diff options
Diffstat (limited to 'arch/x86/platform/efi/quirks.c')
| -rw-r--r-- | arch/x86/platform/efi/quirks.c | 773 |
1 files changed, 773 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c new file mode 100644 index 000000000..b0b848d69 --- /dev/null +++ b/arch/x86/platform/efi/quirks.c @@ -0,0 +1,773 @@ +// 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); +} + +/* + * 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(); + } +} |