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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.c251
1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
new file mode 100644
index 000000000000..67615d6d038d
--- /dev/null
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -0,0 +1,251 @@
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/pstore.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)
+{
+ efivar_entry_iter_begin();
+ psi->data = NULL;
+ return 0;
+}
+
+static int efi_pstore_close(struct pstore_info *psi)
+{
+ efivar_entry_iter_end();
+ psi->data = NULL;
+ return 0;
+}
+
+struct pstore_read_data {
+ u64 *id;
+ enum pstore_type_id *type;
+ int *count;
+ struct timespec *timespec;
+ char **buf;
+};
+
+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];
+ 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",
+ cb_data->type, &part, &cnt, &time) == 4) {
+ *cb_data->id = part;
+ *cb_data->count = cnt;
+ cb_data->timespec->tv_sec = time;
+ cb_data->timespec->tv_nsec = 0;
+ } 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 = part;
+ *cb_data->count = 0;
+ cb_data->timespec->tv_sec = time;
+ cb_data->timespec->tv_nsec = 0;
+ } else
+ return 0;
+
+ entry->var.DataSize = 1024;
+ __efivar_entry_get(entry, &entry->var.Attributes,
+ &entry->var.DataSize, entry->var.Data);
+ size = entry->var.DataSize;
+
+ *cb_data->buf = kmalloc(size, GFP_KERNEL);
+ if (*cb_data->buf == NULL)
+ return -ENOMEM;
+ memcpy(*cb_data->buf, entry->var.Data, size);
+ return size;
+}
+
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+ int *count, struct timespec *timespec,
+ char **buf, struct pstore_info *psi)
+{
+ struct pstore_read_data data;
+
+ data.id = id;
+ data.type = type;
+ data.count = count;
+ data.timespec = timespec;
+ data.buf = buf;
+
+ return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
+ (struct efivar_entry **)&psi->data);
+}
+
+static int efi_pstore_write(enum pstore_type_id type,
+ enum kmsg_dump_reason reason, u64 *id,
+ unsigned int part, int count, 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", type, part, count,
+ get_seconds());
+
+ 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;
+ }
+
+ /* found */
+ __efivar_entry_delete(entry);
+ list_del(&entry->list);
+
+ 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;
+
+ sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
+ time.tv_sec);
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name[i] = name[i];
+
+ edata.id = id;
+ 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);
+ efivar_entry_iter_end();
+
+ if (found)
+ efivar_unregister(entry);
+
+ return 0;
+}
+
+static struct pstore_info efi_pstore_info = {
+ .owner = THIS_MODULE,
+ .name = "efi",
+ .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);
+
+ pstore_register(&efi_pstore_info);
+
+ 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");