Some bugfixes, add debug output

src/elf.c

@@ -11,16 +11,31 @@ void load_elf(elf_header* elf_start)
     // The elf will get its own memory space.
     page_directory_entry* pgdir = page_new_directory();
 
+    void* highest_vpage = (void*)0;
+
+    serial_writestring("Loading elf\n");
+
     // loop through and copy memory segments
     for (int i = 0; i < elf_start->ph_entry_count; i++)
     {
+        serial_writestring("Loading memory segment\n");
+
         // get this section header
         elf_program_header* ph;
-        ph = (elf_program_header*) elf_start + (elf_start->ph_table_offset + (i * elf_start->ph_entry_size));
+        ph = (elf_program_header*) ((uint32_t)elf_start + (uint32_t)(elf_start->ph_table_offset + (i * elf_start->ph_entry_size)));
+
+        serial_hexword((uint32_t)elf_start);
+        serial_writechar('\n');
+        serial_hexword((uint32_t)ph);
+        serial_writechar('\n');
+        serial_hexword((uint32_t)elf_start + (uint32_t)(elf_start->ph_table_offset + (i * elf_start->ph_entry_size)));
+        serial_writechar('\n');
 
         // map and copy
-        for (void* pg = (void*)((uint32_t)ph->p_vaddr & 0xfffff000); (uint32_t)(pg - ph->p_vaddr) < ph->memory_segment_size; pg+=0x1000)
+        for (void* pg = (void*)((uint32_t)ph->p_vaddr & 0xfffff000); ((int)pg - (int)ph->p_vaddr) < (int)ph->memory_segment_size; pg+=0x1000)
         {
+            serial_writestring("Copying in memory segment\n");
+
             void* real_page = page_map(pgdir, pg);
 
             void* start = (pg > ph->p_vaddr) ? pg : ph->p_vaddr;
@@ -30,7 +45,21 @@ void load_elf(elf_header* elf_start)
             size_t offset = (pg > ph->p_vaddr) ? 0 : ph->p_vaddr - pg;
 
             // do some memcpy stuff
+            serial_hexword((uint32_t)real_page);
+            serial_writechar('\n');
             memcpy(real_page + offset, start, size);
+
+            // save the highest start
+            if (pg > highest_vpage)
+            {
+                highest_vpage = pg;
             }
+            break;
         }
+    }
+
+    // Allocate two more pages for stack
+    page_map(pgdir, highest_vpage + 0x1000);
+    page_map(pgdir, highest_vpage + 0x2000);
+    // initial esp = highest_vpage + 0x1000
 }

src/elf.h

@@ -12,6 +12,7 @@
 
 #include "mem.h"
 #include "string.h"
+#include "serial.h"
 
 extern uint8_t elf_hello[]  asm("_binary_hello_elf_start");
 

src/kern.c

@@ -82,6 +82,8 @@ void kernel_main(multiboot_info* mbt, uint32_t magic)
     serial_hexstring(elf_hello, 4);
     serial_writestring("\n");
 
+    load_elf((elf_header*)&elf_hello);
+
     test_idt();
     while(true)
     {

src/mem.c

@@ -9,10 +9,6 @@
 // later. It must be page aligned for the MMU to read properly
 page_directory_entry page_directory[1024] __attribute__((aligned(4096)));
 
-// page_table_one is the first page table, and at the beginning the
-// only page table in the page directory
-page_table_entry page_table_one[1024] __attribute__((aligned(4096)));
-
 // populate_page_table makes a page table at `table` mapping `num`
 // pages to bytes after `start + offset*4KB`
 // both table and start must be properly aligned
@@ -149,16 +145,17 @@ page_directory_entry* mem_init_kern_tables(multiboot_memory_map* mmap, multiboot
 void* page_map(page_directory_entry pgdir[], void* page_start)
 {
     void* page = 0;
-    if ((pgdir[(uint32_t)page_start>>22] & 0xfffff) == 0)
+    if ((pgdir[(uint32_t)page_start>>22] & 0xfffff000) == 0)
     {
         pgdir[(uint32_t)page_start>>22] |= (page_directory_entry)page_new_table();
     }
     page_table_entry* page_table = (page_table_entry*) ((uint32_t) pgdir[(uint32_t)page_start>>22] & 0xfffff000);
-    if ((page_table[((uint32_t)page_start >> 12) % 1024] & 0xfffff) == 0)
+    if ((page_table[((uint32_t)page_start >> 12) % 1024] & 0xfffff000) == 0)
     {
         page = page_allocate();
         page_table[((uint32_t)page_start>>12)%1024] |= (page_table_entry)page;
     }
+
     return page;
 }