1 files changed, 29 insertions, 3 deletions

diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S
index 70e65b13e033..3dc8d8f78499 100644
--- a/arch/powerpc/boot/crt0.S
+++ b/arch/powerpc/boot/crt0.S
@@ -16,6 +16,7 @@
 _zimage_start_opd:
         .long   _zimage_start, 0, 0, 0
 
+        .weak   _zimage_start
         .globl  _zimage_start
 _zimage_start:
         /* Work out the offset between the address we were linked at
@@ -44,7 +45,7 @@ _zimage_start:
         addi    r9,r9,4
         bdnz    2b
 
-        /* Do a cache flush for our text, in case OF didn't */
+        /* Do a cache flush for our text, in case the loader didn't */
 3:      lis     r9,_start@ha
         addi    r9,r9,_start@l
         add     r9,r0,r9
@@ -59,6 +60,31 @@ _zimage_start:
         sync
         isync
 
-        mr      r6,r1
-        b       start
+        /* Clear the BSS */
+        lis     r9,__bss_start@ha
+        addi    r9,r9,__bss_start@l
+        lis     r8,_end@ha
+        addi    r8,r8,_end@l
+        li      r0,0
+5:      stw     r0,0(r9)
+        addi    r9,r9,4
+        cmplw   cr0,r9,r8
+        blt     5b
 
+        /* Possibly set up a custom stack */
+.weak   _platform_stack_top
+        lis     r8,_platform_stack_top@ha
+        addi    r8,r8,_platform_stack_top@l
+        cmpwi   r8,0
+        beq     6f
+        lwz     r1,0(r8)
+        li      r0,0
+        stwu    r0,-16(r1)      /* establish a stack frame */
+6:
+
+        /* Call platform_init() */
+        bl      platform_init
+
+        /* Call start */
+        mr      r3,r1
+        b       start