x86: efi: Add EFI loader support for x86

Add the required pieces to support the EFI loader on x86.

Since U-Boot only builds for 32-bit on x86, only a 32-bit EFI application
is supported. If a 64-bit kernel must be booted, U-Boot supports this
directly using FIT (see doc/uImage.FIT/kernel.its). U-Boot can act as a
payload for both 32-bit and 64-bit EFI.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

arch/x86/cpu/u-boot.lds

@@ -28,7 +28,10 @@ SECTIONS
 	}
 
 	. = ALIGN(4);
-	.rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) }
+	.rodata : {
+		*(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
+		KEEP(*(.rodata.efi.init));
+	}
 
 	. = ALIGN(4);
 	.data : { *(.data*) }
@@ -40,6 +43,37 @@ SECTIONS
 	.got : { *(.got*) }
 
 	. = ALIGN(4);
+
+	.__efi_runtime_start : {
+		*(.__efi_runtime_start)
+	}
+
+	.efi_runtime : {
+		*(efi_runtime_text)
+		*(efi_runtime_data)
+	}
+
+	.__efi_runtime_stop : {
+		*(.__efi_runtime_stop)
+	}
+
+	.efi_runtime_rel_start :
+	{
+		*(.__efi_runtime_rel_start)
+	}
+
+	.efi_runtime_rel : {
+		*(.relefi_runtime_text)
+		*(.relefi_runtime_data)
+	}
+
+	.efi_runtime_rel_stop :
+	{
+		*(.__efi_runtime_rel_stop)
+	}
+
+	. = ALIGN(4);
+
 	__data_end = .;
 	__init_end = .;
 

arch/x86/lib/Makefile

@@ -28,6 +28,7 @@ obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o
 obj-$(CONFIG_X86_RAMTEST) += ramtest.o
+obj-y	+= sections.o
 obj-y += sfi.o
 obj-y	+= string.o
 ifndef CONFIG_QEMU

arch/x86/lib/sections.c

+/*
+ * Copyright 2013 Albert ARIBAUD <albert.u.boot@aribaud.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+char __efi_runtime_start[0] __attribute__((section(".__efi_runtime_start")));
+char __efi_runtime_stop[0] __attribute__((section(".__efi_runtime_stop")));
+char __efi_runtime_rel_start[0]
+		__attribute__((section(".__efi_runtime_rel_start")));
+char __efi_runtime_rel_stop[0]
+		__attribute__((section(".__efi_runtime_rel_stop")));

lib/efi_loader/efi_boottime.c

@@ -39,6 +39,7 @@ static bool efi_is_direct_boot = true;
  */
 static struct efi_configuration_table EFI_RUNTIME_DATA efi_conf_table[2];
 
+#ifdef CONFIG_ARM
 /*
  * The "gd" pointer lives in a register on ARM and AArch64 that we declare
  * fixed when compiling U-Boot. However, the payload does not know about that
@@ -46,16 +47,20 @@ static struct efi_configuration_table EFI_RUNTIME_DATA efi_conf_table[2];
  * EFI callback entry/exit.
  */
 static volatile void *efi_gd, *app_gd;
+#endif
 
 /* Called from do_bootefi_exec() */
 void efi_save_gd(void)
 {
+#ifdef CONFIG_ARM
 	efi_gd = gd;
+#endif
 }
 
 /* Called on every callback entry */
 void efi_restore_gd(void)
 {
+#ifdef CONFIG_ARM
 	/* Only restore if we're already in EFI context */
 	if (!efi_gd)
 		return;
@@ -63,12 +68,16 @@ void efi_restore_gd(void)
 	if (gd != efi_gd)
 		app_gd = gd;
 	gd = efi_gd;
+#endif
 }
 
 /* Called on every callback exit */
 efi_status_t efi_exit_func(efi_status_t ret)
 {
+#ifdef CONFIG_ARM
 	gd = app_gd;
+#endif
+
 	return ret;
 }
 

lib/efi_loader/efi_runtime.c

@@ -44,6 +44,10 @@ static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_invalid_parameter(void);
 #elif defined(CONFIG_ARM)
 #define R_RELATIVE	23
 #define R_MASK		0xffULL
+#elif defined(CONFIG_X86)
+#include <asm/elf.h>
+#define R_RELATIVE	R_386_RELATIVE
+#define R_MASK		0xffULL
 #else
 #error Need to add relocation awareness
 #endif