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@@ -0,0 +1,471 @@
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+/*
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+ * esrt.c
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+ *
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+ * This module exports EFI System Resource Table (ESRT) entries into userspace
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+ * through the sysfs file system. The ESRT provides a read-only catalog of
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+ * system components for which the system accepts firmware upgrades via UEFI's
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+ * "Capsule Update" feature. This module allows userland utilities to evaluate
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+ * what firmware updates can be applied to this system, and potentially arrange
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+ * for those updates to occur.
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+ *
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+ * Data is currently found below /sys/firmware/efi/esrt/...
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+ */
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+#define pr_fmt(fmt) "esrt: " fmt
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+
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+#include <linux/capability.h>
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+#include <linux/device.h>
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+#include <linux/efi.h>
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+#include <linux/init.h>
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+#include <linux/kernel.h>
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+#include <linux/kobject.h>
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+#include <linux/list.h>
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+#include <linux/memblock.h>
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+#include <linux/module.h>
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+#include <linux/slab.h>
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+#include <linux/types.h>
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+
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+#include <asm/io.h>
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+#include <asm/early_ioremap.h>
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+
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+struct efi_system_resource_entry_v1 {
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+ efi_guid_t fw_class;
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+ u32 fw_type;
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+ u32 fw_version;
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+ u32 lowest_supported_fw_version;
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+ u32 capsule_flags;
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+ u32 last_attempt_version;
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+ u32 last_attempt_status;
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+};
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+
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+/*
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+ * _count and _version are what they seem like. _max is actually just
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+ * accounting info for the firmware when creating the table; it should never
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+ * have been exposed to us. To wit, the spec says:
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+ * The maximum number of resource array entries that can be within the
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+ * table without reallocating the table, must not be zero.
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+ * Since there's no guidance about what that means in terms of memory layout,
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+ * it means nothing to us.
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+ */
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+struct efi_system_resource_table {
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+ u32 fw_resource_count;
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+ u32 fw_resource_count_max;
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+ u64 fw_resource_version;
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+ u8 entries[];
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+};
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+
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+static phys_addr_t esrt_data;
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+static size_t esrt_data_size;
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+
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+static struct efi_system_resource_table *esrt;
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+
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+struct esre_entry {
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+ union {
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+ struct efi_system_resource_entry_v1 *esre1;
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+ } esre;
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+
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+ struct kobject kobj;
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+ struct list_head list;
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+};
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+
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+/* global list of esre_entry. */
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+static LIST_HEAD(entry_list);
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+
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+/* entry attribute */
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+struct esre_attribute {
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+ struct attribute attr;
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+ ssize_t (*show)(struct esre_entry *entry, char *buf);
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+ ssize_t (*store)(struct esre_entry *entry,
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+ const char *buf, size_t count);
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+};
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+
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+static struct esre_entry *to_entry(struct kobject *kobj)
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+{
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+ return container_of(kobj, struct esre_entry, kobj);
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+}
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+
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+static struct esre_attribute *to_attr(struct attribute *attr)
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+{
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+ return container_of(attr, struct esre_attribute, attr);
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+}
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+
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+static ssize_t esre_attr_show(struct kobject *kobj,
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+ struct attribute *_attr, char *buf)
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+{
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+ struct esre_entry *entry = to_entry(kobj);
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+ struct esre_attribute *attr = to_attr(_attr);
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+
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+ /* Don't tell normal users what firmware versions we've got... */
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+ if (!capable(CAP_SYS_ADMIN))
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+ return -EACCES;
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+
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+ return attr->show(entry, buf);
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+}
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+
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+static const struct sysfs_ops esre_attr_ops = {
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+ .show = esre_attr_show,
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+};
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+
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+/* Generic ESRT Entry ("ESRE") support. */
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+static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf)
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+{
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+ char *str = buf;
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+
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+ efi_guid_to_str(&entry->esre.esre1->fw_class, str);
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+ str += strlen(str);
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+ str += sprintf(str, "\n");
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+
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+ return str - buf;
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+}
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+
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+static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400,
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+ esre_fw_class_show, NULL);
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+
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+#define esre_attr_decl(name, size, fmt) \
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+static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) \
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+{ \
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+ return sprintf(buf, fmt "\n", \
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+ le##size##_to_cpu(entry->esre.esre1->name)); \
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+} \
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+\
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+static struct esre_attribute esre_##name = __ATTR(name, 0400, \
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+ esre_##name##_show, NULL)
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+
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+esre_attr_decl(fw_type, 32, "%u");
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+esre_attr_decl(fw_version, 32, "%u");
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+esre_attr_decl(lowest_supported_fw_version, 32, "%u");
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+esre_attr_decl(capsule_flags, 32, "0x%x");
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+esre_attr_decl(last_attempt_version, 32, "%u");
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+esre_attr_decl(last_attempt_status, 32, "%u");
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+
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+static struct attribute *esre1_attrs[] = {
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+ &esre_fw_class.attr,
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+ &esre_fw_type.attr,
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+ &esre_fw_version.attr,
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+ &esre_lowest_supported_fw_version.attr,
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+ &esre_capsule_flags.attr,
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+ &esre_last_attempt_version.attr,
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+ &esre_last_attempt_status.attr,
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+ NULL
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+};
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+static void esre_release(struct kobject *kobj)
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+{
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+ struct esre_entry *entry = to_entry(kobj);
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+
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+ list_del(&entry->list);
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+ kfree(entry);
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+}
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+
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+static struct kobj_type esre1_ktype = {
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+ .release = esre_release,
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+ .sysfs_ops = &esre_attr_ops,
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+ .default_attrs = esre1_attrs,
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+};
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+
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+
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+static struct kobject *esrt_kobj;
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+static struct kset *esrt_kset;
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+
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+static int esre_create_sysfs_entry(void *esre, int entry_num)
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+{
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+ struct esre_entry *entry;
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+ char name[20];
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+
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+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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+ if (!entry)
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+ return -ENOMEM;
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+
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+ sprintf(name, "entry%d", entry_num);
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+
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+ entry->kobj.kset = esrt_kset;
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+
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+ if (esrt->fw_resource_version == 1) {
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+ int rc = 0;
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+
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+ entry->esre.esre1 = esre;
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+ rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,
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+ "%s", name);
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+ if (rc) {
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+ kfree(entry);
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+ return rc;
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+ }
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+ }
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+
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+ list_add_tail(&entry->list, &entry_list);
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+ return 0;
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+}
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+
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+/* support for displaying ESRT fields at the top level */
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+#define esrt_attr_decl(name, size, fmt) \
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+static ssize_t esrt_##name##_show(struct kobject *kobj, \
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+ struct kobj_attribute *attr, char *buf)\
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+{ \
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+ return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \
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+} \
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+\
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+static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \
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+ esrt_##name##_show, NULL)
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+
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+esrt_attr_decl(fw_resource_count, 32, "%u");
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+esrt_attr_decl(fw_resource_count_max, 32, "%u");
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+esrt_attr_decl(fw_resource_version, 64, "%llu");
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+
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+static struct attribute *esrt_attrs[] = {
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+ &esrt_fw_resource_count.attr,
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+ &esrt_fw_resource_count_max.attr,
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+ &esrt_fw_resource_version.attr,
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+ NULL,
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+};
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+
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+static inline int esrt_table_exists(void)
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+{
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+ if (!efi_enabled(EFI_CONFIG_TABLES))
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+ return 0;
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+ if (efi.esrt == EFI_INVALID_TABLE_ADDR)
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+ return 0;
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+ return 1;
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+}
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+
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+static umode_t esrt_attr_is_visible(struct kobject *kobj,
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+ struct attribute *attr, int n)
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+{
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+ if (!esrt_table_exists())
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+ return 0;
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+ return attr->mode;
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+}
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+
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+static struct attribute_group esrt_attr_group = {
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+ .attrs = esrt_attrs,
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+ .is_visible = esrt_attr_is_visible,
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+};
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+
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+/*
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+ * remap the table, copy it to kmalloced pages, and unmap it.
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+ */
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+void __init efi_esrt_init(void)
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+{
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+ void *va;
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+ struct efi_system_resource_table tmpesrt;
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+ struct efi_system_resource_entry_v1 *v1_entries;
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+ size_t size, max, entry_size, entries_size;
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+ efi_memory_desc_t md;
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+ int rc;
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+ phys_addr_t end;
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+
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+ pr_debug("esrt-init: loading.\n");
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+ if (!esrt_table_exists())
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+ return;
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+
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+ rc = efi_mem_desc_lookup(efi.esrt, &md);
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+ if (rc < 0) {
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+ pr_err("ESRT header is not in the memory map.\n");
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+ return;
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+ }
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+
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+ max = efi_mem_desc_end(&md);
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+ if (max < efi.esrt) {
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+ pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n",
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+ (void *)efi.esrt, (void *)max);
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+ return;
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+ }
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+
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+ size = sizeof(*esrt);
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+ max -= efi.esrt;
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+
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+ if (max < size) {
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+ pr_err("ESRT header doen't fit on single memory map entry. (size: %zu max: %zu)\n",
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+ size, max);
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+ return;
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+ }
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+
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+ va = early_memremap(efi.esrt, size);
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+ if (!va) {
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+ pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
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+ size);
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+ return;
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+ }
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+
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+ memcpy(&tmpesrt, va, sizeof(tmpesrt));
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+
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+ if (tmpesrt.fw_resource_version == 1) {
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+ entry_size = sizeof (*v1_entries);
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+ } else {
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+ pr_err("Unsupported ESRT version %lld.\n",
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+ tmpesrt.fw_resource_version);
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+ return;
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+ }
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+
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+ if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
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+ pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
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+ max - size, entry_size);
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+ goto err_memunmap;
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+ }
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+
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+ /*
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+ * The format doesn't really give us any boundary to test here,
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+ * so I'm making up 128 as the max number of individually updatable
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+ * components we support.
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+ * 128 should be pretty excessive, but there's still some chance
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+ * somebody will do that someday and we'll need to raise this.
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+ */
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+ if (tmpesrt.fw_resource_count > 128) {
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+ pr_err("ESRT says fw_resource_count has very large value %d.\n",
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+ tmpesrt.fw_resource_count);
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+ goto err_memunmap;
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+ }
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+
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+ /*
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+ * We know it can't be larger than N * sizeof() here, and N is limited
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+ * by the previous test to a small number, so there's no overflow.
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+ */
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+ entries_size = tmpesrt.fw_resource_count * entry_size;
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+ if (max < size + entries_size) {
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+ pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
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+ size, max);
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+ goto err_memunmap;
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+ }
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+
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+ /* remap it with our (plausible) new pages */
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+ early_memunmap(va, size);
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+ size += entries_size;
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+ va = early_memremap(efi.esrt, size);
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+ if (!va) {
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+ pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
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+ size);
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+ return;
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+ }
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+
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+ esrt_data = (phys_addr_t)efi.esrt;
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+ esrt_data_size = size;
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+
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+ end = esrt_data + size;
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+ pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
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+ memblock_reserve(esrt_data, esrt_data_size);
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+
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+ pr_debug("esrt-init: loaded.\n");
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+err_memunmap:
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+ early_memunmap(va, size);
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+}
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+
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+static int __init register_entries(void)
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+{
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+ struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries;
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+ int i, rc;
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+
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+ if (!esrt_table_exists())
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+ return 0;
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+
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+ for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {
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+ void *esre = NULL;
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+ if (esrt->fw_resource_version == 1) {
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+ esre = &v1_entries[i];
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+ } else {
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+ pr_err("Unsupported ESRT version %lld.\n",
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+ esrt->fw_resource_version);
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+ return -EINVAL;
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+ }
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+
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+ rc = esre_create_sysfs_entry(esre, i);
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+ if (rc < 0) {
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+ pr_err("ESRT entry creation failed with error %d.\n",
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+ rc);
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+ return rc;
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+ }
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+ }
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+ return 0;
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+}
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+
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+static void cleanup_entry_list(void)
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+{
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+ struct esre_entry *entry, *next;
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+
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+ list_for_each_entry_safe(entry, next, &entry_list, list) {
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+ kobject_put(&entry->kobj);
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+ }
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+}
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+
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+static int __init esrt_sysfs_init(void)
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+{
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+ int error;
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+ struct efi_system_resource_table __iomem *ioesrt;
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+
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+ pr_debug("esrt-sysfs: loading.\n");
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+ if (!esrt_data || !esrt_data_size)
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+ return -ENOSYS;
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+
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+ ioesrt = ioremap(esrt_data, esrt_data_size);
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+ if (!ioesrt) {
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+ pr_err("ioremap(%pa, %zu) failed.\n", &esrt_data,
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+ esrt_data_size);
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+ return -ENOMEM;
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+ }
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+
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+ esrt = kmalloc(esrt_data_size, GFP_KERNEL);
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+ if (!esrt) {
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+ pr_err("kmalloc failed. (wanted %zu bytes)\n", esrt_data_size);
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+ iounmap(ioesrt);
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+ return -ENOMEM;
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+ }
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+
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|
+ memcpy_fromio(esrt, ioesrt, esrt_data_size);
|
|
|
+
|
|
|
+ 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;
|
|
|
+
|
|
|
+ memblock_remove(esrt_data, esrt_data_size);
|
|
|
+
|
|
|
+ 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@redhat.com>");
|
|
|
+MODULE_DESCRIPTION("EFI System Resource Table support");
|
|
|
+MODULE_LICENSE("GPL");
|
Ingo Molnar