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// 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);
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