// 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/pagemap.h>
#include <linux/ratelimit.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.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);

/*
 * 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);

/* The free page list lock protected variables prepend the lock. */
static unsigned long sgx_nr_free_pages;

/* 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.
 */
static void __sgx_sanitize_pages(struct list_head *dirty_page_list)
{
        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;

                page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);

                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);
                }

                cond_resched();
        }

        list_splice(&dirty, dirty_page_list);
}

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;
        unsigned long mm_list_version;
        struct sgx_encl_mm *encl_mm;
        struct vm_area_struct *vma;
        int idx, ret;

        do {
                mm_list_version = encl->mm_list_version;

                /* Pairs with smp_rmb() in sgx_encl_mm_add(). */
                smp_rmb();

                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_find(encl_mm->mm, addr, &vma);
                        if (!ret && encl == vma->vm_private_data)
                                zap_vma_ptes(vma, addr, PAGE_SIZE);

                        mmap_read_unlock(encl_mm->mm);

                        mmput_async(encl_mm->mm);
                }

                srcu_read_unlock(&encl->srcu, idx);
        } while (unlikely(encl->mm_list_version != mm_list_version));

        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);

        kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
                                              backing->pcmd_offset));
        kunmap_atomic((void *)(unsigned long)pginfo.contents);

        return ret;
}

static void sgx_ipi_cb(void *info)
{
}

static const cpumask_t *sgx_encl_ewb_cpumask(struct sgx_encl *encl)
{
        cpumask_t *cpumask = &encl->cpumask;
        struct sgx_encl_mm *encl_mm;
        int idx;

        /*
         * Can race with sgx_encl_mm_add(), but ETRACK has already been
         * executed, which means that the CPUs running in the new mm will enter
         * into the enclave with a fresh epoch.
         */
        cpumask_clear(cpumask);

        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;

                cpumask_or(cpumask, cpumask, mm_cpumask(encl_mm->mm));

                mmput_async(encl_mm->mm);
        }

        srcu_read_unlock(&encl->srcu, idx);

        return cpumask;
}

/*
 * 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_ewb_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--;

        if (!encl->secs_child_cnt && test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) {
                ret = sgx_encl_get_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, true);
        }

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_epc_section *section;
        struct sgx_encl_page *encl_page;
        struct sgx_epc_page *epc_page;
        struct sgx_numa_node *node;
        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);
                ret = sgx_encl_get_backing(encl_page->encl, page_index, &backing[i]);
                if (ret)
                        goto skip;

                mutex_lock(&encl_page->encl->lock);
                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]);
                sgx_encl_put_backing(&backing[i], true);

                kref_put(&encl_page->encl->refcount, sgx_encl_release);
                epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;

                section = &sgx_epc_sections[epc_page->section];
                node = section->node;

                spin_lock(&node->lock);
                list_add_tail(&epc_page->list, &node->free_page_list);
                sgx_nr_free_pages++;
                spin_unlock(&node->lock);
        }
}

static bool sgx_should_reclaim(unsigned long watermark)
{
        return sgx_nr_free_pages < watermark && !list_empty(&sgx_active_page_list);
}

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);
        __sgx_sanitize_pages(&sgx_dirty_page_list);

        /* sanity check: */
        WARN_ON(!list_empty(&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;
}

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);
        sgx_nr_free_pages--;

        spin_unlock(&node->lock);

        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);

        list_add_tail(&page->list, &node->free_page_list);
        sgx_nr_free_pages++;

        spin_unlock(&node->lock);
}

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;

        for (i = 0; i < nr_pages; i++) {
                section->pages[i].section = index;
                section->pages[i].flags = 0;
                section->pages[i].owner = NULL;
                list_add_tail(&section->pages[i].list, &sgx_dirty_page_list);
        }

        return true;
}

/**
 * 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);
}

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);
                        node_set(nid, sgx_numa_mask);
                }

                sgx_epc_sections[i].node =  &sgx_numa_nodes[nid];

                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);