minor changes to boot code

2 files changed, 10 insertions, 10 deletions

diff --git a/boot.S b/boot.S
index be858ee..0cd0339 100644
--- a/boot.S
+++ b/boot.S
@@ -7,26 +7,24 @@
 // r2 -> 0x00000100 - start of ATAGS
 // preserve these registers as argument for kernel_main
 	
-.globl _boot // make entry point label global
+.global _boot // make entry point label global
 _boot:
-        // Shut off extra cores
-        mrc p15, 0, r5, c0, c0, 5
-        and r5, r5, #3
-        cmp r5, #0
+        // Only let the first core execute
+        mrc p15, 0, r3, c0, c0, 5
+        and r3, r3, #3
+        cmp r3, #0
         beq proceed
 	// this is a kind of blef - races can theoretically still occur
 	// when the main core overwrites this part of memory
 	wfe
 
 proceed:
-	// go to system mode
+	// go to system mode (we had problems doing this later)
 	cps #0b11111
 	isb
 	
-        // Setup the stack.
-	// It shall be directly below our kernel image
-        ldr r5, =__start
-        mov sp, r5
+        // Initialize the stack (_stack_top is defined in linker.ld)
+        ldr sp, =_stack_top
  
         // Call kernel_main
         ldr r3, =kernel_main
diff --git a/linker.ld b/linker.ld
index 33ac68c..e0e72b2 100644
--- a/linker.ld
+++ b/linker.ld
@@ -50,4 +50,6 @@ SECTIONS
     __interrupts_size = __interrupts_end - __interrupts_start;
     
     __end = .;
+
+    _stack_top = __start;
 }