--- zzzz-none-000/linux-3.10.107/arch/powerpc/boot/crt0.S	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/powerpc/boot/crt0.S	2021-02-04 17:41:59.000000000 +0000
@@ -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 @@
 
 	.weak	_platform_stack_top
 p_pstack:	.long	_platform_stack_top
+#endif
 
 	.weak	_zimage_start
 	.globl	_zimage_start
@@ -38,6 +56,7 @@
 	   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 @@
 
 	/* 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 */
@@ -120,9 +137,164 @@
 	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	r13,0
+	li	r8,0
+9:	ld	r12,0(r11)       /* get tag */
+	cmpdi	r12,0
+	beq	12f              /* end of list */
+	cmpdi	r12,RELA
+	bne	10f
+	ld	r13,8(r11)       /* get RELA pointer in r13 */
+	b	11f
+10:	addis	r12,r12,(-RELACOUNT)@ha
+	cmpdi	r12,RELACOUNT@l
+	bne	11f
+	ld	r8,8(r11)       /* get RELACOUNT value in r8 */
+11:	addi	r11,r11,16
+	b	9b
+12:
+	cmpdi	r13,0            /* check we have both RELA and RELACOUNT */
+	cmpdi	cr1,r8,0
+	beq	3f
+	beq	cr1,3f
+
+	/* Calcuate the runtime offset. */
+	subf	r13,r13,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	r12,0(r9)        /* reloc->r_offset */
+	ld	r0,16(r9)       /* reloc->r_addend */
+	add	r0,r0,r13
+	stdx	r0,r13,r12
+	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,-112(r1)	/* establish a stack frame */
+6:
+#endif  /* __powerpc64__ */
 	/* Call platform_init() */
 	bl	platform_init
 
 	/* Call start */
 	b	start
+
+#ifdef __powerpc64__
+
+#define PROM_FRAME_SIZE 512
+#define SAVE_GPR(n, base)       std     n,8*(n)(base)
+#define REST_GPR(n, base)       ld      n,8*(n)(base)
+#define SAVE_2GPRS(n, base)     SAVE_GPR(n, base); SAVE_GPR(n+1, base)
+#define SAVE_4GPRS(n, base)     SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base)
+#define SAVE_8GPRS(n, base)     SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base)
+#define SAVE_10GPRS(n, base)    SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base)
+#define REST_2GPRS(n, base)     REST_GPR(n, base); REST_GPR(n+1, base)
+#define REST_4GPRS(n, base)     REST_2GPRS(n, base); REST_2GPRS(n+2, base)
+#define REST_8GPRS(n, base)     REST_4GPRS(n, base); REST_4GPRS(n+4, base)
+#define REST_10GPRS(n, base)    REST_8GPRS(n, base); REST_2GPRS(n+8, base)
+
+/* prom handles the jump into and return from firmware.  The prom args pointer
+   is loaded in r3. */
+.globl prom
+prom:
+	mflr	r0
+	std	r0,16(r1)
+	stdu	r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
+
+	SAVE_GPR(2, r1)
+	SAVE_GPR(13, r1)
+	SAVE_8GPRS(14, r1)
+	SAVE_10GPRS(22, r1)
+	mfcr    r10
+	std     r10,8*32(r1)
+	mfmsr   r10
+	std     r10,8*33(r1)
+
+	/* remove MSR_LE from msr but keep MSR_SF */
+	mfmsr	r10
+	rldicr	r10,r10,0,62
+	mtsrr1	r10
+
+	/* Load FW address, set LR to label 1, and jump to FW */
+	bl	0f
+0:	mflr	r10
+	addi	r11,r10,(1f-0b)
+	mtlr	r11
+
+	ld	r10,(p_prom-0b)(r10)
+	mtsrr0	r10
+
+	rfid
+
+1:	/* Return from OF */
+	FIXUP_ENDIAN
+
+	/* Restore registers and return. */
+	rldicl  r1,r1,0,32
+
+	/* Restore the MSR (back to 64 bits) */
+	ld      r10,8*(33)(r1)
+	mtmsr	r10
+	isync
+
+	/* Restore other registers */
+	REST_GPR(2, r1)
+	REST_GPR(13, r1)
+	REST_8GPRS(14, r1)
+	REST_10GPRS(22, r1)
+	ld      r10,8*32(r1)
+	mtcr	r10
+
+	addi    r1,r1,PROM_FRAME_SIZE
+	ld      r0,16(r1)
+	mtlr    r0
+	blr
+#endif