Contributors: 48
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Matt Fleming |
552 |
26.89% |
16 |
17.98% |
| Jan Kiszka |
356 |
17.34% |
1 |
1.12% |
| Saurabh Tangri |
267 |
13.01% |
1 |
1.12% |
| Sai Praneeth |
196 |
9.55% |
7 |
7.87% |
| Matthew Garrett |
163 |
7.94% |
5 |
5.62% |
| Ard Biesheuvel |
69 |
3.36% |
6 |
6.74% |
| Andrew Lutomirski |
63 |
3.07% |
2 |
2.25% |
| Dan J Williams |
53 |
2.58% |
2 |
2.25% |
| Huang Ying |
46 |
2.24% |
1 |
1.12% |
| Mike Rapoport |
33 |
1.61% |
2 |
2.25% |
| Richard Weinberger |
29 |
1.41% |
2 |
2.25% |
| Dave Young |
26 |
1.27% |
3 |
3.37% |
| Borislav Petkov |
19 |
0.93% |
1 |
1.12% |
| Maarten Lankhorst |
19 |
0.93% |
1 |
1.12% |
| Paul Jackson |
15 |
0.73% |
1 |
1.12% |
| Ben Hutchings |
14 |
0.68% |
1 |
1.12% |
| Anisse Astier |
12 |
0.58% |
1 |
1.12% |
| Lukas Wunner |
10 |
0.49% |
1 |
1.12% |
| Rob Bradford |
9 |
0.44% |
1 |
1.12% |
| Tom Lendacky |
9 |
0.44% |
1 |
1.12% |
| Andi Kleen |
8 |
0.39% |
1 |
1.12% |
| Sergey Vlasov |
7 |
0.34% |
1 |
1.12% |
| Thomas Gleixner |
6 |
0.29% |
2 |
2.25% |
| Juergen Gross |
6 |
0.29% |
1 |
1.12% |
| Ingo Molnar |
6 |
0.29% |
5 |
5.62% |
| Andrew Morton |
5 |
0.24% |
1 |
1.12% |
| Zachary Amsden |
5 |
0.24% |
1 |
1.12% |
| Leif Lindholm |
4 |
0.19% |
1 |
1.12% |
| Josh Boyer |
4 |
0.19% |
1 |
1.12% |
| Tony Luck |
4 |
0.19% |
1 |
1.12% |
| Nicolai Stange |
4 |
0.19% |
1 |
1.12% |
| Mark Salter |
3 |
0.15% |
1 |
1.12% |
| Alex Thorlton |
3 |
0.15% |
1 |
1.12% |
| Sean Christopherson |
3 |
0.15% |
1 |
1.12% |
| Yinghai Lu |
3 |
0.15% |
1 |
1.12% |
| David Howells |
3 |
0.15% |
1 |
1.12% |
| Alexander Duyck |
2 |
0.10% |
1 |
1.12% |
| Hans de Goede |
2 |
0.10% |
1 |
1.12% |
| Madper Xie |
2 |
0.10% |
1 |
1.12% |
| Suresh B. Siddha |
2 |
0.10% |
1 |
1.12% |
| Chen Yu |
2 |
0.10% |
1 |
1.12% |
| Josh Triplett |
2 |
0.10% |
1 |
1.12% |
| Anders Roxell |
2 |
0.10% |
1 |
1.12% |
| Jia-Ju Bai |
1 |
0.05% |
1 |
1.12% |
| Linus Torvalds (pre-git) |
1 |
0.05% |
1 |
1.12% |
| Tejun Heo |
1 |
0.05% |
1 |
1.12% |
| Rusty Russell |
1 |
0.05% |
1 |
1.12% |
| Andy Whitcroft |
1 |
0.05% |
1 |
1.12% |
| Total |
2053 |
|
89 |
|
// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "efi: " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/efi.h>
#include <linux/slab.h>
#include <linux/memblock.h>
#include <linux/acpi.h>
#include <linux/dmi.h>
#include <asm/e820/api.h>
#include <asm/efi.h>
#include <asm/uv/uv.h>
#include <asm/cpu_device_id.h>
#include <asm/realmode.h>
#include <asm/reboot.h>
#define EFI_MIN_RESERVE 5120
#define EFI_DUMMY_GUID \
EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
#define QUARK_CSH_SIGNATURE 0x5f435348 /* _CSH */
#define QUARK_SECURITY_HEADER_SIZE 0x400
/*
* Header prepended to the standard EFI capsule on Quark systems the are based
* on Intel firmware BSP.
* @csh_signature: Unique identifier to sanity check signed module
* presence ("_CSH").
* @version: Current version of CSH used. Should be one for Quark A0.
* @modulesize: Size of the entire module including the module header
* and payload.
* @security_version_number_index: Index of SVN to use for validation of signed
* module.
* @security_version_number: Used to prevent against roll back of modules.
* @rsvd_module_id: Currently unused for Clanton (Quark).
* @rsvd_module_vendor: Vendor Identifier. For Intel products value is
* 0x00008086.
* @rsvd_date: BCD representation of build date as yyyymmdd, where
* yyyy=4 digit year, mm=1-12, dd=1-31.
* @headersize: Total length of the header including including any
* padding optionally added by the signing tool.
* @hash_algo: What Hash is used in the module signing.
* @cryp_algo: What Crypto is used in the module signing.
* @keysize: Total length of the key data including including any
* padding optionally added by the signing tool.
* @signaturesize: Total length of the signature including including any
* padding optionally added by the signing tool.
* @rsvd_next_header: 32-bit pointer to the next Secure Boot Module in the
* chain, if there is a next header.
* @rsvd: Reserved, padding structure to required size.
*
* See also QuartSecurityHeader_t in
* Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h
* from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP
*/
struct quark_security_header {
u32 csh_signature;
u32 version;
u32 modulesize;
u32 security_version_number_index;
u32 security_version_number;
u32 rsvd_module_id;
u32 rsvd_module_vendor;
u32 rsvd_date;
u32 headersize;
u32 hash_algo;
u32 cryp_algo;
u32 keysize;
u32 signaturesize;
u32 rsvd_next_header;
u32 rsvd[2];
};
static const efi_char16_t efi_dummy_name[] = L"DUMMY";
static bool efi_no_storage_paranoia;
/*
* Some firmware implementations refuse to boot if there's insufficient
* space in the variable store. The implementation of garbage collection
* in some FW versions causes stale (deleted) variables to take up space
* longer than intended and space is only freed once the store becomes
* almost completely full.
*
* Enabling this option disables the space checks in
* efi_query_variable_store() and forces garbage collection.
*
* Only enable this option if deleting EFI variables does not free up
* space in your variable store, e.g. if despite deleting variables
* you're unable to create new ones.
*/
static int __init setup_storage_paranoia(char *arg)
{
efi_no_storage_paranoia = true;
return 0;
}
early_param("efi_no_storage_paranoia", setup_storage_paranoia);
/*
* Deleting the dummy variable which kicks off garbage collection
*/
void efi_delete_dummy_variable(void)
{
efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name,
&EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL);
}
u64 efivar_reserved_space(void)
{
if (efi_no_storage_paranoia)
return 0;
return EFI_MIN_RESERVE;
}
EXPORT_SYMBOL_GPL(efivar_reserved_space);
/*
* In the nonblocking case we do not attempt to perform garbage
* collection if we do not have enough free space. Rather, we do the
* bare minimum check and give up immediately if the available space
* is below EFI_MIN_RESERVE.
*
* This function is intended to be small and simple because it is
* invoked from crash handler paths.
*/
static efi_status_t
query_variable_store_nonblocking(u32 attributes, unsigned long size)
{
efi_status_t status;
u64 storage_size, remaining_size, max_size;
status = efi.query_variable_info_nonblocking(attributes, &storage_size,
&remaining_size,
&max_size);
if (status != EFI_SUCCESS)
return status;
if (remaining_size - size < EFI_MIN_RESERVE)
return EFI_OUT_OF_RESOURCES;
return EFI_SUCCESS;
}
/*
* Some firmware implementations refuse to boot if there's insufficient space
* in the variable store. Ensure that we never use more than a safe limit.
*
* Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
* store.
*/
efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
bool nonblocking)
{
efi_status_t status;
u64 storage_size, remaining_size, max_size;
if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
return 0;
if (nonblocking)
return query_variable_store_nonblocking(attributes, size);
status = efi.query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
if (status != EFI_SUCCESS)
return status;
/*
* We account for that by refusing the write if permitting it would
* reduce the available space to under 5KB. This figure was provided by
* Samsung, so should be safe.
*/
if ((remaining_size - size < EFI_MIN_RESERVE) &&
!efi_no_storage_paranoia) {
/*
* Triggering garbage collection may require that the firmware
* generate a real EFI_OUT_OF_RESOURCES error. We can force
* that by attempting to use more space than is available.
*/
unsigned long dummy_size = remaining_size + 1024;
void *dummy = kzalloc(dummy_size, GFP_KERNEL);
if (!dummy)
return EFI_OUT_OF_RESOURCES;
status = efi.set_variable((efi_char16_t *)efi_dummy_name,
&EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
dummy_size, dummy);
if (status == EFI_SUCCESS) {
/*
* This should have failed, so if it didn't make sure
* that we delete it...
*/
efi_delete_dummy_variable();
}
kfree(dummy);
/*
* The runtime code may now have triggered a garbage collection
* run, so check the variable info again
*/
status = efi.query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
if (status != EFI_SUCCESS)
return status;
/*
* There still isn't enough room, so return an error
*/
if (remaining_size - size < EFI_MIN_RESERVE)
return EFI_OUT_OF_RESOURCES;
}
return EFI_SUCCESS;
}
EXPORT_SYMBOL_GPL(efi_query_variable_store);
/*
* The UEFI specification makes it clear that the operating system is
* free to do whatever it wants with boot services code after
* ExitBootServices() has been called. Ignoring this recommendation a
* significant bunch of EFI implementations continue calling into boot
* services code (SetVirtualAddressMap). In order to work around such
* buggy implementations we reserve boot services region during EFI
* init and make sure it stays executable. Then, after
* SetVirtualAddressMap(), it is discarded.
*
* However, some boot services regions contain data that is required
* by drivers, so we need to track which memory ranges can never be
* freed. This is done by tagging those regions with the
* EFI_MEMORY_RUNTIME attribute.
*
* Any driver that wants to mark a region as reserved must use
* efi_mem_reserve() which will insert a new EFI memory descriptor
* into efi.memmap (splitting existing regions if necessary) and tag
* it with EFI_MEMORY_RUNTIME.
*/
void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
{
struct efi_memory_map_data data = { 0 };
struct efi_mem_range mr;
efi_memory_desc_t md;
int num_entries;
void *new;
if (efi_mem_desc_lookup(addr, &md) ||
md.type != EFI_BOOT_SERVICES_DATA) {
pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
return;
}
if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
return;
}
size += addr % EFI_PAGE_SIZE;
size = round_up(size, EFI_PAGE_SIZE);
addr = round_down(addr, EFI_PAGE_SIZE);
mr.range.start = addr;
mr.range.end = addr + size - 1;
mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
num_entries = efi_memmap_split_count(&md, &mr.range);
num_entries += efi.memmap.nr_map;
if (efi_memmap_alloc(num_entries, &data) != 0) {
pr_err("Could not allocate boot services memmap\n");
return;
}
new = early_memremap_prot(data.phys_map, data.size,
pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL)));
if (!new) {
pr_err("Failed to map new boot services memmap\n");
return;
}
efi_memmap_insert(&efi.memmap, new, &mr);
early_memunmap(new, data.size);
efi_memmap_install(&data);
e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
e820__update_table(e820_table);
}
/*
* Helper function for efi_reserve_boot_services() to figure out if we
* can free regions in efi_free_boot_services().
*
* Use this function to ensure we do not free regions owned by somebody
* else. We must only reserve (and then free) regions:
*
* - Not within any part of the kernel
* - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
*/
static __init bool can_free_region(u64 start, u64 size)
{
if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
return false;
if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
return false;
return true;
}
void __init efi_reserve_boot_services(void)
{
efi_memory_desc_t *md;
if (!efi_enabled(EFI_MEMMAP))
return;
for_each_efi_memory_desc(md) {
u64 start = md->phys_addr;
u64 size = md->num_pages << EFI_PAGE_SHIFT;
bool already_reserved;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
already_reserved = memblock_is_region_reserved(start, size);
/*
* Because the following memblock_reserve() is paired
* with memblock_free_late() for this region in
* efi_free_boot_services(), we must be extremely
* careful not to reserve, and subsequently free,
* critical regions of memory (like the kernel image) or
* those regions that somebody else has already
* reserved.
*
* A good example of a critical region that must not be
* freed is page zero (first 4Kb of memory), which may
* contain boot services code/data but is marked
* E820_TYPE_RESERVED by trim_bios_range().
*/
if (!already_reserved) {
memblock_reserve(start, size);
/*
* If we are the first to reserve the region, no
* one else cares about it. We own it and can
* free it later.
*/
if (can_free_region(start, size))
continue;
}
/*
* We don't own the region. We must not free it.
*
* Setting this bit for a boot services region really
* doesn't make sense as far as the firmware is
* concerned, but it does provide us with a way to tag
* those regions that must not be paired with
* memblock_free_late().
*/
md->attribute |= EFI_MEMORY_RUNTIME;
}
}
/*
* Apart from having VA mappings for EFI boot services code/data regions,
* (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So,
* unmap both 1:1 and VA mappings.
*/
static void __init efi_unmap_pages(efi_memory_desc_t *md)
{
pgd_t *pgd = efi_mm.pgd;
u64 pa = md->phys_addr;
u64 va = md->virt_addr;
/*
* EFI mixed mode has all RAM mapped to access arguments while making
* EFI runtime calls, hence don't unmap EFI boot services code/data
* regions.
*/
if (efi_is_mixed())
return;
if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages))
pr_err("Failed to unmap VA mapping for 0x%llx\n", va);
}
void __init efi_free_boot_services(void)
{
struct efi_memory_map_data data = { 0 };
efi_memory_desc_t *md;
int num_entries = 0;
void *new, *new_md;
/* Keep all regions for /sys/kernel/debug/efi */
if (efi_enabled(EFI_DBG))
return;
for_each_efi_memory_desc(md) {
unsigned long long start = md->phys_addr;
unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
size_t rm_size;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA) {
num_entries++;
continue;
}
/* Do not free, someone else owns it: */
if (md->attribute & EFI_MEMORY_RUNTIME) {
num_entries++;
continue;
}
/*
* Before calling set_virtual_address_map(), EFI boot services
* code/data regions were mapped as a quirk for buggy firmware.
* Unmap them from efi_pgd before freeing them up.
*/
efi_unmap_pages(md);
/*
* Nasty quirk: if all sub-1MB memory is used for boot
* services, we can get here without having allocated the
* real mode trampoline. It's too late to hand boot services
* memory back to the memblock allocator, so instead
* try to manually allocate the trampoline if needed.
*
* I've seen this on a Dell XPS 13 9350 with firmware
* 1.4.4 with SGX enabled booting Linux via Fedora 24's
* grub2-efi on a hard disk. (And no, I don't know why
* this happened, but Linux should still try to boot rather
* panicking early.)
*/
rm_size = real_mode_size_needed();
if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
set_real_mode_mem(start);
start += rm_size;
size -= rm_size;
}
/*
* Don't free memory under 1M for two reasons:
* - BIOS might clobber it
* - Crash kernel needs it to be reserved
*/
if (start + size < SZ_1M)
continue;
if (start < SZ_1M) {
size -= (SZ_1M - start);
start = SZ_1M;
}
memblock_free_late(start, size);
}
if (!num_entries)
return;
if (efi_memmap_alloc(num_entries, &data) != 0) {
pr_err("Failed to allocate new EFI memmap\n");
return;
}
new = memremap(data.phys_map, data.size, MEMREMAP_WB);
if (!new) {
pr_err("Failed to map new EFI memmap\n");
return;
}
/*
* Build a new EFI memmap that excludes any boot services
* regions that are not tagged EFI_MEMORY_RUNTIME, since those
* regions have now been freed.
*/
new_md = new;
for_each_efi_memory_desc(md) {
if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
(md->type == EFI_BOOT_SERVICES_CODE ||
md->type == EFI_BOOT_SERVICES_DATA))
continue;
memcpy(new_md, md, efi.memmap.desc_size);
new_md += efi.memmap.desc_size;
}
memunmap(new);
if (efi_memmap_install(&data) != 0) {
pr_err("Could not install new EFI memmap\n");
return;
}
}
/*
* A number of config table entries get remapped to virtual addresses
* after entering EFI virtual mode. However, the kexec kernel requires
* their physical addresses therefore we pass them via setup_data and
* correct those entries to their respective physical addresses here.
*
* Currently only handles smbios which is necessary for some firmware
* implementation.
*/
int __init efi_reuse_config(u64 tables, int nr_tables)
{
int i, sz, ret = 0;
void *p, *tablep;
struct efi_setup_data *data;
if (nr_tables == 0)
return 0;
if (!efi_setup)
return 0;
if (!efi_enabled(EFI_64BIT))
return 0;
data = early_memremap(efi_setup, sizeof(*data));
if (!data) {
ret = -ENOMEM;
goto out;
}
if (!data->smbios)
goto out_memremap;
sz = sizeof(efi_config_table_64_t);
p = tablep = early_memremap(tables, nr_tables * sz);
if (!p) {
pr_err("Could not map Configuration table!\n");
ret = -ENOMEM;
goto out_memremap;
}
for (i = 0; i < nr_tables; i++) {
efi_guid_t guid;
guid = ((efi_config_table_64_t *)p)->guid;
if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
((efi_config_table_64_t *)p)->table = data->smbios;
p += sz;
}
early_memunmap(tablep, nr_tables * sz);
out_memremap:
early_memunmap(data, sizeof(*data));
out:
return ret;
}
void __init efi_apply_memmap_quirks(void)
{
/*
* Once setup is done earlier, unmap the EFI memory map on mismatched
* firmware/kernel architectures since there is no support for runtime
* services.
*/
if (!efi_runtime_supported()) {
pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
efi_memmap_unmap();
}
}
/*
* For most modern platforms the preferred method of powering off is via
* ACPI. However, there are some that are known to require the use of
* EFI runtime services and for which ACPI does not work at all.
*
* Using EFI is a last resort, to be used only if no other option
* exists.
*/
bool efi_reboot_required(void)
{
if (!acpi_gbl_reduced_hardware)
return false;
efi_reboot_quirk_mode = EFI_RESET_WARM;
return true;
}
bool efi_poweroff_required(void)
{
return acpi_gbl_reduced_hardware || acpi_no_s5;
}
#ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
size_t hdr_bytes)
{
struct quark_security_header *csh = *pkbuff;
/* Only process data block that is larger than the security header */
if (hdr_bytes < sizeof(struct quark_security_header))
return 0;
if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
csh->headersize != QUARK_SECURITY_HEADER_SIZE)
return 1;
/* Only process data block if EFI header is included */
if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
sizeof(efi_capsule_header_t))
return 0;
pr_debug("Quark security header detected\n");
if (csh->rsvd_next_header != 0) {
pr_err("multiple Quark security headers not supported\n");
return -EINVAL;
}
*pkbuff += csh->headersize;
cap_info->total_size = csh->headersize;
/*
* Update the first page pointer to skip over the CSH header.
*/
cap_info->phys[0] += csh->headersize;
/*
* cap_info->capsule should point at a virtual mapping of the entire
* capsule, starting at the capsule header. Our image has the Quark
* security header prepended, so we cannot rely on the default vmap()
* mapping created by the generic capsule code.
* Given that the Quark firmware does not appear to care about the
* virtual mapping, let's just point cap_info->capsule at our copy
* of the capsule header.
*/
cap_info->capsule = &cap_info->header;
return 1;
}
static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
X86_MATCH_VENDOR_FAM_MODEL(INTEL, 5, INTEL_FAM5_QUARK_X1000,
&qrk_capsule_setup_info),
{ }
};
int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
size_t hdr_bytes)
{
int (*quirk_handler)(struct capsule_info *, void **, size_t);
const struct x86_cpu_id *id;
int ret;
if (hdr_bytes < sizeof(efi_capsule_header_t))
return 0;
cap_info->total_size = 0;
id = x86_match_cpu(efi_capsule_quirk_ids);
if (id) {
/*
* The quirk handler is supposed to return
* - a value > 0 if the setup should continue, after advancing
* kbuff as needed
* - 0 if not enough hdr_bytes are available yet
* - a negative error code otherwise
*/
quirk_handler = (typeof(quirk_handler))id->driver_data;
ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
if (ret <= 0)
return ret;
}
memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
cap_info->total_size += cap_info->header.imagesize;
return __efi_capsule_setup_info(cap_info);
}
#endif
/*
* If any access by any efi runtime service causes a page fault, then,
* 1. If it's efi_reset_system(), reboot through BIOS.
* 2. If any other efi runtime service, then
* a. Return error status to the efi caller process.
* b. Disable EFI Runtime Services forever and
* c. Freeze efi_rts_wq and schedule new process.
*
* @return: Returns, if the page fault is not handled. This function
* will never return if the page fault is handled successfully.
*/
void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
{
if (!IS_ENABLED(CONFIG_X86_64))
return;
/*
* If we get an interrupt/NMI while processing an EFI runtime service
* then this is a regular OOPS, not an EFI failure.
*/
if (in_interrupt())
return;
/*
* Make sure that an efi runtime service caused the page fault.
* READ_ONCE() because we might be OOPSing in a different thread,
* and we don't want to trip KTSAN while trying to OOPS.
*/
if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
current_work() != &efi_rts_work.work)
return;
/*
* Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
* page faulting on these addresses isn't expected.
*/
if (phys_addr <= 0x0fff)
return;
/*
* Print stack trace as it might be useful to know which EFI Runtime
* Service is buggy.
*/
WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
phys_addr);
/*
* Buggy efi_reset_system() is handled differently from other EFI
* Runtime Services as it doesn't use efi_rts_wq. Although,
* native_machine_emergency_restart() says that machine_real_restart()
* could fail, it's better not to complicate this fault handler
* because this case occurs *very* rarely and hence could be improved
* on a need by basis.
*/
if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
machine_real_restart(MRR_BIOS);
return;
}
/*
* Before calling EFI Runtime Service, the kernel has switched the
* calling process to efi_mm. Hence, switch back to task_mm.
*/
arch_efi_call_virt_teardown();
/* Signal error status to the efi caller process */
efi_rts_work.status = EFI_ABORTED;
complete(&efi_rts_work.efi_rts_comp);
clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
/*
* Call schedule() in an infinite loop, so that any spurious wake ups
* will never run efi_rts_wq again.
*/
for (;;) {
set_current_state(TASK_IDLE);
schedule();
}
}