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path: root/drivers/firmware/efi/efi-pstore.c
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Diffstat (limited to 'drivers/firmware/efi/efi-pstore.c')
-rw-r--r--drivers/firmware/efi/efi-pstore.c402
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
new file mode 100644
index 000000000..e992abc5e
--- /dev/null
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -0,0 +1,402 @@
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/pstore.h>
+#include <linux/slab.h>
+#include <linux/ucs2_string.h>
+
+#define DUMP_NAME_LEN 52
+
+static bool efivars_pstore_disable =
+ IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
+
+module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
+
+#define PSTORE_EFI_ATTRIBUTES \
+ (EFI_VARIABLE_NON_VOLATILE | \
+ EFI_VARIABLE_BOOTSERVICE_ACCESS | \
+ EFI_VARIABLE_RUNTIME_ACCESS)
+
+static int efi_pstore_open(struct pstore_info *psi)
+{
+ psi->data = NULL;
+ return 0;
+}
+
+static int efi_pstore_close(struct pstore_info *psi)
+{
+ psi->data = NULL;
+ return 0;
+}
+
+struct pstore_read_data {
+ u64 *id;
+ enum pstore_type_id *type;
+ int *count;
+ struct timespec *timespec;
+ bool *compressed;
+ char **buf;
+};
+
+static inline u64 generic_id(unsigned long timestamp,
+ unsigned int part, int count)
+{
+ return ((u64) timestamp * 100 + part) * 1000 + count;
+}
+
+static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
+{
+ efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+ struct pstore_read_data *cb_data = data;
+ char name[DUMP_NAME_LEN], data_type;
+ int i;
+ int cnt;
+ unsigned int part;
+ unsigned long time, size;
+
+ if (efi_guidcmp(entry->var.VendorGuid, vendor))
+ return 0;
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ name[i] = entry->var.VariableName[i];
+
+ if (sscanf(name, "dump-type%u-%u-%d-%lu-%c",
+ cb_data->type, &part, &cnt, &time, &data_type) == 5) {
+ *cb_data->id = generic_id(time, part, cnt);
+ *cb_data->count = cnt;
+ cb_data->timespec->tv_sec = time;
+ cb_data->timespec->tv_nsec = 0;
+ if (data_type == 'C')
+ *cb_data->compressed = true;
+ else
+ *cb_data->compressed = false;
+ } else if (sscanf(name, "dump-type%u-%u-%d-%lu",
+ cb_data->type, &part, &cnt, &time) == 4) {
+ *cb_data->id = generic_id(time, part, cnt);
+ *cb_data->count = cnt;
+ cb_data->timespec->tv_sec = time;
+ cb_data->timespec->tv_nsec = 0;
+ *cb_data->compressed = false;
+ } else if (sscanf(name, "dump-type%u-%u-%lu",
+ cb_data->type, &part, &time) == 3) {
+ /*
+ * Check if an old format,
+ * which doesn't support holding
+ * multiple logs, remains.
+ */
+ *cb_data->id = generic_id(time, part, 0);
+ *cb_data->count = 0;
+ cb_data->timespec->tv_sec = time;
+ cb_data->timespec->tv_nsec = 0;
+ *cb_data->compressed = false;
+ } else
+ return 0;
+
+ entry->var.DataSize = 1024;
+ __efivar_entry_get(entry, &entry->var.Attributes,
+ &entry->var.DataSize, entry->var.Data);
+ size = entry->var.DataSize;
+ memcpy(*cb_data->buf, entry->var.Data,
+ (size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX, size));
+
+ return size;
+}
+
+/**
+ * efi_pstore_scan_sysfs_enter
+ * @entry: scanning entry
+ * @next: next entry
+ * @head: list head
+ */
+static void efi_pstore_scan_sysfs_enter(struct efivar_entry *pos,
+ struct efivar_entry *next,
+ struct list_head *head)
+{
+ pos->scanning = true;
+ if (&next->list != head)
+ next->scanning = true;
+}
+
+/**
+ * __efi_pstore_scan_sysfs_exit
+ * @entry: deleting entry
+ * @turn_off_scanning: Check if a scanning flag should be turned off
+ */
+static inline void __efi_pstore_scan_sysfs_exit(struct efivar_entry *entry,
+ bool turn_off_scanning)
+{
+ if (entry->deleting) {
+ list_del(&entry->list);
+ efivar_entry_iter_end();
+ efivar_unregister(entry);
+ efivar_entry_iter_begin();
+ } else if (turn_off_scanning)
+ entry->scanning = false;
+}
+
+/**
+ * efi_pstore_scan_sysfs_exit
+ * @pos: scanning entry
+ * @next: next entry
+ * @head: list head
+ * @stop: a flag checking if scanning will stop
+ */
+static void efi_pstore_scan_sysfs_exit(struct efivar_entry *pos,
+ struct efivar_entry *next,
+ struct list_head *head, bool stop)
+{
+ __efi_pstore_scan_sysfs_exit(pos, true);
+ if (stop)
+ __efi_pstore_scan_sysfs_exit(next, &next->list != head);
+}
+
+/**
+ * efi_pstore_sysfs_entry_iter
+ *
+ * @data: function-specific data to pass to callback
+ * @pos: entry to begin iterating from
+ *
+ * You MUST call efivar_enter_iter_begin() before this function, and
+ * efivar_entry_iter_end() afterwards.
+ *
+ * It is possible to begin iteration from an arbitrary entry within
+ * the list by passing @pos. @pos is updated on return to point to
+ * the next entry of the last one passed to efi_pstore_read_func().
+ * To begin iterating from the beginning of the list @pos must be %NULL.
+ */
+static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
+{
+ struct efivar_entry *entry, *n;
+ struct list_head *head = &efivar_sysfs_list;
+ int size = 0;
+
+ if (!*pos) {
+ list_for_each_entry_safe(entry, n, head, list) {
+ efi_pstore_scan_sysfs_enter(entry, n, head);
+
+ size = efi_pstore_read_func(entry, data);
+ efi_pstore_scan_sysfs_exit(entry, n, head, size < 0);
+ if (size)
+ break;
+ }
+ *pos = n;
+ return size;
+ }
+
+ list_for_each_entry_safe_from((*pos), n, head, list) {
+ efi_pstore_scan_sysfs_enter((*pos), n, head);
+
+ size = efi_pstore_read_func((*pos), data);
+ efi_pstore_scan_sysfs_exit((*pos), n, head, size < 0);
+ if (size)
+ break;
+ }
+ *pos = n;
+ return size;
+}
+
+/**
+ * efi_pstore_read
+ *
+ * This function returns a size of NVRAM entry logged via efi_pstore_write().
+ * The meaning and behavior of efi_pstore/pstore are as below.
+ *
+ * size > 0: Got data of an entry logged via efi_pstore_write() successfully,
+ * and pstore filesystem will continue reading subsequent entries.
+ * size == 0: Entry was not logged via efi_pstore_write(),
+ * and efi_pstore driver will continue reading subsequent entries.
+ * size < 0: Failed to get data of entry logging via efi_pstore_write(),
+ * and pstore will stop reading entry.
+ */
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+ int *count, struct timespec *timespec,
+ char **buf, bool *compressed,
+ struct pstore_info *psi)
+{
+ struct pstore_read_data data;
+ ssize_t size;
+
+ data.id = id;
+ data.type = type;
+ data.count = count;
+ data.timespec = timespec;
+ data.compressed = compressed;
+ data.buf = buf;
+
+ *data.buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL);
+ if (!*data.buf)
+ return -ENOMEM;
+
+ efivar_entry_iter_begin();
+ size = efi_pstore_sysfs_entry_iter(&data,
+ (struct efivar_entry **)&psi->data);
+ efivar_entry_iter_end();
+ if (size <= 0)
+ kfree(*data.buf);
+ return size;
+}
+
+static int efi_pstore_write(enum pstore_type_id type,
+ enum kmsg_dump_reason reason, u64 *id,
+ unsigned int part, int count, bool compressed, size_t size,
+ struct pstore_info *psi)
+{
+ char name[DUMP_NAME_LEN];
+ efi_char16_t efi_name[DUMP_NAME_LEN];
+ efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+ int i, ret = 0;
+
+ sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count,
+ get_seconds(), compressed ? 'C' : 'D');
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name[i] = name[i];
+
+ efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
+ !pstore_cannot_block_path(reason),
+ size, psi->buf);
+
+ if (reason == KMSG_DUMP_OOPS)
+ efivar_run_worker();
+
+ *id = part;
+ return ret;
+};
+
+struct pstore_erase_data {
+ u64 id;
+ enum pstore_type_id type;
+ int count;
+ struct timespec time;
+ efi_char16_t *name;
+};
+
+/*
+ * Clean up an entry with the same name
+ */
+static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
+{
+ struct pstore_erase_data *ed = data;
+ efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+ efi_char16_t efi_name_old[DUMP_NAME_LEN];
+ efi_char16_t *efi_name = ed->name;
+ unsigned long ucs2_len = ucs2_strlen(ed->name);
+ char name_old[DUMP_NAME_LEN];
+ int i;
+
+ if (efi_guidcmp(entry->var.VendorGuid, vendor))
+ return 0;
+
+ if (ucs2_strncmp(entry->var.VariableName,
+ efi_name, (size_t)ucs2_len)) {
+ /*
+ * Check if an old format, which doesn't support
+ * holding multiple logs, remains.
+ */
+ sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
+ (unsigned int)ed->id, ed->time.tv_sec);
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name_old[i] = name_old[i];
+
+ if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
+ ucs2_strlen(efi_name_old)))
+ return 0;
+ }
+
+ if (entry->scanning) {
+ /*
+ * Skip deletion because this entry will be deleted
+ * after scanning is completed.
+ */
+ entry->deleting = true;
+ } else
+ list_del(&entry->list);
+
+ /* found */
+ __efivar_entry_delete(entry);
+
+ return 1;
+}
+
+static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
+ struct timespec time, struct pstore_info *psi)
+{
+ struct pstore_erase_data edata;
+ struct efivar_entry *entry = NULL;
+ char name[DUMP_NAME_LEN];
+ efi_char16_t efi_name[DUMP_NAME_LEN];
+ int found, i;
+ unsigned int part;
+
+ do_div(id, 1000);
+ part = do_div(id, 100);
+ sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, time.tv_sec);
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name[i] = name[i];
+
+ edata.id = part;
+ edata.type = type;
+ edata.count = count;
+ edata.time = time;
+ edata.name = efi_name;
+
+ efivar_entry_iter_begin();
+ found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
+
+ if (found && !entry->scanning) {
+ efivar_entry_iter_end();
+ efivar_unregister(entry);
+ } else
+ efivar_entry_iter_end();
+
+ return 0;
+}
+
+static struct pstore_info efi_pstore_info = {
+ .owner = THIS_MODULE,
+ .name = "efi",
+ .flags = PSTORE_FLAGS_FRAGILE,
+ .open = efi_pstore_open,
+ .close = efi_pstore_close,
+ .read = efi_pstore_read,
+ .write = efi_pstore_write,
+ .erase = efi_pstore_erase,
+};
+
+static __init int efivars_pstore_init(void)
+{
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return 0;
+
+ if (!efivars_kobject())
+ return 0;
+
+ if (efivars_pstore_disable)
+ return 0;
+
+ efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+ if (!efi_pstore_info.buf)
+ return -ENOMEM;
+
+ efi_pstore_info.bufsize = 1024;
+ spin_lock_init(&efi_pstore_info.buf_lock);
+
+ if (pstore_register(&efi_pstore_info)) {
+ kfree(efi_pstore_info.buf);
+ efi_pstore_info.buf = NULL;
+ efi_pstore_info.bufsize = 0;
+ }
+
+ return 0;
+}
+
+static __exit void efivars_pstore_exit(void)
+{
+}
+
+module_init(efivars_pstore_init);
+module_exit(efivars_pstore_exit);
+
+MODULE_DESCRIPTION("EFI variable backend for pstore");
+MODULE_LICENSE("GPL");