[PATCH v5 08/14] efi: export efi runtime memory mapping to sysfs
From: Dave Young
Date: Mon Dec 09 2013 - 04:45:28 EST
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
Matt: s/efi-runtime-map.c/runtime-map.c
change dir name to runtime-map
update to use desc_size in efi_runtime_map
cleaup the code, add function efi_save_runtime_map
improve err handling
Matt: changelog fix;
Documentation fixes.
only export runtime-map sysfs file in case CONFIG_KEXEC
Add macros for sysfs _show functions
move functions to front of .c, remove forward declarations.
Boris: Documentation grammer/spelling fix
better error handling for krealloc
other code improvements.
move efi_runtime_map_init to subsys_initcall.
set efi_kobj = NULL in case efisubsys_init fails. And then efi_runtime_map_init
will bail out.
Kconfig EFI_RUNTIME_MAP depends on X86 && KEXEC && EFI
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
---
.../ABI/testing/sysfs-firmware-efi-runtime-map | 36 +++++
arch/x86/platform/efi/efi.c | 28 ++++
drivers/firmware/efi/Kconfig | 11 ++
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/efi.c | 4 +-
drivers/firmware/efi/runtime-map.c | 176 +++++++++++++++++++++
include/linux/efi.h | 6 +
7 files changed, 261 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi-runtime-map
create mode 100644 drivers/firmware/efi/runtime-map.c
diff --git a/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map
new file mode 100644
index 0000000..2ab7dd2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map
@@ -0,0 +1,36 @@
+What: /sys/firmware/efi/runtime-map/
+Date: December 2013
+Contact: Dave Young <dyoung@xxxxxxxxxx>
+Description:
+ Switching efi runtime services to virtual mode requires
+ that all efi memory ranges which have the runtime attribute
+ bit set to be mapped to virtual addresses.
+
+ The efi runtime services can only be switched to virtual
+ mode once without rebooting. The kexec kernel must maintain
+ the same physical to virtual address mappings as the first
+ kernel. The mappings are exported to sysfs so userspace tools
+ can reassemble them and pass them into the kexec kernel.
+
+ /sys/firmware/efi/runtime-map/ is the directory the kernel
+ exports that information in.
+
+ subdirectories are named with the number of the memory range:
+
+ /sys/firmware/efi/runtime-map/0
+ /sys/firmware/efi/runtime-map/1
+ /sys/firmware/efi/runtime-map/2
+ /sys/firmware/efi/runtime-map/3
+ ...
+
+ Each subdirectory contains five files:
+
+ attribute : The attributes of the memory range.
+ num_pages : The size of the memory range in pages.
+ phys_addr : The physical address of the memory range.
+ type : The type of the memory range.
+ virt_addr : The virtual address of the memory range.
+
+ Above values are all hexadecimal numbers with the '0x' prefix.
+
+Users: Kexec
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 3e8b760..8289e0c 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -76,6 +76,9 @@ static __initdata efi_config_table_type_t arch_tables[] = {
{NULL_GUID, NULL, NULL},
};
+void *efi_runtime_map;
+int nr_efi_runtime_map;
+
/*
* Returns 1 if 'facility' is enabled, 0 otherwise.
*/
@@ -810,6 +813,19 @@ static void __init efi_merge_regions(void)
}
}
+static int __init save_runtime_map(efi_memory_desc_t *md, int idx)
+{
+ void *p;
+ p = krealloc(efi_runtime_map, (idx + 1) * memmap.desc_size, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ efi_runtime_map = p;
+ memcpy(efi_runtime_map + idx * memmap.desc_size, md, memmap.desc_size);
+
+ return 0;
+}
+
/*
* Map efi memory ranges for runtime serivce and update new_memmap with virtual
* addresses.
@@ -820,6 +836,7 @@ static void * __init efi_map_regions(int *count)
void *p, *tmp, *new_memmap = NULL;
unsigned long size;
u64 end, systab;
+ int err = 0;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
@@ -848,10 +865,21 @@ static void * __init efi_map_regions(int *count)
new_memmap = tmp;
memcpy(new_memmap + (*count * memmap.desc_size), md,
memmap.desc_size);
+ if (md->type != EFI_BOOT_SERVICES_CODE &&
+ md->type != EFI_BOOT_SERVICES_DATA) {
+ err = save_runtime_map(md, nr_efi_runtime_map);
+ if (err)
+ goto out_save_runtime;
+ nr_efi_runtime_map++;
+ }
(*count)++;
}
return new_memmap;
+out_save_runtime:
+ kfree(efi_runtime_map);
+ nr_efi_runtime_map = 0;
+ efi_runtime_map = NULL;
out_krealloc:
kfree(new_memmap);
return NULL;
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 3150aa4..3d8d6f6 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -39,4 +39,15 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE
config UEFI_CPER
def_bool n
+config EFI_RUNTIME_MAP
+ bool "Export efi runtime maps to sysfs" if EXPERT
+ depends on X86 && EFI && KEXEC
+ default y
+ help
+ Export efi runtime memory maps to /sys/firmware/efi/runtime-map.
+ That memory map is used for example by kexec to set up efi virtual
+ mapping the 2nd kernel, but can also be used for debugging purposes.
+
+ See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
+
endmenu
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 9ba156d..a58e0f1 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -5,3 +5,4 @@ obj-y += efi.o vars.o
obj-$(CONFIG_EFI_VARS) += efivars.o
obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
obj-$(CONFIG_UEFI_CPER) += cper.o
+obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 0ecccab..0a288e3 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -38,7 +38,8 @@ struct efi __read_mostly efi = {
};
EXPORT_SYMBOL(efi);
-static struct kobject *efi_kobj;
+struct kobject *efi_kobj;
+EXPORT_SYMBOL_GPL(efi_kobj);
static struct kobject *efivars_kobj;
/*
@@ -183,6 +184,7 @@ err_unregister:
generic_ops_unregister();
err_put:
kobject_put(efi_kobj);
+ efi_kobj = NULL;
return error;
}
diff --git a/drivers/firmware/efi/runtime-map.c b/drivers/firmware/efi/runtime-map.c
new file mode 100644
index 0000000..e5e9984
--- /dev/null
+++ b/drivers/firmware/efi/runtime-map.c
@@ -0,0 +1,176 @@
+/*
+ * linux/drivers/efi/runtime-map.c
+ * Copyright (C) 2013 Red Hat, Inc., Dave Young <dyoung@xxxxxxxxxx>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+
+#include <asm/setup.h>
+
+struct efi_runtime_map_entry {
+ efi_memory_desc_t md;
+ struct kobject kobj; /* kobject for each entry */
+};
+
+static struct efi_runtime_map_entry **map_entries;
+
+struct map_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct efi_runtime_map_entry *entry, char *buf);
+};
+
+static inline struct map_attribute *to_map_attr(struct attribute *attr)
+{
+ return container_of(attr, struct map_attribute, attr);
+}
+
+static ssize_t type_show(struct efi_runtime_map_entry *entry, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%x\n", entry->md.type);
+}
+
+#define EFI_RUNTIME_FIELD(var) entry->md.var
+
+#define EFI_RUNTIME_U64_ATTR_SHOW(name) \
+static ssize_t name##_show(struct efi_runtime_map_entry *entry, char *buf) \
+{ \
+ return snprintf(buf, PAGE_SIZE, "0x%llx\n", EFI_RUNTIME_FIELD(name)); \
+}
+
+EFI_RUNTIME_U64_ATTR_SHOW(phys_addr);
+EFI_RUNTIME_U64_ATTR_SHOW(virt_addr);
+EFI_RUNTIME_U64_ATTR_SHOW(num_pages);
+EFI_RUNTIME_U64_ATTR_SHOW(attribute);
+
+static inline struct efi_runtime_map_entry *to_map_entry(struct kobject *kobj)
+{
+ return container_of(kobj, struct efi_runtime_map_entry, kobj);
+}
+
+static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr,
+ char *buf)
+{
+ struct efi_runtime_map_entry *entry = to_map_entry(kobj);
+ struct map_attribute *map_attr = to_map_attr(attr);
+
+ return map_attr->show(entry, buf);
+}
+
+static struct map_attribute map_type_attr = __ATTR_RO(type);
+static struct map_attribute map_phys_addr_attr = __ATTR_RO(phys_addr);
+static struct map_attribute map_virt_addr_attr = __ATTR_RO(virt_addr);
+static struct map_attribute map_num_pages_attr = __ATTR_RO(num_pages);
+static struct map_attribute map_attribute_attr = __ATTR_RO(attribute);
+
+/*
+ * These are default attributes that are added for every memmap entry.
+ */
+static struct attribute *def_attrs[] = {
+ &map_type_attr.attr,
+ &map_phys_addr_attr.attr,
+ &map_virt_addr_attr.attr,
+ &map_num_pages_attr.attr,
+ &map_attribute_attr.attr,
+ NULL
+};
+
+static const struct sysfs_ops map_attr_ops = {
+ .show = map_attr_show,
+};
+
+static void map_release(struct kobject *kobj)
+{
+ struct efi_runtime_map_entry *entry;
+
+ entry = to_map_entry(kobj);
+ kfree(entry);
+}
+
+static struct kobj_type __refdata map_ktype = {
+ .sysfs_ops = &map_attr_ops,
+ .default_attrs = def_attrs,
+ .release = map_release,
+};
+
+static struct kset *map_kset;
+
+static struct efi_runtime_map_entry *add_sysfs_runtime_map_entry(int nr)
+{
+ int ret;
+ struct efi_runtime_map_entry *entry;
+ struct efi_info *e = &boot_params.efi_info;
+
+ if (!map_kset) {
+ map_kset = kset_create_and_add("runtime-map", NULL,
+ efi_kobj);
+ if (!map_kset)
+ return ERR_PTR(-ENOMEM);
+ }
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry) {
+ kset_unregister(map_kset);
+ return entry;
+ }
+
+ memcpy(&entry->md, efi_runtime_map + nr * e->efi_memdesc_size,
+ sizeof(efi_memory_desc_t));
+
+ kobject_init(&entry->kobj, &map_ktype);
+ entry->kobj.kset = map_kset;
+ ret = kobject_add(&entry->kobj, NULL, "%d", nr);
+ if (ret) {
+ kobject_put(&entry->kobj);
+ kset_unregister(map_kset);
+ return ERR_PTR(ret);
+ }
+
+ return entry;
+}
+
+static int __init efi_runtime_map_init(void)
+{
+ int i, j, ret = 0;
+ struct efi_runtime_map_entry *entry;
+
+ if (!efi_kobj)
+ return 0;
+
+ if (!efi_runtime_map)
+ return 0;
+
+ map_entries = kzalloc(nr_efi_runtime_map * sizeof(entry), GFP_KERNEL);
+ if (!map_entries) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ for (i = 0; i < nr_efi_runtime_map; i++) {
+ entry = add_sysfs_runtime_map_entry(i);
+ if (IS_ERR(entry)) {
+ ret = PTR_ERR(entry);
+ goto out_add_entry;
+ }
+ *(map_entries + i) = entry;
+ }
+
+ return 0;
+out_add_entry:
+ for (j = i - 1; j > 0; j--) {
+ entry = *(map_entries + j);
+ kobject_put(&entry->kobj);
+ }
+ if (map_kset)
+ kset_unregister(map_kset);
+out:
+ return ret;
+}
+
+subsys_initcall(efi_runtime_map_init);
diff --git a/include/linux/efi.h b/include/linux/efi.h
index fb60b10..4f1651d 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -872,4 +872,10 @@ int efivars_sysfs_init(void);
#endif /* CONFIG_EFI_VARS */
+#ifdef CONFIG_EFI_RUNTIME_MAP
+extern void *efi_runtime_map;
+extern int nr_efi_runtime_map;
+extern struct kobject *efi_kobj;
+#endif
+
#endif /* _LINUX_EFI_H */
--
1.8.3.1
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