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Date:   Fri, 8 May 2020 12:09:30 -0700
From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
        dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com,
        haitao.huang@intel.com, andriy.shevchenko@linux.intel.com,
        tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de,
        josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com,
        rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com,
        linux-security-module@vger.kernel.org,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Haitao Huang <haitao.huang@linux.intel.com>,
        Jethro Beekman <jethro@fortanix.com>,
        Chunyang Hui <sanqian.hcy@antfin.com>,
        Jordan Hand <jorhand@linux.microsoft.com>,
        Seth Moore <sethmo@google.com>, asapek@google.com,
        conradparker@google.com, Keith Moyer <kmoy@google.com>,
        yaozhangx@google.com, chenalexchen@google.com, ludloff@google.com,
        cyhanish@google.com
Subject: Re: [PATCH v29 11/20] x86/sgx: Linux Enclave Driver
Message-ID: <20200508190930.GQ27052@linux.intel.com>
References: <20200421215316.56503-1-jarkko.sakkinen@linux.intel.com>
 <20200421215316.56503-12-jarkko.sakkinen@linux.intel.com>
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+cc Google folks

On Wed, Apr 22, 2020 at 12:53:07AM +0300, Jarkko Sakkinen wrote:
> Intel Software Guard eXtensions (SGX) is a set of CPU instructions that
> can be used by applications to set aside private regions of code and
> data. The code outside the SGX hosted software entity is disallowed to
> access the memory inside the enclave enforced by the CPU. We call these
> entities as enclaves.
> 
> This commit implements a driver that provides an ioctl API to construct
> and run enclaves. Enclaves are constructed from pages residing in
> reserved physical memory areas. The contents of these pages can only be
> accessed when they are mapped as part of an enclave, by a hardware
> thread running inside the enclave.
> 
> The starting state of an enclave consists of a fixed measured set of
> pages that are copied to the EPC during the construction process by
> using ENCLS leaf functions and Software Enclave Control Structure (SECS)
> that defines the enclave properties.
> 
> Enclave are constructed by using ENCLS leaf functions ECREATE, EADD and
> EINIT. ECREATE initializes SECS, EADD copies pages from system memory to
> the EPC and EINIT check a given signed measurement and moves the enclave
> into a state ready for execution.
> 
> An initialized enclave can only be accessed through special Thread Control
> Structure (TCS) pages by using ENCLU (ring-3 only) leaf EENTER.  This leaf
> function converts a thread into enclave mode and continues the execution in
> the offset defined by the TCS provided to EENTER. An enclave is exited
> through syscall, exception, interrupts or by explicitly calling another
> ENCLU leaf EEXIT.
> 
> The permissions, which enclave page is added will set the limit for maximum
> permissions that can be set for mmap() and mprotect(). This will
> effectively allow to build different security schemes between producers and
> consumers of enclaves. Later on we can increase granularity with LSM hooks
> for page addition (i.e. for producers) and mapping of the enclave (i.e. for
> consumers)
> 
> Cc: linux-security-module@vger.kernel.org
> Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Suresh Siddha <suresh.b.siddha@intel.com>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
> Tested-by: Haitao Huang <haitao.huang@linux.intel.com>
> Tested-by: Jethro Beekman <jethro@fortanix.com>
> Tested-by: Chunyang Hui <sanqian.hcy@antfin.com>
> Tested-by: Jordan Hand <jorhand@linux.microsoft.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>  arch/x86/include/uapi/asm/sgx.h               |  66 ++
>  arch/x86/kernel/cpu/sgx/Makefile              |   3 +
>  arch/x86/kernel/cpu/sgx/driver.c              | 194 +++++
>  arch/x86/kernel/cpu/sgx/driver.h              |  30 +
>  arch/x86/kernel/cpu/sgx/encl.c                | 332 +++++++++
>  arch/x86/kernel/cpu/sgx/encl.h                |  87 +++
>  arch/x86/kernel/cpu/sgx/encls.h               |   5 +-
>  arch/x86/kernel/cpu/sgx/ioctl.c               | 687 ++++++++++++++++++
>  arch/x86/kernel/cpu/sgx/main.c                |  12 +-
>  arch/x86/kernel/cpu/sgx/reclaim.c             |   1 +
>  11 files changed, 1414 insertions(+), 4 deletions(-)
>  create mode 100644 arch/x86/include/uapi/asm/sgx.h
>  create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
>  create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
>  create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
>  create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
>  create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
> 
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 2e91370dc159..1c54dd2704db 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -321,6 +321,7 @@ Code  Seq#    Include File                                           Comments
>                                                                       <mailto:tlewis@mindspring.com>
>  0xA3  90-9F  linux/dtlk.h
>  0xA4  00-1F  uapi/linux/tee.h                                        Generic TEE subsystem
> +0xA4  00-1F  uapi/asm/sgx.h                                          Intel SGX subsystem (a legit conflict as TEE and SGX do not co-exist)
>  0xAA  00-3F  linux/uapi/linux/userfaultfd.h
>  0xAB  00-1F  linux/nbd.h
>  0xAC  00-1F  linux/raw.h
> diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
> new file mode 100644
> index 000000000000..5edb08ab8fd0
> --- /dev/null
> +++ b/arch/x86/include/uapi/asm/sgx.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
> +/*
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _UAPI_ASM_X86_SGX_H
> +#define _UAPI_ASM_X86_SGX_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +/**
> + * enum sgx_epage_flags - page control flags
> + * %SGX_PAGE_MEASURE:	Measure the page contents with a sequence of
> + *			ENCLS[EEXTEND] operations.
> + */
> +enum sgx_page_flags {
> +	SGX_PAGE_MEASURE	= 0x01,
> +};
> +
> +#define SGX_MAGIC 0xA4
> +
> +#define SGX_IOC_ENCLAVE_CREATE \
> +	_IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
> +#define SGX_IOC_ENCLAVE_ADD_PAGES \
> +	_IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
> +#define SGX_IOC_ENCLAVE_INIT \
> +	_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
> +
> +/**
> + * struct sgx_enclave_create - parameter structure for the
> + *                             %SGX_IOC_ENCLAVE_CREATE ioctl
> + * @src:	address for the SECS page data
> + */
> +struct sgx_enclave_create  {
> +	__u64	src;
> +};
> +
> +/**
> + * struct sgx_enclave_add_pages - parameter structure for the
> + *                                %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
> + * @src:	start address for the page data
> + * @offset:	starting page offset
> + * @length:	length of the data (multiple of the page size)
> + * @secinfo:	address for the SECINFO data
> + * @flags:	page control flags
> + * @count:	number of bytes added (multiple of the page size)
> + */
> +struct sgx_enclave_add_pages {
> +	__u64	src;
> +	__u64	offset;
> +	__u64	length;
> +	__u64	secinfo;
> +	__u64	flags;
> +	__u64	count;
> +};
> +
> +/**
> + * struct sgx_enclave_init - parameter structure for the
> + *                           %SGX_IOC_ENCLAVE_INIT ioctl
> + * @sigstruct:	address for the SIGSTRUCT data
> + */
> +struct sgx_enclave_init {
> +	__u64 sigstruct;
> +};
> +
> +#endif /* _UAPI_ASM_X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
> index 2dec75916a5e..f8d32da3a67a 100644
> --- a/arch/x86/kernel/cpu/sgx/Makefile
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -1,3 +1,6 @@
>  obj-y += \
> +	driver.o \
> +	encl.o \
> +	ioctl.o \
>  	main.o \
>  	reclaim.o
> diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
> new file mode 100644
> index 000000000000..b4aa7b9f8376
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.c
> @@ -0,0 +1,194 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/acpi.h>
> +#include <linux/miscdevice.h>
> +#include <linux/mman.h>
> +#include <linux/security.h>
> +#include <linux/suspend.h>
> +#include <asm/traps.h>
> +#include "driver.h"
> +#include "encl.h"
> +
> +MODULE_DESCRIPTION("Intel SGX Enclave Driver");
> +MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
> +MODULE_LICENSE("Dual BSD/GPL");
> +
> +u64 sgx_encl_size_max_32;
> +u64 sgx_encl_size_max_64;
> +u32 sgx_misc_reserved_mask;
> +u64 sgx_attributes_reserved_mask;
> +u64 sgx_xfrm_reserved_mask = ~0x3;
> +u32 sgx_xsave_size_tbl[64];
> +
> +static int sgx_open(struct inode *inode, struct file *file)
> +{
> +	struct sgx_encl *encl;
> +	int ret;
> +
> +	encl = kzalloc(sizeof(*encl), GFP_KERNEL);
> +	if (!encl)
> +		return -ENOMEM;
> +
> +	atomic_set(&encl->flags, 0);
> +	kref_init(&encl->refcount);
> +	INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
> +	mutex_init(&encl->lock);
> +	INIT_LIST_HEAD(&encl->mm_list);
> +	spin_lock_init(&encl->mm_lock);
> +
> +	ret = init_srcu_struct(&encl->srcu);
> +	if (ret) {
> +		kfree(encl);
> +		return ret;
> +	}
> +
> +	file->private_data = encl;
> +
> +	return 0;
> +}
> +
> +static int sgx_release(struct inode *inode, struct file *file)
> +{
> +	struct sgx_encl *encl = file->private_data;
> +	struct sgx_encl_mm *encl_mm;
> +
> +	for ( ; ; )  {
> +		spin_lock(&encl->mm_lock);
> +
> +		if (list_empty(&encl->mm_list)) {
> +			encl_mm = NULL;
> +		} else {
> +			encl_mm = list_first_entry(&encl->mm_list,
> +						   struct sgx_encl_mm, list);
> +			list_del_rcu(&encl_mm->list);
> +		}
> +
> +		spin_unlock(&encl->mm_lock);
> +
> +		/* The list is empty, ready to go. */
> +		if (!encl_mm)
> +			break;
> +
> +		synchronize_srcu(&encl->srcu);
> +		mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
> +		kfree(encl_mm);
> +	};
> +
> +	mutex_lock(&encl->lock);
> +	atomic_or(SGX_ENCL_DEAD, &encl->flags);
> +	mutex_unlock(&encl->lock);
> +
> +	kref_put(&encl->refcount, sgx_encl_release);
> +	return 0;
> +}
> +
> +#ifdef CONFIG_COMPAT
> +static long sgx_compat_ioctl(struct file *filep, unsigned int cmd,
> +			      unsigned long arg)
> +{
> +	return sgx_ioctl(filep, cmd, arg);
> +}
> +#endif
> +
> +static int sgx_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> +	struct sgx_encl *encl = file->private_data;
> +	int ret;
> +
> +	ret = sgx_encl_may_map(encl, vma->vm_start, vma->vm_end,
> +			       vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC));
> +	if (ret)
> +		return ret;
> +
> +	ret = sgx_encl_mm_add(encl, vma->vm_mm);
> +	if (ret)
> +		return ret;
> +
> +	vma->vm_ops = &sgx_vm_ops;
> +	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
> +	vma->vm_private_data = encl;
> +
> +	return 0;
> +}
> +
> +static unsigned long sgx_get_unmapped_area(struct file *file,
> +					   unsigned long addr,
> +					   unsigned long len,
> +					   unsigned long pgoff,
> +					   unsigned long flags)
> +{
> +	if (flags & MAP_PRIVATE)
> +		return -EINVAL;
> +
> +	if (flags & MAP_FIXED)
> +		return addr;
> +
> +	return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
> +}
> +
> +static const struct file_operations sgx_encl_fops = {
> +	.owner			= THIS_MODULE,
> +	.open			= sgx_open,
> +	.release		= sgx_release,
> +	.unlocked_ioctl		= sgx_ioctl,
> +#ifdef CONFIG_COMPAT
> +	.compat_ioctl		= sgx_compat_ioctl,
> +#endif
> +	.mmap			= sgx_mmap,
> +	.get_unmapped_area	= sgx_get_unmapped_area,
> +};
> +
> +const struct file_operations sgx_provision_fops = {
> +	.owner			= THIS_MODULE,
> +};
> +
> +static struct miscdevice sgx_dev_enclave = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = "enclave",
> +	.nodename = "sgx/enclave",
> +	.fops = &sgx_encl_fops,
> +};
> +
> +int __init sgx_drv_init(void)
> +{
> +	unsigned int eax, ebx, ecx, edx;
> +	u64 attr_mask, xfrm_mask;
> +	int ret;
> +	int i;
> +
> +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> +		pr_info("The public key MSRs are not writable.\n");
> +		return -ENODEV;
> +	}
> +
> +	cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
> +	sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
> +	sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
> +	sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
> +
> +	cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
> +
> +	attr_mask = (((u64)ebx) << 32) + (u64)eax;
> +	sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
> +
> +	if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
> +		xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
> +
> +		for (i = 2; i < 64; i++) {
> +			cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
> +			if ((1 << i) & xfrm_mask)
> +				sgx_xsave_size_tbl[i] = eax + ebx;
> +		}
> +
> +		sgx_xfrm_reserved_mask = ~xfrm_mask;
> +	}
> +
> +	ret = misc_register(&sgx_dev_enclave);
> +	if (ret) {
> +		pr_err("Creating /dev/sgx/enclave failed with %d.\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
> new file mode 100644
> index 000000000000..e4063923115b
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +#ifndef __ARCH_SGX_DRIVER_H__
> +#define __ARCH_SGX_DRIVER_H__
> +
> +#include <crypto/hash.h>
> +#include <linux/kref.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/rwsem.h>
> +#include <linux/sched.h>
> +#include <linux/workqueue.h>
> +#include <uapi/asm/sgx.h>
> +#include "sgx.h"
> +
> +#define SGX_EINIT_SPIN_COUNT	20
> +#define SGX_EINIT_SLEEP_COUNT	50
> +#define SGX_EINIT_SLEEP_TIME	20
> +
> +extern u64 sgx_encl_size_max_32;
> +extern u64 sgx_encl_size_max_64;
> +extern u32 sgx_misc_reserved_mask;
> +extern u64 sgx_attributes_reserved_mask;
> +extern u64 sgx_xfrm_reserved_mask;
> +extern u32 sgx_xsave_size_tbl[64];
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
> +
> +int sgx_drv_init(void);
> +
> +#endif /* __ARCH_X86_SGX_DRIVER_H__ */
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> new file mode 100644
> index 000000000000..17e44bf8fa56
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -0,0 +1,332 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/lockdep.h>
> +#include <linux/mm.h>
> +#include <linux/mman.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/suspend.h>
> +#include <linux/sched/mm.h>
> +#include "arch.h"
> +#include "encl.h"
> +#include "sgx.h"
> +
> +static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
> +						unsigned long addr)
> +{
> +	struct sgx_encl_page *entry;
> +	unsigned int flags;
> +
> +	/* If process was forked, VMA is still there but vm_private_data is set
> +	 * to NULL.
> +	 */
> +	if (!encl)
> +		return ERR_PTR(-EFAULT);
> +
> +	flags = atomic_read(&encl->flags);
> +
> +	if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
> +		return ERR_PTR(-EFAULT);
> +
> +	entry = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT);
> +	if (!entry)
> +		return ERR_PTR(-EFAULT);
> +
> +	/* Page is already resident in the EPC. */
> +	if (entry->epc_page)
> +		return entry;
> +
> +	return ERR_PTR(-EFAULT);
> +}
> +
> +static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
> +				     struct mm_struct *mm)
> +{
> +	struct sgx_encl_mm *encl_mm =
> +		container_of(mn, struct sgx_encl_mm, mmu_notifier);
> +	struct sgx_encl_mm *tmp = NULL;
> +
> +	/*
> +	 * The enclave itself can remove encl_mm.  Note, objects can't be moved
> +	 * off an RCU protected list, but deletion is ok.
> +	 */
> +	spin_lock(&encl_mm->encl->mm_lock);
> +	list_for_each_entry(tmp, &encl_mm->encl->mm_list, list) {
> +		if (tmp == encl_mm) {
> +			list_del_rcu(&encl_mm->list);
> +			break;
> +		}
> +	}
> +	spin_unlock(&encl_mm->encl->mm_lock);
> +
> +	if (tmp == encl_mm) {
> +		synchronize_srcu(&encl_mm->encl->srcu);
> +		mmu_notifier_put(mn);
> +	}
> +}
> +
> +static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
> +{
> +	struct sgx_encl_mm *encl_mm =
> +		container_of(mn, struct sgx_encl_mm, mmu_notifier);
> +
> +	kfree(encl_mm);
> +}
> +
> +static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
> +	.release		= sgx_mmu_notifier_release,
> +	.free_notifier		= sgx_mmu_notifier_free,
> +};
> +
> +static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
> +					    struct mm_struct *mm)
> +{
> +	struct sgx_encl_mm *encl_mm = NULL;
> +	struct sgx_encl_mm *tmp;
> +	int idx;
> +
> +	idx = srcu_read_lock(&encl->srcu);
> +
> +	list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
> +		if (tmp->mm == mm) {
> +			encl_mm = tmp;
> +			break;
> +		}
> +	}
> +
> +	srcu_read_unlock(&encl->srcu, idx);
> +
> +	return encl_mm;
> +}
> +
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
> +{
> +	struct sgx_encl_mm *encl_mm;
> +	int ret;
> +
> +	/* mm_list can be accessed only by a single thread at a time. */
> +	lockdep_assert_held_write(&mm->mmap_sem);
> +
> +	if (atomic_read(&encl->flags) & SGX_ENCL_DEAD)
> +		return -EINVAL;
> +
> +	/*
> +	 * mm_structs are kept on mm_list until the mm or the enclave dies,
> +	 * i.e. once an mm is off the list, it's gone for good, therefore it's
> +	 * impossible to get a false positive on @mm due to a stale mm_list.
> +	 */
> +	if (sgx_encl_find_mm(encl, mm))
> +		return 0;
> +
> +	encl_mm = kzalloc(sizeof(*encl_mm), GFP_KERNEL);
> +	if (!encl_mm)
> +		return -ENOMEM;
> +
> +	encl_mm->encl = encl;
> +	encl_mm->mm = mm;
> +	encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;
> +
> +	ret = __mmu_notifier_register(&encl_mm->mmu_notifier, mm);
> +	if (ret) {
> +		kfree(encl_mm);
> +		return ret;
> +	}
> +
> +	spin_lock(&encl->mm_lock);
> +	list_add_rcu(&encl_mm->list, &encl->mm_list);
> +	spin_unlock(&encl->mm_lock);
> +
> +	return 0;
> +}
> +
> +static void sgx_vma_open(struct vm_area_struct *vma)
> +{
> +	struct sgx_encl *encl = vma->vm_private_data;
> +
> +	if (!encl)
> +		return;
> +
> +	if (sgx_encl_mm_add(encl, vma->vm_mm))
> +		vma->vm_private_data = NULL;
> +}
> +
> +static unsigned int sgx_vma_fault(struct vm_fault *vmf)
> +{
> +	unsigned long addr = (unsigned long)vmf->address;
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct sgx_encl *encl = vma->vm_private_data;
> +	struct sgx_encl_page *entry;
> +	int ret = VM_FAULT_NOPAGE;
> +	unsigned long pfn;
> +
> +	if (!encl)
> +		return VM_FAULT_SIGBUS;
> +
> +	mutex_lock(&encl->lock);
> +
> +	entry = sgx_encl_load_page(encl, addr);
> +	if (IS_ERR(entry)) {
> +		if (unlikely(PTR_ERR(entry) != -EBUSY))
> +			ret = VM_FAULT_SIGBUS;
> +
> +		goto out;
> +	}
> +
> +	if (!follow_pfn(vma, addr, &pfn))
> +		goto out;
> +
> +	ret = vmf_insert_pfn(vma, addr, PFN_DOWN(entry->epc_page->desc));
> +	if (ret != VM_FAULT_NOPAGE) {
> +		ret = VM_FAULT_SIGBUS;
> +		goto out;
> +	}
> +
> +out:
> +	mutex_unlock(&encl->lock);
> +	return ret;
> +}
> +
> +/**
> + * sgx_encl_may_map() - Check if a requested VMA mapping is allowed
> + * @encl:		an enclave
> + * @start:		lower bound of the address range, inclusive
> + * @end:		upper bound of the address range, exclusive
> + * @vm_prot_bits:	requested protections of the address range
> + *
> + * Iterate through the enclave pages contained within [@start, @end) to verify
> + * the permissions requested by @vm_prot_bits do not exceed that of any enclave
> + * page to be mapped.
> + *
> + * Return:
> + *   0 on success,
> + *   -EACCES if VMA permissions exceed enclave page permissions
> + */
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> +		     unsigned long end, unsigned long vm_prot_bits)
> +{
> +	unsigned long idx, idx_start, idx_end;
> +	struct sgx_encl_page *page;
> +
> +	/*
> +	 * Disallow RIE tasks as their VMA permissions might conflict with the
> +	 * enclave page permissions.
> +	 */
> +	if (!!(current->personality & READ_IMPLIES_EXEC))
> +		return -EACCES;
> +
> +	idx_start = PFN_DOWN(start);
> +	idx_end = PFN_DOWN(end - 1);
> +
> +	for (idx = idx_start; idx <= idx_end; ++idx) {
> +		mutex_lock(&encl->lock);
> +		page = radix_tree_lookup(&encl->page_tree, idx);
> +		mutex_unlock(&encl->lock);
> +
> +		if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> +			return -EACCES;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
> +			    unsigned long end, unsigned long prot)
> +{
> +	return sgx_encl_may_map(vma->vm_private_data, start, end,
> +				calc_vm_prot_bits(prot, 0));
> +}
> +
> +const struct vm_operations_struct sgx_vm_ops = {
> +	.open = sgx_vma_open,
> +	.fault = sgx_vma_fault,
> +	.may_mprotect = sgx_vma_mprotect,
> +};
> +
> +/**
> + * sgx_encl_find - find an enclave
> + * @mm:		mm struct of the current process
> + * @addr:	address in the ELRANGE
> + * @vma:	the resulting VMA
> + *
> + * Find an enclave identified by the given address. Give back a VMA that is
> + * part of the enclave and located in that address. The VMA is given back if it
> + * is a proper enclave VMA even if an &sgx_encl instance does not exist yet
> + * (enclave creation has not been performed).
> + *
> + * Return:
> + *   0 on success,
> + *   -EINVAL if an enclave was not found,
> + *   -ENOENT if the enclave has not been created yet
> + */
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> +		  struct vm_area_struct **vma)
> +{
> +	struct vm_area_struct *result;
> +	struct sgx_encl *encl;
> +
> +	result = find_vma(mm, addr);
> +	if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
> +		return -EINVAL;
> +
> +	encl = result->vm_private_data;
> +	*vma = result;
> +
> +	return encl ? 0 : -ENOENT;
> +}
> +
> +/**
> + * sgx_encl_destroy() - destroy enclave resources
> + * @encl:	an &sgx_encl instance
> + */
> +void sgx_encl_destroy(struct sgx_encl *encl)
> +{
> +	struct sgx_encl_page *entry;
> +	struct radix_tree_iter iter;
> +	void **slot;
> +
> +	atomic_or(SGX_ENCL_DEAD, &encl->flags);
> +
> +	radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
> +		entry = *slot;
> +
> +		if (entry->epc_page) {
> +			sgx_free_page(entry->epc_page);
> +			encl->secs_child_cnt--;
> +			entry->epc_page = NULL;
> +		}
> +
> +		radix_tree_delete(&entry->encl->page_tree,
> +				  PFN_DOWN(entry->desc));
> +		kfree(entry);
> +	}
> +
> +	if (!encl->secs_child_cnt && encl->secs.epc_page) {
> +		sgx_free_page(encl->secs.epc_page);
> +		encl->secs.epc_page = NULL;
> +	}
> +}
> +
> +/**
> + * sgx_encl_release - Destroy an enclave instance
> + * @kref:	address of a kref inside &sgx_encl
> + *
> + * Used together with kref_put(). Frees all the resources associated with the
> + * enclave and the instance itself.
> + */
> +void sgx_encl_release(struct kref *ref)
> +{
> +	struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
> +
> +	sgx_encl_destroy(encl);
> +
> +	if (encl->backing)
> +		fput(encl->backing);
> +
> +	WARN_ON_ONCE(!list_empty(&encl->mm_list));
> +
> +	/* Detect EPC page leak's. */
> +	WARN_ON_ONCE(encl->secs_child_cnt);
> +	WARN_ON_ONCE(encl->secs.epc_page);
> +
> +	kfree(encl);
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
> new file mode 100644
> index 000000000000..1d1bc5d590ee
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.h
> @@ -0,0 +1,87 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +/**
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _X86_ENCL_H
> +#define _X86_ENCL_H
> +
> +#include <linux/cpumask.h>
> +#include <linux/kref.h>
> +#include <linux/list.h>
> +#include <linux/mm_types.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/mutex.h>
> +#include <linux/notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/srcu.h>
> +#include <linux/workqueue.h>
> +#include "sgx.h"
> +
> +/**
> + * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
> + * %SGX_ENCL_PAGE_ADDR_MASK:		Holds the virtual address of the page.
> + *
> + * The page address for SECS is zero and is used by the subsystem to recognize
> + * the SECS page.
> + */
> +enum sgx_encl_page_desc {
> +	/* Bits 11:3 are available when the page is not swapped. */
> +	SGX_ENCL_PAGE_ADDR_MASK		= PAGE_MASK,
> +};
> +
> +#define SGX_ENCL_PAGE_ADDR(page) \
> +	((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
> +
> +struct sgx_encl_page {
> +	unsigned long desc;
> +	unsigned long vm_max_prot_bits;
> +	struct sgx_epc_page *epc_page;
> +	struct sgx_encl *encl;
> +};
> +
> +enum sgx_encl_flags {
> +	SGX_ENCL_CREATED	= BIT(0),
> +	SGX_ENCL_INITIALIZED	= BIT(1),
> +	SGX_ENCL_DEBUG		= BIT(2),
> +	SGX_ENCL_DEAD		= BIT(3),
> +	SGX_ENCL_IOCTL		= BIT(4),
> +};
> +
> +struct sgx_encl_mm {
> +	struct sgx_encl *encl;
> +	struct mm_struct *mm;
> +	struct list_head list;
> +	struct mmu_notifier mmu_notifier;
> +};
> +
> +struct sgx_encl {
> +	atomic_t flags;
> +	u64 secs_attributes;
> +	u64 allowed_attributes;
> +	unsigned int page_cnt;
> +	unsigned int secs_child_cnt;
> +	struct mutex lock;
> +	struct list_head mm_list;
> +	spinlock_t mm_lock;
> +	struct file *backing;
> +	struct kref refcount;
> +	struct srcu_struct srcu;
> +	unsigned long base;
> +	unsigned long size;
> +	unsigned long ssaframesize;
> +	struct radix_tree_root page_tree;
> +	struct sgx_encl_page secs;
> +	cpumask_t cpumask;
> +};
> +
> +extern const struct vm_operations_struct sgx_vm_ops;
> +
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> +		  struct vm_area_struct **vma);
> +void sgx_encl_destroy(struct sgx_encl *encl);
> +void sgx_encl_release(struct kref *ref);
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> +		     unsigned long end, unsigned long vm_prot_bits);
> +
> +#endif /* _X86_ENCL_H */
> diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
> index 376cdedb9a43..f716b4328614 100644
> --- a/arch/x86/kernel/cpu/sgx/encls.h
> +++ b/arch/x86/kernel/cpu/sgx/encls.h
> @@ -186,10 +186,9 @@ static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
>  	return __encls_2(EADD, pginfo, addr);
>  }
>  
> -static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
> -			  void *secs)
> +static inline int __einit(void *sigstruct, void *token, void *secs)
>  {
> -	return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
> +	return __encls_ret_3(EINIT, sigstruct, secs, token);
>  }
>  
>  static inline int __eremove(void *addr)
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> new file mode 100644
> index 000000000000..26d0425d7252
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -0,0 +1,687 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-19 Intel Corporation.
> +
> +#include <asm/mman.h>
> +#include <linux/mman.h>
> +#include <linux/delay.h>
> +#include <linux/file.h>
> +#include <linux/hashtable.h>
> +#include <linux/highmem.h>
> +#include <linux/ratelimit.h>
> +#include <linux/sched/signal.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
> +#include "driver.h"
> +#include "encl.h"
> +#include "encls.h"
> +
> +/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
> +static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
> +
> +static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
> +{
> +	u32 size_max = PAGE_SIZE;
> +	u32 size;
> +	int i;
> +
> +	for (i = 2; i < 64; i++) {
> +		if (!((1 << i) & xfrm))
> +			continue;
> +
> +		size = SGX_SSA_GPRS_SIZE + sgx_xsave_size_tbl[i];
> +		if (miscselect & SGX_MISC_EXINFO)
> +			size += SGX_SSA_MISC_EXINFO_SIZE;
> +
> +		if (size > size_max)
> +			size_max = size;
> +	}
> +
> +	return PFN_UP(size_max);
> +}
> +
> +static int sgx_validate_secs(const struct sgx_secs *secs,
> +			     unsigned long ssaframesize)
> +{
> +	if (secs->size < (2 * PAGE_SIZE) || !is_power_of_2(secs->size))
> +		return -EINVAL;
> +
> +	if (secs->base & (secs->size - 1))
> +		return -EINVAL;
> +
> +	if (secs->miscselect & sgx_misc_reserved_mask ||
> +	    secs->attributes & sgx_attributes_reserved_mask ||
> +	    secs->xfrm & sgx_xfrm_reserved_mask)
> +		return -EINVAL;
> +
> +	if (secs->attributes & SGX_ATTR_MODE64BIT) {
> +		if (secs->size > sgx_encl_size_max_64)
> +			return -EINVAL;
> +	} else if (secs->size > sgx_encl_size_max_32)
> +		return -EINVAL;
> +
> +	if (!(secs->xfrm & XFEATURE_MASK_FP) ||
> +	    !(secs->xfrm & XFEATURE_MASK_SSE) ||
> +	    (((secs->xfrm >> XFEATURE_BNDREGS) & 1) !=
> +	     ((secs->xfrm >> XFEATURE_BNDCSR) & 1)))
> +		return -EINVAL;
> +
> +	if (!secs->ssa_frame_size || ssaframesize > secs->ssa_frame_size)
> +		return -EINVAL;
> +
> +	if (memchr_inv(secs->reserved1, 0, sizeof(secs->reserved1)) ||
> +	    memchr_inv(secs->reserved2, 0, sizeof(secs->reserved2)) ||
> +	    memchr_inv(secs->reserved3, 0, sizeof(secs->reserved3)) ||
> +	    memchr_inv(secs->reserved4, 0, sizeof(secs->reserved4)))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
> +						 unsigned long offset,
> +						 u64 secinfo_flags)
> +{
> +	struct sgx_encl_page *encl_page;
> +	unsigned long prot;
> +
> +	encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
> +	if (!encl_page)
> +		return ERR_PTR(-ENOMEM);
> +
> +	encl_page->desc = encl->base + offset;
> +	encl_page->encl = encl;
> +
> +	prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ)  |
> +	       _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
> +	       _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
> +
> +	/*
> +	 * TCS pages must always RW set for CPU access while the SECINFO
> +	 * permissions are *always* zero - the CPU ignores the user provided
> +	 * values and silently overwrites them with zero permissions.
> +	 */
> +	if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
> +		prot |= PROT_READ | PROT_WRITE;
> +
> +	/* Calculate maximum of the VM flags for the page. */
> +	encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
> +
> +	return encl_page;
> +}
> +
> +static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
> +{
> +	unsigned long encl_size = secs->size + PAGE_SIZE;
> +	struct sgx_epc_page *secs_epc;
> +	unsigned long ssaframesize;
> +	struct sgx_pageinfo pginfo;
> +	struct sgx_secinfo secinfo;
> +	struct file *backing;
> +	long ret;
> +
> +	if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
> +		return -EINVAL;
> +
> +	ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
> +	if (sgx_validate_secs(secs, ssaframesize)) {
> +		pr_debug("invalid SECS\n");
> +		return -EINVAL;
> +	}
> +
> +	backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
> +				   VM_NORESERVE);
> +	if (IS_ERR(backing))
> +		return PTR_ERR(backing);
> +
> +	encl->backing = backing;
> +
> +	secs_epc = sgx_try_alloc_page();
> +	if (IS_ERR(secs_epc)) {
> +		ret = PTR_ERR(secs_epc);
> +		goto err_out_backing;
> +	}
> +
> +	encl->secs.epc_page = secs_epc;
> +
> +	pginfo.addr = 0;
> +	pginfo.contents = (unsigned long)secs;
> +	pginfo.metadata = (unsigned long)&secinfo;
> +	pginfo.secs = 0;
> +	memset(&secinfo, 0, sizeof(secinfo));
> +
> +	ret = __ecreate((void *)&pginfo, sgx_epc_addr(secs_epc));
> +	if (ret) {
> +		pr_debug("ECREATE returned %ld\n", ret);
> +		goto err_out;
> +	}
> +
> +	if (secs->attributes & SGX_ATTR_DEBUG)
> +		atomic_or(SGX_ENCL_DEBUG, &encl->flags);
> +
> +	encl->secs.encl = encl;
> +	encl->secs_attributes = secs->attributes;
> +	encl->allowed_attributes |= SGX_ATTR_ALLOWED_MASK;
> +	encl->base = secs->base;
> +	encl->size = secs->size;
> +	encl->ssaframesize = secs->ssa_frame_size;
> +
> +	/*
> +	 * Set SGX_ENCL_CREATED only after the enclave is fully prepped.  This
> +	 * allows setting and checking enclave creation without having to take
> +	 * encl->lock.
> +	 */
> +	atomic_or(SGX_ENCL_CREATED, &encl->flags);
> +
> +	return 0;
> +
> +err_out:
> +	sgx_free_page(encl->secs.epc_page);
> +	encl->secs.epc_page = NULL;
> +
> +err_out_backing:
> +	fput(encl->backing);
> +	encl->backing = NULL;
> +
> +	return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_create - handler for %SGX_IOC_ENCLAVE_CREATE
> + * @filep:	open file to /dev/sgx
> + * @arg:	userspace pointer to a struct sgx_enclave_create instance
> + *
> + * Allocate kernel data structures for a new enclave and execute ECREATE after
> + * verifying the correctness of the provided SECS.
> + *
> + * Note, enforcement of restricted and disallowed attributes is deferred until
> + * sgx_ioc_enclave_init(), only the architectural correctness of the SECS is
> + * checked by sgx_ioc_enclave_create().
> + *
> + * Return:
> + *   0 on success,
> + *   -errno otherwise
> + */
> +static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
> +{
> +	struct sgx_enclave_create ecreate;
> +	struct page *secs_page;
> +	struct sgx_secs *secs;
> +	int ret;
> +
> +	if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
> +		return -EFAULT;
> +
> +	secs_page = alloc_page(GFP_KERNEL);
> +	if (!secs_page)
> +		return -ENOMEM;
> +
> +	secs = kmap(secs_page);
> +	if (copy_from_user(secs, (void __user *)ecreate.src, sizeof(*secs))) {
> +		ret = -EFAULT;
> +		goto out;
> +	}
> +
> +	ret = sgx_encl_create(encl, secs);
> +
> +out:
> +	kunmap(secs_page);
> +	__free_page(secs_page);
> +	return ret;
> +}
> +
> +static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> +{
> +	u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
> +	u64 pt = secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK;
> +
> +	if (pt != SGX_SECINFO_REG && pt != SGX_SECINFO_TCS)
> +		return -EINVAL;
> +
> +	if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
> +		return -EINVAL;
> +
> +	/*
> +	 * CPU will silently overwrite the permissions as zero, which means
> +	 * that we need to validate it ourselves.
> +	 */
> +	if (pt == SGX_SECINFO_TCS && perm)
> +		return -EINVAL;
> +
> +	if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
> +		return -EINVAL;
> +
> +	if (memchr_inv(secinfo->reserved, 0, sizeof(secinfo->reserved)))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int __sgx_encl_add_page(struct sgx_encl *encl,
> +			       struct sgx_encl_page *encl_page,
> +			       struct sgx_epc_page *epc_page,
> +			       struct sgx_secinfo *secinfo, unsigned long src)
> +{
> +	struct sgx_pageinfo pginfo;
> +	struct vm_area_struct *vma;
> +	struct page *src_page;
> +	int ret;
> +
> +	/* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
> +	if (encl_page->vm_max_prot_bits & VM_EXEC) {
> +		vma = find_vma(current->mm, src);
> +		if (!vma)
> +			return -EFAULT;
> +
> +		if (!(vma->vm_flags & VM_MAYEXEC))
> +			return -EACCES;
> +	}
> +
> +	ret = get_user_pages(src, 1, 0, &src_page, NULL);
> +	if (ret < 1)
> +		return ret;
> +
> +	pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
> +	pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
> +	pginfo.metadata = (unsigned long)secinfo;
> +	pginfo.contents = (unsigned long)kmap_atomic(src_page);
> +
> +	ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
> +
> +	kunmap_atomic((void *)pginfo.contents);
> +	put_page(src_page);
> +
> +	return ret ? -EIO : 0;
> +}
> +
> +static int __sgx_encl_extend(struct sgx_encl *encl,
> +			     struct sgx_epc_page *epc_page)
> +{
> +	int ret;
> +	int i;
> +
> +	for (i = 0; i < 16; i++) {
> +		ret = __eextend(sgx_epc_addr(encl->secs.epc_page),
> +				sgx_epc_addr(epc_page) + (i * 0x100));
> +		if (ret) {
> +			if (encls_failed(ret))
> +				ENCLS_WARN(ret, "EEXTEND");
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
> +			     unsigned long offset, unsigned long length,
> +			     struct sgx_secinfo *secinfo, unsigned long flags)
> +{
> +	struct sgx_encl_page *encl_page;
> +	struct sgx_epc_page *epc_page;
> +	int ret;
> +
> +	encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
> +	if (IS_ERR(encl_page))
> +		return PTR_ERR(encl_page);
> +
> +	epc_page = sgx_try_alloc_page();
> +	if (IS_ERR(epc_page)) {
> +		kfree(encl_page);
> +		return PTR_ERR(epc_page);
> +	}
> +
> +	if (atomic_read(&encl->flags) &
> +	    (SGX_ENCL_INITIALIZED | SGX_ENCL_DEAD)) {
> +		ret = -EFAULT;
> +		goto err_out_free;
> +	}
> +
> +	down_read(&current->mm->mmap_sem);
> +	mutex_lock(&encl->lock);
> +
> +	/*
> +	 * Insert prior to EADD in case of OOM.  EADD modifies MRENCLAVE, i.e.
> +	 * can't be gracefully unwound, while failure on EADD/EXTEND is limited
> +	 * to userspace errors (or kernel/hardware bugs).
> +	 */
> +	ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
> +				encl_page);
> +	if (ret)
> +		goto err_out_unlock;
> +
> +	ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
> +				  src);
> +	if (ret)
> +		goto err_out;
> +
> +	/*
> +	 * Complete the "add" before doing the "extend" so that the "add"
> +	 * isn't in a half-baked state in the extremely unlikely scenario the
> +	 * the enclave will be destroyed in response to EEXTEND failure.
> +	 */
> +	encl_page->encl = encl;
> +	encl_page->epc_page = epc_page;
> +	encl->secs_child_cnt++;
> +
> +	if (flags & SGX_PAGE_MEASURE) {
> +		ret = __sgx_encl_extend(encl, epc_page);
> +		if (ret)
> +			goto err_out;
> +	}
> +
> +	mutex_unlock(&encl->lock);
> +	up_read(&current->mm->mmap_sem);
> +	return ret;
> +
> +err_out:
> +	radix_tree_delete(&encl_page->encl->page_tree,
> +			  PFN_DOWN(encl_page->desc));
> +
> +err_out_unlock:
> +	mutex_unlock(&encl->lock);
> +	up_read(&current->mm->mmap_sem);
> +
> +err_out_free:
> +	sgx_free_page(epc_page);
> +	kfree(encl_page);
> +
> +	/*
> +	 * Destroy enclave on ENCLS failure as this means that EPC has been
> +	 * invalidated.
> +	 */
> +	if (ret == -EIO)
> +		sgx_encl_destroy(encl);
> +
> +	return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
> + * @encl:       pointer to an enclave instance (via ioctl() file pointer)
> + * @arg:	a user pointer to a struct sgx_enclave_add_pages instance
> + *
> + * Add one or more pages to an uninitialized enclave, and optionally extend the
> + * measurement with the contents of the page. The address range of pages must
> + * be contiguous. The SECINFO and measurement mask are applied to all pages.
> + *
> + * A SECINFO for a TCS is required to always contain zero permissions because
> + * CPU silently zeros them. Allowing anything else would cause a mismatch in
> + * the measurement.
> + *
> + * mmap()'s protection bits are capped by the page permissions. For each page
> + * address, the maximum protection bits are computed with the following
> + * heuristics:
> + *
> + * 1. A regular page: PROT_R, PROT_W and PROT_X match the SECINFO permissions.
> + * 2. A TCS page: PROT_R | PROT_W.
> + *
> + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> + * within the given address range.
> + *
> + * If ENCLS opcode fails, that effectively means that EPC has been invalidated.
> + * When this happens the enclave is destroyed and -EIO is returned to the
> + * caller.
> + *
> + * Return:
> + *   0 on success,
> + *   -EACCES if an executable source page is located in a noexec partition,
> + *   -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails
> + *   -errno otherwise
> + */
> +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
> +{
> +	struct sgx_enclave_add_pages addp;
> +	struct sgx_secinfo secinfo;
> +	unsigned long c;
> +	int ret;
> +
> +	if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> +		return -EINVAL;
> +
> +	if (copy_from_user(&addp, arg, sizeof(addp)))
> +		return -EFAULT;
> +
> +	if (!IS_ALIGNED(addp.offset, PAGE_SIZE) ||
> +	    !IS_ALIGNED(addp.src, PAGE_SIZE))
> +		return -EINVAL;
> +
> +	if (!(access_ok(addp.src, PAGE_SIZE)))
> +		return -EFAULT;
> +
> +	if (addp.length & (PAGE_SIZE - 1))
> +		return -EINVAL;
> +
> +	if (addp.offset + addp.length - PAGE_SIZE >= encl->size)
> +		return -EINVAL;
> +
> +	if (copy_from_user(&secinfo, (void __user *)addp.secinfo,
> +			   sizeof(secinfo)))
> +		return -EFAULT;
> +
> +	if (sgx_validate_secinfo(&secinfo))
> +		return -EINVAL;
> +
> +	for (c = 0 ; c < addp.length; c += PAGE_SIZE) {
> +		if (signal_pending(current)) {
> +			ret = -EINTR;
> +			break;
> +		}
> +
> +		if (need_resched())
> +			cond_resched();
> +
> +		ret = sgx_encl_add_page(encl, addp.src + c, addp.offset + c,
> +					addp.length - c, &secinfo, addp.flags);
> +		if (ret)
> +			break;
> +	}
> +
> +	addp.count = c;
> +
> +	if (copy_to_user(arg, &addp, sizeof(addp)))
> +		return -EFAULT;
> +
> +	return ret;
> +}
> +
> +static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
> +			      void *hash)
> +{
> +	SHASH_DESC_ON_STACK(shash, tfm);
> +
> +	shash->tfm = tfm;
> +
> +	return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
> +}
> +
> +static int sgx_get_key_hash(const void *modulus, void *hash)
> +{
> +	struct crypto_shash *tfm;
> +	int ret;
> +
> +	tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
> +	if (IS_ERR(tfm))
> +		return PTR_ERR(tfm);
> +
> +	ret = __sgx_get_key_hash(tfm, modulus, hash);
> +
> +	crypto_free_shash(tfm);
> +	return ret;
> +}
> +
> +static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
> +{
> +	u64 *cache;
> +	int i;
> +
> +	cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
> +	for (i = 0; i < 4; i++) {
> +		if (enforce || (lepubkeyhash[i] != cache[i])) {
> +			wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
> +			cache[i] = lepubkeyhash[i];
> +		}
> +	}
> +}
> +
> +static int sgx_einit(struct sgx_sigstruct *sigstruct, void *token,
> +		     struct sgx_epc_page *secs, u64 *lepubkeyhash)
> +{
> +	int ret;
> +
> +	preempt_disable();
> +	sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
> +	ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> +	if (ret == SGX_INVALID_EINITTOKEN) {
> +		sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
> +		ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> +	}
> +	preempt_enable();
> +	return ret;
> +}
> +
> +static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
> +			 void *token)
> +{
> +	u64 mrsigner[4];
> +	int ret;
> +	int i;
> +	int j;
> +
> +	/* Check that the required attributes have been authorized. */
> +	if (encl->secs_attributes & ~encl->allowed_attributes)
> +		return -EACCES;
> +
> +	ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
> +	if (ret)
> +		return ret;
> +
> +	mutex_lock(&encl->lock);
> +
> +	if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
> +		ret = -EFAULT;
> +		goto err_out;
> +	}
> +
> +	for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
> +		for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
> +			ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
> +					mrsigner);
> +			if (ret == SGX_UNMASKED_EVENT)
> +				continue;
> +			else
> +				break;
> +		}
> +
> +		if (ret != SGX_UNMASKED_EVENT)
> +			break;
> +
> +		msleep_interruptible(SGX_EINIT_SLEEP_TIME);
> +
> +		if (signal_pending(current)) {
> +			ret = -ERESTARTSYS;
> +			goto err_out;
> +		}
> +	}
> +
> +	if (ret & ENCLS_FAULT_FLAG) {
> +		if (encls_failed(ret))
> +			ENCLS_WARN(ret, "EINIT");
> +
> +		sgx_encl_destroy(encl);
> +		ret = -EFAULT;
> +	} else if (ret) {
> +		pr_debug("EINIT returned %d\n", ret);
> +		ret = -EPERM;
> +	} else {
> +		atomic_or(SGX_ENCL_INITIALIZED, &encl->flags);
> +	}
> +
> +err_out:
> +	mutex_unlock(&encl->lock);
> +	return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
> + *
> + * @filep:	open file to /dev/sgx
> + * @arg:	userspace pointer to a struct sgx_enclave_init instance
> + *
> + * Flush any outstanding enqueued EADD operations and perform EINIT.  The
> + * Launch Enclave Public Key Hash MSRs are rewritten as necessary to match
> + * the enclave's MRSIGNER, which is caculated from the provided sigstruct.
> + *
> + * Return:
> + *   0 on success,
> + *   SGX error code on EINIT failure,
> + *   -errno otherwise
> + */
> +static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
> +{
> +	struct sgx_sigstruct *sigstruct;
> +	struct sgx_enclave_init einit;
> +	struct page *initp_page;
> +	void *token;
> +	int ret;
> +
> +	if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> +		return -EINVAL;
> +
> +	if (copy_from_user(&einit, arg, sizeof(einit)))
> +		return -EFAULT;
> +
> +	initp_page = alloc_page(GFP_KERNEL);
> +	if (!initp_page)
> +		return -ENOMEM;
> +
> +	sigstruct = kmap(initp_page);
> +	token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
> +	memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
> +
> +	if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
> +			   sizeof(*sigstruct))) {
> +		ret = -EFAULT;
> +		goto out;
> +	}
> +
> +	ret = sgx_encl_init(encl, sigstruct, token);
> +
> +out:
> +	kunmap(initp_page);
> +	__free_page(initp_page);
> +	return ret;
> +}
> +
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> +{
> +	struct sgx_encl *encl = filep->private_data;
> +	int ret, encl_flags;
> +
> +	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> +	if (encl_flags & SGX_ENCL_IOCTL)
> +		return -EBUSY;
> +
> +	if (encl_flags & SGX_ENCL_DEAD)
> +		return -EFAULT;
> +
> +	switch (cmd) {
> +	case SGX_IOC_ENCLAVE_CREATE:
> +		ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> +		break;
> +	case SGX_IOC_ENCLAVE_ADD_PAGES:
> +		ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> +		break;
> +	case SGX_IOC_ENCLAVE_INIT:
> +		ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> +		break;
> +	default:
> +		ret = -ENOIOCTLCMD;
> +		break;
> +	}
> +
> +	atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> +
> +	return ret;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 60d82e7537c8..842f9abba1c0 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -8,6 +8,7 @@
>  #include <linux/ratelimit.h>
>  #include <linux/sched/signal.h>
>  #include <linux/slab.h>
> +#include "driver.h"
>  #include "encls.h"
>  
>  struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> @@ -193,6 +194,8 @@ static bool __init sgx_page_cache_init(void)
>  
>  static void __init sgx_init(void)
>  {
> +	int ret;
> +
>  	if (!boot_cpu_has(X86_FEATURE_SGX))
>  		return;
>  
> @@ -202,10 +205,17 @@ static void __init sgx_init(void)
>  	if (!sgx_page_reclaimer_init())
>  		goto err_page_cache;
>  
> +	ret = sgx_drv_init();
> +	if (ret)
> +		goto err_kthread;
> +
>  	return;
>  
> +err_kthread:
> +	kthread_stop(ksgxswapd_tsk);
> +
>  err_page_cache:
>  	sgx_page_cache_teardown();
>  }
>  
> -arch_initcall(sgx_init);
> +device_initcall(sgx_init);
> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> index 215371588a25..9e6d3e147aa2 100644
> --- a/arch/x86/kernel/cpu/sgx/reclaim.c
> +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> @@ -10,6 +10,7 @@
>  #include <linux/sched/mm.h>
>  #include <linux/sched/signal.h>
>  #include "encls.h"
> +#include "driver.h"
>  
>  struct task_struct *ksgxswapd_tsk;
>  
> -- 
> 2.25.1
>