diff options
Diffstat (limited to 'arch/x86/platform/efi/quirks.c')
-rw-r--r-- | arch/x86/platform/efi/quirks.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c new file mode 100644 index 0000000..1c7380d --- /dev/null +++ b/arch/x86/platform/efi/quirks.c @@ -0,0 +1,290 @@ +#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/bootmem.h> +#include <linux/acpi.h> +#include <asm/efi.h> +#include <asm/uv/uv.h> + +#define EFI_MIN_RESERVE 5120 + +#define EFI_DUMMY_GUID \ + EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9) + +static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 }; + +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(efi_dummy_name, &EFI_DUMMY_GUID, + EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS, + 0, NULL); +} + +/* + * 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) +{ + efi_status_t status; + u64 storage_size, remaining_size, max_size; + + if (!(attributes & EFI_VARIABLE_NON_VOLATILE)) + return 0; + + 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_ATOMIC); + + if (!dummy) + return EFI_OUT_OF_RESOURCES; + + status = efi.set_variable(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. +*/ +void __init efi_reserve_boot_services(void) +{ + void *p; + + for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { + efi_memory_desc_t *md = p; + u64 start = md->phys_addr; + u64 size = md->num_pages << EFI_PAGE_SHIFT; + + if (md->type != EFI_BOOT_SERVICES_CODE && + md->type != EFI_BOOT_SERVICES_DATA) + continue; + /* Only reserve where possible: + * - Not within any already allocated areas + * - Not over any memory area (really needed, if above?) + * - Not within any part of the kernel + * - Not the bios reserved area + */ + if ((start + size > __pa_symbol(_text) + && start <= __pa_symbol(_end)) || + !e820_all_mapped(start, start+size, E820_RAM) || + memblock_is_region_reserved(start, size)) { + /* Could not reserve, skip it */ + md->num_pages = 0; + memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n", + start, start+size-1); + } else + memblock_reserve(start, size); + } +} + +void __init efi_free_boot_services(void) +{ + void *p; + + for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { + efi_memory_desc_t *md = p; + unsigned long long start = md->phys_addr; + unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; + + if (md->type != EFI_BOOT_SERVICES_CODE && + md->type != EFI_BOOT_SERVICES_DATA) + continue; + + /* Could not reserve boot area */ + if (!size) + continue; + + free_bootmem_late(start, size); + } + + efi_unmap_memmap(); +} + +/* + * 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 (!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; +} + +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("efi: Setup done, disabling due to 32/64-bit mismatch\n"); + efi_unmap_memmap(); + } + + /* + * UV doesn't support the new EFI pagetable mapping yet. + */ + if (is_uv_system()) + 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; +} |