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u-boot/arch/openrisc/cpu/start.S
Franck Jullien 9cd73bf859 openrisc: fix relocation code 
The relocation code can now relocate from anywhere to
the RAM.

The old code assumed that the binary was copied to the RAM
by some PBL and then it just relocated the .text section
from the loaded address to the linked address.

Now, it first checks if vectors are somewhere else than the
linked address. If yes, there are copied to address 0 (or
to the exception vector base address if register EVBAR is
present).

Then, the .text section is relocated from its current location
to the RAM.

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
2014-06-05 14:44:56 -04:00

353 lines
6.2 KiB
ArmAsm
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/*
* (C) Copyright 2011, Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
* (C) Copyright 2011, Julius Baxter <julius@opencores.org>
* (C) Copyright 2014, Franck Jullien <franck.jullien@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <config.h>
#include <asm-offsets.h>
#include <asm/spr-defs.h>
#define EXCEPTION_STACK_SIZE (128+128)
#define HANDLE_EXCEPTION \
l.addi r1, r1, -EXCEPTION_STACK_SIZE ;\
l.sw 0x00(r1), r2 ;\
l.sw 0x1c(r1), r9 ;\
l.movhi r2,hi(_exception_handler) ;\
l.ori r2,r2,lo(_exception_handler) ;\
l.jalr r2 ;\
l.nop ;\
l.lwz r9, 0x1c(r1) ;\
l.addi r1, r1, EXCEPTION_STACK_SIZE ;\
l.rfe ;\
l.nop
.section .vectors, "ax"
.global __reset
/* reset */
.org 0x100
__reset:
/* there is no guarantee r0 is hardwired to zero, clear it here */
l.andi r0, r0, 0
/* reset stack and frame pointers */
l.andi r1, r0, 0
l.andi r2, r0, 0
/* set supervisor mode */
l.ori r3,r0,SPR_SR_SM
l.mtspr r0,r3,SPR_SR
l.jal _cur
l.nop
_cur:
l.ori r8, r9, 0 /* Get _cur current address */
l.movhi r3, hi(_cur)
l.ori r3, r3, lo(_cur)
l.sfeq r8, r3 /* If we are running at the linked address */
l.bf _no_vector_reloc /* there is not need for relocation */
l.sub r8, r8, r3
l.mfspr r4, r0, SPR_CPUCFGR
l.andi r4, r4, SPR_CPUCFGR_EVBARP /* Exception Vector Base Address Register present ? */
l.sfnei r4,0
l.bnf _reloc_vectors
l.movhi r5, 0 /* Destination */
l.mfspr r4, r0, SPR_EVBAR
l.add r5, r5, r4
_reloc_vectors:
/* Relocate vectors*/
l.movhi r5, 0 /* Destination */
l.movhi r6, hi(__start) /* Length */
l.ori r6, r6, lo(__start)
l.ori r3, r8, 0
.L_relocvectors:
l.lwz r7, 0(r3)
l.sw 0(r5), r7
l.addi r5, r5, 4
l.sfeq r5, r6
l.bnf .L_relocvectors
l.addi r3, r3, 4
_no_vector_reloc:
/* Relocate u-boot */
l.movhi r3,hi(__start) /* source start offset */
l.ori r3,r3,lo(__start)
l.add r3,r8,r3
l.movhi r4,hi(_stext) /* dest start address */
l.ori r4,r4,lo(_stext)
l.movhi r5,hi(__end) /* dest end address */
l.ori r5,r5,lo(__end)
.L_reloc:
l.lwz r6,0(r3)
l.sw 0(r4),r6
l.addi r3,r3,4
l.sfltu r4,r5
l.bf .L_reloc
l.addi r4,r4,4 /* delay slot */
l.movhi r4,hi(_start)
l.ori r4,r4,lo(_start)
l.jr r4
l.nop
/* bus error */
.org 0x200
HANDLE_EXCEPTION
/* data page fault */
.org 0x300
HANDLE_EXCEPTION
/* instruction page fault */
.org 0x400
HANDLE_EXCEPTION
/* tick timer */
.org 0x500
HANDLE_EXCEPTION
/* alignment */
.org 0x600
HANDLE_EXCEPTION
/* illegal instruction */
.org 0x700
HANDLE_EXCEPTION
/* external interrupt */
.org 0x800
HANDLE_EXCEPTION
/* D-TLB miss */
.org 0x900
HANDLE_EXCEPTION
/* I-TLB miss */
.org 0xa00
HANDLE_EXCEPTION
/* range */
.org 0xb00
HANDLE_EXCEPTION
/* system call */
.org 0xc00
HANDLE_EXCEPTION
/* floating point */
.org 0xd00
HANDLE_EXCEPTION
/* trap */
.org 0xe00
HANDLE_EXCEPTION
/* reserved */
.org 0xf00
HANDLE_EXCEPTION
/* reserved */
.org 0x1100
HANDLE_EXCEPTION
/* reserved */
.org 0x1200
HANDLE_EXCEPTION
/* reserved */
.org 0x1300
HANDLE_EXCEPTION
/* reserved */
.org 0x1400
HANDLE_EXCEPTION
/* reserved */
.org 0x1500
HANDLE_EXCEPTION
/* reserved */
.org 0x1600
HANDLE_EXCEPTION
/* reserved */
.org 0x1700
HANDLE_EXCEPTION
/* reserved */
.org 0x1800
HANDLE_EXCEPTION
/* reserved */
.org 0x1900
HANDLE_EXCEPTION
/* reserved */
.org 0x1a00
HANDLE_EXCEPTION
/* reserved */
.org 0x1b00
HANDLE_EXCEPTION
/* reserved */
.org 0x1c00
HANDLE_EXCEPTION
/* reserved */
.org 0x1d00
HANDLE_EXCEPTION
/* reserved */
.org 0x1e00
HANDLE_EXCEPTION
/* reserved */
.org 0x1f00
HANDLE_EXCEPTION
/* Startup routine */
.text
.global _start
_start:
/* Init stack and frame pointers */
l.movhi r1, hi(CONFIG_SYS_INIT_SP_ADDR)
l.ori r1, r1, lo(CONFIG_SYS_INIT_SP_ADDR)
l.or r2, r0, r1
/* clear BSS segments */
l.movhi r4, hi(_bss_start)
l.ori r4, r4, lo(_bss_start)
l.movhi r5, hi(_bss_end)
l.ori r5, r5, lo(_bss_end)
.L_clear_bss:
l.sw 0(r4), r0
l.sfltu r4,r5
l.bf .L_clear_bss
l.addi r4,r4,4
/* Reset registers before jumping to board_init */
l.andi r3, r0, 0
l.andi r4, r0, 0
l.andi r5, r0, 0
l.andi r6, r0, 0
l.andi r7, r0, 0
l.andi r8, r0, 0
l.andi r9, r0, 0
l.andi r10, r0, 0
l.andi r11, r0, 0
l.andi r12, r0, 0
l.andi r13, r0, 0
l.andi r14, r0, 0
l.andi r15, r0, 0
l.andi r17, r0, 0
l.andi r18, r0, 0
l.andi r19, r0, 0
l.andi r20, r0, 0
l.andi r21, r0, 0
l.andi r22, r0, 0
l.andi r23, r0, 0
l.andi r24, r0, 0
l.andi r25, r0, 0
l.andi r26, r0, 0
l.andi r27, r0, 0
l.andi r28, r0, 0
l.andi r29, r0, 0
l.andi r30, r0, 0
l.andi r31, r0, 0
l.j board_init
l.nop
.size _start, .-_start
/*
* Store state onto stack and call the real exception handler
*/
.section .text
.extern exception_handler
.type _exception_handler,@function
_exception_handler:
/* Store state (r2 and r9 already saved)*/
l.sw 0x04(r1), r3
l.sw 0x08(r1), r4
l.sw 0x0c(r1), r5
l.sw 0x10(r1), r6
l.sw 0x14(r1), r7
l.sw 0x18(r1), r8
l.sw 0x20(r1), r10
l.sw 0x24(r1), r11
l.sw 0x28(r1), r12
l.sw 0x2c(r1), r13
l.sw 0x30(r1), r14
l.sw 0x34(r1), r15
l.sw 0x38(r1), r16
l.sw 0x3c(r1), r17
l.sw 0x40(r1), r18
l.sw 0x44(r1), r19
l.sw 0x48(r1), r20
l.sw 0x4c(r1), r21
l.sw 0x50(r1), r22
l.sw 0x54(r1), r23
l.sw 0x58(r1), r24
l.sw 0x5c(r1), r25
l.sw 0x60(r1), r26
l.sw 0x64(r1), r27
l.sw 0x68(r1), r28
l.sw 0x6c(r1), r29
l.sw 0x70(r1), r30
l.sw 0x74(r1), r31
/* Save return address */
l.or r14, r0, r9
/* Call exception handler with the link address as argument */
l.jal exception_handler
l.or r3, r0, r14
/* Load return address */
l.or r9, r0, r14
/* Restore state */
l.lwz r2, 0x00(r1)
l.lwz r3, 0x04(r1)
l.lwz r4, 0x08(r1)
l.lwz r5, 0x0c(r1)
l.lwz r6, 0x10(r1)
l.lwz r7, 0x14(r1)
l.lwz r8, 0x18(r1)
l.lwz r10, 0x20(r1)
l.lwz r11, 0x24(r1)
l.lwz r12, 0x28(r1)
l.lwz r13, 0x2c(r1)
l.lwz r14, 0x30(r1)
l.lwz r15, 0x34(r1)
l.lwz r16, 0x38(r1)
l.lwz r17, 0x3c(r1)
l.lwz r18, 0x40(r1)
l.lwz r19, 0x44(r1)
l.lwz r20, 0x48(r1)
l.lwz r21, 0x4c(r1)
l.lwz r22, 0x50(r1)
l.lwz r23, 0x54(r1)
l.lwz r24, 0x58(r1)
l.lwz r25, 0x5c(r1)
l.lwz r26, 0x60(r1)
l.lwz r27, 0x64(r1)
l.lwz r28, 0x68(r1)
l.lwz r29, 0x6c(r1)
l.lwz r30, 0x70(r1)
l.lwz r31, 0x74(r1)
l.jr r9
l.nop
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