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- /* Copyright (C) 2014 Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS is free software: you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License
- as published by the Free Software Foundation, either version 3 of the
- License, or (at your option) any later version.
- Graphene Library OS is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /*
- * db_misc.c
- *
- * This file contains APIs for miscellaneous use.
- */
- #include <asm/fcntl.h>
- #include <linux/time.h>
- #include "api.h"
- #include "pal.h"
- #include "pal_debug.h"
- #include "pal_defs.h"
- #include "pal_error.h"
- #include "pal_internal.h"
- #include "pal_linux.h"
- #include "pal_linux_defs.h"
- #include "pal_security.h"
- #include "sgx_api.h"
- unsigned long _DkSystemTimeQuery(void) {
- unsigned long microsec;
- int ret = ocall_gettime(µsec);
- if (ret)
- return -PAL_ERROR_DENIED;
- return microsec;
- }
- size_t _DkRandomBitsRead(void* buffer, size_t size) {
- uint32_t rand;
- for (size_t i = 0; i < size; i += sizeof(rand)) {
- rand = rdrand();
- memcpy(buffer + i, &rand, MIN(sizeof(rand), size - i));
- }
- return 0;
- }
- int _DkInstructionCacheFlush(const void* addr, int size) {
- __UNUSED(addr);
- __UNUSED(size);
- return -PAL_ERROR_NOTIMPLEMENTED;
- }
- int _DkSegmentRegisterSet(int reg, const void* addr) {
- /* GS is internally used, denied any access to it */
- if (reg != PAL_SEGMENT_FS)
- return -PAL_ERROR_DENIED;
- SET_ENCLAVE_TLS(fsbase, (void*)addr);
- wrfsbase((uint64_t)addr);
- return 0;
- }
- int _DkSegmentRegisterGet(int reg, void** addr) {
- /* GS is internally used, denied any access to it */
- if (reg != PAL_SEGMENT_FS)
- return -PAL_ERROR_DENIED;
- *addr = (void*)GET_ENCLAVE_TLS(fsbase);
- return 0;
- }
- #define CPUID_CACHE_SIZE 64
- #define CPUID_CACHE_INVALID ((unsigned int)-1)
- static PAL_LOCK cpuid_cache_lock = LOCK_INIT;
- static struct pal_cpuid {
- unsigned int recently;
- unsigned int leaf, subleaf;
- unsigned int values[4];
- } pal_cpuid_cache[CPUID_CACHE_SIZE];
- static int pal_cpuid_cache_top = 0;
- static unsigned int pal_cpuid_clock = 0;
- int get_cpuid_from_cache(unsigned int leaf, unsigned int subleaf, unsigned int values[4]) {
- _DkInternalLock(&cpuid_cache_lock);
- for (int i = 0; i < pal_cpuid_cache_top; i++)
- if (pal_cpuid_cache[i].leaf == leaf && pal_cpuid_cache[i].subleaf == subleaf) {
- values[0] = pal_cpuid_cache[i].values[0];
- values[1] = pal_cpuid_cache[i].values[1];
- values[2] = pal_cpuid_cache[i].values[2];
- values[3] = pal_cpuid_cache[i].values[3];
- pal_cpuid_cache[i].recently = ++pal_cpuid_clock;
- _DkInternalUnlock(&cpuid_cache_lock);
- return 0;
- }
- _DkInternalUnlock(&cpuid_cache_lock);
- return -PAL_ERROR_DENIED;
- }
- void add_cpuid_to_cache(unsigned int leaf, unsigned int subleaf, unsigned int values[4]) {
- struct pal_cpuid* chosen;
- _DkInternalLock(&cpuid_cache_lock);
- if (pal_cpuid_cache_top < CPUID_CACHE_SIZE) {
- for (int i = 0; i < pal_cpuid_cache_top; i++)
- if (pal_cpuid_cache[i].leaf == leaf && pal_cpuid_cache[i].subleaf == subleaf) {
- _DkInternalUnlock(&cpuid_cache_lock);
- return;
- }
- chosen = &pal_cpuid_cache[pal_cpuid_cache_top++];
- } else {
- unsigned int oldest_clock = pal_cpuid_cache[0].recently;
- chosen = &pal_cpuid_cache[0];
- if (pal_cpuid_cache[0].leaf == leaf && pal_cpuid_cache[0].subleaf == subleaf) {
- _DkInternalUnlock(&cpuid_cache_lock);
- return;
- }
- for (int i = 1; i < pal_cpuid_cache_top; i++) {
- if (pal_cpuid_cache[i].leaf == leaf && pal_cpuid_cache[i].subleaf == subleaf) {
- _DkInternalUnlock(&cpuid_cache_lock);
- return;
- }
- if (pal_cpuid_cache[i].recently > oldest_clock) {
- chosen = &pal_cpuid_cache[i];
- oldest_clock = pal_cpuid_cache[i].recently;
- }
- }
- }
- chosen->leaf = leaf;
- chosen->subleaf = subleaf;
- chosen->values[0] = values[0];
- chosen->values[1] = values[1];
- chosen->values[2] = values[2];
- chosen->values[3] = values[3];
- chosen->recently = ++pal_cpuid_clock;
- _DkInternalUnlock(&cpuid_cache_lock);
- }
- static inline uint32_t extension_enabled(uint32_t xfrm, uint32_t bit_idx) {
- uint32_t feature_bit = 1U << bit_idx;
- return xfrm & feature_bit;
- }
- static __sgx_mem_aligned sgx_report_t report;
- static __sgx_mem_aligned sgx_target_info_t target_info;
- static __sgx_mem_aligned sgx_report_data_t report_data;
- /**
- * Initialize the data structures used for CPUID emulation.
- */
- void init_cpuid(void) {
- memset(&report, 0, sizeof(report));
- memset(&target_info, 0, sizeof(target_info));
- memset(&report_data, 0, sizeof(report_data));
- sgx_report(&target_info, &report_data, &report);
- }
- /**
- * Sanity check untrusted CPUID inputs.
- *
- * The basic idea is that there are only a handful of extensions and we know the size needed to
- * store each extension's state. Use this to sanitize host's untrusted cpuid output. We also know
- * through xfrm what extensions are enabled inside the enclave.
- */
- static void sanity_check_cpuid(uint32_t leaf, uint32_t subleaf, uint32_t values[4]) {
- uint64_t xfrm = report.body.attributes.xfrm;
- enum cpu_extension {
- x87 = 0, SSE, AVX, MPX_1, MPX_2, AVX512_1, AVX512_2, AVX512_3, PKRU = 9 };
- const uint32_t extension_sizes_bytes[] =
- { [AVX] = 256, [MPX_1] = 64, [MPX_2] = 64, [AVX512_1] = 64, [AVX512_2] = 512,
- [AVX512_3] = 1024, [PKRU] = 8};
- /* Note that AVX offset is 576 bytes and MPX_1 starts at 960. The AVX state size is 256, leaving
- * 128 bytes unaccounted for. */
- const uint32_t extension_offset_bytes[] =
- { [AVX] = 576, [MPX_1] = 960, [MPX_2] = 1024, [AVX512_1] = 1088, [AVX512_2] = 1152,
- [AVX512_3] = 1664, [PKRU] = 2688};
- enum register_index {
- EAX = 0, EBX, ECX, EDX
- };
- const uint32_t EXTENDED_STATE_LEAF = 0xd;
- if (leaf == EXTENDED_STATE_LEAF) {
- switch (subleaf) {
- case 0x0:
- /* From the SDM: "EDX:EAX is a bitmap of all the user state components that can be
- * managed using the XSAVE feature set. A bit can be set in XCR0 if and only if the
- * corresponding bit is set in this bitmap. Every processor that supports the XSAVE
- * feature set will set EAX[0] (x87 state) and EAX[1] (SSE state)."
- *
- * On EENTER/ERESUME, the system installs xfrm into XCR0. Hence, we return xfrm here in
- * EAX.
- */
- values[EAX] = xfrm;
- /* From the SDM: "EBX enumerates the size (in bytes) required by the XSAVE instruction
- * for an XSAVE area containing all the user state components corresponding to bits
- * currently set in XCR0."
- */
- uint32_t xsave_size = 0;
- /* Start from AVX since x87 and SSE are always captured using XSAVE. Also, x87 and SSE
- * state size is implicitly included in the extension's offset, e.g., AVX's offset is
- * 576 which includes x87 and SSE state as well as the XSAVE header. */
- for (int i = AVX; i <= PKRU; i++) {
- if (extension_enabled(xfrm, i)) {
- xsave_size = extension_offset_bytes[i] + extension_sizes_bytes[i];
- }
- }
- values[EBX] = xsave_size;
- /* From the SDM: "ECX enumerates the size (in bytes) required by the XSAVE instruction
- * for an XSAVE area containing all the user state components supported by this
- * processor."
- *
- * We are assuming here that inside the enclave, ECX and EBX for leaf 0xD and subleaf
- * 0x1 should always be identical, while outside they can potentially be
- * different. Also, outside of SGX EBX can change at runtime, while ECX is a static
- * property.
- */
- values[ECX] = values[EBX];
- values[EDX] = 0;
- break;
- case 0x1: {
- const uint32_t xsave_legacy_size = 512;
- const uint32_t xsave_header = 64;
- uint32_t save_size_bytes = xsave_legacy_size + xsave_header;
- /* Start with AVX, since x87 and SSE state is already included when initializing
- * `save_size_bytes`. */
- for (int i = AVX; i <= PKRU; i++) {
- if (extension_enabled(xfrm, i)) {
- save_size_bytes += extension_sizes_bytes[i];
- }
- }
- /* EBX reports the actual size occupied by those extensions irrespective of their
- * offsets within the xsave area.
- */
- values[EBX] = save_size_bytes;
- break;
- }
- case AVX:
- case MPX_1:
- case MPX_2:
- case AVX512_1:
- case AVX512_2:
- case AVX512_3:
- case PKRU:
- if (extension_enabled(xfrm, subleaf)) {
- if (values[EAX] != extension_sizes_bytes[subleaf]) {
- SGX_DBG(DBG_E, "Unexpected value in host CPUID. Exiting...\n");
- _DkProcessExit(1);
- }
- } else {
- if (values[EAX] != 0) {
- SGX_DBG(DBG_E, "Unexpected value in host CPUID. Exiting...\n");
- _DkProcessExit(1);
- }
- }
- break;
- }
- }
- }
- int _DkCpuIdRetrieve(unsigned int leaf, unsigned int subleaf, unsigned int values[4]) {
- if (!get_cpuid_from_cache(leaf, subleaf, values))
- return 0;
- if (IS_ERR(ocall_cpuid(leaf, subleaf, values)))
- return -PAL_ERROR_DENIED;
- sanity_check_cpuid(leaf, subleaf, values);
- add_cpuid_to_cache(leaf, subleaf, values);
- return 0;
- }
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