Add sysfs files for EFI System Resource Table under
/sys/firmware/efi/esrt and for each EFI System Resource Entry under
entries/ as a subdir.
v2 with suggestions from bpetkov.
Signed-off-by: Peter Jones <pjones@xxxxxxxxxx>
---
drivers/firmware/efi/Makefile | 2 +-
drivers/firmware/efi/efi.c | 45 ++++-
drivers/firmware/efi/esrt.c | 392 ++++++++++++++++++++++++++++++++++++++++++
include/linux/efi.h | 6 +
4 files changed, 443 insertions(+), 2 deletions(-)
create mode 100644 drivers/firmware/efi/esrt.c
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index aef6a95..0d61089 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -1,7 +1,7 @@
#
# Makefile for linux kernel
#
-obj-$(CONFIG_EFI) += efi.o vars.o reboot.o
+obj-$(CONFIG_EFI) += efi.o esrt.o vars.o reboot.o
obj-$(CONFIG_EFI_VARS) += efivars.o
obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
obj-$(CONFIG_UEFI_CPER) += cper.o
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8590099..bc7eaca 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -38,6 +38,7 @@ struct efi __read_mostly efi = {
.fw_vendor = EFI_INVALID_TABLE_ADDR,
.runtime = EFI_INVALID_TABLE_ADDR,
.config_table = EFI_INVALID_TABLE_ADDR,
+ .esrt = EFI_INVALID_TABLE_ADDR,
};
EXPORT_SYMBOL(efi);
@@ -63,7 +64,7 @@ static int __init parse_efi_cmdline(char *str)
}
early_param("efi", parse_efi_cmdline);
-static struct kobject *efi_kobj;
+struct kobject *efi_kobj;
static struct kobject *efivars_kobj;
/*
@@ -92,6 +93,8 @@ static ssize_t systab_show(struct kobject *kobj,
str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
if (efi.uga != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "UGA=0x%lx\n", efi.uga);
+ if (efi.esrt != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "ESRT=0x%lx\n", efi.esrt);
return str - buf;
}
@@ -220,6 +223,45 @@ err_put:
subsys_initcall(efisubsys_init);
+/*
+ * Given a physicall address, determine if it exists within an EFI Memory Map
+ * entry, and if so, how much of that map exists at a higher address. That
+ * is, if this is the address of something in an EFI map, what's the highest
+ * address at which it's likely to end.
+ */
+u64 efi_mem_max_reasonable_size(u64 phys_addr)
+{
+ struct efi_memory_map *map = efi.memmap;
+ void *p, *e;
+
+ if (!map)
+ return -1;
+ if (WARN_ON(!map->phys_map))
+ return -1;
+ if (WARN_ON(map->nr_map == 0) || WARN_ON(map->desc_size == 0))
+ return -1;
+
+ e = map->phys_map + map->nr_map * map->desc_size;
+ for (p = map->phys_map; p < e; p += map->desc_size) {
+ /*
+ * If a driver calls this after efi_free_boot_services,
+ * ->map will be NULL.
+ * So just always get our own virtual map on the CPU.
+ */
+ efi_memory_desc_t *md = phys_to_virt((phys_addr_t)p);
+ u64 size = md->num_pages << EFI_PAGE_SHIFT;
+ u64 end = md->phys_addr + size;
+ if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+ md->type != EFI_BOOT_SERVICES_CODE &&
+ md->type != EFI_BOOT_SERVICES_DATA)
+ continue;
+ if (!md->virt_addr)
+ continue;
+ if (phys_addr >= md->phys_addr && phys_addr < end)
+ return end - phys_addr;
+ }
+ return -1;
+}
/*
* We can't ioremap data in EFI boot services RAM, because we've already mapped
@@ -261,6 +303,7 @@ static __initdata efi_config_table_type_t common_tables[] = {
{SAL_SYSTEM_TABLE_GUID, "SALsystab", &efi.sal_systab},
{SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
{UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
+ {EFI_SYSTEM_RESOURCE_TABLE_GUID, "ESRT", &efi.esrt},
{NULL_GUID, NULL, NULL},
};
diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
new file mode 100644
index 0000000..ffa2144
--- /dev/null
+++ b/drivers/firmware/efi/esrt.c
@@ -0,0 +1,392 @@
+/*
+ * esrt.c
+ *
+ * This module exports EFI System Resource Table (ESRT) entries into userspace
+ * through the sysfs file system. The ESRT provides a read-only catalog of
+ * system components for which the system accepts firmware upgrades via UEFI's
+ * "Capsule Update" feature. This module allows userland utilties to evaluate
+ * what firmware updates can be applied to this system, and potentially arrange
+ * for those updates to occur.
+ *
+ * Data is currently found below /sys/firmware/efi/esrt/...
+ */
+#define pr_fmt(fmt) "esrt: " fmt
+
+#include <linux/capability.h>
+#include <linux/device.h>
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+typedef struct {
+ efi_guid_t fw_class;
+ u32 fw_type;
+ u32 fw_version;
+ u32 lowest_supported_fw_version;
+ u32 capsule_flags;
+ u32 last_attempt_version;
+ u32 last_attempt_status;
+} efi_system_resource_entry_t;
+
+/*
+ * _count and _version are what they seem like. _max is actually just
+ * accounting info for the firmware when creating the table; it should never
+ * have been exposed to us. To wit, the spec says:
+ * The maximum number of resource array entries that can be within the
+ * table without reallocating the table, must not be zero.
+ * Since there's no guidance about what that means in terms of memory layout,
+ * it means nothing to us.
+ */
+typedef struct {
+ u32 fw_resource_count;
+ u32 fw_resource_count_max;
+ u64 fw_resource_version;
+ efi_system_resource_entry_t entries[];
+} efi_system_resource_table_t;
+
+static efi_system_resource_table_t *esrt;
+
+struct esre_entry {
+ efi_system_resource_entry_t *esre;
+
+ struct kobject kobj;
+ struct list_head list;
+};
+
+/* global list of esre_entry. */
+static LIST_HEAD(entry_list);
+
+/* entry attribute */
+struct esre_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct esre_entry *entry, char *buf);
+ ssize_t (*store)(struct esre_entry *entry,
+ const char *buf, size_t count);
+};
+
+static struct esre_entry *to_entry(struct kobject *kobj)
+{
+ return container_of(kobj, struct esre_entry, kobj);
+}
+
+static struct esre_attribute *to_attr(struct attribute *attr)
+{
+ return container_of(attr, struct esre_attribute, attr);
+}
+
+static ssize_t esre_attr_show(struct kobject *kobj,
+ struct attribute *_attr, char *buf)
+{
+ struct esre_entry *entry = to_entry(kobj);
+ struct esre_attribute *attr = to_attr(_attr);
+
+ /* Don't tell normal users what firmware versions we've got... */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ return attr->show(entry, buf);
+}
+
+static const struct sysfs_ops esre_attr_ops = {
+ .show = esre_attr_show,
+};
+
+/* Generic ESRT Entry ("ESRE") support. */
+static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf)
+{
+ char *str = buf;
+ efi_guid_unparse(&entry->esre->fw_class, str);
+ str += strlen(str);
+ str += sprintf(str, "\n");
+
+ return str - buf;
+}
+
+static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400,
+ esre_fw_class_show, NULL);
+
+#define esre_attr_decl(name, size, fmt) \
+static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) { \
+ return sprintf(buf, fmt "\n", le##size##_to_cpu(entry->esre->name)); \
+} \
+\
+static struct esre_attribute esre_##name = __ATTR(name, 0400, \
+ esre_##name##_show, NULL)
+
+esre_attr_decl(fw_type, 32, "%u");
+esre_attr_decl(fw_version, 32, "%u");
+esre_attr_decl(lowest_supported_fw_version, 32,"%u");
+esre_attr_decl(capsule_flags, 32, "0x%x");
+esre_attr_decl(last_attempt_version, 32, "%u");
+esre_attr_decl(last_attempt_status, 32, "%u");
+
+static struct attribute *esre_attrs[] = {
+ &esre_fw_class.attr,
+ &esre_fw_type.attr,
+ &esre_fw_version.attr,
+ &esre_lowest_supported_fw_version.attr,
+ &esre_capsule_flags.attr,
+ &esre_last_attempt_version.attr,
+ &esre_last_attempt_status.attr,
+ NULL
+};
+
+static void esre_release(struct kobject *kobj)
+{
+ struct esre_entry *entry = to_entry(kobj);
+
+ list_del(&entry->list);
+ kfree(entry);
+}
+
+static struct kobj_type esre_ktype = {
+ .release = esre_release,
+ .sysfs_ops = &esre_attr_ops,
+ .default_attrs = esre_attrs,
+};
+
+static struct kobject *esrt_kobj;
+static struct kset *esrt_kset;
+
+static int esre_create_sysfs_entry(efi_system_resource_entry_t *esre)
+{
+ int rc;
+ struct esre_entry *entry;
+ char name[EFI_VARIABLE_GUID_LEN + 1];
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return -ENOMEM;
+
+ efi_guid_unparse(&esre->fw_class, name);
+
+ entry->esre = esre;
+ entry->kobj.kset = esrt_kset;
+ rc = kobject_init_and_add(&entry->kobj, &esre_ktype, NULL,
+ "%s", name);
+ if (rc) {
+ kfree(entry);
+ return rc;
+ }
+
+ list_add_tail(&entry->list, &entry_list);
+ return 0;
+}
+
+/* support for displaying ESRT fields at the top level */
+#define esrt_attr_decl(name, size, fmt) \
+static ssize_t esrt_##name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+{ \
+ return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \
+} \
+\
+static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \
+ esrt_##name##_show, NULL)
+
+esrt_attr_decl(fw_resource_count, 32, "%u");
+esrt_attr_decl(fw_resource_count_max, 32, "%u");
+esrt_attr_decl(fw_resource_version, 64, "%llu");
+
+static struct attribute *esrt_attrs[] = {
+ &esrt_fw_resource_count.attr,
+ &esrt_fw_resource_count_max.attr,
+ &esrt_fw_resource_version.attr,
+ NULL,
+};
+
+static inline int esrt_table_exists(void)
+{
+ if (!efi_enabled(EFI_CONFIG_TABLES))
+ return 0;
+ if (efi.esrt == EFI_INVALID_TABLE_ADDR)
+ return 0;
+ return 1;
+}
+
+static umode_t esrt_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ if (!esrt_table_exists())
+ return 0;
+ return attr->mode;
+}
+
+static struct attribute_group esrt_attr_group = {
+ .attrs = esrt_attrs,
+ .is_visible = esrt_attr_is_visible,
+};
+
+/*
+ * ioremap the table, copy it to kmalloced pages, and unmap it.
+ */
+static int esrt_duplicate_pages(void)
+{
+ efi_system_resource_table_t *tmpesrt;
+ efi_system_resource_entry_t *entries;
+ size_t size, max;
+ int err = -EINVAL;
+
+ if (!esrt_table_exists())
+ return err;
+
+ max = efi_mem_max_reasonable_size(efi.esrt);
+ if (max < 0) {
+ pr_err("ESRT header is not in the memory map.\n");
+ return err;
+ }
+ size = sizeof(*esrt);
+
+ if (max < size) {
+ pr_err("ESRT header doen't fit on single memory map entry.\n");
+ return err;
+ }
+
+ tmpesrt = ioremap(efi.esrt, size);
+ if (!tmpesrt) {
+ pr_err("ioremap failed.\n");
+ return -ENOMEM;
+ }
+
+ if (tmpesrt->fw_resource_count > 0 && max - size < sizeof (*entries)) {
+ pr_err("ESRT memory map entry can only hold the header.\n");
+ goto err_iounmap;
+ }
+
+ /*
+ * The format doesn't really give us any boundary to test here,
+ * so I'm making up 128 as the max number of individually updatable
+ * components we support.
+ * 128 should be pretty excessive, but there's still some chance
+ * somebody will do that someday and we'll need to raise this.
+ */
+ if (tmpesrt->fw_resource_count > 128) {
+ pr_err("ESRT says fw_resource_count has very large value %d.\n",
+ tmpesrt->fw_resource_count);
+ goto err_iounmap;
+ }
+
+ /*
+ * We know it can't be larger than N * sizeof() here, and N is limited
+ * by the previous test to a small number, so there's no overflow.
+ */
+ size += tmpesrt->fw_resource_count * sizeof (*entries);
+ if (max < size) {
+ pr_err("ESRT does not fit on single memory map entry.\n");
+ goto err_iounmap;
+ }
+
+ esrt = kmalloc(size, GFP_KERNEL);
+ if (!esrt) {
+ pr_err("kmalloc failed.\n");
+ err = -ENOMEM;
+ goto err_iounmap;
+ }
+
+ memcpy(esrt, tmpesrt, size);
+ err = 0;
+err_iounmap:
+ iounmap(tmpesrt);
+ return err;
+}
+
+static int register_entries(void)
+{
+ efi_system_resource_entry_t *entries = esrt->entries;
+ int i, rc;
+
+ if (!esrt_table_exists())
+ return 0;
+
+ for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {
+ rc = esre_create_sysfs_entry(&entries[i]);
+ if (rc < 0) {
+ pr_err("EFI System Resource Entry creation "
+ "failed with error %d.\n", rc);
+ return rc;
+ }
+ }
+ return 0;
+}
+
+static void cleanup_entry_list(void)
+{
+ struct esre_entry *entry, *next;
+
+ list_for_each_entry_safe(entry, next, &entry_list, list) {
+ kobject_put(&entry->kobj);
+ }
+}
+
+static int __init esrt_sysfs_init(void)
+{
+ int error;
+
+ error = esrt_duplicate_pages();
+ if (error)
+ return error;
+
+ esrt_kobj = kobject_create_and_add("esrt", efi_kobj);
+ if (!esrt_kobj) {
+ pr_err("Firmware table registration failed.\n");
+ error = -ENOMEM;
+ goto err;
+ }
+
+ error = sysfs_create_group(esrt_kobj, &esrt_attr_group);
+ if (error) {
+ pr_err("Sysfs attribute export failed with error %d.\n",
+ error);
+ goto err_remove_esrt;
+ }
+
+ esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj);
+ if (!esrt_kset) {
+ pr_err("kset creation failed.\n");
+ error = -ENOMEM;
+ goto err_remove_group;
+ }
+
+ error = register_entries();
+ if (error)
+ goto err_cleanup_list;
+
+ pr_debug("esrt-sysfs: loaded.\n");
+
+ return 0;
+err_cleanup_list:
+ cleanup_entry_list();
+ kset_unregister(esrt_kset);
+err_remove_group:
+ sysfs_remove_group(esrt_kobj, &esrt_attr_group);
+err_remove_esrt:
+ kobject_put(esrt_kobj);
+err:
+ kfree(esrt);
+ esrt = NULL;
+ return error;
+}
+
+static void __exit esrt_sysfs_exit(void)
+{
+ pr_debug("esrt-sysfs: unloading.\n");
+ cleanup_entry_list();
+ kset_unregister(esrt_kset);
+ sysfs_remove_group(esrt_kobj, &esrt_attr_group);
+ kfree(esrt);
+ esrt = NULL;
+ kobject_del(esrt_kobj);
+ kobject_put(esrt_kobj);
+}
+
+module_init(esrt_sysfs_init);
+module_exit(esrt_sysfs_exit);
+
+MODULE_AUTHOR("Peter Jones <pjones@xxxxxxxxxx>");
+MODULE_DESCRIPTION("EFI System Resource Table support");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 0949f9c..5b663a7 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -562,6 +562,9 @@ void efi_native_runtime_setup(void);
#define UV_SYSTEM_TABLE_GUID \
EFI_GUID( 0x3b13a7d4, 0x633e, 0x11dd, 0x93, 0xec, 0xda, 0x25, 0x56, 0xd8, 0x95, 0x93 )
+#define EFI_SYSTEM_RESOURCE_TABLE_GUID \
+ EFI_GUID( 0xb122a263, 0x3661, 0x4f68, 0x99, 0x29, 0x78, 0xf8, 0xb0, 0xd6, 0x21, 0x80 )
+
#define LINUX_EFI_CRASH_GUID \
EFI_GUID( 0xcfc8fc79, 0xbe2e, 0x4ddc, 0x97, 0xf0, 0x9f, 0x98, 0xbf, 0xe2, 0x98, 0xa0 )
@@ -819,6 +822,7 @@ extern struct efi {
unsigned long fw_vendor; /* fw_vendor */
unsigned long runtime; /* runtime table */
unsigned long config_table; /* config tables */
+ unsigned long esrt; /* EFI System Resource Table */
efi_get_time_t *get_time;
efi_set_time_t *set_time;
efi_get_wakeup_time_t *get_wakeup_time;
@@ -875,6 +879,7 @@ extern u64 efi_get_iobase (void);
extern u32 efi_mem_type (unsigned long phys_addr);
extern u64 efi_mem_attributes (unsigned long phys_addr);
extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size);
+extern u64 efi_mem_max_reasonable_size(u64 phys_addr);
extern int __init efi_uart_console_only (void);
extern void efi_initialize_iomem_resources(struct resource *code_resource,
struct resource *data_resource, struct resource *bss_resource);
@@ -882,6 +887,7 @@ extern void efi_get_time(struct timespec *now);
extern void efi_reserve_boot_services(void);
extern int efi_get_fdt_params(struct efi_fdt_params *params, int verbose);
extern struct efi_memory_map memmap;
+extern struct kobject *efi_kobj;
extern int efi_reboot_quirk_mode;
extern bool efi_poweroff_required(void);
--
2.1.0
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