3 files changed, 116 insertions(+), 29 deletions(-)

M boot1.asm
M kernel.c
M kmem.c

@@ 4,10 4,17 @@ global pread_sector
 
 extern boot2_main
 
+%define BIOS_MEMDETECT_MAGIC 0x534d4150
+%define MMAP_BASE 0x1000
+
 start:
   mov si, hallo
   call print
 
+  push dword MMAP_BASE
+  call near detect_memory
+  add esp, 4
+
   ; hide cursor
   mov ah, 0x01
   mov cx, 0x2607


@@ 15,9 22,80 @@ start:
 
   jmp enter_protected
 
-idle:
-  hlt
-  jmp idle
+hallo: db 'xos boot loader stage 1 ...', 0xa, 0xd, 0
+
+print:
+  mov ah, 0x0e
+.repeat:
+  lodsb
+  cmp al, 0
+  je .done
+  int 0x10
+  jmp .repeat
+.done:
+  ret
+
+enter_protected:
+  cli
+  lgdt [gdt_desc]
+
+  mov eax, cr0
+  or al, 1
+  mov cr0, eax
+
+  jmp 0x08:protected_main
+
+detect_memory:
+  mov di, [esp + 2] ; mmap base
+  add di, 4 ; first dword reserved for count
+  xor ebp, ebp ; valid entries counter
+
+  xor ebx, ebx
+
+  call .e820
+  jc .failed
+
+  ; first call checks:
+  cmp eax, BIOS_MEMDETECT_MAGIC
+  jne .failed
+  test ebx, ebx
+  je .failed
+
+.item:
+  jcxz .next
+  cmp cl, 0x18 ; extended record?
+  jb .normal
+.extended:
+  test [di + 20], byte 1 ; ignored
+  je .next
+.normal:
+  mov ecx, [di + 8]
+  or ecx, [di + 12] ; zero length?
+  jz .next
+  inc bp
+  add di, 20
+
+.next:
+  test ebx, ebx
+  je .finish
+  call .e820
+  jc .finish
+  jmp .item
+
+.failed:
+  mov ebp, 0
+.finish:
+  mov di, [esp+2]
+  mov [di], ebp
+  ret
+
+.e820
+  mov eax, 0xe820
+  mov edx, BIOS_MEMDETECT_MAGIC
+  mov [di + 20], dword 1
+  mov ecx, 24
+  int 0x15
+  ret
 
 bits 32
 


@@ 105,30 183,6 @@ pread_sector:
 
 bits 16
 
-hallo: db 'xos boot loader stage 1 ...', 0xa, 0xd, 0
-
-print:
-  mov ah, 0x0e
-.repeat:
-  lodsb
-  cmp al, 0
-  je .done
-  int 0x10
-  jmp .repeat
-.done:
-  ret
-
-enter_protected:
-  cli
-  lgdt [gdt_desc]
-
-  mov eax, cr0
-  or al, 1
-  mov cr0, eax
-
-  jmp 0x08:protected_main
-
-
 gdt_desc:
   dw 0x1f
   dd gdt

@@ 47,13 47,13 @@ static struct proc *launch(const char *binary, uint32_t mem);
 
 void kernel_main() {
   kprint("kernel main entered\n");
+  console_init(&global_console);
+  setup_gdt();
 
   kmem_init();
   paging_init();
 
-  setup_gdt();
 
-  console_init(&global_console);
   console_clear(&global_console);
   console_print(&global_console, "xos kernel loaded\n");
 

@@ 1,10 1,23 @@
+#include <sys/console.h>
 #include <sys/kernel.h>
 #include <sys/memory.h>
 #include <sys/paging.h>
 
+#define DEBUG
+#include <debug.h>
+
 #define KMEM_ARENA_START 0x200000
 #define KMEM_ARENA_END 0x400000
 
+struct detect_mmap_info {
+  uint32_t base_low;
+  uint32_t base_high;
+  uint32_t length_low;
+  uint32_t length_high;
+  uint16_t type;
+  uint16_t pad;
+} __attribute__ ((__packed__));
+
 struct kmem {
   void *free; // first free page
 };


@@ 15,7 28,11 @@ struct free_info {
 
 static struct kmem kmem_state;
 
+void kmem_detect(void);
+
 void kmem_init(void) {
+  kmem_detect();
+
   // begin with the last page
   void *page = (void *)(KMEM_ARENA_END - PAGE_SIZE);
 


@@ 32,6 49,22 @@ void kmem_init(void) {
   kmem_state.free = previous;
 }
 
+void
+kmem_detect(void) {
+  uint32_t mmap_count = *(uint32_t *)0x1000;
+  struct detect_mmap_info *mmap = (struct detect_mmap_info *)(0x1000 + 4);
+  khexprint("mmap count", mmap_count);
+  khexprint("mmap size", sizeof(struct detect_mmap_info));
+  for (int i=0; i<mmap_count; ++i) {
+    khexprint("=========== mmap entry", i);
+    khexprint("base_low", mmap[i].base_low);
+    khexprint("base_high", mmap[i].base_high);
+    khexprint("length_low", mmap[i].length_low);
+    khexprint("length_high", mmap[i].length_high);
+    khexprint("type", mmap[i].type);
+  }
+}
+
 void *kmem_alloc_pages(size_t pages) {
   if (pages != 1) {
     panic("can only alloc one page at a time");