Re: [PATCH v29 00/20] Intel SGX foundations

[Sean Christopherson]

Adding some Google folks to the party.

On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> Intel(R) 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 enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
> 
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
> 
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
> 
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
> 
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> 
> 	cat /proc/cpuinfo  | grep sgx
> 
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
>   environment of its own, it really isn't a great fit with more "standard"
>   x86 tests.
> 
>   The RSA key is now generated on fly and the whole signing process has
>   been made as part of the enclave loader instead of signing the enclave
>   during the compilation time.
> 
>   Finally, the enclave loader loads now the test enclave directly from its
>   ELF file, which means that ELF file does not need to be coverted as raw
>   binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
>   entries. We hold the write lock for the mm_struct, and dup_mm() can thus
>   deadlock with the page reclaimer, which could hold the lock for the old
>   mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
>   be used to reserve the address range. Now /dev/sgx supports only opaque
>   mappings to the (initialized) enclave data.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
>   from RCX.
> 
> v28:
> * Documented to Documentation/x86/sgx.rst how the kernel manages the
>   enclave ownership.
> * Removed non-LC flow from sgx_einit().
> * Removed struct sgx_einittoken since only the size of the corresponding
>   microarchitectural structure is used in the series ATM.
> 
> v27:
> * Disallow RIE processes to use enclaves as there could a permission
>   conflict between VMA and enclave permissions.
> * In the documentation, replace "grep /proc/cpuinfo" with
>   "grep sgx /proc/cpuinfo".
> 
> v26:
> * Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
>   changed in v25 by mistake.
> * Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
>   again for such a detailed feedback).
> * Added back the MAINTAINERS update commit, which was mistakenly removed
>   in v25.
> * EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
>   CPU does not allow to remove a SECS page before all of its children have
>   been removed, and a child page can be in some other section than the one
>   currently being processed. Thus, removed special SECS processing from
>   sgx_sanitize_page() and instead put sections through it twice. In the
>   2nd round the lists should only contain SECS pages.
> 
> v25:
> * Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
>   fails on executing ENCLS[EADD]. The rollback path executed
>   radix_tree_delete() on the same address twice when this happened.
> * Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
>   a signal is pending.
> * As requested by Borislav, move the CPUID 0x12 features to their own word
>   in cpufeatures.
> * Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
>   was called with an uninitialized pointer when sgx_encl_get_backing()
>   fails.
> * Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
>   has 'groups' for setting up sysfs attributes for the device.
> * Use device_initcall instead of subsys_initcall so that misc_class is
>   initialized before SGX is initialized.
> * Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
>   enclave attributes that we the kernel does not allow it to set instead
>   of -EINVAL.
> * Unless SGX public key MSRs are writable always deny the feature from
>   Linux. Previously this was only denied from driver. How VMs should be
>   supported is not really part of initial patch set, which makes this
>   an obvious choice.
> * Cleaned up and refined documentation to be more approachable.
> 
> v24:
> * Reclaim unmeasured and TCS pages (regression in v23).
> * Replace usages of GFP_HIGHUSER with GFP_KERNEL.
> * Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
>   and use the same rollback (destroy enclave). This can happen when host
>   suspends itself unknowingly to a VM running enclaves. From -EIO the user
>   space can deduce what happened.
> * Have a separate @count in struct sgx_enclave_add_pages to output number
>   of bytes processed instead of overwriting the input parameters for
>   clarity and more importantly that the API provides means for partial
>   processing (@count could be less than @length in success case).
> 
> v23:
> * Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
>   with %SGX_PAGE_MEASURE flag.
> * Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
> * In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
>   (because of OOM) even in legit behaviour and after EBLOCK the reclaiming
>   flow can be only reverted by killing the whole enclave.
> * Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
>   it should have been bit 6 (Table 37-3 in the SDM).
> * Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
>   error code.
> 
> v22:
> * Refined bunch commit messages and added associated SDM references as
>   many of them were too exhausting and some outdated.
> * Alignment checks have been removed from mmap() because it does not define the
>   ELRANGE. VMAs only act as windows to the enclave. The semantics compare
>   somewhat how mmap() works with regular files.
> * We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
>   page aligned so that we can pass the page directly to EADD and do not have
>   to do an extra copy. This was made effectively possible by removing the
>   worker thread for adding pages.
> * The selftest build files have been refined throughout of various glitches
>   and work properly in a cross compilation environment such as BuildRoot.
>   In addition, libcalls fail the build with an assertion in the linker
>   script, if they end up to the enclave binary.
> * CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
>   for anything without having the driver. This could change when KVM support
>   is added.
> * We require zero permissions in SECINFO for TCS pages because the CPU
>   overwrites SECINFO flags with zero permissions and measures the page
>   only after that. Allowing to pass TCS with non-zero permissions would
>   cause mismatching measurement between the one provided in SIGSTRUCT and
>   the one computed by the CPU.
> * Obviously lots of small fixes and clean ups (does make sense to
>   document them all).
> 
> v21:
> * Check on mmap() that the VMA does cover an area that does not have
>   enclave pages. Only mapping with PROT_NONE can do that to reserve
>   initial address space for an enclave.
> * Check om mmap() and mprotect() that the VMA permissions do not
>   surpass the enclave permissions.
> * Remove two refcounts from vma_close(): mm_list and encl->refcount.
>   Enclave refcount is only need for swapper/enclave sync and we can
>   remove mm_list refcount by destroying mm_struct when the process
>   is closed. By not having vm_close() the Linux MM can merge VMAs.
> * Do not naturally align MAP_FIXED address.
> * Numerous small fixes and clean ups.
> * Use SRCU for synchronizing the list of mm_struct's.
> * Move to stack based call convention in the vDSO.
> 
> v20:
> * Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
>   dependency as MMU notifiers are no longer used in the driver.
> * Use mm_users instead of mm_count as refcount for mm_struct as mm_count
>   only protects from deleting mm_struct, not removing its contents.
> * Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
>   of them. They could be in initialized state when the kernel starts
>   because it might be spawned by kexec().
> * Documentation overhaul.
> * Use a device /dev/sgx/provision for delivering the provision token
>   instead of securityfs.
> * Create a reference to the enclave when already when opening
>   /dev/sgx/enclave.  The file is then associated with this enclave only.
>   mmap() can be done at free at any point and always get a reference to
>   the enclave. To summarize the file now represents the enclave.
> 
> v19:
> * Took 3-4 months but in some sense this was more like a rewrite of most
>   of the corners of the source code. If I've forgotten to deal with some
>   feedback, please don't shout me. Make a remark and I will fix it for
>   the next version. Hopefully there won't be this big turnovers anymore.
> * Validate SECS attributes properly against CPUID given attributes and
>   against allowed attributes. SECS attributes are the ones that are
>   enforced whereas SIGSTRUCT attributes tell what is required to run
>   the enclave.
> * Add KSS (Key Sharing Support) to the enclave attributes.
> * Deny MAP_PRIVATE as an enclave is always a shared memory entity.
> * Revert back to shmem backing storage so that it can be easily shared
>   by multiple processes.
> * Split the recognization of an ENCLS leaf failure by using three
>   functions to detect it: encsl_faulted(), encls_returned_code() and
>   sgx_failed(). encls_failed() is only caused by a spurious expections that
>   should never happen. Thus, it is not defined as an inline function in
>   order to easily insert a kprobe to it.
> * Move low-level enclave management routines, page fault handler and page
>   reclaiming routines from driver to the core. These cannot be separated
>   from each other as they are heavily interdependent. The rationale is that
>   the core does not call any code from the driver.
> * Allow the driver to be compiled as a module now that it no code is using
>   its routines and it only uses exported symbols. Now the driver is
>   essentially just a thin ioctl layer.
> * Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
>   add new entries to this list as the process is forked. Each entry has
>   its own refcount because they have a different life-cycle as the enclave
>   does. In effect @tgid and @mm have been removed from struct sgx_encl
>   and we allow forking by removing VM_DONTCOPY from vm flags.
> * Generate a cpu mask in the reclaimer from the cpu mask's of all
>   mm_struct's. This will kick out the hardware threads out of the enclave
>   from multiple processes. It is not a local variable because it would
>   eat too much of the stack space but instead a field in struct
>   sgx_encl.
> * Allow forking i.e. remove VM_DONTCOPY. I did not change the API
>   because the old API scaled to the workload that Andy described. The
>   codebase is now mostly API independent i.e. changing the API is a
>   small task. For me the proper trigger to chanage it is a as concrete
>   as possible workload that cannot be fulfilled. I hope you understand
>   my thinking here. I don't want to change anything w/o proper basis
>   but I'm ready to change anything if there is a proper basis. I do
>   not have any kind of attachment to any particular type of API.
> * Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
>   new vDSO.
> 
> v18:
> * Update the ioctl-number.txt.
> * Move the driver under arch/x86.
> * Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
> * Rename the selftest as test_sgx (previously sgx-selftest).
> * In order to enable process accounting, swap EPC pages and PCMD's to a VMA
>   instead of shmem.
> * Allow only to initialize and run enclaves with a subset of
>   {DEBUG, MODE64BIT} set.
> * Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
>   attributes e.g. PROVISIONKEY.
> 
> v17:
> * Add a simple selftest.
> * Fix a null pointer dereference to section->pages when its
>   allocation fails.
> * Add Sean's description of the exception handling to the documentation.
> 
> v16:
> * Fixed SOB's in the commits that were a bit corrupted in v15.
> * Implemented exceptio handling properly to detect_sgx().
> * Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
> * Updated the documentation to use rst definition lists.
> * Added the missing Documentation/x86/index.rst, which has a link to
>   intel_sgx.rst. Now the SGX and uapi documentation is properly generated
>   with 'make htmldocs'.
> * While enumerating EPC sections, if an undefined section is found, fail
>   the driver initialization instead of continuing the initialization.
> * Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
> * Remove copyright notice from arch/x86/include/asm/sgx.h.
> * Migrated from ioremap_cache() to memremap().
> 
> v15:
> * Split into more digestable size patches.
> * Lots of small fixes and clean ups.
> * Signal a "plain" SIGSEGV on an EPCM violation.
> 
> v14:
> * Change the comment about X86_FEATURE_SGX_LC from âSGX launch
>   configurationâ to âSGX launch controlâ.
> * Move the SGX-related CPU feature flags as part of the Linux defined
>   virtual leaf 8.
> * Add SGX_ prefix to the constants defining the ENCLS leaf functions.
> * Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
> * Refine the long description for CONFIG_INTEL_SGX_CORE.
> * Do not use pr_*_ratelimited()  in the driver. The use of the rate limited
>   versions is legacy cruft from the prototyping phase.
> * Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
>   cycles.
> * Manually prefix with âsgx:â in the core SGX code instead of redefining
>   pr_fmt.
> * Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
>   instead of core because it is a driver requirement.
> * Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
>   default is ânâ.
> * Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
>   the SDM.
> * Allocate struct sgx_epc_page instances one at a time.
> * Use â__iomem void *â pointers for the mapped EPC memory consistently.
> * Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
>   cycles.
> * Call enclave swapping operations directly from the driver instead of
>   calling them .indirectly through struct sgx_epc_page_ops because indirect
>   calls are not required yet as the patch set does not contain the KVM
>   support.
> * Added special signal SEGV_SGXERR to notify about SGX EPCM violation
>   errors.
> 
> v13:
> * Always use SGX_CPUID constant instead of a hardcoded value.
> * Simplified and documented the macros and functions for ENCLS leaves.
> * Enable sgx_free_page() to free active enclave pages on demand
>   in order to allow sgx_invalidate() to delete enclave pages.
>   It no longer performs EREMOVE if a page is in the process of
>   being reclaimed.
> * Use PM notifier per enclave so that we don't have to traverse
>   the global list of active EPC pages to find enclaves.
> * Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
> * Always use ioremap() to map EPC banks as we only support 64-bit kernel.
> * Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
>   to sleep.
> 
> v12:
> * Split to more narrow scoped commits in order to ease the review process and
>   use co-developed-by tag for co-authors of commits instead of listing them in
>   the source files.
> * Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
> * Removed in-kernel LE i.e. this version of the SGX software stack only
>   supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
> * Refined documentation on launching enclaves, swapping and enclave
>   construction.
> * Refined sgx_arch.h to include alignment information for every struct that
>   requires it and removed structs that are not needed without an LE.
> * Got rid of SGX_CPUID.
> * SGX detection now prints log messages about firmware configuration issues.
> 
> v11:
> * Polished ENCLS wrappers with refined exception handling.
> * ksgxswapd was not stopped (regression in v5) in
>   sgx_page_cache_teardown(), which causes a leaked kthread after driver
>   deinitialization.
> * Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
>   invalidated when resuming, which will cause it not function properly
>   anymore.
> * Set EINITTOKEN.VALID to zero for a token that is passed when
>   SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
>   page.
> * Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
>   around the flags field, which causes a #GP. Only flags read is readable.
> * On read access memcpy() call inside sgx_vma_access() had src and dest
>   parameters in wrong order.
> * The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
>   to LE even if âKASAN_SANITIZE := falseâ was set in the makefile.
> * Fixed a regression in the #PF handler. If a page has
>   SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
>   It did not, which caused weird races when trying to change other parts of
>   swapping code.
> * EPC management has been refactored to a flat LRU cache and moved to
>   arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
>   of them. It can now swap from multiple enclaves in the same round.
> * For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
>   when an enclave is already initialized or dead instead of zero.
> 
> v10:
> * Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
>   of the driver.
> * Unset the reserved flag from an enclave page if EDBGRD/WR fails
>   (regression in v6).
> * Close the anon inode when LE is stopped (regression in v9).
> * Update the documentation with a more detailed description of SGX.
> 
> v9:
> * Replaced kernel-LE IPC based on pipes with an anonymous inode.
>   The driver does not require anymore new exports.
> 
> v8:
> * Check that public key MSRs match the LE public key hash in the
>   driver initialization when the MSRs are read-only.
> * Fix the race in VA slot allocation by checking the fullness
>   immediately after succeesful allocation.
> * Fix the race in hash mrsigner calculation between the launch
>   enclave and user enclaves by having a separate lock for hash
>   calculation.
> 
> v7:
> * Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
>   when it should have been masked with ~PAGE_MASK.
> * Fixed a memory leak in sgx_ioc_enclave_create().
> * Simplified swapping code by using a pointer array for a cluster
>   instead of a linked list.
> * Squeezed struct sgx_encl_page to 32 bytes.
> * Fixed deferencing of an RSA key on OpenSSL 1.1.0.
> * Modified TC's CMAC to use kernel AES-NI. Restructured the code
>   a bit in order to better align with kernel conventions.
> 
> v6:
> * Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
> * In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
> * Removed virtualization chapter from the documentation.
> * Changed the default filename for the signing key as signing_key.pem.
> * Reworked EPC management in a way that instead of a linked list of
>   struct sgx_epc_page instances there is an array of integers that
>   encodes address and bank of an EPC page (the same data as 'pa' field
>   earlier). The locking has been moved to the EPC bank level instead
>   of a global lock.
> * Relaxed locking requirements for EPC management. EPC pages can be
>   released back to the EPC bank concurrently.
> * Cleaned up ptrace() code.
> * Refined commit messages for new architectural constants.
> * Sorted includes in every source file.
> * Sorted local variable declarations according to the line length in
>   every function.
> * Style fixes based on Darren's comments to sgx_le.c.
> 
> v5:
> * Described IPC between the Launch Enclave and kernel in the commit messages.
> * Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
>   versions except those that exist in the imported TinyCrypt code.
> * Fixed spelling mistakes in the documentation.
> * Forgot to check the return value of sgx_drv_subsys_init().
> * Encapsulated properly page cache init and teardown.
> * Collect epc pages to a temp list in sgx_add_epc_bank
> * Removed SGX_ENCLAVE_INIT_ARCH constant.
> 
> v4:
> * Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
> * Removed __exit annotation from sgx_drv_subsys_exit().
> * Fixed a leak of a backing page in sgx_process_add_page_req() in the
>   case when vm_insert_pfn() fails.
> * Removed unused symbol exports for sgx_page_cache.c.
> * Updated sgx_alloc_page() to require encl parameter and documented the
>   behavior (Sean Christopherson).
> * Refactored a more lean API for sgx_encl_find() and documented the behavior.
> * Moved #PF handler to sgx_fault.c.
> * Replaced subsys_system_register() with plain bus_register().
> * Retry EINIT 2nd time only if MSRs are not locked.
> 
> v3:
> * Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
> * Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
> * Use unused bits in epc_page->pa to store the bank number.
> * Removed #ifdef for WQ_NONREENTRANT.
> * If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
> * Added --remove-section=.got.plt to objcopy flags in order to prevent a
>   dummy .got.plt, which will cause an inconsistent size for the LE.
> * Documented sgx_encl_* functions.
> * Added remark about AES implementation used inside the LE.
> * Removed redundant sgx_sys_exit() from le/main.c.
> * Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
> * Validate miscselect in sgx_encl_create().
> * Fixed SSA frame size calculation to take the misc region into account.
> * Implemented consistent exception handling to __encls() and __encls_ret().
> * Implemented a proper device model in order to allow sysfs attributes
>   and in-kernel API.
> * Cleaned up various "find enclave" implementations to the unified
>   sgx_encl_find().
> * Validate that vm_pgoff is zero.
> * Discard backing pages with shmem_truncate_range() after EADD.
> * Added missing EEXTEND operations to LE signing and launch.
> * Fixed SSA size for GPRS region from 168 to 184 bytes.
> * Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
> * Check that TCS addresses are in ELRANGE and not just page aligned.
> * Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
> * Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.
> 
> v2:
> * get_rand_uint32() changed the value of the pointer instead of value
>   where it is pointing at.
> * Launch enclave incorrectly used sigstruct attributes-field instead of
>   enclave attributes-field.
> * Removed unused struct sgx_add_page_req from sgx_ioctl.c
> * Removed unused sgx_has_sgx2.
> * Updated arch/x86/include/asm/sgx.h so that it provides stub
>   implementations when sgx in not enabled.
> * Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
> * return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
> * removed unused global sgx_nr_pids
> * moved sgx_encl_release to sgx_encl.c
> * return -ERESTARTSYS instead of -EINTR in sgx_encl_init()
> 
> Jarkko Sakkinen (10):
>   x86/sgx: Update MAINTAINERS
>   x86/sgx: Add SGX microarchitectural data structures
>   x86/sgx: Add wrappers for ENCLS leaf functions
>   x86/sgx: Add functions to allocate and free EPC pages
>   x86/sgx: Linux Enclave Driver
>   x86/sgx: Add provisioning
>   x86/sgx: Add a page reclaimer
>   x86/sgx: ptrace() support for the SGX driver
>   selftests/x86: Add a selftest for SGX
>   docs: x86/sgx: Document SGX micro architecture and kernel internals
> 
> Sean Christopherson (10):
>   x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
>   x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
>   x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
>   x86/cpu/intel: Detect SGX support
>   x86/sgx: Enumerate and track EPC sections
>   mm: Introduce vm_ops->may_mprotect()
>   x86/vdso: Add support for exception fixup in vDSO functions
>   x86/fault: Add helper function to sanitize error code
>   x86/traps: Attempt to fixup exceptions in vDSO before signaling
>   x86/vdso: Implement a vDSO for Intel SGX enclave call
> 
>  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>  Documentation/x86/index.rst                   |   1 +
>  Documentation/x86/sgx.rst                     | 206 +++++
>  MAINTAINERS                                   |  11 +
>  arch/x86/Kconfig                              |  14 +
>  arch/x86/entry/vdso/Makefile                  |   8 +-
>  arch/x86/entry/vdso/extable.c                 |  46 +
>  arch/x86/entry/vdso/extable.h                 |  29 +
>  arch/x86/entry/vdso/vdso-layout.lds.S         |   9 +-
>  arch/x86/entry/vdso/vdso.lds.S                |   1 +
>  arch/x86/entry/vdso/vdso2c.h                  |  58 +-
>  arch/x86/entry/vdso/vsgx_enter_enclave.S      | 131 +++
>  arch/x86/include/asm/cpufeature.h             |   5 +-
>  arch/x86/include/asm/cpufeatures.h            |   8 +-
>  arch/x86/include/asm/disabled-features.h      |  18 +-
>  arch/x86/include/asm/enclu.h                  |   8 +
>  arch/x86/include/asm/msr-index.h              |   8 +
>  arch/x86/include/asm/required-features.h      |   2 +-
>  arch/x86/include/asm/traps.h                  |   1 +
>  arch/x86/include/asm/vdso.h                   |   5 +
>  arch/x86/include/uapi/asm/sgx.h               | 175 ++++
>  arch/x86/kernel/cpu/Makefile                  |   1 +
>  arch/x86/kernel/cpu/common.c                  |   4 +
>  arch/x86/kernel/cpu/feat_ctl.c                |  32 +-
>  arch/x86/kernel/cpu/sgx/Makefile              |   6 +
>  arch/x86/kernel/cpu/sgx/arch.h                | 343 ++++++++
>  arch/x86/kernel/cpu/sgx/driver.c              | 209 +++++
>  arch/x86/kernel/cpu/sgx/driver.h              |  32 +
>  arch/x86/kernel/cpu/sgx/encl.c                | 756 +++++++++++++++++
>  arch/x86/kernel/cpu/sgx/encl.h                | 128 +++
>  arch/x86/kernel/cpu/sgx/encls.h               | 238 ++++++
>  arch/x86/kernel/cpu/sgx/ioctl.c               | 800 ++++++++++++++++++
>  arch/x86/kernel/cpu/sgx/main.c                | 280 ++++++
>  arch/x86/kernel/cpu/sgx/reclaim.c             | 471 +++++++++++
>  arch/x86/kernel/cpu/sgx/sgx.h                 | 108 +++
>  arch/x86/kernel/traps.c                       |  14 +
>  arch/x86/mm/fault.c                           |  45 +-
>  include/linux/mm.h                            |   2 +
>  mm/mprotect.c                                 |  14 +-
>  tools/arch/x86/include/asm/cpufeatures.h      |   7 +-
>  tools/testing/selftests/Makefile              |   1 +
>  tools/testing/selftests/sgx/.gitignore        |   2 +
>  tools/testing/selftests/sgx/Makefile          |  53 ++
>  tools/testing/selftests/sgx/call.S            |  54 ++
>  tools/testing/selftests/sgx/defines.h         |  21 +
>  tools/testing/selftests/sgx/load.c            | 282 ++++++
>  tools/testing/selftests/sgx/main.c            | 199 +++++
>  tools/testing/selftests/sgx/main.h            |  38 +
>  tools/testing/selftests/sgx/sigstruct.c       | 395 +++++++++
>  tools/testing/selftests/sgx/test_encl.c       |  20 +
>  tools/testing/selftests/sgx/test_encl.lds     |  40 +
>  .../selftests/sgx/test_encl_bootstrap.S       |  89 ++
>  52 files changed, 5398 insertions(+), 31 deletions(-)
>  create mode 100644 Documentation/x86/sgx.rst
>  create mode 100644 arch/x86/entry/vdso/extable.c
>  create mode 100644 arch/x86/entry/vdso/extable.h
>  create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
>  create mode 100644 arch/x86/include/asm/enclu.h
>  create mode 100644 arch/x86/include/uapi/asm/sgx.h
>  create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
>  create mode 100644 arch/x86/kernel/cpu/sgx/arch.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/encls.h
>  create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
>  create mode 100644 arch/x86/kernel/cpu/sgx/main.c
>  create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
>  create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
>  create mode 100644 tools/testing/selftests/sgx/.gitignore
>  create mode 100644 tools/testing/selftests/sgx/Makefile
>  create mode 100644 tools/testing/selftests/sgx/call.S
>  create mode 100644 tools/testing/selftests/sgx/defines.h
>  create mode 100644 tools/testing/selftests/sgx/load.c
>  create mode 100644 tools/testing/selftests/sgx/main.c
>  create mode 100644 tools/testing/selftests/sgx/main.h
>  create mode 100644 tools/testing/selftests/sgx/sigstruct.c
>  create mode 100644 tools/testing/selftests/sgx/test_encl.c
>  create mode 100644 tools/testing/selftests/sgx/test_encl.lds
>  create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
> 
> -- 
> 2.25.1
>