diff options
| -rw-r--r-- | arch/x86/Kconfig | 17 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/sgx/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/sgx/main.c | 190 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/sgx/sgx.h | 60 |
5 files changed, 270 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f6946b81f74a..618d1aabccb8 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1930,6 +1930,23 @@ config X86_INTEL_TSX_MODE_AUTO side channel attacks- equals the tsx=auto command line parameter. endchoice +config X86_SGX + bool "Software Guard eXtensions (SGX)" + depends on X86_64 && CPU_SUP_INTEL + depends on CRYPTO=y + depends on CRYPTO_SHA256=y + select SRCU + select MMU_NOTIFIER + help + Intel(R) 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, referred to as enclaves. An enclave's private memory can + only be accessed by code running within the enclave. Accesses from + outside the enclave, including other enclaves, are disallowed by + hardware. + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 93792b457b81..637b499450d1 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -48,6 +48,7 @@ obj-$(CONFIG_X86_MCE) += mce/ obj-$(CONFIG_MTRR) += mtrr/ obj-$(CONFIG_MICROCODE) += microcode/ obj-$(CONFIG_X86_CPU_RESCTRL) += resctrl/ +obj-$(CONFIG_X86_SGX) += sgx/ obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile new file mode 100644 index 000000000000..79510ce01b3b --- /dev/null +++ b/arch/x86/kernel/cpu/sgx/Makefile @@ -0,0 +1,2 @@ +obj-y += \ + main.o diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c new file mode 100644 index 000000000000..187a237eec38 --- /dev/null +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2016-20 Intel Corporation. */ + +#include <linux/freezer.h> +#include <linux/highmem.h> +#include <linux/kthread.h> +#include <linux/pagemap.h> +#include <linux/ratelimit.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/slab.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; + +/* + * Reset dirty EPC pages to uninitialized state. Laundry can be left with SECS + * pages whose child pages blocked EREMOVE. + */ +static void sgx_sanitize_section(struct sgx_epc_section *section) +{ + struct sgx_epc_page *page; + LIST_HEAD(dirty); + int ret; + + while (!list_empty(§ion->laundry_list)) { + if (kthread_should_stop()) + return; + + spin_lock(§ion->lock); + + page = list_first_entry(§ion->laundry_list, + struct sgx_epc_page, list); + + ret = __eremove(sgx_get_epc_virt_addr(page)); + if (!ret) + list_move(&page->list, §ion->page_list); + else + list_move_tail(&page->list, &dirty); + + spin_unlock(§ion->lock); + + cond_resched(); + } + + list_splice(&dirty, §ion->laundry_list); +} + +static int ksgxd(void *p) +{ + int i; + + set_freezable(); + + /* + * Sanitize pages in order to recover from kexec(). The 2nd pass is + * required for SECS pages, whose child pages blocked EREMOVE. + */ + for (i = 0; i < sgx_nr_epc_sections; i++) + sgx_sanitize_section(&sgx_epc_sections[i]); + + for (i = 0; i < sgx_nr_epc_sections; i++) { + sgx_sanitize_section(&sgx_epc_sections[i]); + + /* Should never happen. */ + if (!list_empty(&sgx_epc_sections[i].laundry_list)) + WARN(1, "EPC section %d has unsanitized pages.\n", i); + } + + 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 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; + spin_lock_init(§ion->lock); + INIT_LIST_HEAD(§ion->page_list); + INIT_LIST_HEAD(§ion->laundry_list); + + for (i = 0; i < nr_pages; i++) { + section->pages[i].section = index; + list_add_tail(§ion->pages[i].list, §ion->laundry_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 i; + + 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; + } + + sgx_nr_epc_sections++; + } + + if (!sgx_nr_epc_sections) { + pr_err("There are zero EPC sections.\n"); + return false; + } + + return true; +} + +static void __init sgx_init(void) +{ + int i; + + if (!boot_cpu_has(X86_FEATURE_SGX)) + return; + + if (!sgx_page_cache_init()) + return; + + if (!sgx_page_reclaimer_init()) + goto err_page_cache; + + return; + +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); + } +} + +device_initcall(sgx_init); diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h new file mode 100644 index 000000000000..02afa84dd8fd --- /dev/null +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _X86_SGX_H +#define _X86_SGX_H + +#include <linux/bitops.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/rwsem.h> +#include <linux/types.h> +#include <asm/asm.h> +#include "arch.h" + +#undef pr_fmt +#define pr_fmt(fmt) "sgx: " fmt + +#define SGX_MAX_EPC_SECTIONS 8 + +struct sgx_epc_page { + unsigned int section; + struct list_head list; +}; + +/* + * The firmware can define multiple chunks of EPC to the different areas of the + * physical memory e.g. for memory areas of the each node. This structure is + * used to store EPC pages for one EPC section and virtual memory area where + * the pages have been mapped. + */ +struct sgx_epc_section { + unsigned long phys_addr; + void *virt_addr; + struct list_head page_list; + struct list_head laundry_list; + struct sgx_epc_page *pages; + spinlock_t lock; +}; + +extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS]; + +static inline unsigned long sgx_get_epc_phys_addr(struct sgx_epc_page *page) +{ + struct sgx_epc_section *section = &sgx_epc_sections[page->section]; + unsigned long index; + + index = ((unsigned long)page - (unsigned long)section->pages) / sizeof(*page); + + return section->phys_addr + index * PAGE_SIZE; +} + +static inline void *sgx_get_epc_virt_addr(struct sgx_epc_page *page) +{ + struct sgx_epc_section *section = &sgx_epc_sections[page->section]; + unsigned long index; + + index = ((unsigned long)page - (unsigned long)section->pages) / sizeof(*page); + + return section->virt_addr + index * PAGE_SIZE; +} + +#endif /* _X86_SGX_H */ |