efi_loader: Fix efi_exit gd clobbering

Commit f494950b (efi_loader: call __efi_exit_check in efi_exit) added a call
to __efi_exit_check inside efi_exit to account for the fact that we're exiting
the efi_exit function via a longjmp call.

However, __efi_exit_check also swizzles gd to the application gd while the
longjmp will put us back into EFI context, so we need the efi (u-boot) gd.

This patch fixes that up by explicitly setting gd back to efi_gd before
doing the longjmp. It also adds a few comments on why it does that.

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 99c5a6ee0cabcec7277f9253148d9aa39b29484f..90e9ead7b25ec4403387560acb39fcda57e1d264 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -798,8 +798,15 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
        EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
                  exit_data_size, exit_data);
 
+       /* Make sure entry/exit counts for EFI world cross-overs match */
        __efi_exit_check();
 
+       /*
+        * But longjmp out with the U-Boot gd, not the application's, as
+        * the other end is a setjmp call inside EFI context.
+        */
+       efi_restore_gd();
+
        loaded_image_info->exit_status = exit_status;
        longjmp(&loaded_image_info->exit_jmp, 1);