This patch adds support a 64bit wrapper entry point. As in 32bit, the
entry point does its own relocation and can be loaded at any address
by the firmware.
Signed-off-by: Cédric Le Goater <c...@fr.ibm.com>
---
arch/powerpc/boot/crt0.S | 108 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 104 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S
index dbd99d064828..689290561e69 100644
--- a/arch/powerpc/boot/crt0.S
+++ b/arch/powerpc/boot/crt0.S
@@ -1,17 +1,20 @@
/*
* Copyright (C) Paul Mackerras 1997.
*
+ * Adapted for 64 bit LE PowerPC by Andrew Tauferner
+ *
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
- * NOTE: this code runs in 32 bit mode, is position-independent,
- * and is packaged as ELF32.
*/
#include "ppc_asm.h"
+RELA = 7
+RELACOUNT = 0x6ffffff9
+
.text
/* A procedure descriptor used when booting this as a COFF file.
* When making COFF, this comes first in the link and we're
@@ -21,6 +24,20 @@
_zimage_start_opd:
.long 0x500000, 0, 0, 0
+#ifdef __powerpc64__
+.balign 8
+p_start: .llong _start
+p_etext: .llong _etext
+p_bss_start: .llong __bss_start
+p_end: .llong _end
+
+p_toc: .llong __toc_start + 0x8000 - p_base
+p_dyn: .llong __dynamic_start - p_base
+p_rela: .llong __rela_dyn_start - p_base
+p_prom: .llong 0
+ .weak _platform_stack_top
+p_pstack: .llong _platform_stack_top
+#else
p_start: .long _start
p_etext: .long _etext
p_bss_start: .long __bss_start
@@ -28,6 +45,7 @@ p_end: .long _end
.weak _platform_stack_top
p_pstack: .long _platform_stack_top
+#endif
.weak _zimage_start
.globl _zimage_start
@@ -38,6 +56,7 @@ _zimage_start_lib:
and the address where we're running. */
bl .+4
p_base: mflr r10 /* r10 now points to runtime addr of
p_base */
+#ifndef __powerpc64__
/* grab the link address of the dynamic section in r11 */
addis r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha
lwz r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11)
@@ -51,8 +70,6 @@ p_base: mflr r10 /* r10 now points to
runtime addr of p_base */
/* The dynamic section contains a series of tagged entries.
* We need the RELA and RELACOUNT entries. */
-RELA = 7
-RELACOUNT = 0x6ffffff9
li r9,0
li r0,0
9: lwz r8,0(r12) /* get tag */
@@ -120,7 +137,90 @@ RELACOUNT = 0x6ffffff9
li r0,0
stwu r0,-16(r1) /* establish a stack frame */
6:
+#else /* __powerpc64__ */
+ /* Save the prom pointer at p_prom. */
+ std r5,(p_prom-p_base)(r10)
+
+ /* Set r2 to the TOC. */
+ ld r2,(p_toc-p_base)(r10)
+ add r2,r2,r10
+
+ /* Grab the link address of the dynamic section in r11. */
+ ld r11,-32768(r2)
+ cmpwi r11,0
+ beq 3f /* if not linked -pie then no dynamic section */
+
+ ld r11,(p_dyn-p_base)(r10)
+ add r11,r11,r10
+ ld r9,(p_rela-p_base)(r10)
+ add r9,r9,r10
+
+ li r7,0
+ li r8,0
+9: ld r6,0(r11) /* get tag */
+ cmpdi r6,0
+ beq 12f /* end of list */
+ cmpdi r6,RELA
+ bne 10f
+ ld r7,8(r11) /* get RELA pointer in r7 */
+ b 11f
+10: addis r6,r6,(-RELACOUNT)@ha
+ cmpdi r6,RELACOUNT@l
+ bne 11f
+ ld r8,8(r11) /* get RELACOUNT value in r8 */
+11: addi r11,r11,16
+ b 9b
+12:
+ cmpdi r7,0 /* check we have both RELA and RELACOUNT */
+ cmpdi cr1,r8,0
+ beq 3f
+ beq cr1,3f
+
+ /* Calcuate the runtime offset. */
+ subf r7,r7,r9
+ /* Run through the list of relocations and process the
+ * R_PPC64_RELATIVE ones. */
+ mtctr r8
+13: ld r0,8(r9) /* ELF64_R_TYPE(reloc->r_info) */
+ cmpdi r0,22 /* R_PPC64_RELATIVE */
+ bne 3f
+ ld r6,0(r9) /* reloc->r_offset */
+ ld r0,16(r9) /* reloc->r_addend */
+ add r0,r0,r7
+ stdx r0,r7,r6
+ addi r9,r9,24
+ bdnz 13b
+
+ /* Do a cache flush for our text, in case the loader didn't */
+3: ld r9,p_start-p_base(r10) /* note: these are relocated now */
+ ld r8,p_etext-p_base(r10)
+4: dcbf r0,r9
+ icbi r0,r9
+ addi r9,r9,0x20
+ cmpld cr0,r9,r8
+ blt 4b
+ sync
+ isync
+
+ /* Clear the BSS */
+ ld r9,p_bss_start-p_base(r10)
+ ld r8,p_end-p_base(r10)
+ li r0,0
+5: std r0,0(r9)
+ addi r9,r9,8
+ cmpld cr0,r9,r8
+ blt 5b
+
+ /* Possibly set up a custom stack */
+ ld r8,p_pstack-p_base(r10)
+ cmpdi r8,0
+ beq 6f
+ ld r1,0(r8)
+ li r0,0
+ stdu r0,-16(r1) /* establish a stack frame */
+6:
+#endif /* __powerpc64__ */
/* Call platform_init() */
bl platform_init
--
1.7.10.4
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