efi: Export EFI runtime memory mapping to sysfs
kexec kernel will need exactly same mapping for EFI runtime memory ranges. Thus here export the runtime ranges mapping to sysfs, kexec-tools will assemble them and pass to 2nd kernel via setup_data. Introducing a new directory /sys/firmware/efi/runtime-map just like /sys/firmware/memmap. Containing below attribute in each file of that directory: attribute num_pages phys_addr type virt_addr Signed-off-by: Dave Young <dyoung@redhat.com> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>hifive-unleashed-5.1
Dave Young
Matt Fleming
parent
a0998eb15a
commit
926172d460
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@ -0,0 +1,34 @@
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What: /sys/firmware/efi/runtime-map/
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Date: December 2013
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Contact: Dave Young <dyoung@redhat.com>
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Description: Switching efi runtime services to virtual mode requires
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that all efi memory ranges which have the runtime attribute
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bit set to be mapped to virtual addresses.
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The efi runtime services can only be switched to virtual
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mode once without rebooting. The kexec kernel must maintain
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the same physical to virtual address mappings as the first
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kernel. The mappings are exported to sysfs so userspace tools
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can reassemble them and pass them into the kexec kernel.
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/sys/firmware/efi/runtime-map/ is the directory the kernel
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exports that information in.
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subdirectories are named with the number of the memory range:
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/sys/firmware/efi/runtime-map/0
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/sys/firmware/efi/runtime-map/1
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/sys/firmware/efi/runtime-map/2
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/sys/firmware/efi/runtime-map/3
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...
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Each subdirectory contains five files:
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attribute : The attributes of the memory range.
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num_pages : The size of the memory range in pages.
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phys_addr : The physical address of the memory range.
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type : The type of the memory range.
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virt_addr : The virtual address of the memory range.
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Above values are all hexadecimal numbers with the '0x' prefix.
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Users: Kexec
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@ -76,6 +76,9 @@ static __initdata efi_config_table_type_t arch_tables[] = {
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{NULL_GUID, NULL, NULL},
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};
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static void *efi_runtime_map;
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static int nr_efi_runtime_map;
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/*
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* Returns 1 if 'facility' is enabled, 0 otherwise.
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*/
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@ -824,6 +827,39 @@ static void __init get_systab_virt_addr(efi_memory_desc_t *md)
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}
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}
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static int __init save_runtime_map(void)
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{
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efi_memory_desc_t *md;
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void *tmp, *p, *q = NULL;
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int count = 0;
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for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
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md = p;
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if (!(md->attribute & EFI_MEMORY_RUNTIME) ||
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(md->type == EFI_BOOT_SERVICES_CODE) ||
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(md->type == EFI_BOOT_SERVICES_DATA))
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continue;
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tmp = krealloc(q, (count + 1) * memmap.desc_size, GFP_KERNEL);
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if (!tmp)
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goto out;
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q = tmp;
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memcpy(q + count * memmap.desc_size, md, memmap.desc_size);
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count++;
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}
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efi_runtime_map = q;
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nr_efi_runtime_map = count;
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efi_runtime_map_setup(efi_runtime_map, nr_efi_runtime_map,
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boot_params.efi_info.efi_memdesc_size);
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return 0;
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out:
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kfree(q);
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return -ENOMEM;
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}
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/*
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* Map efi memory ranges for runtime serivce and update new_memmap with virtual
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* addresses.
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@ -849,7 +885,7 @@ static void * __init efi_map_regions(int *count)
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tmp = krealloc(new_memmap, (*count + 1) * memmap.desc_size,
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GFP_KERNEL);
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if (!tmp)
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goto out_krealloc;
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goto out;
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new_memmap = tmp;
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memcpy(new_memmap + (*count * memmap.desc_size), md,
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memmap.desc_size);
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@ -857,7 +893,7 @@ static void * __init efi_map_regions(int *count)
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}
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return new_memmap;
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out_krealloc:
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out:
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kfree(new_memmap);
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return NULL;
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}
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@ -883,7 +919,7 @@ void __init efi_enter_virtual_mode(void)
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{
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efi_status_t status;
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void *new_memmap = NULL;
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int count = 0;
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int err, count = 0;
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efi.systab = NULL;
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@ -904,6 +940,10 @@ void __init efi_enter_virtual_mode(void)
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return;
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}
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err = save_runtime_map();
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if (err)
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pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");
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BUG_ON(!efi.systab);
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efi_setup_page_tables();
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@ -39,4 +39,15 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE
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config UEFI_CPER
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def_bool n
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config EFI_RUNTIME_MAP
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bool "Export efi runtime maps to sysfs"
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depends on X86 && EFI && KEXEC
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default y
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help
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Export efi runtime memory maps to /sys/firmware/efi/runtime-map.
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That memory map is used for example by kexec to set up efi virtual
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mapping the 2nd kernel, but can also be used for debugging purposes.
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See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
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endmenu
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@ -5,3 +5,4 @@ obj-y += efi.o vars.o
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obj-$(CONFIG_EFI_VARS) += efivars.o
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obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
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obj-$(CONFIG_UEFI_CPER) += cper.o
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obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
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@ -167,6 +167,10 @@ static int __init efisubsys_init(void)
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goto err_unregister;
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}
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error = efi_runtime_map_init(efi_kobj);
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if (error)
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goto err_remove_group;
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/* and the standard mountpoint for efivarfs */
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efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
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if (!efivars_kobj) {
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@ -0,0 +1,181 @@
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/*
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* linux/drivers/efi/runtime-map.c
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* Copyright (C) 2013 Red Hat, Inc., Dave Young <dyoung@redhat.com>
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/efi.h>
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#include <linux/slab.h>
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#include <asm/setup.h>
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static void *efi_runtime_map;
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static int nr_efi_runtime_map;
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static u32 efi_memdesc_size;
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struct efi_runtime_map_entry {
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efi_memory_desc_t md;
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struct kobject kobj; /* kobject for each entry */
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};
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static struct efi_runtime_map_entry **map_entries;
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struct map_attribute {
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struct attribute attr;
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ssize_t (*show)(struct efi_runtime_map_entry *entry, char *buf);
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};
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static inline struct map_attribute *to_map_attr(struct attribute *attr)
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{
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return container_of(attr, struct map_attribute, attr);
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}
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static ssize_t type_show(struct efi_runtime_map_entry *entry, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "0x%x\n", entry->md.type);
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}
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#define EFI_RUNTIME_FIELD(var) entry->md.var
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#define EFI_RUNTIME_U64_ATTR_SHOW(name) \
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static ssize_t name##_show(struct efi_runtime_map_entry *entry, char *buf) \
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{ \
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return snprintf(buf, PAGE_SIZE, "0x%llx\n", EFI_RUNTIME_FIELD(name)); \
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}
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EFI_RUNTIME_U64_ATTR_SHOW(phys_addr);
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EFI_RUNTIME_U64_ATTR_SHOW(virt_addr);
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EFI_RUNTIME_U64_ATTR_SHOW(num_pages);
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EFI_RUNTIME_U64_ATTR_SHOW(attribute);
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static inline struct efi_runtime_map_entry *to_map_entry(struct kobject *kobj)
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{
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return container_of(kobj, struct efi_runtime_map_entry, kobj);
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}
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static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct efi_runtime_map_entry *entry = to_map_entry(kobj);
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struct map_attribute *map_attr = to_map_attr(attr);
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return map_attr->show(entry, buf);
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}
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static struct map_attribute map_type_attr = __ATTR_RO(type);
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static struct map_attribute map_phys_addr_attr = __ATTR_RO(phys_addr);
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static struct map_attribute map_virt_addr_attr = __ATTR_RO(virt_addr);
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static struct map_attribute map_num_pages_attr = __ATTR_RO(num_pages);
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static struct map_attribute map_attribute_attr = __ATTR_RO(attribute);
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/*
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* These are default attributes that are added for every memmap entry.
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*/
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static struct attribute *def_attrs[] = {
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&map_type_attr.attr,
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&map_phys_addr_attr.attr,
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&map_virt_addr_attr.attr,
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&map_num_pages_attr.attr,
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&map_attribute_attr.attr,
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NULL
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};
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static const struct sysfs_ops map_attr_ops = {
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.show = map_attr_show,
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};
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static void map_release(struct kobject *kobj)
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{
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struct efi_runtime_map_entry *entry;
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entry = to_map_entry(kobj);
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kfree(entry);
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}
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static struct kobj_type __refdata map_ktype = {
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.sysfs_ops = &map_attr_ops,
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.default_attrs = def_attrs,
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.release = map_release,
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};
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static struct kset *map_kset;
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static struct efi_runtime_map_entry *
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add_sysfs_runtime_map_entry(struct kobject *kobj, int nr)
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{
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int ret;
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struct efi_runtime_map_entry *entry;
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if (!map_kset) {
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map_kset = kset_create_and_add("runtime-map", NULL, kobj);
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if (!map_kset)
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return ERR_PTR(-ENOMEM);
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}
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entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry) {
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kset_unregister(map_kset);
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return entry;
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}
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memcpy(&entry->md, efi_runtime_map + nr * efi_memdesc_size,
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sizeof(efi_memory_desc_t));
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kobject_init(&entry->kobj, &map_ktype);
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entry->kobj.kset = map_kset;
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ret = kobject_add(&entry->kobj, NULL, "%d", nr);
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if (ret) {
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kobject_put(&entry->kobj);
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kset_unregister(map_kset);
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return ERR_PTR(ret);
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}
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return entry;
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}
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void efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size)
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{
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efi_runtime_map = map;
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nr_efi_runtime_map = nr_entries;
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efi_memdesc_size = desc_size;
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}
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int __init efi_runtime_map_init(struct kobject *efi_kobj)
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{
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int i, j, ret = 0;
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struct efi_runtime_map_entry *entry;
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if (!efi_runtime_map)
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return 0;
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map_entries = kzalloc(nr_efi_runtime_map * sizeof(entry), GFP_KERNEL);
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if (!map_entries) {
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ret = -ENOMEM;
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goto out;
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}
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for (i = 0; i < nr_efi_runtime_map; i++) {
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entry = add_sysfs_runtime_map_entry(efi_kobj, i);
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if (IS_ERR(entry)) {
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ret = PTR_ERR(entry);
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goto out_add_entry;
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}
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*(map_entries + i) = entry;
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}
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return 0;
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out_add_entry:
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for (j = i - 1; j > 0; j--) {
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entry = *(map_entries + j);
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kobject_put(&entry->kobj);
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}
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if (map_kset)
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kset_unregister(map_kset);
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out:
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return ret;
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}
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@ -872,4 +872,17 @@ int efivars_sysfs_init(void);
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#endif /* CONFIG_EFI_VARS */
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#ifdef CONFIG_EFI_RUNTIME_MAP
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int efi_runtime_map_init(struct kobject *);
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void efi_runtime_map_setup(void *, int, u32);
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#else
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static inline int efi_runtime_map_init(struct kobject *kobj)
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{
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return 0;
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}
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static inline void
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efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size) {}
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#endif
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#endif /* _LINUX_EFI_H */
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