wip: multiboot struct is now in the page directory/page table

headers/memory.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "multiboot.h"
+
 #include <stddef.h>
 #include <stdint.h>
 
@@ -17,16 +19,16 @@
 #define PT_START   256
 
 #define GET_PAGE_ADDR(pd_index, pt_index)                                      \
-	(((pd_index * 1024) + pt_index) * 4096)
+	((((uint32_t)pd_index * 1024) + (uint32_t)pt_index) * 4096)
 
 extern uint32_t _kernel_end;
 extern uint32_t boot_page_directory;
 extern uint32_t *page_directory;
 extern uint32_t page_table_default[1024];
-extern uint64_t mem_size;
+extern uint32_t mem_size;
 
 uint32_t *virt_to_phys(uint32_t *virt_addr);
-void init_memory(void);
+void init_memory(multiboot_info_t *mbd, uint32_t magic);
 void *alloc_frames(size_t size);
 int free_frames(void *frame_ptr, size_t size);
 void *alloc_pages(size_t size);

src/boot.s

@@ -34,7 +34,6 @@ boot_page_table1:
 # The kernel entry point.
 .section .multiboot.text, "a"
 .global _start
-.global end_mem
 .type _start, @function
 _start:
 	# Physical address of boot_page_table1.
@@ -90,10 +89,6 @@ _start:
 	movl $(boot_page_directory - 0xC0000000), %ecx
 	movl %ecx, %cr3
 
-	jmp set_mem_size
-
-end_mem:
-
 	# Enable paging and the write-protect bit.
 	movl %cr0, %ecx
 	orl $0x80000000, %ecx
@@ -118,6 +113,9 @@ end_mem:
 	# Set up the stack.
 	mov $stack_top, %esp
 
+	push %eax
+	push %ebx
+
 	# Enter the high-level kernel.
 	call kernel_main
 

src/kernel.c

@@ -55,14 +55,13 @@ static void set_mem_size(multiboot_info_t *mbd, uint32_t magic)
 	}
 }
 
-void kernel_main(void)
+void kernel_main(multiboot_info_t *mbd, uint32_t magic)
 {
 	terminal_initialize();
 	init_gdt();
 	init_idt();
-	init_memory();
+	init_memory(mbd, magic);
 	load_drivers();
-	/* set_mem_size(mbd, magic); */
 	kprintf(KERN_ALERT
 	        "I see no way to confuse an array of 256 seg:off pairs with a "
 	        "complex 8*unknown quantity -byte descriptor table. -- Troy "

src/memory/memory.c

@@ -1,18 +1,59 @@
 #include "memory.h"
 #include "debug.h"
 #include "kprintf.h"
+#include "utils.h"
 
 #include <stdint.h>
 
 uint32_t *page_directory = &boot_page_directory;
-uint32_t page_table_default[1024] __attribute__((aligned(4096)));
+uint32_t page_table_default[1024] __attribute__((aligned(PAGE_SIZE)));
-uint64_t mem_size;
+uint32_t multiboot_page_table[1024] __attribute__((aligned(PAGE_SIZE)));
+uint32_t mem_size;
+multiboot_uint32_t *mmap_addr;
+multiboot_uint32_t mmap_length;
 
-void init_memory(void)
+static void init_multiboot(multiboot_info_t *mbd, uint32_t magic)
+{
+	if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
+		kpanic("invalid magic number! (git good skill issue)");
+
+	init_page_table(multiboot_page_table, 0);
+	page_directory[1023] =
+	    ((uint32_t)multiboot_page_table - HEAP_END) | 0x03;
+	const size_t mbd_size = CEIL(
+	    (uint32_t)mbd % PAGE_SIZE + sizeof(multiboot_info_t), PAGE_SIZE);
+
+	kprintf("cramptes0\n");
+	// Index multiboot_info_t struct
+	for (uint32_t i = 0; i < mbd_size; i++)
+		multiboot_page_table[i] =
+		    ((uint32_t)mbd + PAGE_SIZE * i) & PAGE_MASK;
+	multiboot_info_t *mbd_virt =
+	    (multiboot_info_t *)(GET_PAGE_ADDR(1023, 0) +
+	                         (uint32_t)mbd % PAGE_SIZE);
+
+	kprintf("cramptes1\n");
+	PRINT_PTR(mbd_virt);
+	/* PRINT_UINT(mbd_virt->mmap_length); */
+	// Index mbd->mmap_addr pointers
+	for (uint32_t i = 0; i < mbd_virt->mmap_length; i++)
+		multiboot_page_table[i + mbd_size] =
+		    ((mbd_virt->mmap_addr + i * PAGE_SIZE) & PAGE_MASK) |
+		    INIT_FLAGS;
+	kprintf("cramptes2\n");
+	mmap_addr =
+	    (multiboot_uint32_t *)(GET_PAGE_ADDR(1023, mbd_size) +
+	                           (uint32_t)mbd_virt->mmap_addr % PAGE_SIZE);
+	kprintf("cramptes3\n");
+	mmap_length = mbd_virt->mmap_length;
+}
+
+void init_memory(multiboot_info_t *mbd, uint32_t magic)
 {
 	assert(page_directory);
 	for (uint16_t i = 0; i < 0x300; i++)
 		page_directory[i] = 0x02;
 	init_page_table(page_table_default, 0);
 	page_directory[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03;
+	init_multiboot(mbd, magic);
 }

src/set_mem_size.s

@@ -1,28 +0,0 @@
-.intel_syntax noprefix
-
-.section .text
-	.global set_mem_size
-	
-	set_mem_size:
-	jmp end_mem
-		xor ebx, ebx		// i = 0
-.L1:
-		// loop condition
-		cmp ebx, [eax + 44] // mbd->mmap_length
-		jge end_mem
-		
-		// declare mmmt
-		mov ecx, [eax + 48] // mbd->mmap_addr
-		add ecx, ebx		// + i
-
-		// check if the mmmt->type is available (1)
-		mov edx, [ecx + 20]
-		cmp edx, 1
-		jne .L2
-
-		// add the size of the block
-		mov edx, [ecx + 0] // mmmt->size
-		add mem_size, edx
-.L2:
-		add ebx, 24			// i += sizeof(multiboot_memory_map_t)
-		jmp .L1