ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/arch/x86/platform/efi/quirks.c b/marvell/linux/arch/x86/platform/efi/quirks.c
new file mode 100644
index 0000000..6ca88fb
--- /dev/null
+++ b/marvell/linux/arch/x86/platform/efi/quirks.c
@@ -0,0 +1,777 @@
+// 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/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);
+}
+
+/*
+ * 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)
+{
+ phys_addr_t new_phys, new_size;
+ 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;
+
+ new_size = efi.memmap.desc_size * num_entries;
+
+ new_phys = efi_memmap_alloc(num_entries);
+ if (!new_phys) {
+ pr_err("Could not allocate boot services memmap\n");
+ return;
+ }
+
+ new = early_memremap_prot(new_phys, new_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, new_size);
+
+ efi_memmap_install(new_phys, num_entries);
+ 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;
+
+ 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;
+
+ /*
+ * To Do: Remove this check after adding functionality to unmap EFI boot
+ * services code/data regions from direct mapping area because
+ * "efi=old_map" maps EFI regions in swapper_pg_dir.
+ */
+ if (efi_enabled(EFI_OLD_MEMMAP))
+ return;
+
+ /*
+ * 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_native())
+ 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)
+{
+ phys_addr_t new_phys, new_size;
+ efi_memory_desc_t *md;
+ int num_entries = 0;
+ void *new, *new_md;
+
+ 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
+ * panicing 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;
+ }
+
+ memblock_free_late(start, size);
+ }
+
+ if (!num_entries)
+ return;
+
+ new_size = efi.memmap.desc_size * num_entries;
+ new_phys = efi_memmap_alloc(num_entries);
+ if (!new_phys) {
+ pr_err("Failed to allocate new EFI memmap\n");
+ return;
+ }
+
+ new = memremap(new_phys, new_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(new_phys, num_entries)) {
+ 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 < efi.systab->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;
+}
+
+static const struct dmi_system_id sgi_uv1_dmi[] = {
+ { NULL, "SGI UV1",
+ { DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"),
+ DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"),
+ DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"),
+ }
+ },
+ { } /* NULL entry stops DMI scanning */
+};
+
+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();
+ }
+
+ /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
+ if (dmi_check_system(sgi_uv1_dmi))
+ set_bit(EFI_OLD_MEMMAP, &efi.flags);
+}
+
+/*
+ * 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;
+}
+
+#define ICPU(family, model, quirk_handler) \
+ { X86_VENDOR_INTEL, family, model, X86_FEATURE_ANY, \
+ (unsigned long)&quirk_handler }
+
+static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
+ ICPU(5, 9, qrk_capsule_setup_info), /* Intel Quark X1000 */
+ { }
+};
+
+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_recover_from_page_fault(unsigned long phys_addr)
+{
+ if (!IS_ENABLED(CONFIG_X86_64))
+ return;
+
+ /*
+ * Make sure that an efi runtime service caused the page fault.
+ * "efi_mm" cannot be used to check if the page fault had occurred
+ * in the firmware context because efi=old_map doesn't use efi_pgd.
+ */
+ if (efi_rts_work.efi_rts_id == EFI_NONE)
+ 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 compilcate 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();
+ }
+
+ return;
+}