Abstract out support for locating an EFI config table

We want to grab a pointer to the TPM final events table, so abstract out
the existing code for finding an FDT table and make it generic.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

3 files changed, 26 insertions, 18 deletions

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index e4610e72b78f..1db780c0f07b 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -926,3 +926,18 @@ free_map:
 fail:
         return status;
 }
+
+void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid)
+{
+        efi_config_table_t *tables = (efi_config_table_t *)sys_table->tables;
+        int i;
+
+        for (i = 0; i < sys_table->nr_tables; i++) {
+                if (efi_guidcmp(tables[i].guid, guid) != 0)
+                        continue;
+
+                return (void *)tables[i].table;
+        }
+
+        return NULL;
+}
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 1b1dfcaa6fb9..7f1556fd867d 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -65,6 +65,8 @@ efi_status_t check_platform_features(efi_system_table_t *sys_table_arg);
 
 efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg);
 
+void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid);
+
 /* Helper macros for the usual case of using simple C variables: */
 #ifndef fdt_setprop_inplace_var
 #define fdt_setprop_inplace_var(fdt, node_offset, name, var) \
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 5440ba17a1c5..0bf0190917e0 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -363,26 +363,17 @@ fail:
 
 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
 {
-        efi_guid_t fdt_guid = DEVICE_TREE_GUID;
-        efi_config_table_t *tables;
-        int i;
+        void *fdt;
 
-        tables = (efi_config_table_t *)sys_table->tables;
+        fdt = get_efi_config_table(sys_table, DEVICE_TREE_GUID);
 
-        for (i = 0; i < sys_table->nr_tables; i++) {
-                void *fdt;
+        if (!fdt)
+                return NULL;
 
-                if (efi_guidcmp(tables[i].guid, fdt_guid) != 0)
-                        continue;
-
-                fdt = (void *)tables[i].table;
-                if (fdt_check_header(fdt) != 0) {
-                        pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
-                        return NULL;
-                }
-                *fdt_size = fdt_totalsize(fdt);
-                return fdt;
+        if (fdt_check_header(fdt) != 0) {
+                pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
+                return NULL;
         }
-
-        return NULL;
+        *fdt_size = fdt_totalsize(fdt);
+        return fdt;
 }