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+/*
+ * Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
+ * Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
+ * Copyright (C) 2000, 2001, 2002, 2007 Wolfgang Denk <wd@denx.de>
+ * Copyright Freescale Semiconductor, Inc. 2004, 2006. All rights reserved.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ * Based on the MPC83xx code.
+ */
+
+/*
+ * U-Boot - Startup Code for MPC512x based Embedded Boards
+ */
+
+#include <config.h>
+#include <mpc512x.h>
+#include <version.h>
+
+#define CONFIG_521X 1 /* needed for Linux kernel header files*/
+
+#include <ppc_asm.tmpl>
+#include <ppc_defs.h>
+
+#include <asm/cache.h>
+#include <asm/mmu.h>
+
+#ifndef CONFIG_IDENT_STRING
+#define CONFIG_IDENT_STRING "MPC512X"
+#endif
+
+/*
+ * Floating Point enable, Machine Check and Recoverable Interr.
+ */
+#undef MSR_KERNEL
+#ifdef DEBUG
+#define MSR_KERNEL (MSR_FP|MSR_RI)
+#else
+#define MSR_KERNEL (MSR_FP|MSR_ME|MSR_RI)
+#endif
+
+/* Macros for manipulating CSx_START/STOP */
+#define START_REG(start) ((start) >> 16)
+#define STOP_REG(start, size) (((start) + (size) - 1) >> 16)
+
+/*
+ * Set up GOT: Global Offset Table
+ *
+ * Use r14 to access the GOT
+ */
+ START_GOT
+ GOT_ENTRY(_GOT2_TABLE_)
+ GOT_ENTRY(_FIXUP_TABLE_)
+
+ GOT_ENTRY(_start)
+ GOT_ENTRY(_start_of_vectors)
+ GOT_ENTRY(_end_of_vectors)
+ GOT_ENTRY(transfer_to_handler)
+
+ GOT_ENTRY(__init_end)
+ GOT_ENTRY(_end)
+ GOT_ENTRY(__bss_start)
+ END_GOT
+
+/*
+ * Magic number and version string
+ */
+ .long 0x27051956 /* U-Boot Magic Number */
+ .globl version_string
+version_string:
+ .ascii U_BOOT_VERSION
+ .ascii " (", __DATE__, " - ", __TIME__, ")"
+ .ascii " ", CONFIG_IDENT_STRING, "\0"
+
+/*
+ * Vector Table
+ */
+ .text
+ . = EXC_OFF_SYS_RESET
+
+ .globl _start
+ /* Start from here after reset/power on */
+_start:
+ li r21, BOOTFLAG_COLD /* Normal Power-On: Boot from FLASH */
+ b boot_cold
+
+ .globl _start_of_vectors
+_start_of_vectors:
+
+/* Machine check */
+ STD_EXCEPTION(0x200, MachineCheck, MachineCheckException)
+
+/* Data Storage exception. */
+ STD_EXCEPTION(0x300, DataStorage, UnknownException)
+
+/* Instruction Storage exception. */
+ STD_EXCEPTION(0x400, InstStorage, UnknownException)
+
+/* External Interrupt exception. */
+ STD_EXCEPTION(0x500, ExtInterrupt, UnknownException)
+
+/* Alignment exception. */
+ . = 0x600
+Alignment:
+ EXCEPTION_PROLOG(SRR0, SRR1)
+ mfspr r4,DAR
+ stw r4,_DAR(r21)
+ mfspr r5,DSISR
+ stw r5,_DSISR(r21)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ li r20,MSR_KERNEL
+ rlwimi r20,r23,0,16,16 /* copy EE bit from saved MSR */
+ rlwimi r20,r23,0,25,25 /* copy IP bit from saved MSR */
+ lwz r6,GOT(transfer_to_handler)
+ mtlr r6
+ blrl
+.L_Alignment:
+ .long AlignmentException - _start + EXC_OFF_SYS_RESET
+ .long int_return - _start + EXC_OFF_SYS_RESET
+
+/* Program check exception */
+ . = 0x700
+ProgramCheck:
+ EXCEPTION_PROLOG(SRR0, SRR1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ li r20,MSR_KERNEL
+ rlwimi r20,r23,0,16,16 /* copy EE bit from saved MSR */
+ rlwimi r20,r23,0,25,25 /* copy IP bit from saved MSR */
+ lwz r6,GOT(transfer_to_handler)
+ mtlr r6
+ blrl
+.L_ProgramCheck:
+ .long ProgramCheckException - _start + EXC_OFF_SYS_RESET
+ .long int_return - _start + EXC_OFF_SYS_RESET
+
+/* Floating Point Unit unavailable exception */
+ STD_EXCEPTION(0x800, FPUnavailable, UnknownException)
+
+/* Decrementer */
+ STD_EXCEPTION(0x900, Decrementer, timer_interrupt)
+
+/* Critical interrupt */
+ STD_EXCEPTION(0xa00, Critical, UnknownException)
+
+/* System Call */
+ STD_EXCEPTION(0xc00, SystemCall, UnknownException)
+
+/* Trace interrupt */
+ STD_EXCEPTION(0xd00, Trace, UnknownException)
+
+/* Performance Monitor interrupt */
+ STD_EXCEPTION(0xf00, PerfMon, UnknownException)
+
+/* Intruction Translation Miss */
+ STD_EXCEPTION(0x1000, InstructionTLBMiss, UnknownException)
+
+/* Data Load Translation Miss */
+ STD_EXCEPTION(0x1100, DataLoadTLBMiss, UnknownException)
+
+/* Data Store Translation Miss */
+ STD_EXCEPTION(0x1200, DataStoreTLBMiss, UnknownException)
+
+/* Instruction Address Breakpoint */
+ STD_EXCEPTION(0x1300, InstructionAddrBreakpoint, DebugException)
+
+/* System Management interrupt */
+ STD_EXCEPTION(0x1400, SystemMgmtInterrupt, UnknownException)
+
+ .globl _end_of_vectors
+_end_of_vectors:
+
+ . = 0x3000
+boot_cold:
+ /* Save msr contents */
+ mfmsr r5
+
+ /* Set IMMR area to our preferred location */
+ lis r4, CONFIG_DEFAULT_IMMR@h
+ lis r3, CFG_IMMR@h
+ ori r3, r3, CFG_IMMR@l
+ stw r3, IMMRBAR(r4)
+ mtspr MBAR, r3 /* IMMRBAR is mirrored into the MBAR SPR (311) */
+
+ /* Initialise the machine */
+ bl cpu_early_init
+
+ /*
+ * Set up Local Access Windows:
+ *
+ * 1) Boot/CS0 (boot FLASH)
+ * 2) On-chip SRAM (initial stack purposes)
+ */
+
+ /* Boot CS/CS0 window range */
+ lis r3, CFG_IMMR@h
+ ori r3, r3, CFG_IMMR@l
+
+ lis r4, START_REG(CFG_FLASH_BASE)
+ ori r4, r4, STOP_REG(CFG_FLASH_BASE, CFG_FLASH_SIZE)
+ stw r4, LPCS0AW(r3)
+
+ /*
+ * The SRAM window has a fixed size (256K), so only the start address
+ * is necessary
+ */
+ lis r4, START_REG(CFG_SRAM_BASE) & 0xff00
+ stw r4, SRAMBAR(r3)
+
+ /*
+ * According to MPC5121e RM, configuring local access windows should
+ * be followed by a dummy read of the config register that was
+ * modified last and an isync
+ */
+ lwz r4, SRAMBAR(r3)
+ isync
+
+ /*
+ * Set configuration of the Boot/CS0, the SRAM window does not have a
+ * config register so no params can be set for it
+ */
+ lis r3, (CFG_IMMR + LPC_OFFSET)@h
+ ori r3, r3, (CFG_IMMR + LPC_OFFSET)@l
+
+ lis r4, CFG_CS0_CFG@h
+ ori r4, r4, CFG_CS0_CFG@l
+ stw r4, CS0_CONFIG(r3)
+
+ /* Master enable all CS's */
+ lis r4, CS_CTRL_ME@h
+ ori r4, r4, CS_CTRL_ME@l
+ stw r4, CS_CTRL(r3)
+
+ lis r4, (CFG_MONITOR_BASE)@h
+ ori r4, r4, (CFG_MONITOR_BASE)@l
+ addi r5, r4, in_flash - _start + EXC_OFF_SYS_RESET
+ mtlr r5
+ blr
+
+in_flash:
+ lis r1, (CFG_INIT_RAM_ADDR + CFG_GBL_DATA_OFFSET)@h
+ ori r1, r1, (CFG_INIT_RAM_ADDR + CFG_GBL_DATA_OFFSET)@l
+
+ li r0, 0 /* Make room for stack frame header and */
+ stwu r0, -4(r1) /* clear final stack frame so that */
+ stwu r0, -4(r1) /* stack backtraces terminate cleanly */
+
+ /* let the C-code set up the rest */
+ /* */
+ /* Be careful to keep code relocatable & stack humble */
+ /*------------------------------------------------------*/
+
+ GET_GOT /* initialize GOT access */
+
+ /* r3: IMMR */
+ lis r3, CFG_IMMR@h
+ /* run low-level CPU init code (in Flash) */
+ bl cpu_init_f
+
+ /* r3: BOOTFLAG */
+ mr r3, r21
+ /* run 1st part of board init code (in Flash) */
+ bl board_init_f
+
+ /* NOTREACHED - board_init_f() does not return */
+
+/*
+ * This code finishes saving the registers to the exception frame
+ * and jumps to the appropriate handler for the exception.
+ * Register r21 is pointer into trap frame, r1 has new stack pointer.
+ */
+ .globl transfer_to_handler
+transfer_to_handler:
+ stw r22,_NIP(r21)
+ lis r22,MSR_POW@h
+ andc r23,r23,r22
+ stw r23,_MSR(r21)
+ SAVE_GPR(7, r21)
+ SAVE_4GPRS(8, r21)
+ SAVE_8GPRS(12, r21)
+ SAVE_8GPRS(24, r21)
+ mflr r23
+ andi. r24,r23,0x3f00 /* get vector offset */
+ stw r24,TRAP(r21)
+ li r22,0
+ stw r22,RESULT(r21)
+ lwz r24,0(r23) /* virtual address of handler */
+ lwz r23,4(r23) /* where to go when done */
+ mtspr SRR0,r24
+ mtspr SRR1,r20
+ mtlr r23
+ SYNC
+ rfi /* jump to handler, enable MMU */
+
+int_return:
+ mfmsr r28 /* Disable interrupts */
+ li r4,0
+ ori r4,r4,MSR_EE
+ andc r28,r28,r4
+ SYNC /* Some chip revs need this... */
+ mtmsr r28
+ SYNC
+ lwz r2,_CTR(r1)
+ lwz r0,_LINK(r1)
+ mtctr r2
+ mtlr r0
+ lwz r2,_XER(r1)
+ lwz r0,_CCR(r1)
+ mtspr XER,r2
+ mtcrf 0xFF,r0
+ REST_10GPRS(3, r1)
+ REST_10GPRS(13, r1)
+ REST_8GPRS(23, r1)
+ REST_GPR(31, r1)
+ lwz r2,_NIP(r1) /* Restore environment */
+ lwz r0,_MSR(r1)
+ mtspr SRR0,r2
+ mtspr SRR1,r0
+ lwz r0,GPR0(r1)
+ lwz r2,GPR2(r1)
+ lwz r1,GPR1(r1)
+ SYNC
+ rfi
+
+/*
+ * This code initialises the machine, it expects original MSR contents to be in r5.
+ */
+cpu_early_init:
+ /* Initialize machine status; enable machine check interrupt */
+ /*-----------------------------------------------------------*/
+
+ li r3, MSR_KERNEL /* Set ME and RI flags */
+ rlwimi r3, r5, 0, 25, 25 /* preserve IP bit */
+#ifdef DEBUG
+ rlwimi r3, r5, 0, 21, 22 /* debugger might set SE, BE bits */
+#endif
+ mtmsr r3
+ SYNC
+ mtspr SRR1, r3 /* Mirror current MSR state in SRR1 */
+
+ lis r3, CFG_IMMR@h
+
+#if defined(CONFIG_WATCHDOG)
+ /* Initialise the watchdog and reset it */
+ /*--------------------------------------*/
+ lis r4, CFG_WATCHDOG_VALUE
+ ori r4, r4, (SWCRR_SWEN | SWCRR_SWRI | SWCRR_SWPR)
+ stw r4, SWCRR(r3)
+
+ /* reset */
+ li r4, 0x556C
+ sth r4, SWSRR@l(r3)
+ li r4, 0x0
+ ori r4, r4, 0xAA39
+ sth r4, SWSRR@l(r3)
+#else
+ /* Disable the watchdog */
+ /*----------------------*/
+ lwz r4, SWCRR(r3)
+ /*
+ * Check to see if it's enabled for disabling: once disabled by s/w
+ * it's not possible to re-enable it
+ */
+ andi. r4, r4, 0x4
+ beq 1f
+ xor r4, r4, r4
+ stw r4, SWCRR(r3)
+1:
+#endif /* CONFIG_WATCHDOG */
+
+ /* Initialize the Hardware Implementation-dependent Registers */
+ /* HID0 also contains cache control */
+ /*------------------------------------------------------*/
+ lis r3, CFG_HID0_INIT@h
+ ori r3, r3, CFG_HID0_INIT@l
+ SYNC
+ mtspr HID0, r3
+
+ lis r3, CFG_HID0_FINAL@h
+ ori r3, r3, CFG_HID0_FINAL@l
+ SYNC
+ mtspr HID0, r3
+
+ lis r3, CFG_HID2@h
+ ori r3, r3, CFG_HID2@l
+ SYNC
+ mtspr HID2, r3
+ sync
+ blr
+
+
+/* Cache functions.
+ *
+ * Note: requires that all cache bits in
+ * HID0 are in the low half word.
+ */
+ .globl icache_enable
+icache_enable:
+ mfspr r3, HID0
+ ori r3, r3, HID0_ICE
+ lis r4, 0
+ ori r4, r4, HID0_ILOCK
+ andc r3, r3, r4
+ ori r4, r3, HID0_ICFI
+ isync
+ mtspr HID0, r4 /* sets enable and invalidate, clears lock */
+ isync
+ mtspr HID0, r3 /* clears invalidate */
+ blr
+
+ .globl icache_disable
+icache_disable:
+ mfspr r3, HID0
+ lis r4, 0
+ ori r4, r4, HID0_ICE|HID0_ILOCK
+ andc r3, r3, r4
+ ori r4, r3, HID0_ICFI
+ isync
+ mtspr HID0, r4 /* sets invalidate, clears enable and lock*/
+ isync
+ mtspr HID0, r3 /* clears invalidate */
+ blr
+
+ .globl icache_status
+icache_status:
+ mfspr r3, HID0
+ rlwinm r3, r3, (31 - HID0_ICE_SHIFT + 1), 31, 31
+ blr
+
+ .globl dcache_enable
+dcache_enable:
+ mfspr r3, HID0
+ li r5, HID0_DCFI|HID0_DLOCK
+ andc r3, r3, r5
+ mtspr HID0, r3 /* no invalidate, unlock */
+ ori r3, r3, HID0_DCE
+ ori r5, r3, HID0_DCFI
+ mtspr HID0, r5 /* enable + invalidate */
+ mtspr HID0, r3 /* enable */
+ sync
+ blr
+
+ .globl dcache_disable
+dcache_disable:
+ mfspr r3, HID0
+ lis r4, 0
+ ori r4, r4, HID0_DCE|HID0_DLOCK
+ andc r3, r3, r4
+ ori r4, r3, HID0_DCI
+ sync
+ mtspr HID0, r4 /* sets invalidate, clears enable and lock */
+ sync
+ mtspr HID0, r3 /* clears invalidate */
+ blr
+
+ .globl dcache_status
+dcache_status:
+ mfspr r3, HID0
+ rlwinm r3, r3, (31 - HID0_DCE_SHIFT + 1), 31, 31
+ blr
+
+ .globl get_pvr
+get_pvr:
+ mfspr r3, PVR
+ blr
+
+/*------------------------------------------------------------------------------- */
+/* Function: ppcDcbf */
+/* Description: Data Cache block flush */
+/* Input: r3 = effective address */
+/* Output: none. */
+/*------------------------------------------------------------------------------- */
+ .globl ppcDcbf
+ppcDcbf:
+ dcbf r0,r3
+ blr
+
+/*------------------------------------------------------------------------------- */
+/* Function: ppcDcbi */
+/* Description: Data Cache block Invalidate */
+/* Input: r3 = effective address */
+/* Output: none. */
+/*------------------------------------------------------------------------------- */
+ .globl ppcDcbi
+ppcDcbi:
+ dcbi r0,r3
+ blr
+
+/*--------------------------------------------------------------------------
+ * Function: ppcDcbz
+ * Description: Data Cache block zero.
+ * Input: r3 = effective address
+ * Output: none.
+ *-------------------------------------------------------------------------- */
+
+ .globl ppcDcbz
+ppcDcbz:
+ dcbz r0,r3
+ blr
+
+ .globl ppcDWstore
+ppcDWstore:
+ lfd 1, 0(r4)
+ stfd 1, 0(r3)
+ blr
+
+ .globl ppcDWload
+ppcDWload:
+ lfd 1, 0(r3)
+ stfd 1, 0(r4)
+ blr
+
+/*-------------------------------------------------------------------*/
+
+/*
+ * void relocate_code (addr_sp, gd, addr_moni)
+ *
+ * This "function" does not return, instead it continues in RAM
+ * after relocating the monitor code.
+ *
+ * r3 = dest
+ * r4 = src
+ * r5 = length in bytes
+ * r6 = cachelinesize
+ */
+ .globl relocate_code
+relocate_code:
+ mr r1, r3 /* Set new stack pointer */
+ mr r9, r4 /* Save copy of Global Data pointer */
+ mr r10, r5 /* Save copy of Destination Address */
+
+ mr r3, r5 /* Destination Address */
+ lis r4, CFG_MONITOR_BASE@h /* Source Address */
+ ori r4, r4, CFG_MONITOR_BASE@l
+ lwz r5, GOT(__init_end)
+ sub r5, r5, r4
+ li r6, CFG_CACHELINE_SIZE /* Cache Line Size */
+
+ /*
+ * Fix GOT pointer:
+ *
+ * New GOT-PTR = (old GOT-PTR - CFG_MONITOR_BASE)
+ * + Destination Address
+ *
+ * Offset:
+ */
+ sub r15, r10, r4
+
+ /* First our own GOT */
+ add r14, r14, r15
+ /* then the one used by the C code */
+ add r30, r30, r15
+
+ /*
+ * Now relocate code
+ */
+ cmplw cr1,r3,r4
+ addi r0,r5,3
+ srwi. r0,r0,2
+ beq cr1,4f /* In place copy is not necessary */
+ beq 7f /* Protect against 0 count */
+ mtctr r0
+ bge cr1,2f
+ la r8,-4(r4)
+ la r7,-4(r3)
+
+ /* copy */
+1: lwzu r0,4(r8)
+ stwu r0,4(r7)
+ bdnz 1b
+
+ addi r0,r5,3
+ srwi. r0,r0,2
+ mtctr r0
+ la r8,-4(r4)
+ la r7,-4(r3)
+
+ /* and compare */
+20: lwzu r20,4(r8)
+ lwzu r21,4(r7)
+ xor. r22, r20, r21
+ bne 30f
+ bdnz 20b
+ b 4f
+
+ /* compare failed */
+30: li r3, 0
+ blr
+
+2: slwi r0,r0,2 /* re copy in reverse order ... y do we needed it? */
+ add r8,r4,r0
+ add r7,r3,r0
+3: lwzu r0,-4(r8)
+ stwu r0,-4(r7)
+ bdnz 3b
+
+/*
+ * Now flush the cache: note that we must start from a cache aligned
+ * address. Otherwise we might miss one cache line.
+ */
+4: cmpwi r6,0
+ add r5,r3,r5
+ beq 7f /* Always flush prefetch queue in any case */
+ subi r0,r6,1
+ andc r3,r3,r0
+ mr r4,r3
+5: dcbst 0,r4
+ add r4,r4,r6
+ cmplw r4,r5
+ blt 5b
+ sync /* Wait for all dcbst to complete on bus */
+ mr r4,r3
+6: icbi 0,r4
+ add r4,r4,r6
+ cmplw r4,r5
+ blt 6b
+7: sync /* Wait for all icbi to complete on bus */
+ isync
+
+/*
+ * We are done. Do not return, instead branch to second part of board
+ * initialization, now running from RAM.
+ */
+ addi r0, r10, in_ram - _start + EXC_OFF_SYS_RESET
+ mtlr r0
+ blr
+
+in_ram:
+ /*
+ * Relocation Function, r14 point to got2+0x8000
+ *
+ * Adjust got2 pointers, no need to check for 0, this code
+ * already puts a few entries in the table.
+ */
+ li r0,__got2_entries@sectoff@l
+ la r3,GOT(_GOT2_TABLE_)
+ lwz r11,GOT(_GOT2_TABLE_)
+ mtctr r0
+ sub r11,r3,r11
+ addi r3,r3,-4
+1: lwzu r0,4(r3)
+ add r0,r0,r11
+ stw r0,0(r3)
+ bdnz 1b
+
+ /*
+ * Now adjust the fixups and the pointers to the fixups
+ * in case we need to move ourselves again.
+ */
+2: li r0,__fixup_entries@sectoff@l
+ lwz r3,GOT(_FIXUP_TABLE_)
+ cmpwi r0,0
+ mtctr r0
+ addi r3,r3,-4
+ beq 4f
+3: lwzu r4,4(r3)
+ lwzux r0,r4,r11
+ add r0,r0,r11
+ stw r10,0(r3)
+ stw r0,0(r4)
+ bdnz 3b
+4:
+clear_bss:
+ /*
+ * Now clear BSS segment
+ */
+ lwz r3,GOT(__bss_start)
+ lwz r4,GOT(_end)
+
+ cmplw 0, r3, r4
+ beq 6f
+
+ li r0, 0
+5:
+ stw r0, 0(r3)
+ addi r3, r3, 4
+ cmplw 0, r3, r4
+ bne 5b
+6:
+ mr r3, r9 /* Global Data pointer */
+ mr r4, r10 /* Destination Address */
+ bl board_init_r
+
+ /*
+ * Copy exception vector code to low memory
+ *
+ * r3: dest_addr
+ * r7: source address, r8: end address, r9: target address
+ */
+ .globl trap_init
+trap_init:
+ lwz r7, GOT(_start)
+ lwz r8, GOT(_end_of_vectors)
+
+ li r9, 0x100 /* reset vector at 0x100 */
+
+ cmplw 0, r7, r8
+ bgelr /* return if r7>=r8 - just in case */
+
+ mflr r4 /* save link register */
+1:
+ lwz r0, 0(r7)
+ stw r0, 0(r9)
+ addi r7, r7, 4
+ addi r9, r9, 4
+ cmplw 0, r7, r8
+ bne 1b
+
+ /*
+ * relocate `hdlr' and `int_return' entries
+ */
+ li r7, .L_MachineCheck - _start + EXC_OFF_SYS_RESET
+ li r8, Alignment - _start + EXC_OFF_SYS_RESET
+2:
+ bl trap_reloc
+ addi r7, r7, 0x100 /* next exception vector */
+ cmplw 0, r7, r8
+ blt 2b
+
+ li r7, .L_Alignment - _start + EXC_OFF_SYS_RESET
+ bl trap_reloc
+
+ li r7, .L_ProgramCheck - _start + EXC_OFF_SYS_RESET
+ bl trap_reloc
+
+ li r7, .L_FPUnavailable - _start + EXC_OFF_SYS_RESET
+ li r8, SystemCall - _start + EXC_OFF_SYS_RESET
+3:
+ bl trap_reloc
+ addi r7, r7, 0x100 /* next exception vector */
+ cmplw 0, r7, r8
+ blt 3b
+
+ li r7, .L_Trace - _start + EXC_OFF_SYS_RESET
+ li r8, _end_of_vectors - _start + EXC_OFF_SYS_RESET
+4:
+ bl trap_reloc
+ addi r7, r7, 0x100 /* next exception vector */
+ cmplw 0, r7, r8
+ blt 4b
+
+ mfmsr r3 /* now that the vectors have */
+ lis r7, MSR_IP@h /* relocated into low memory */
+ ori r7, r7, MSR_IP@l /* MSR[IP] can be turned off */
+ andc r3, r3, r7 /* (if it was on) */
+ SYNC /* Some chip revs need this... */
+ mtmsr r3
+ SYNC
+
+ mtlr r4 /* restore link register */
+ blr
+
+ /*
+ * Function: relocate entries for one exception vector
+ */
+trap_reloc:
+ lwz r0, 0(r7) /* hdlr ... */
+ add r0, r0, r3 /* ... += dest_addr */
+ stw r0, 0(r7)
+
+ lwz r0, 4(r7) /* int_return ... */
+ add r0, r0, r3 /* ... += dest_addr */
+ stw r0, 4(r7)
+
+ blr