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");