x86: efi: Tweak the code used for the 64-bit EFI app

Add an empty CPU init function to avoid fiddling with low-level CPU
features in the app. Set up the C runtime correctly for 64-bit use
and avoid clearing BSS, since this is done by EFI when U-Boot is loaded.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/x86_64/cpu.c

@@ -45,3 +45,8 @@ int cpu_phys_address_size(void)
 {
 	return CONFIG_CPU_ADDR_BITS;
 }
+
+int x86_cpu_init_f(void)
+{
+	return 0;
+}

arch/x86/lib/Makefile

@@ -65,9 +65,8 @@ endif
 
 lib-$(CONFIG_USE_PRIVATE_LIBGCC) += div64.o
 
-ifeq ($(CONFIG_$(SPL_)X86_64),)
-obj-$(CONFIG_EFI_APP) += crt0_ia32_efi.o reloc_ia32_efi.o
-endif
+obj-$(CONFIG_EFI_APP_32BIT) += crt0_ia32_efi.o reloc_ia32_efi.o
+obj-$(CONFIG_EFI_APP_64BIT) += crt0_x86_64_efi.o reloc_x86_64_efi.o
 
 ifneq ($(CONFIG_EFI_STUB),)
 

arch/x86/lib/relocate.c

@@ -35,6 +35,7 @@ int copy_uboot_to_ram(void)
 	return 0;
 }
 
+#ifndef CONFIG_EFI_APP
 int clear_bss(void)
 {
 	ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
@@ -46,6 +47,7 @@ int clear_bss(void)
 
 	return 0;
 }
+#endif
 
 #if CONFIG_IS_ENABLED(X86_64)
 static void do_elf_reloc_fixups64(unsigned int text_base, uintptr_t size,