diff options
| -rw-r--r-- | arch/x86/platform/efi/quirks.c | 121 | ||||
| -rw-r--r-- | drivers/firmware/efi/efi.c | 30 | ||||
| -rw-r--r-- | include/linux/efi.h | 1 |
3 files changed, 141 insertions, 11 deletions
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 9faf18874692..f14b7a9da24b 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -164,6 +164,71 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size, 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)) { + 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; + } + + mr.range.start = addr; + mr.range.end = addr + size; + 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 = memblock_alloc(new_size, 0); + if (!new_phys) { + pr_err("Could not allocate boot services memmap\n"); + return; + } + + new = early_memremap(new_phys, new_size); + 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); +} + +/* * Helper function for efi_reserve_boot_services() to figure out if we * can free regions in efi_free_boot_services(). * @@ -184,15 +249,6 @@ static bool can_free_region(u64 start, u64 size) return true; } -/* - * 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) { efi_memory_desc_t *md; @@ -249,7 +305,10 @@ void __init efi_reserve_boot_services(void) 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; @@ -257,12 +316,16 @@ void __init efi_free_boot_services(void) size_t rm_size; if (md->type != EFI_BOOT_SERVICES_CODE && - md->type != EFI_BOOT_SERVICES_DATA) + md->type != EFI_BOOT_SERVICES_DATA) { + num_entries++; continue; + } /* Do not free, someone else owns it: */ - if (md->attribute & EFI_MEMORY_RUNTIME) + if (md->attribute & EFI_MEMORY_RUNTIME) { + num_entries++; continue; + } /* * Nasty quirk: if all sub-1MB memory is used for boot @@ -286,6 +349,42 @@ void __init efi_free_boot_services(void) free_bootmem_late(start, size); } + + new_size = efi.memmap.desc_size * num_entries; + new_phys = memblock_alloc(new_size, 0); + 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; + } } /* diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index d4886fd50c16..dfe07316cae5 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -27,6 +27,7 @@ #include <linux/slab.h> #include <linux/acpi.h> #include <linux/ucs2_string.h> +#include <linux/memblock.h> #include <asm/early_ioremap.h> @@ -396,6 +397,35 @@ u64 __init efi_mem_desc_end(efi_memory_desc_t *md) return end; } +void __init __weak efi_arch_mem_reserve(phys_addr_t addr, u64 size) {} + +/** + * efi_mem_reserve - Reserve an EFI memory region + * @addr: Physical address to reserve + * @size: Size of reservation + * + * Mark a region as reserved from general kernel allocation and + * prevent it being released by efi_free_boot_services(). + * + * This function should be called drivers once they've parsed EFI + * configuration tables to figure out where their data lives, e.g. + * efi_esrt_init(). + */ +void __init efi_mem_reserve(phys_addr_t addr, u64 size) +{ + if (!memblock_is_region_reserved(addr, size)) + memblock_reserve(addr, size); + + /* + * Some architectures (x86) reserve all boot services ranges + * until efi_free_boot_services() because of buggy firmware + * implementations. This means the above memblock_reserve() is + * superfluous on x86 and instead what it needs to do is + * ensure the @start, @size is not freed. + */ + efi_arch_mem_reserve(addr, size); +} + static __initdata efi_config_table_type_t common_tables[] = { {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20}, {ACPI_TABLE_GUID, "ACPI", &efi.acpi}, diff --git a/include/linux/efi.h b/include/linux/efi.h index 987c18f6fcae..3fe4f3c47834 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -944,6 +944,7 @@ extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size); extern int __init efi_uart_console_only (void); extern u64 efi_mem_desc_end(efi_memory_desc_t *md); extern int efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md); +extern void efi_mem_reserve(phys_addr_t addr, u64 size); extern void efi_initialize_iomem_resources(struct resource *code_resource, struct resource *data_resource, struct resource *bss_resource); extern void efi_reserve_boot_services(void); |