseudo_lock_cstates_relax(plr);
 out_region:
     pseudo_lock_region_clear(plr);
 out:
     return ret;
 }
 
 /**
  * rdtgroup_pseudo_lock_remove - Remove a pseudo-locked region
  * @rdtgrp: resource group to which the pseudo-locked region belongs
  *
  * The removal of a pseudo-locked region can be initiated when the resource
  * group is removed from user space via a "rmdir" from userspace or the
  * unmount of the resctrl filesystem. On removal the resource group does
  * not go back to pseudo-locksetup mode before it is removed, instead it is
  * removed directly. There is thus asymmetry with the creation where the
  * &struct pseudo_lock_region is removed here while it was not created in
  * rdtgroup_pseudo_lock_create().
  *
  * Return: void
  */
 void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp)
 {
     struct pseudo_lock_region *plr = rdtgrp->plr;
 
     if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
         /*
          * Default group cannot be a pseudo-locked region so we can
          * free closid here.
          */
         closid_free(rdtgrp->closid);
         goto free;
     }
 
     pseudo_lock_cstates_relax(plr);
     debugfs_remove_recursive(rdtgrp->plr->debugfs_dir);
     device_destroy(pseudo_lock_class, MKDEV(pseudo_lock_major, plr->minor));
     pseudo_lock_minor_release(plr->minor);
 
 free:
     pseudo_lock_free(rdtgrp);
 }
 
 static int pseudo_lock_dev_open(struct inode *inode, struct file *filp)
 {
     struct rdtgroup *rdtgrp;
 
     mutex_lock(&rdtgroup_mutex);
 
     rdtgrp = region_find_by_minor(iminor(inode));
     if (!rdtgrp) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENODEV;
     }
 
     filp->private_data = rdtgrp;
     atomic_inc(&rdtgrp->waitcount);
     /* Perform a non-seekable open - llseek is not supported */
     filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
 
     mutex_unlock(&rdtgroup_mutex);
 
     return 0;
 }
 
 static int pseudo_lock_dev_release(struct inode *inode, struct file *filp)
 {
     struct rdtgroup *rdtgrp;
 
     mutex_lock(&rdtgroup_mutex);
     rdtgrp = filp->private_data;
     WARN_ON(!rdtgrp);
     if (!rdtgrp) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENODEV;
     }
     filp->private_data = NULL;
     atomic_dec(&rdtgrp->waitcount);
     mutex_unlock(&rdtgroup_mutex);
     return 0;
 }
 
 static int pseudo_lock_dev_mremap(struct vm_area_struct *area)
 {
     /* Not supported */
     return -EINVAL;
 }
 
 static const struct vm_operations_struct pseudo_mmap_ops = {
     .mremap = pseudo_lock_dev_mremap,
 };
 
 static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
 {
     unsigned long vsize = vma->vm_end - vma->vm_start;
     unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
     struct pseudo_lock_region *plr;
     struct rdtgroup *rdtgrp;
     unsigned long physical;
     unsigned long psize;
 
     mutex_lock(&rdtgroup_mutex);
 
     rdtgrp = filp->private_data;
     WARN_ON(!rdtgrp);
     if (!rdtgrp) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENODEV;
     }
 
     plr = rdtgrp->plr;
 
     if (!plr->d) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENODEV;
     }
 
     /*
      * Task is required to run with affinity to the cpus associated
      * with the pseudo-locked region. If this is not the case the task
      * may be scheduled elsewhere and invalidate entries in the
      * pseudo-locked region.
      */
     if (!cpumask_subset(current->cpus_ptr, &plr->d->cpu_mask)) {
         mutex_unlock(&rdtgroup_mutex);
         return -EINVAL;
     }
 
     physical = __pa(plr->kmem) >> PAGE_SHIFT;
     psize = plr->size - off;
 
     if (off > plr->size) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENOSPC;
     }
 
     /*
      * Ensure changes are carried directly to the memory being mapped,
      * do not allow copy-on-write mapping.
      */
     if (!(vma->vm_flags & VM_SHARED)) {
         mutex_unlock(&rdtgroup_mutex);
         return -EINVAL;
     }
 
     if (vsize > psize) {
         mutex_unlock(&rdtgroup_mutex);
         return -ENOSPC;
     }
 
     memset(plr->kmem + off, 0, vsize);
 
     if (remap_pfn_range(vma, vma->vm_start, physical + vma->vm_pgoff,
                 vsize, vma->vm_page_prot)) {
         mutex_unlock(&rdtgroup_mutex);
         return -EAGAIN;
     }
     vma->vm_ops = &pseudo_mmap_ops;
     mutex_unlock(&rdtgroup_mutex);
     return 0;
 }
 
 static const struct file_operations pseudo_lock_dev_fops = {
     .owner =    THIS_MODULE,
     .llseek =   no_llseek,
     .read =     NULL,
     .write =    NULL,
     .open =     pseudo_lock_dev_open,
     .release =  pseudo_lock_dev_release,
     .mmap =     pseudo_lock_dev_mmap,
 };
 
 static char *pseudo_lock_devnode(struct device *dev, umode_t *mode)
 {
     struct rdtgroup *rdtgrp;
 
     rdtgrp = dev_get_drvdata(dev);
     if (mode)
         *mode = 0600;
     return kasprintf(GFP_KERNEL, "pseudo_lock/%s", rdtgrp->kn->name);
 }
 
 int rdt_pseudo_lock_init(void)
 {
     int ret;
 
     ret = register_chrdev(0, "pseudo_lock", &pseudo_lock_dev_fops);
     if (ret < 0)
         return ret;
 
     pseudo_lock_major = ret;
 
     pseudo_lock_class = class_create(THIS_MODULE, "pseudo_lock");
     if (IS_ERR(pseudo_lock_class)) {
         ret = PTR_ERR(pseudo_lock_class);
         unregister_chrdev(pseudo_lock_major, "pseudo_lock");
         return ret;
     }
 
     pseudo_lock_class->devnode = pseudo_lock_devnode;
     return 0;
 }
 
 void rdt_pseudo_lock_release(void)
 {
     class_destroy(pseudo_lock_class);
     pseudo_lock_class = NULL;
     unregister_chrdev(pseudo_lock_major, "pseudo_lock");
     pseudo_lock_major = 0;
 }

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