From e7897de9471e1d94ad79e2b03fcb8afc685760f1 Mon Sep 17 00:00:00 2001
From: Regia König
Date: Thu, 25 Aug 2022 15:08:09 +0200
Subject: Setup.S documentation and new command in create_debug.sh

---
 Makefile_for_memtest_gdb                           |  2 +-
 create_debug.sh                                    | 13 ++++-
 .../24_08_22_memtest_build_process                 | 39 +++++++++++++++
 memtest_efi_modified.lds                           | 57 ++++++++++++++++++++--
 4 files changed, 103 insertions(+), 8 deletions(-)

diff --git a/Makefile_for_memtest_gdb b/Makefile_for_memtest_gdb
index 58025f7..3413741 100644
--- a/Makefile_for_memtest_gdb
+++ b/Makefile_for_memtest_gdb
@@ -91,7 +91,7 @@ boot/startup.s: ../boot/startup64.S ../boot/boot.h
 
 boot/%.s: ../boot/%.S ../boot/boot.h
 	@mkdir -p boot
-	$(CC) -E -traditional -I../boot -o $@ $<
+	$(CC) -E -traditional -fPIC -I../boot -o $@ $<
 
 boot/efisetup.o: ../boot/efisetup.c
 	@mkdir -p boot
diff --git a/create_debug.sh b/create_debug.sh
index ada21f9..45f4c1f 100755
--- a/create_debug.sh
+++ b/create_debug.sh
@@ -8,6 +8,15 @@ BSS_SIZE=$(size -B -d memtest_shared | grep memtest_shared | tr -s ' ' | cut -d'
 echo $BSS_SIZE
 echo "bss_size: $BSS_SIZE"
 
+ld --defsym=_bss_size=$(size -B -d memtest_shared | grep memtest_shared | tr -s ' ' | cut -d ' ' -f3) \
+	-shared \
+	--print-memory-usage \
+	--print-output-format \
+	-Bsymbolic \
+	-M \
+	-nostdlib \
+	-T linker_modified.lds \
+	-o memtest_modified.efi \
+	boot/setup.o boot/startup.o boot/efisetup.o app/*.o lib/*.o system/*.o  tests/*.o
 
-
-ld --defsym=_bss_size=$BSS_SIZE -T memtest_efi_modified.lds boot/header.o boot/setup.o -b memtest_shared -o memtest_modified.efi
+# ld -N --defsym=_bss_size=$BSS_SIZE -T linker_modified.lds boot/header.o boot/setup.o -b elf64-x86-64 memtest_shared -o memtest_modified.efi
diff --git a/documentation/memtest86_build_process/24_08_22_memtest_build_process b/documentation/memtest86_build_process/24_08_22_memtest_build_process
index 9847a5b..fc8f33c 100644
--- a/documentation/memtest86_build_process/24_08_22_memtest_build_process
+++ b/documentation/memtest86_build_process/24_08_22_memtest_build_process
@@ -203,3 +203,42 @@ coff_header:
 #
 #	setup.S
 #
+Collects memory map information from the BIOS, disables APM, enables A20 and performs
+the switch from real mode to protected mode before jumping to the main program entry
+point.
+
+The memory map information is stored in the 4KB block of memory immediately following
+the setup code. The layout of the information matches the Linux boot_params struct.
+A pointer to this block is passed to the main program, for compatibility with the Linux
+32-bit boot protocol.
+
+. # define BOOT_PARAMS_START	(SETUP_SECS * 512)	|| SETUP_SEC is defined in boot.h
+. # define BOOT_PARAMS_END	(BOOT_PARAMS_START + 4096)  <--- here are the 4K
+
+	.section ".setup",  "ax", @progbits
+	.code16
+
+Emulate the Linux boot header, to allow loading by other boot loaders. Indicate that the
+main program code should be loaded in high memory.
+
+	.globl setup
+setup: jmp do_setup
+
+101: do_setup:
+	Reload the segment registers, except for the stack
+	Get the memory map and disable APM
+	Disable interrupts
+	Enable A20
+	...
+
+179: flush:
+	Reload the segment registers and jump to the main test program <------------!!!!
+
+	...
+188: jump:
+	data32 ljmp $KERNEL_CS, $0
+
+
+
+389: Pad to the declared size
+	.org	(ESTUP_SECS*512)
diff --git a/memtest_efi_modified.lds b/memtest_efi_modified.lds
index 179fe93..6f035c8 100644
--- a/memtest_efi_modified.lds
+++ b/memtest_efi_modified.lds
@@ -1,5 +1,6 @@
-OUTPUT_FORMAT("binary")
-OUTPUT_ARCH(i386:x86-64)
+OUTPUT_FORMAT("elf64-x86-64");
+OUTPUT_ARCH(i386:x86-64);
+
 
 ENTRY(boot);
 SECTIONS {
@@ -13,14 +14,60 @@ SECTIONS {
 	. = ALIGN(512);
 	.text : {
 		_text_start = . ;
-		*(.data)
-		. = ALIGN(512);
+		_start = .;
+		*(.text)
+		*(.text.*)
+		*(.plt)
+		_etext = . ;
 		_text_end = . ;
+	}= 0x9090
+
+	.rodata : {
+		*(.rodata)
+		*(.rodata.*)
 	}
+	.dynsym     : { *(.dynsym) }
+	.dynstr     : { *(.dynstr) }
+	.hash       : { *(.hash) }
+	.gnu.hash   : { *(.gnu.hash) }
+	.dynamic    : { *(.dynamic) }
+
+	.rela.text    : { *(.rela.text   .rela.text.*) }
+	.rela.rodata  : { *(.rela.rodata .rela.rodata.*) }
+	.rela.data    : { *(.rela.data   .rela.data.*) }
+	.rela.got     : { *(.rela.got    .rela.got.*) }
+	.rela.plt     : { *(.rela.plt    .rela.plt.*) }
+
+	. = ALIGN(4);
+	.data : {
+		 _data = .;
+		*(.data)
+		*(.data.*)
+	}
+	.got : {
+		*(.got.plt)
+		*(.got)
+		_edata = . ;
+	}
+	. = ALIGN(4);
+	.bss : {
+		_bss = .;
+		*(.dynbss)
+		*(.bss)
+		*(.bss.*)
+		*(COMMON)
+		. = ALIGN(16);
+		_stacks = .;
+		*(.stacks)
+		/* _end must be at least 256 byte aligned */
+		. = ALIGN(256);
+		_end = .;
+	}
+
 	.debug : {
 		*(.debug*)
 	}
-
+	
 	_text_size = (_text_end  - _text_start);
 
 	_sys_size  = _text_size >> 4;
-- 
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