[U-Boot] [PATCH] mpc83xx: Add -fpic relocation support

[Joakim Tjernlund]

This add relocation of .got entries produced
by -fpic. -fpic produces 2-3% smaller code and
is faster. Unfortunately gcc promotes -fpic to
-fPIC when -mrelocatable is used so one need a very
small patch to gcc too(sent upstream).

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
---
 arch/powerpc/cpu/mpc83xx/start.S    |   18 ++++++++++++++++++
 arch/powerpc/cpu/mpc83xx/u-boot.lds |    1 +
 2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/cpu/mpc83xx/start.S b/arch/powerpc/cpu/mpc83xx/start.S
index c7d85a8..95ae1d8 100644
--- a/arch/powerpc/cpu/mpc83xx/start.S
+++ b/arch/powerpc/cpu/mpc83xx/start.S
@@ -69,6 +69,8 @@
  */
 	START_GOT
 	GOT_ENTRY(_GOT2_TABLE_)
+	GOT_ENTRY(_GOT_TABLE_)
+	GOT_ENTRY(_GLOBAL_OFFSET_TABLE_)
 	GOT_ENTRY(__bss_start)
 	GOT_ENTRY(_end)
 
@@ -951,6 +953,22 @@ in_ram:
 	stw	r0,0(r3)
 2:	bdnz	1b
 
+	lwz	r4,GOT(_GLOBAL_OFFSET_TABLE_)
+	addi	r4,r4,-4 /* don't write over blrl in GOT */
+	lwz	r3,GOT(_GOT_TABLE_)
+	subf.	r4,r3,r4 /* r4 - r3 */
+	ble	3f
+	srwi	r4,r4,2 /* r4/4 */
+	mr	r5,r11
+	mtctr	r4
+	addi	r3,r3,-4
+1:	lwzu	r0,4(r3)
+	cmpwi	r0,0
+	beq-	2f
+	add	r0,r0,r11
+	stw	r0,0(r3)
+2:	bdnz	1b
+3:
 #ifndef CONFIG_NAND_SPL
 	/*
 	 * Now adjust the fixups and the pointers to the fixups
diff --git a/arch/powerpc/cpu/mpc83xx/u-boot.lds b/arch/powerpc/cpu/mpc83xx/u-boot.lds
index 0b74a13..a498a37 100644
--- a/arch/powerpc/cpu/mpc83xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc83xx/u-boot.lds
@@ -67,6 +67,7 @@ SECTIONS
   PROVIDE (erotext = .);
   .reloc   :
   {
+    _GOT_TABLE_ = .;
     *(.got)
     _GOT2_TABLE_ = .;
     *(.got2)
-- 
1.7.2.2