Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 963 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
new file mode 100644
index 000000000..0aad028f0
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -0,0 +1,963 @@
+// 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);