From 1e1e1c27c5b46acfdc8927002baa7d4cb9a888db Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Wed, 3 Oct 2018 23:55:38 +0200 Subject: [PATCH] efi_loader: execute efi_save_gd() first If DEBUG is defined we may be calling EFI_CALL already during the initialization of the EFI subsystem. We must make sure efi_save_gd() has already been called at that moment. Anyway it is better to have this call in one location instead of three. This fixes an illegal memory access occurring since 4e6b5d6503ce ("efi_loader: create root node") with DEBUG = 1. Fixes: 4e6b5d6503ce ("efi_loader: create root node") Signed-off-by: Heinrich Schuchardt Signed-off-by: Alexander Graf --- cmd/bootefi.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) diff --git a/cmd/bootefi.c b/cmd/bootefi.c index 82d755c..4d68d80 100644 --- a/cmd/bootefi.c +++ b/cmd/bootefi.c @@ -40,6 +40,13 @@ efi_status_t efi_init_obj_list(void) { efi_status_t ret = EFI_SUCCESS; + /* + * On the ARM architecture gd is mapped to a fixed register (r9 or x18). + * As this register may be overwritten by an EFI payload we save it here + * and restore it on every callback entered. + */ + efi_save_gd(); + /* Initialize once only */ if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED) return efi_obj_list_initialized; @@ -374,12 +381,6 @@ static efi_status_t do_bootefi_exec(void *efi, if (ret != EFI_SUCCESS) goto exit; - /* - * gd lives in a fixed register which may get clobbered while we execute - * the payload. So save it here and restore it on every callback entry - */ - efi_save_gd(); - /* Transfer environment variable bootargs as load options */ set_load_options(loaded_image_info, "bootargs"); /* Load the EFI payload */ @@ -460,12 +461,6 @@ static int do_bootefi_bootmgr_exec(void) void *addr; efi_status_t r; - /* - * gd lives in a fixed register which may get clobbered while we execute - * the payload. So save it here and restore it on every callback entry - */ - efi_save_gd(); - addr = efi_bootmgr_load(&device_path, &file_path); if (!addr) return 1; @@ -547,11 +542,6 @@ static int do_bootefi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) if (r != EFI_SUCCESS) return CMD_RET_FAILURE; - /* - * gd lives in a fixed register which may get clobbered while we - * execute the payload. So save it here and restore it on every - * callback entry - */ efi_save_gd(); /* Transfer environment variable efi_selftest as load options */ set_load_options(loaded_image_info, "efi_selftest");