arm: Allow EFI payload code to take exceptions

There are 2 ways an EFI payload could return into u-boot:

  - Callback function
  - Exception

While in EFI payload mode, r9 is owned by the payload and may not contain
a valid pointer to gd, so we need to fix it up. We do that properly for the
payload to callback path already.

This patch also adds gd pointer restoral for the exception path.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/arm/lib/interrupts.c b/arch/arm/lib/interrupts.c
index ec3fb77..ed83043 100644
--- a/arch/arm/lib/interrupts.c
+++ b/arch/arm/lib/interrupts.c
@@ -22,6 +22,7 @@
 #include <common.h>
 #include <asm/proc-armv/ptrace.h>
 #include <asm/u-boot-arm.h>
+#include <efi_loader.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -165,6 +166,7 @@
 
 void do_undefined_instruction (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("undefined instruction\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -172,6 +174,7 @@
 
 void do_software_interrupt (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("software interrupt\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -179,6 +182,7 @@
 
 void do_prefetch_abort (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("prefetch abort\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -186,6 +190,7 @@
 
 void do_data_abort (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("data abort\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -193,6 +198,7 @@
 
 void do_not_used (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("not used\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -200,6 +206,7 @@
 
 void do_fiq (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("fast interrupt request\n");
 	show_regs (pt_regs);
 	bad_mode ();
@@ -208,6 +215,7 @@
 #ifndef CONFIG_USE_IRQ
 void do_irq (struct pt_regs *pt_regs)
 {
+	efi_restore_gd();
 	printf ("interrupt request\n");
 	show_regs (pt_regs);
 	bad_mode ();