efi_loader: Improve install_configuration_table

The INSTALL_CONFIGURATION_TABLE callback also provides the ability to
remove table entries. This patch adds that functionality.

Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 9a1a93fade15f5ba1de84b26af6e22321121f872..17c531a480e145dcc31acccbb5eec78990b067cc 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -630,6 +630,17 @@ static efi_status_t EFIAPI efi_locate_device_path(efi_guid_t *protocol,
        return EFI_EXIT(EFI_NOT_FOUND);
 }
 
+/* Collapses configuration table entries, removing index i */
+static void efi_remove_configuration_table(int i)
+{
+       struct efi_configuration_table *this = &efi_conf_table[i];
+       struct efi_configuration_table *next = &efi_conf_table[i+1];
+       struct efi_configuration_table *end = &efi_conf_table[systab.nr_tables];
+
+       memmove(this, next, (ulong)end - (ulong)next);
+       systab.nr_tables--;
+}
+
 efi_status_t efi_install_configuration_table(const efi_guid_t *guid, void *table)
 {
        int i;
@@ -637,11 +648,17 @@ efi_status_t efi_install_configuration_table(const efi_guid_t *guid, void *table
        /* Check for guid override */
        for (i = 0; i < systab.nr_tables; i++) {
                if (!guidcmp(guid, &efi_conf_table[i].guid)) {
-                       efi_conf_table[i].table = table;
+                       if (table)
+                               efi_conf_table[i].table = table;
+                       else
+                               efi_remove_configuration_table(i);
                        return EFI_SUCCESS;
                }
        }
 
+       if (!table)
+               return EFI_NOT_FOUND;
+
        /* No override, check for overflow */
        if (i >= ARRAY_SIZE(efi_conf_table))
                return EFI_OUT_OF_RESOURCES;