powerpc/64: Change the way relocation copy is calculated

With a subsequent patch to put text into different sections,
(_end - _stext) can no longer be computed at link time to determine
the end of the copy. Instead, calculate it at runtime with
(copy_to_here - _stext) + (_end - copy_to_here).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 9 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index f765b0434731..6e21812ee672 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -628,11 +628,16 @@ __after_prom_start:
         bctr
 
 .balign 8
-p_end:  .llong  _end - _stext
+p_end: .llong _end - copy_to_here
 
-4:      /* Now copy the rest of the kernel up to _end */
-        addis   r5,r26,(p_end - _stext)@ha
-        ld      r5,(p_end - _stext)@l(r5)       /* get _end */
+4:
+        /*
+         * Now copy the rest of the kernel up to _end, add
+         * _end - copy_to_here to the copy limit and run again.
+         */
+        addis   r8,r26,(p_end - _stext)@ha
+        ld      r8,(p_end - _stext)@l(r8)
+        add     r5,r5,r8
 5:      bl      copy_and_flush          /* copy the rest */
 
 9:      b       start_here_multiplatform