Patch by Anders Larsen, 09 Jan 2004:

ARM memory layout fixes: the abort-stack is now set up in the
correct RAM area, and the BSS is zeroed out as it should be.

Furthermore, the magic variables 'armboot_end' and 'armboot_end_data'
of the linker scripts are replaced by '__bss_start' and '_end',
resp., which is a further step to eliminate unnecessary differences
between the implementation of the CPU architectures.

1 files changed, 25 insertions, 18 deletions

diff --git a/cpu/at91rm9200/start.S b/cpu/at91rm9200/start.S
index a93d0454d6..b9b889ab8c 100644
--- a/cpu/at91rm9200/start.S
+++ b/cpu/at91rm9200/start.S
@@ -79,19 +79,15 @@ _armboot_start:
 	.word _start
 
 /*
- * Note: _armboot_end_data and _armboot_end are defined
- * by the (board-dependent) linker script.
- * _armboot_end_data is the first usable FLASH address after armboot
+ * These are defined in the board-specific linker script.
  */
-.globl _armboot_end_data
-_armboot_end_data:
-	.word armboot_end_data
-/*
- * Note: armboot_end is defined by the (board-dependent) linker script
- */
-.globl _armboot_end
-_armboot_end:
-	.word armboot_end
+.globl _bss_start
+_bss_start:
+	.word __bss_start
+
+.globl _bss_end
+_bss_end:
+	.word _end
 
 #ifdef CONFIG_USE_IRQ
 /* IRQ stack memory (calculated at run-time) */
@@ -149,6 +145,17 @@ stack_setup:
 #endif
 	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
 
+clear_bss:
+	ldr	r0, _bss_start		/* find start of bss segment        */
+	add	r0, r0, #4		/* start at first byte of bss       */
+	ldr	r1, _bss_end		/* stop here                        */
+	mov 	r2, #0x00000000		/* clear                            */
+
+clbss_l:str	r2, [r0]		/* clear loop...                    */
+	add	r0, r0, #4
+	cmp	r0, r1
+	bne	clbss_l
+
 	ldr pc,_start_armboot
 
 _start_armboot: .word start_armboot
@@ -212,9 +219,9 @@ cpu_init_crit:
 	stmia	sp, {r0 - r12}			@ Calling r0-r12
 	add     r8, sp, #S_PC
 
-	ldr	r2, _armboot_end
-	add	r2, r2, #CONFIG_STACKSIZE
-	sub	r2, r2, #8
+	ldr	r2, _armboot_start
+	sub	r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
+	sub	r2, r2, #(CFG_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
 	ldmia	r2, {r2 - r4}                   @ get pc, cpsr, old_r0
 	add	r0, sp, #S_FRAME_SIZE		@ restore sp_SVC
 
@@ -245,9 +252,9 @@ cpu_init_crit:
 	.endm
 
 	.macro get_bad_stack
-	ldr	r13, _armboot_end		@ setup our mode stack
-	add	r13, r13, #CONFIG_STACKSIZE	@ resides at top of normal stack
-	sub	r13, r13, #8
+	ldr	r13, _armboot_start		@ setup our mode stack
+	sub	r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
+	sub	r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
 
 	str	lr, [r13]			@ save caller lr / spsr
 	mrs	lr, spsr