[U-Boot] [PATCH 4/6] x86: efi: Add EFI loader support for x86

[Simon Glass]

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: Simon Glass <sjg at chromium.org>
---

 arch/x86/cpu/u-boot.lds       | 36 +++++++++++++++++++++++++++++++++++-
 arch/x86/lib/Makefile         |  1 +
 arch/x86/lib/sections.c       | 12 ++++++++++++
 include/efi.h                 |  3 ++-
 lib/efi_loader/efi_boottime.c |  9 +++++++++
 lib/efi_loader/efi_runtime.c  |  4 ++++
 6 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 arch/x86/lib/sections.c

diff --git a/arch/x86/cpu/u-boot.lds b/arch/x86/cpu/u-boot.lds
index 36f59ea..cca536b 100644
--- a/arch/x86/cpu/u-boot.lds
+++ b/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 = .;
 
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index e17f0bb..e46e7f1 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -28,6 +28,7 @@ obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o
 obj-$(CONFIG_X86_RAMTEST) += ramtest.o
+obj-y	+= sections.o
 obj-y += sfi.o
 obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += smbios.o
 obj-y	+= string.o
diff --git a/arch/x86/lib/sections.c b/arch/x86/lib/sections.c
new file mode 100644
index 0000000..6455e0f
--- /dev/null
+++ b/arch/x86/lib/sections.c
@@ -0,0 +1,12 @@
+/*
+ * Copyright 2013 Albert ARIBAUD <albert.u.boot at 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")));
diff --git a/include/efi.h b/include/efi.h
index 1dbc3b7..47b351f 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -15,6 +15,7 @@
 #ifndef _EFI_H
 #define _EFI_H
 
+#include <linux/linkage.h>
 #include <linux/string.h>
 #include <linux/types.h>
 
@@ -22,7 +23,7 @@
 /* EFI uses the Microsoft ABI which is not the default for GCC */
 #define EFIAPI __attribute__((ms_abi))
 #else
-#define EFIAPI
+#define EFIAPI asmlinkage
 #endif
 
 struct efi_device_path;
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 798b566..e027bd3 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/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[1];
 
+#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[1];
  * 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;
 }
 
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index 99b5ef1..3793471 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -34,6 +34,10 @@ 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
-- 
2.8.0.rc3.226.g39d4020