CeDOS - Commit 71a76074

Added method to copy kernel Doesn't work yet, probably because of A20 gate
Celina Sophie Kalus
hello@celinakalus.de
Thu, 21 Dec 2017 23:07:31 +0100
7 files changed, 67 insertions(+), 7 deletions(-)
A include/linker.h 
@@ -0,0 +1,22 @@
+#ifndef LINKER_H
+#define LINKER_H
+
+#include <stdint.h>
+
+extern uint8_t __SS_VMA;
+extern uint8_t __SS_LMA;
+extern uint8_t __SS_SIZE;
+
+extern uint8_t __KERNEL_VMA;
+extern uint8_t __KERNEL_LMA;
+extern uint8_t __KERNEL_SIZE;
+
+#define SS_VMA (&__SS_VMA)
+#define SS_LMA (&__SS_LMA)
+#define SS_SIZE (uint32_t)(&__SS_SIZE)
+
+#define KERNEL_VMA (&__KERNEL_VMA)
+#define KERNEL_LMA (&__KERNEL_LMA)
+#define KERNEL_SIZE (uint32_t)(&__KERNEL_SIZE)
+
+#endif
M link.txt → link.txt 
@@ -8,18 +8,31 @@ MEMORY
 {
   BOOT :          ORIGIN = 0x00007C00, LENGTH = 0x00000200
   SECOND_STAGE :  ORIGIN = 0x00010000, LENGTH = 0x00090000
+  KERNEL :        ORIGIN = 0xC0000000, LENGTH = 0x30000000
 }
 
 SECTIONS
 {
   BOOT : AT(0x0000)
   {
-    build/boot.o(.text)
+    build/boot.o(.*)
   } >BOOT
 
   SECOND_STAGE : AT(LOADADDR(BOOT) + SIZEOF(BOOT))
   {
-    build/second_stage.o(.text)
-    build/second_stage.o(.data)
+    build/second_stage.o(.*)
   } >SECOND_STAGE
+
+  KERNEL : AT(LOADADDR(SECOND_STAGE) + SIZEOF(SECOND_STAGE))
+  {
+
+  } >KERNEL
 }
+
+__SS_LMA = LOADADDR(SECOND_STAGE);
+__SS_VMA = ADDR(SECOND_STAGE);
+__SS_SIZE = SIZEOF(SECOND_STAGE);
+
+__KERNEL_LMA = LOADADDR(KERNEL);
+__KERNEL_VMA = ADDR(KERNEL);
+__KERNEL_SIZE = SIZEOF(KERNEL);
M second_stage/entry.s → second_stage/entry.s 
@@ -18,6 +18,8 @@
 
   # TODO:
   #  - copy the kernel code to 0x00100000
+  call copy_kernel
+
   #  - create a page directory for the kernel that maps it to 0xC0000000
   #    and identity maps the first 1M of memory
   #  - enable paging
M second_stage/gdt.c → second_stage/gdt.c 
@@ -20,4 +20,4 @@ GDT_MAKE_ENTRY(0x00000000, 0x000FFFFF, 0x9A, 0xC),
 
     // identity mapping (data)
     GDT_MAKE_ENTRY(0x00000000, 0x000FFFFF, 0x92, 0xC)
-};+};
M second_stage/link.txt → second_stage/link.txt 
@@ -1,4 +1,4 @@
-INPUT(build/entry.o build/gdt.o)
+INPUT(build/entry.o build/gdt.o build/main.o)
 OUTPUT_FORMAT(elf32-i386)
 OUTPUT_ARCH(i386)
 ENTRY(_ss_start)

@@ -9,11 +9,13 @@ .text :
   {
       build/entry.o(.text)
       build/gdt.o(.text)
+      build/main.o(.text)
   }
 
   .data :
   {
       build/entry.o(.data)
       build/gdt.o(.data)
+      build/main.o(.data)
   }
 }
A second_stage/main.c 
@@ -0,0 +1,18 @@
+#include "linker.h"
+
+void copy_kernel(void) {
+    uint8_t *display = (uint8_t*)0xB8000;
+    uint8_t *text = (uint8_t*)"THIS WORKS";
+    
+    while (*text) {
+        *display++ = *text++;
+        *display++ = 0x0F;
+    }
+
+    uint8_t *kernel_dest = (uint8_t*)0x00100000;
+    uint8_t *kernel_src = (SS_VMA + (KERNEL_LMA - SS_LMA));
+    
+    for (uint32_t i = 0; i < KERNEL_SIZE; i++) {
+        kernel_dest[i] = kernel_src[i];
+    }
+}
M second_stage/makefile → second_stage/makefile 
@@ -1,8 +1,8 @@
 .RECIPEPREFIX = >
 
 .PHONY: build
-build: build/entry.o build/gdt.o
-> $(GCC_PREFIX)ld -T link.txt -o $(BUILD_DIR)/second_stage.o --oformat elf32-i386
+build: build/entry.o build/gdt.o build/main.o
+> $(GCC_PREFIX)ld -r -T link.txt -o $(BUILD_DIR)/second_stage.o --oformat elf32-i386
 
 .PHONY: clear
 clear:

@@ -17,4 +17,7 @@ build/entry.o: entry.s
 > $(GCC_PREFIX)as -o $@ $<
 
 build/gdt.o: gdt.c gdt.h
+> $(GCC_PREFIX)gcc -c -I$(INCLUDE_DIR) --prefix=$(GCC_PREFIX) $(GCC_OPTIONS) -o $@ $<
+
+build/main.o: main.c
 > $(GCC_PREFIX)gcc -c -I$(INCLUDE_DIR) --prefix=$(GCC_PREFIX) $(GCC_OPTIONS) -o $@ $<