hw2 done

bootloader/Start.S

@@ -12,8 +12,9 @@ wait:
 	b wait
 
 run:
+  // move dtb to x20
 	mov x20, x0
-	adr x0, _start
+	adrp x0, __stack_end
 	mov sp, x0
 
 	adr x0, __text_start
@@ -25,6 +26,7 @@ run:
 	adr x1, __bss_end
 	bl memzero
 
+	// move dtb back to x0
 	mov x0, x20
 	bl main
 	b wait
@@ -36,7 +38,8 @@ relocate:
 	adr x2, __text_end
 	sub x2, x2, x1
 	bl memcpy
-	mov x19, x0
+
+	mov x19, x0 // save return pointer
 
 	// move rodata section
 	ldr x0, =__new_ro_start
@@ -52,5 +55,6 @@ relocate:
 	sub x2, x2, x1
 	bl memcpy
 
+	mov x0, x20
 	br x19
 	b wait

bootloader/linker.ld

@@ -1,16 +1,16 @@
 ENTRY(_start)
 MEMORY
 {
-  NEWTEXT (rx) : ORIGIN = 0x10000, LENGTH = 128K
-  NEWRO (r) : ORIGIN = 0x30000, LENGTH = 128K
-  NEWDATA (rw) : ORIGIN = 0x50000, LENGTH = 64K
-  NEWBSS (rw) : ORIGIN = 0x60000, LENGTH = 64K
+  NEWTEXT (rx) : ORIGIN = 0x10000, LENGTH = 64K
+  NEWRO (r) : ORIGIN = 0x20000, LENGTH = 16K
+  NEWDATA (rw) : ORIGIN = 0x24000, LENGTH = 16K
+  NEWBSS (rw) : ORIGIN = 0x28000, LENGTH = 16K
 
-  TEXT (rx) : ORIGIN = 0x80000, LENGTH = 128K
-  RO (r) : ORIGIN = 0xa0000, LENGTH = 128K
-  DATA (rw) : ORIGIN = 0xc0000, LENGTH = 64K
-  BSS (rw) : ORIGIN = 0xd0000, LENGTH = 64K
-  RAM (rw) : ORIGIN = 0xf0000, LENGTH = 8M
+  TEXT (rx) : ORIGIN = 0x80000, LENGTH = 64K
+  RO (r) : ORIGIN = 0x90000, LENGTH = 16K
+  DATA (rw) : ORIGIN = 0x94000, LENGTH = 16K
+  BSS (rw) : ORIGIN = 0x98000, LENGTH = 16K
+  RAM (rw) : ORIGIN = 0x9c000, LENGTH = 4M 
 }
 
 SECTIONS
@@ -36,6 +36,7 @@ SECTIONS
     *(.bss)
     __bss_end = .;
   } >BSS
+
   __stack_end = ORIGIN(RAM) + LENGTH(RAM);
 
   __new_text_start = ORIGIN(NEWTEXT);
@@ -44,7 +45,6 @@ SECTIONS
   __new_bss_start = ORIGIN(NEWBSS);
 }
 
-__kernel = 0x80000;
 __heap_start = ORIGIN(RAM);
 __heap_end = ORIGIN(RAM) + LENGTH(RAM) - 2M;
 __bss_size = (__bss_end - __bss_start)>>3;

bootloader/main.c

@@ -2,20 +2,44 @@
 #include <shell.h>
 #include <uart.h>
 
-extern byte_t __kernel[];
-byte_t *kernel = __kernel;
+// extern uint64_t __kernel;
+uint64_t __kernel = 0x80000;
 
-void main()
+typedef void (*main_func_t)(void *);
+
+void main(void *dtb)
 {
   uart_init();
 
-  uart_getc();
+  uart_puts("waiting for kernel to be sent ..." ENDL);
+
+  union {
+    int size;
+    uint8_t buf[4];
+  } kernel_header;
+  kernel_header.size = 0;
+  for (int i = 0; i < (int)sizeof(kernel_header); ++i)
+    kernel_header.buf[i] = uart_getb();
+
+  uart_puts("received kernel size: ");
+  uart_int(kernel_header.size);
+  uart_puts(ENDL);
+
   uart_puts("loaded addr: ");
   uart_hex((unsigned int)(unsigned long)main);
   uart_puts(ENDL);
-  
-  int shell_cont = 1;
-  while (shell_cont) {
-    shell_cont = shell();
-  }
+
+  uart_puts("dtb addr: ");
+  uart_hex((unsigned int)(unsigned long)dtb);
+  uart_puts(ENDL);
+
+  uint8_t *kernel = (void *)__kernel;
+  uart_puts("kernel addr: ");
+  uart_hex((unsigned int)(unsigned long)kernel);
+  uart_puts("$" ENDL);
+
+  for (int i = 0; i < kernel_header.size; ++i)
+    kernel[i] = uart_getb();
+
+  ((main_func_t)kernel)(dtb);
 }