hwstub: allow the stub to relocate itself

Change-Id: Iab60c6ec0e8eda19c76c84241f8367d53cb4f87b

1 files changed, 22 insertions, 0 deletions

diff --git a/utils/hwstub/stub/crt0.S b/utils/hwstub/stub/crt0.S
index e2d4742d36..5ba71905c9 100644
--- a/utils/hwstub/stub/crt0.S
+++ b/utils/hwstub/stub/crt0.S
@@ -3,8 +3,30 @@
 .align      0x04
 .global     start
 start:
+    sub     r7, pc, #8 /* Copy running address */
     msr     cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */
+    /* Disable MMU, disable caching and buffering;
+     * use low exception range address */
+    mrc     p15, 0, r0, c1, c0, 0
+    ldr     r1, =0x3005
+    bic     r0, r1
+    mcr     p15, 0, r0, c1, c0, 0
     ldr     sp, =oc_stackend
+    /* Relocate to right address */
+    mov    r2, r7
+    ldr    r3, =_copystart
+    ldr    r4, =_copyend
+1:
+    cmp     r4, r3
+    ldrhi   r5, [r2], #4
+    strhi   r5, [r3], #4
+    bhi     1b
+
+    mov     r2, #0
+    mcr     p15, 0, r2, c7, c5, 0   @ Invalidate ICache
+    /* Jump to real location */
+    ldr     pc, =remap
+remap:
     /* clear bss */
     ldr     r2, =bss_start
     ldr     r3, =bss_end