From 6538e70b391ab51896ee3c9f7bb7a5cc4b249373 Mon Sep 17 00:00:00 2001
From: Bahadir Balban <bbalban@b-labs.co.uk>
Date: Thu, 17 Sep 2009 19:19:03 +0300
Subject: [PATCH] Fixed few issues with loader and basic image loading.

Declaring section of the form:

.align 4
.section "kernel"
.incbin "path-to-kernel"

And defining a linker variable before the section output does not always seem to work.
The linker seems to add padding even though .align directive comes before .section

	modified:   SConstruct.loader
	modified:   loader/linker.lds
	modified:   loader/main.c
---
 SConstruct.loader |  7 +++++--
 loader/linker.lds |  2 +-
 loader/main.c     | 26 ++++++++++++++++++++++----
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/SConstruct.loader b/SConstruct.loader
index fc63086..58ab851 100644
--- a/SConstruct.loader
+++ b/SConstruct.loader
@@ -33,7 +33,8 @@ env = Environment(CC = 'arm-none-eabi-gcc',
 		  ASFLAGS = ['-D__ASSEMBLY__'],
 		  PROGSUFFIX = '.elf',
 		  ENV = {'PATH' : os.environ['PATH']},
-		  LIBS = ['gcc'],
+		  LIBS = ['gcc', 'elf', 'c-baremetal', 'gcc'],
+          LIBPATH = [join('build', LIBELF_PATH), join('build', LIBC_PATH)],
           CPPPATH = ['#include', LIBC_INCPATH, LIBELF_INCPATH])
 
 libc = SConscript('loader/libs/c/SConscript', \
@@ -45,4 +46,6 @@ libelf = SConscript('loader/libs/elf/SConscript', exports = { 'env' : env }, \
 loader_objs = SConscript('loader/SConscript', exports = { 'env' : env }, \
                          duplicate = 0, variant_dir = 'build/loader')
 
-env.Program('build/final.elf', [loader_objs + libc + libelf])
+env.Program('build/final.elf', [libelf + libc + loader_objs])
+Depends(loader_objs, libelf)
+Depends(loader_objs, libc)
diff --git a/loader/linker.lds b/loader/linker.lds
index f25b5db..81a630d 100644
--- a/loader/linker.lds
+++ b/loader/linker.lds
@@ -13,7 +13,6 @@ SECTIONS
 	.rodata1 : { *(.rodata1) }
 	.data :
 	{
-        	*(.data)
 		_start_kernel = .;
 		*(.kernel)
 		_end_kernel = .;
@@ -21,6 +20,7 @@ SECTIONS
 		_start_containers = .;
 		*(.containers)
 		_end_containers = .;
+        	*(.data)
 	}
 	.got : { *(.got) *(.got.plt) }
 	.bss : { *(.bss) }
diff --git a/loader/main.c b/loader/main.c
index 988305e..148da7e 100644
--- a/loader/main.c
+++ b/loader/main.c
@@ -1,4 +1,5 @@
 #include <elf/elf.h>
+#include <elf/elf32.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include "arch.h"
@@ -22,24 +23,41 @@ void load_container_images(unsigned long start, unsigned long end)
 
 }
 */
+
+int load_elf_image(unsigned long **entry, void *filebuf)
+{
+	if (!elf32_checkFile((struct Elf32_Header *)filebuf)) {
+		**entry = (unsigned long)elf32_getEntryPoint((struct Elf32_Header *)filebuf);
+		printf("Entry point: %lx\n", **entry);
+	} else {
+		printf("Not a valid elf image.\n");
+		return -1;
+	}
+	if (!elf_loadFile(filebuf, 1)) {
+		printf("Elf image seems valid, but unable to load.\n");
+		return -1;
+	}
+	return 0;
+}
+
 int main(void)
 {
-	void *kernel_entry = 0;
+	unsigned long *kernel_entry;
 
 	arch_init();
 
 	printf("ELF Loader: Started.\n");
 
 	printf("Loading the kernel...\n");
-//	load_elf_image(&kernel_entry, _start_kernel, _end_kernel);
+	load_elf_image(&kernel_entry, (void *)_start_kernel);
 
 	printf("Loading containers...\n");
 //	load_container_images(_start_containers, _end_containers)
 
-	printf("elf-loader:\tkernel entry point is %p\n", kernel_entry);
+	printf("elf-loader:\tkernel entry point is %lx\n", *kernel_entry);
 //	arch_start_kernel(kernel_entry);
 
-	printf("elf-loader:\tKernel start failed!\n");
+//	printf("elf-loader:\tKernel start failed!\n");
 
 	return -1;
 }