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 // SPDX-License-Identifier: GPL-2.0
 /*  Copyright(c) 2016-20 Intel Corporation. */
 
 #include <linux/file.h>
 #include <linux/freezer.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
 #include <linux/miscdevice.h>
 #include <linux/node.h>
 #include <linux/pagemap.h>
 #include <linux/ratelimit.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <asm/sgx.h>
 #include "driver.h"
 #include "encl.h"
 #include "encls.h"
 
 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
 static int sgx_nr_epc_sections;
 static struct task_struct *ksgxd_tsk;
 static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq);
 static DEFINE_XARRAY(sgx_epc_address_space);
 
 /*
  * These variables are part of the state of the reclaimer, and must be accessed
  * with sgx_reclaimer_lock acquired.
  */
 static LIST_HEAD(sgx_active_page_list);
 static DEFINE_SPINLOCK(sgx_reclaimer_lock);
 
 static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
 
 /* Nodes with one or more EPC sections. */
 static nodemask_t sgx_numa_mask;
 
 /*
  * Array with one list_head for each possible NUMA node.  Each
  * list contains all the sgx_epc_section's which are on that
  * node.
  */
 static struct sgx_numa_node *sgx_numa_nodes;
 
 static LIST_HEAD(sgx_dirty_page_list);
 
 /*
  * Reset post-kexec EPC pages to the uninitialized state. The pages are removed
  * from the input list, and made available for the page allocator. SECS pages
  * prepending their children in the input list are left intact.
  *
  * Return 0 when sanitization was successful or kthread was stopped, and the
  * number of unsanitized pages otherwise.
  */
 static unsigned long __sgx_sanitize_pages(struct list_head *dirty_page_list)
 {
     unsigned long left_dirty = 0;
     struct sgx_epc_page *page;
     LIST_HEAD(dirty);
     int ret;
 
     /* dirty_page_list is thread-local, no need for a lock: */
     while (!list_empty(dirty_page_list)) {
         if (kthread_should_stop())
             return 0;
 
         page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);
 
         /*
          * Checking page->poison without holding the node->lock
          * is racy, but losing the race (i.e. poison is set just
          * after the check) just means __eremove() will be uselessly
          * called for a page that sgx_free_epc_page() will put onto
          * the node->sgx_poison_page_list later.
          */
         if (page->poison) {
             struct sgx_epc_section *section = &sgx_epc_sections[page->section];
             struct sgx_numa_node *node = section->node;
 
             spin_lock(&node->lock);
             list_move(&page->list, &node->sgx_poison_page_list);
             spin_unlock(&node->lock);
 
             continue;
         }
 
         ret = __eremove(sgx_get_epc_virt_addr(page));
         if (!ret) {
             /*
              * page is now sanitized.  Make it available via the SGX
              * page allocator:
              */
             list_del(&page->list);
             sgx_free_epc_page(page);
         } else {
             /* The page is not yet clean - move to the dirty list. */
             list_move_tail(&page->list, &dirty);
             left_dirty++;
         }
 
         cond_resched();
     }
 
     list_splice(&dirty, dirty_page_list);
     return left_dirty;
 }
 
 static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page)
 {
     struct sgx_encl_page *page = epc_page->owner;
     struct sgx_encl *encl = page->encl;
     struct sgx_encl_mm *encl_mm;
     bool ret = true;
     int idx;
 
     idx = srcu_read_lock(&encl->srcu);
 
     list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
         if (!mmget_not_zero(encl_mm->mm))
             continue;
 
         mmap_read_lock(encl_mm->mm);
         ret = !sgx_encl_test_and_clear_young(encl_mm->mm, page);
         mmap_read_unlock(encl_mm->mm);
 
         mmput_async(encl_mm->mm);
 
         if (!ret)
             break;
     }
 
     srcu_read_unlock(&encl->srcu, idx);
 
     if (!ret)
         return false;
 
     return true;
 }
 
 static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
 {
     struct sgx_encl_page *page = epc_page->owner;
     unsigned long addr = page->desc & PAGE_MASK;
     struct sgx_encl *encl = page->encl;
     int ret;
 
     sgx_zap_enclave_ptes(encl, addr);
 
     mutex_lock(&encl->lock);
 
     ret = __eblock(sgx_get_epc_virt_addr(epc_page));
     if (encls_failed(ret))
         ENCLS_WARN(ret, "EBLOCK");
 
     mutex_unlock(&encl->lock);
 }
 
 static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
               struct sgx_backing *backing)
 {
     struct sgx_pageinfo pginfo;
     int ret;
 
     pginfo.addr = 0;
     pginfo.secs = 0;
 
     pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
     pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
               backing->pcmd_offset;
 
     ret = __ewb(&pginfo, sgx_get_epc_virt_addr(epc_page), va_slot);
     set_page_dirty(backing->pcmd);
     set_page_dirty(backing->contents);
 
     kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
                           backing->pcmd_offset));
     kunmap_atomic((void *)(unsigned long)pginfo.contents);
 
     return ret;
 }
 
 void sgx_ipi_cb(void *info)
 {
 }
 
 /*
  * Swap page to the regular memory transformed to the blocked state by using
  * EBLOCK, which means that it can no longer be referenced (no new TLB entries).
  *
  * The first trial just tries to write the page assuming that some other thread
  * has reset the count for threads inside the enclave by using ETRACK, and
  * previous thread count has been zeroed out. The second trial calls ETRACK
  * before EWB. If that fails we kick all the HW threads out, and then do EWB,
  * which should be guaranteed the succeed.
  */
 static void sgx_encl_ewb(struct sgx_epc_page *epc_page,
              struct sgx_backing *backing)
 {
     struct sgx_encl_page *encl_page = epc_page->owner;
     struct sgx_encl *encl = encl_page->encl;
     struct sgx_va_page *va_page;
     unsigned int va_offset;
     void *va_slot;
     int ret;
 
     encl_page->desc &= ~SGX_ENCL_PAGE_BEING_RECLAIMED;
 
     va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
                    list);
     va_offset = sgx_alloc_va_slot(va_page);
     va_slot = sgx_get_epc_virt_addr(va_page->epc_page) + va_offset;
     if (sgx_va_page_full(va_page))
         list_move_tail(&va_page->list, &encl->va_pages);
 
     ret = __sgx_encl_ewb(epc_page, va_slot, backing);
     if (ret == SGX_NOT_TRACKED) {
         ret = __etrack(sgx_get_epc_virt_addr(encl->secs.epc_page));
         if (ret) {
             if (encls_failed(ret))
                 ENCLS_WARN(ret, "ETRACK");
         }
 
         ret = __sgx_encl_ewb(epc_page, va_slot, backing);
         if (ret == SGX_NOT_TRACKED) {
             /*
              * Slow path, send IPIs to kick cpus out of the
              * enclave.  Note, it's imperative that the cpu
              * mask is generated *after* ETRACK, else we'll
              * miss cpus that entered the enclave between
              * generating the mask and incrementing epoch.
              */
             on_each_cpu_mask(sgx_encl_cpumask(encl),
                      sgx_ipi_cb, NULL, 1);
             ret = __sgx_encl_ewb(epc_page, va_slot, backing);
         }
     }
 
     if (ret) {
         if (encls_failed(ret))
             ENCLS_WARN(ret, "EWB");
 
         sgx_free_va_slot(va_page, va_offset);
     } else {
         encl_page->desc |= va_offset;
         encl_page->va_page = va_page;
     }
 }
 
 static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
                 struct sgx_backing *backing)
 {
     struct sgx_encl_page *encl_page = epc_page->owner;
     struct sgx_encl *encl = encl_page->encl;
     struct sgx_backing secs_backing;
     int ret;
 
     mutex_lock(&encl->lock);
 
     sgx_encl_ewb(epc_page, backing);
     encl_page->epc_page = NULL;
     encl->secs_child_cnt--;
     sgx_encl_put_backing(backing);
 
     if (!encl->secs_child_cnt && test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) {
         ret = sgx_encl_alloc_backing(encl, PFN_DOWN(encl->size),
                        &secs_backing);
         if (ret)
             goto out;
 
         sgx_encl_ewb(encl->secs.epc_page, &secs_backing);
 
         sgx_encl_free_epc_page(encl->secs.epc_page);
         encl->secs.epc_page = NULL;
 
         sgx_encl_put_backing(&secs_backing);
     }
 
 out:
     mutex_unlock(&encl->lock);
 }
 
 /*
  * Take a fixed number of pages from the head of the active page pool and
  * reclaim them to the enclave's private shmem files. Skip the pages, which have
  * been accessed since the last scan. Move those pages to the tail of active
  * page pool so that the pages get scanned in LRU like fashion.
  *
  * Batch process a chunk of pages (at the moment 16) in order to degrade amount
  * of IPI's and ETRACK's potentially required. sgx_encl_ewb() does degrade a bit
  * among the HW threads with three stage EWB pipeline (EWB, ETRACK + EWB and IPI
  * + EWB) but not sufficiently. Reclaiming one page at a time would also be
  * problematic as it would increase the lock contention too much, which would
  * halt forward progress.
  */
 static void sgx_reclaim_pages(void)
 {
     struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
     struct sgx_backing backing[SGX_NR_TO_SCAN];
     struct sgx_encl_page *encl_page;
     struct sgx_epc_page *epc_page;
     pgoff_t page_index;
     int cnt = 0;
     int ret;
     int i;
 
     spin_lock(&sgx_reclaimer_lock);
     for (i = 0; i < SGX_NR_TO_SCAN; i++) {
         if (list_empty(&sgx_active_page_list))
             break;
 
         epc_page = list_first_entry(&sgx_active_page_list,
                         struct sgx_epc_page, list);
         list_del_init(&epc_page->list);
         encl_page = epc_page->owner;
 
         if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
             chunk[cnt++] = epc_page;
         else
             /* The owner is freeing the page. No need to add the
              * page back to the list of reclaimable pages.
              */
             epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
     }
     spin_unlock(&sgx_reclaimer_lock);
 
     for (i = 0; i < cnt; i++) {
         epc_page = chunk[i];
         encl_page = epc_page->owner;
 
         if (!sgx_reclaimer_age(epc_page))
             goto skip;
 
         page_index = PFN_DOWN(encl_page->desc - encl_page->encl->base);
 
         mutex_lock(&encl_page->encl->lock);
         ret = sgx_encl_alloc_backing(encl_page->encl, page_index, &backing[i]);
         if (ret) {
             mutex_unlock(&encl_page->encl->lock);
             goto skip;
         }
 
         encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED;
         mutex_unlock(&encl_page->encl->lock);
         continue;
 
 skip:
         spin_lock(&sgx_reclaimer_lock);
         list_add_tail(&epc_page->list, &sgx_active_page_list);
         spin_unlock(&sgx_reclaimer_lock);
 
         kref_put(&encl_page->encl->refcount, sgx_encl_release);
 
         chunk[i] = NULL;
     }
 
     for (i = 0; i < cnt; i++) {
         epc_page = chunk[i];
         if (epc_page)
             sgx_reclaimer_block(epc_page);
     }
 
     for (i = 0; i < cnt; i++) {
         epc_page = chunk[i];
         if (!epc_page)
             continue;
 
         encl_page = epc_page->owner;
         sgx_reclaimer_write(epc_page, &backing[i]);
 
         kref_put(&encl_page->encl->refcount, sgx_encl_release);
         epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
 
         sgx_free_epc_page(epc_page);
     }
 }
 
 static bool sgx_should_reclaim(unsigned long watermark)
 {
     return atomic_long_read(&sgx_nr_free_pages) < watermark &&
            !list_empty(&sgx_active_page_list);
 }
 
 /*
  * sgx_reclaim_direct() should be called (without enclave's mutex held)
  * in locations where SGX memory resources might be low and might be
  * needed in order to make forward progress.
  */
 void sgx_reclaim_direct(void)
 {
     if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
         sgx_reclaim_pages();
 }
 
 static int ksgxd(void *p)
 {
     set_freezable();
 
     /*
      * Sanitize pages in order to recover from kexec(). The 2nd pass is
      * required for SECS pages, whose child pages blocked EREMOVE.
      */
     __sgx_sanitize_pages(&sgx_dirty_page_list);
     WARN_ON(__sgx_sanitize_pages(&sgx_dirty_page_list));
 
     while (!kthread_should_stop()) {
         if (try_to_freeze())
             continue;
 
         wait_event_freezable(ksgxd_waitq,
                      kthread_should_stop() ||
                      sgx_should_reclaim(SGX_NR_HIGH_PAGES));
 
         if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
             sgx_reclaim_pages();
 
         cond_resched();
     }
 
     return 0;
 }
 
 static bool __init sgx_page_reclaimer_init(void)
 {
     struct task_struct *tsk;
 
     tsk = kthread_run(ksgxd, NULL, "ksgxd");
     if (IS_ERR(tsk))
         return false;
 
     ksgxd_tsk = tsk;
 
     return true;
 }
 
 bool current_is_ksgxd(void)
 {
     return current == ksgxd_tsk;
 }
 
 static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid)
 {
     struct sgx_numa_node *node = &sgx_numa_nodes[nid];
     struct sgx_epc_page *page = NULL;
 
     spin_lock(&node->lock);
 
     if (list_empty(&node->free_page_list)) {
         spin_unlock(&node->lock);
         return NULL;
     }
 
     page = list_first_entry(&node->free_page_list, struct sgx_epc_page, list);
     list_del_init(&page->list);
     page->flags = 0;
 
     spin_unlock(&node->lock);
     atomic_long_dec(&sgx_nr_free_pages);
 
     return page;
 }
 
 /**
  * __sgx_alloc_epc_page() - Allocate an EPC page
  *
  * Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start
  * from the NUMA node, where the caller is executing.
  *
  * Return:
  * - an EPC page:   A borrowed EPC pages were available.
  * - NULL:      Out of EPC pages.
  */
 struct sgx_epc_page *__sgx_alloc_epc_page(void)
 {
     struct sgx_epc_page *page;
     int nid_of_current = numa_node_id();
     int nid = nid_of_current;
 
     if (node_isset(nid_of_current, sgx_numa_mask)) {
         page = __sgx_alloc_epc_page_from_node(nid_of_current);
         if (page)
             return page;
     }
 
     /* Fall back to the non-local NUMA nodes: */
     while (true) {
         nid = next_node_in(nid, sgx_numa_mask);
         if (nid == nid_of_current)
             break;
 
         page = __sgx_alloc_epc_page_from_node(nid);
         if (page)
             return page;
     }
 
     return ERR_PTR(-ENOMEM);
 }
 
 /**
  * sgx_mark_page_reclaimable() - Mark a page as reclaimable
  * @page:   EPC page
  *
  * Mark a page as reclaimable and add it to the active page list. Pages
  * are automatically removed from the active list when freed.
  */
 void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
 {
     spin_lock(&sgx_reclaimer_lock);
     page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
     list_add_tail(&page->list, &sgx_active_page_list);
     spin_unlock(&sgx_reclaimer_lock);
 }
 
 /**
  * sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
  * @page:   EPC page
  *
  * Clear the reclaimable flag and remove the page from the active page list.
  *
  * Return:
  *   0 on success,
  *   -EBUSY if the page is in the process of being reclaimed
  */
 int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
 {
     spin_lock(&sgx_reclaimer_lock);
     if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
         /* The page is being reclaimed. */
         if (list_empty(&page->list)) {
             spin_unlock(&sgx_reclaimer_lock);
             return -EBUSY;
         }
 
         list_del(&page->list);
         page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
     }
     spin_unlock(&sgx_reclaimer_lock);
 
     return 0;
 }
 
 /**
  * sgx_alloc_epc_page() - Allocate an EPC page
  * @owner:  the owner of the EPC page
  * @reclaim:    reclaim pages if necessary
  *
  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
  * page is no longer needed it must be released with sgx_free_epc_page(). If
  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
  * mm's can be locked when @reclaim is set to true.
  *
  * Finally, wake up ksgxd when the number of pages goes below the watermark
  * before returning back to the caller.
  *
  * Return:
  *   an EPC page,
  *   -errno on error
  */
 struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
 {
     struct sgx_epc_page *page;
 
     for ( ; ; ) {
         page = __sgx_alloc_epc_page();
         if (!IS_ERR(page)) {
             page->owner = owner;
             break;
         }
 
         if (list_empty(&sgx_active_page_list))
             return ERR_PTR(-ENOMEM);
 
         if (!reclaim) {
             page = ERR_PTR(-EBUSY);
             break;
         }
 
         if (signal_pending(current)) {
             page = ERR_PTR(-ERESTARTSYS);
             break;
         }
 
         sgx_reclaim_pages();
         cond_resched();
     }
 
     if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
         wake_up(&ksgxd_waitq);
 
     return page;
 }
 
 /**
  * sgx_free_epc_page() - Free an EPC page
  * @page:   an EPC page
  *
  * Put the EPC page back to the list of free pages. It's the caller's
  * responsibility to make sure that the page is in uninitialized state. In other
  * words, do EREMOVE, EWB or whatever operation is necessary before calling
  * this function.
  */
 void sgx_free_epc_page(struct sgx_epc_page *page)
 {
     struct sgx_epc_section *section = &sgx_epc_sections[page->section];
     struct sgx_numa_node *node = section->node;
 
     spin_lock(&node->lock);
 
     page->owner = NULL;
     if (page->poison)
         list_add(&page->list, &node->sgx_poison_page_list);
     else
         list_add_tail(&page->list, &node->free_page_list);
     page->flags = SGX_EPC_PAGE_IS_FREE;
 
     spin_unlock(&node->lock);
     atomic_long_inc(&sgx_nr_free_pages);
 }
 
 static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
                      unsigned long index,
                      struct sgx_epc_section *section)
 {
     unsigned long nr_pages = size >> PAGE_SHIFT;
     unsigned long i;
 
     section->virt_addr = memremap(phys_addr, size, MEMREMAP_WB);
     if (!section->virt_addr)
         return false;
 
     section->pages = vmalloc(nr_pages * sizeof(struct sgx_epc_page));
     if (!section->pages) {
         memunmap(section->virt_addr);
         return false;
     }
 
     section->phys_addr = phys_addr;
     xa_store_range(&sgx_epc_address_space, section->phys_addr,
                phys_addr + size - 1, section, GFP_KERNEL);
 
     for (i = 0; i < nr_pages; i++) {
         section->pages[i].section = index;
         section->pages[i].flags = 0;
         section->pages[i].owner = NULL;
         section->pages[i].poison = 0;
         list_add_tail(&section->pages[i].list, &sgx_dirty_page_list);
     }
 
     return true;
 }
 
 bool arch_is_platform_page(u64 paddr)
 {
     return !!xa_load(&sgx_epc_address_space, paddr);
 }
 EXPORT_SYMBOL_GPL(arch_is_platform_page);
 
 static struct sgx_epc_page *sgx_paddr_to_page(u64 paddr)
 {
     struct sgx_epc_section *section;
 
     section = xa_load(&sgx_epc_address_space, paddr);
     if (!section)
         return NULL;
 
     return &section->pages[PFN_DOWN(paddr - section->phys_addr)];
 }
 
 /*
  * Called in process context to handle a hardware reported
  * error in an SGX EPC page.
  * If the MF_ACTION_REQUIRED bit is set in flags, then the
  * context is the task that consumed the poison data. Otherwise
  * this is called from a kernel thread unrelated to the page.
  */
 int arch_memory_failure(unsigned long pfn, int flags)
 {
     struct sgx_epc_page *page = sgx_paddr_to_page(pfn << PAGE_SHIFT);
     struct sgx_epc_section *section;
     struct sgx_numa_node *node;
 
     /*
      * mm/memory-failure.c calls this routine for all errors
      * where there isn't a "struct page" for the address. But that
      * includes other address ranges besides SGX.
      */
     if (!page)
         return -ENXIO;
 
     /*
      * If poison was consumed synchronously. Send a SIGBUS to
      * the task. Hardware has already exited the SGX enclave and
      * will not allow re-entry to an enclave that has a memory
      * error. The signal may help the task understand why the
      * enclave is broken.
      */
     if (flags & MF_ACTION_REQUIRED)
         force_sig(SIGBUS);
 
     section = &sgx_epc_sections[page->section];
     node = section->node;
 
     spin_lock(&node->lock);
 
     /* Already poisoned? Nothing more to do */
     if (page->poison)
         goto out;
 
     page->poison = 1;
 
     /*
      * If the page is on a free list, move it to the per-node
      * poison page list.
      */
     if (page->flags & SGX_EPC_PAGE_IS_FREE) {
         list_move(&page->list, &node->sgx_poison_page_list);
         goto out;
     }
 
     /*
      * TBD: Add additional plumbing to enable pre-emptive
      * action for asynchronous poison notification. Until
      * then just hope that the poison:
      * a) is not accessed - sgx_free_epc_page() will deal with it
      *    when the user gives it back
      * b) results in a recoverable machine check rather than
      *    a fatal one
      */
 out:
     spin_unlock(&node->lock);
     return 0;
 }
 
 /**
  * A section metric is concatenated in a way that @low bits 12-31 define the
  * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
  * metric.
  */
 static inline u64 __init sgx_calc_section_metric(u64 low, u64 high)
 {
     return (low & GENMASK_ULL(31, 12)) +
            ((high & GENMASK_ULL(19, 0)) << 32);
 }
 
 #ifdef CONFIG_NUMA
 static ssize_t sgx_total_bytes_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
     return sysfs_emit(buf, "%lu\n", sgx_numa_nodes[dev->id].size);
 }
 static DEVICE_ATTR_RO(sgx_total_bytes);
 
 static umode_t arch_node_attr_is_visible(struct kobject *kobj,
         struct attribute *attr, int idx)
 {
     /* Make all x86/ attributes invisible when SGX is not initialized: */
     if (nodes_empty(sgx_numa_mask))
         return 0;
 
     return attr->mode;
 }
 
 static struct attribute *arch_node_dev_attrs[] = {
     &dev_attr_sgx_total_bytes.attr,
     NULL,
 };
 
 const struct attribute_group arch_node_dev_group = {
     .name = "x86",
     .attrs = arch_node_dev_attrs,
     .is_visible = arch_node_attr_is_visible,
 };
 
 static void __init arch_update_sysfs_visibility(int nid)
 {
     struct node *node = node_devices[nid];
     int ret;
 
     ret = sysfs_update_group(&node->dev.kobj, &arch_node_dev_group);
 
     if (ret)
         pr_err("sysfs update failed (%d), files may be invisible", ret);
 }
 #else /* !CONFIG_NUMA */
 static void __init arch_update_sysfs_visibility(int nid) {}
 #endif
 
 static bool __init sgx_page_cache_init(void)
 {
     u32 eax, ebx, ecx, edx, type;
     u64 pa, size;
     int nid;
     int i;
 
     sgx_numa_nodes = kmalloc_array(num_possible_nodes(), sizeof(*sgx_numa_nodes), GFP_KERNEL);
     if (!sgx_numa_nodes)
         return false;
 
     for (i = 0; i < ARRAY_SIZE(sgx_epc_sections); i++) {
         cpuid_count(SGX_CPUID, i + SGX_CPUID_EPC, &eax, &ebx, &ecx, &edx);
 
         type = eax & SGX_CPUID_EPC_MASK;
         if (type == SGX_CPUID_EPC_INVALID)
             break;
 
         if (type != SGX_CPUID_EPC_SECTION) {
             pr_err_once("Unknown EPC section type: %u\n", type);
             break;
         }
 
         pa   = sgx_calc_section_metric(eax, ebx);
         size = sgx_calc_section_metric(ecx, edx);
 
         pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
 
         if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i])) {
             pr_err("No free memory for an EPC section\n");
             break;
         }
 
         nid = numa_map_to_online_node(phys_to_target_node(pa));
         if (nid == NUMA_NO_NODE) {
             /* The physical address is already printed above. */
             pr_warn(FW_BUG "Unable to map EPC section to online node. Fallback to the NUMA node 0.\n");
             nid = 0;
         }
 
         if (!node_isset(nid, sgx_numa_mask)) {
             spin_lock_init(&sgx_numa_nodes[nid].lock);
             INIT_LIST_HEAD(&sgx_numa_nodes[nid].free_page_list);
             INIT_LIST_HEAD(&sgx_numa_nodes[nid].sgx_poison_page_list);
             node_set(nid, sgx_numa_mask);
             sgx_numa_nodes[nid].size = 0;
 
             /* Make SGX-specific node sysfs files visible: */
             arch_update_sysfs_visibility(nid);
         }
 
         sgx_epc_sections[i].node =  &sgx_numa_nodes[nid];
         sgx_numa_nodes[nid].size += size;
 
         sgx_nr_epc_sections++;
     }
 
     if (!sgx_nr_epc_sections) {
         pr_err("There are zero EPC sections.\n");
         return false;
     }
 
     return true;
 }
 
 /*
  * Update the SGX_LEPUBKEYHASH MSRs to the values specified by caller.
  * Bare-metal driver requires to update them to hash of enclave's signer
  * before EINIT. KVM needs to update them to guest's virtual MSR values
  * before doing EINIT from guest.
  */
 void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
 {
     int i;
 
     WARN_ON_ONCE(preemptible());
 
     for (i = 0; i < 4; i++)
         wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
 }
 
 const struct file_operations sgx_provision_fops = {
     .owner          = THIS_MODULE,
 };
 
 static struct miscdevice sgx_dev_provision = {
     .minor = MISC_DYNAMIC_MINOR,
     .name = "sgx_provision",
     .nodename = "sgx_provision",
     .fops = &sgx_provision_fops,
 };
 
 /**
  * sgx_set_attribute() - Update allowed attributes given file descriptor
  * @allowed_attributes:     Pointer to allowed enclave attributes
  * @attribute_fd:       File descriptor for specific attribute
  *
  * Append enclave attribute indicated by file descriptor to allowed
  * attributes. Currently only SGX_ATTR_PROVISIONKEY indicated by
  * /dev/sgx_provision is supported.
  *
  * Return:
  * -0:      SGX_ATTR_PROVISIONKEY is appended to allowed_attributes
  * -EINVAL: Invalid, or not supported file descriptor
  */
 int sgx_set_attribute(unsigned long *allowed_attributes,
               unsigned int attribute_fd)
 {
     struct file *file;
 
     file = fget(attribute_fd);
     if (!file)
         return -EINVAL;
 
     if (file->f_op != &sgx_provision_fops) {
         fput(file);
         return -EINVAL;
     }
 
     *allowed_attributes |= SGX_ATTR_PROVISIONKEY;
 
     fput(file);
     return 0;
 }
 EXPORT_SYMBOL_GPL(sgx_set_attribute);
 
 static int __init sgx_init(void)
 {
     int ret;
     int i;
 
     if (!cpu_feature_enabled(X86_FEATURE_SGX))
         return -ENODEV;
 
     if (!sgx_page_cache_init())
         return -ENOMEM;
 
     if (!sgx_page_reclaimer_init()) {
         ret = -ENOMEM;
         goto err_page_cache;
     }
 
     ret = misc_register(&sgx_dev_provision);
     if (ret)
         goto err_kthread;
 
     /*
      * Always try to initialize the native *and* KVM drivers.
      * The KVM driver is less picky than the native one and
      * can function if the native one is not supported on the
      * current system or fails to initialize.
      *
      * Error out only if both fail to initialize.
      */
     ret = sgx_drv_init();
 
     if (sgx_vepc_init() && ret)
         goto err_provision;
 
     return 0;
 
 err_provision:
     misc_deregister(&sgx_dev_provision);
 
 err_kthread:
     kthread_stop(ksgxd_tsk);
 
 err_page_cache:
     for (i = 0; i < sgx_nr_epc_sections; i++) {
         vfree(sgx_epc_sections[i].pages);
         memunmap(sgx_epc_sections[i].virt_addr);
     }
 
     return ret;
 }
 
 device_initcall(sgx_init);

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