efi: split off remapping code from efi_config_init()

Split of the remapping code from efi_config_init() so that the caller
can perform its own remapping. This is necessary to correctly handle
virtually remapped UEFI memory regions under kexec, as efi.systab will
have been updated to a virtual address.

Acked-by: Matt Fleming <matt.fleming@intel.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

2 files changed, 34 insertions, 24 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 9035c1b74d58..b7ba9d8ec4b0 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -293,29 +293,15 @@ static __init int match_config_table(efi_guid_t *guid,
         return 0;
 }
 
-int __init efi_config_init(efi_config_table_type_t *arch_tables)
+int __init efi_config_parse_tables(void *config_tables, int count, int sz,
+                                   efi_config_table_type_t *arch_tables)
 {
-        void *config_tables, *tablep;
-        int i, sz;
-
-        if (efi_enabled(EFI_64BIT))
-                sz = sizeof(efi_config_table_64_t);
-        else
-                sz = sizeof(efi_config_table_32_t);
-
-        /*
-         * Let's see what config tables the firmware passed to us.
-         */
-        config_tables = early_memremap(efi.systab->tables,
-                                       efi.systab->nr_tables * sz);
-        if (config_tables == NULL) {
-                pr_err("Could not map Configuration table!\n");
-                return -ENOMEM;
-        }
+        void *tablep;
+        int i;
 
         tablep = config_tables;
         pr_info("");
-        for (i = 0; i < efi.systab->nr_tables; i++) {
+        for (i = 0; i < count; i++) {
                 efi_guid_t guid;
                 unsigned long table;
 
@@ -328,8 +314,6 @@ int __init efi_config_init(efi_config_table_type_t *arch_tables)
                         if (table64 >> 32) {
                                 pr_cont("\n");
                                 pr_err("Table located above 4GB, disabling EFI.\n");
-                                early_memunmap(config_tables,
-                                               efi.systab->nr_tables * sz);
                                 return -EINVAL;
                         }
 #endif
@@ -344,13 +328,37 @@ int __init efi_config_init(efi_config_table_type_t *arch_tables)
                 tablep += sz;
         }
         pr_cont("\n");
-        early_memunmap(config_tables, efi.systab->nr_tables * sz);
-
         set_bit(EFI_CONFIG_TABLES, &efi.flags);
-
         return 0;
 }
 
+int __init efi_config_init(efi_config_table_type_t *arch_tables)
+{
+        void *config_tables;
+        int sz, ret;
+
+        if (efi_enabled(EFI_64BIT))
+                sz = sizeof(efi_config_table_64_t);
+        else
+                sz = sizeof(efi_config_table_32_t);
+
+        /*
+         * Let's see what config tables the firmware passed to us.
+         */
+        config_tables = early_memremap(efi.systab->tables,
+                                       efi.systab->nr_tables * sz);
+        if (config_tables == NULL) {
+                pr_err("Could not map Configuration table!\n");
+                return -ENOMEM;
+        }
+
+        ret = efi_config_parse_tables(config_tables, efi.systab->nr_tables, sz,
+                                      arch_tables);
+
+        early_memunmap(config_tables, efi.systab->nr_tables * sz);
+        return ret;
+}
+
 #ifdef CONFIG_EFI_VARS_MODULE
 static int __init efi_load_efivars(void)
 {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 0238d612750e..5ffe5115951f 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -875,6 +875,8 @@ static inline efi_status_t efi_query_variable_store(u32 attributes, unsigned lon
 #endif
 extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
 extern int efi_config_init(efi_config_table_type_t *arch_tables);
+extern int efi_config_parse_tables(void *config_tables, int count, int sz,
+                                   efi_config_table_type_t *arch_tables);
 extern u64 efi_get_iobase (void);
 extern u32 efi_mem_type (unsigned long phys_addr);
 extern u64 efi_mem_attributes (unsigned long phys_addr);