microblaze: Remove _start symbol handling at U-Boot start

Right now U-Boot runs all the time from the same address where it is loaded
but going to full relocation code starting address doesn't need to be fixed
and can be simply discovered from reading PC register. That's why use r20
to get PC address and subtract offset from the beginning to get starting
address.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/044b727c33dfbe662f68512d0da0775a4805f360.1655299267.git.michal.simek@amd.com

diff --git a/arch/microblaze/cpu/start.S b/arch/microblaze/cpu/start.S
index c3d925c..db3998f 100644 (file)
--- a/arch/microblaze/cpu/start.S
+++ b/arch/microblaze/cpu/start.S
@@ -14,15 +14,16 @@
        .global _start
 _start:
        mts     rmsr, r0        /* disable cache */
+       mfs     r20, rpc
+       addi    r20, r20, -4
 
        mts     rslr, r0
-       addi    r8, r0, _start
-       mts     rshr, r8
+       mts     rshr, r20
 
 #if defined(CONFIG_SPL_BUILD)
        addi    r1, r0, CONFIG_SPL_STACK_ADDR
 #else
-       add     r1, r0, r8
+       add     r1, r0, r20
 #endif
 
        addi    r1, r1, -4      /* Decrement SP to top of memory */