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| /*
| * linux/arch/unicore32/boot/compressed/head.S
| *
| * Code specific to PKUnity SoC and UniCore ISA
| *
| * Copyright (C) 2001-2010 GUAN Xue-tao
| *
| * This program is free software; you can redistribute it and/or modify
| * it under the terms of the GNU General Public License version 2 as
| * published by the Free Software Foundation.
| */
| #include <linux/linkage.h>
| #include <mach/memory.h>
|
| #define csub cmpsub
| #define cand cmpand
| #define nop8 nop; nop; nop; nop; nop; nop; nop; nop
|
| .section ".start", #alloc, #execinstr
| .text
| start:
| .type start,#function
|
| /* Initialize ASR, PRIV mode and INTR off */
| mov r0, #0xD3
| mov.a asr, r0
|
| adr r0, LC0
| ldm (r1, r2, r3, r5, r6, r7, r8), [r0]+
| ldw sp, [r0+], #28
| sub.a r0, r0, r1 @ calculate the delta offset
|
| /*
| * if delta is zero, we are running at the address
| * we were linked at.
| */
| beq not_relocated
|
| /*
| * We're running at a different address. We need to fix
| * up various pointers:
| * r5 - zImage base address (_start)
| * r7 - GOT start
| * r8 - GOT end
| */
| add r5, r5, r0
| add r7, r7, r0
| add r8, r8, r0
|
| /*
| * we need to fix up pointers into the BSS region.
| * r2 - BSS start
| * r3 - BSS end
| * sp - stack pointer
| */
| add r2, r2, r0
| add r3, r3, r0
| add sp, sp, r0
|
| /*
| * Relocate all entries in the GOT table.
| * This fixes up the C references.
| * r7 - GOT start
| * r8 - GOT end
| */
| 1001: ldw r1, [r7+], #0
| add r1, r1, r0
| stw.w r1, [r7]+, #4
| csub.a r7, r8
| bub 1001b
|
| not_relocated:
| /*
| * Clear BSS region.
| * r2 - BSS start
| * r3 - BSS end
| */
| mov r0, #0
| 1002: stw.w r0, [r2]+, #4
| csub.a r2, r3
| bub 1002b
|
| /*
| * Turn on the cache.
| */
| mov r0, #0
| movc p0.c5, r0, #28 @ cache invalidate all
| nop8
| movc p0.c6, r0, #6 @ tlb invalidate all
| nop8
|
| mov r0, #0x1c @ en icache and wb dcache
| movc p0.c1, r0, #0
| nop8
|
| /*
| * Set up some pointers, for starting decompressing.
| */
|
| mov r1, sp @ malloc space above stack
| add r2, sp, #0x10000 @ 64k max
|
| /*
| * Check to see if we will overwrite ourselves.
| * r4 = final kernel address
| * r5 = start of this image
| * r6 = size of decompressed image
| * r2 = end of malloc space (and therefore this image)
| * We basically want:
| * r4 >= r2 -> OK
| * r4 + image length <= r5 -> OK
| */
| ldw r4, =KERNEL_IMAGE_START
| csub.a r4, r2
| bea wont_overwrite
| add r0, r4, r6
| csub.a r0, r5
| beb wont_overwrite
|
| /*
| * If overwrite, just print error message
| */
| b __error_overwrite
|
| /*
| * We're not in danger of overwriting ourselves.
| * Do this the simple way.
| */
| wont_overwrite:
| /*
| * decompress_kernel:
| * r0: output_start
| * r1: free_mem_ptr_p
| * r2: free_mem_ptr_end_p
| */
| mov r0, r4
| b.l decompress_kernel @ C functions
|
| /*
| * Clean and flush the cache to maintain consistency.
| */
| mov r0, #0
| movc p0.c5, r0, #14 @ flush dcache
| nop8
| movc p0.c5, r0, #20 @ icache invalidate all
| nop8
|
| /*
| * Turn off the Cache and MMU.
| */
| mov r0, #0 @ disable i/d cache and MMU
| movc p0.c1, r0, #0
| nop8
|
| mov r0, #0 @ must be zero
| ldw r4, =KERNEL_IMAGE_START
| mov pc, r4 @ call kernel
|
|
| .align 2
| .type LC0, #object
| LC0: .word LC0 @ r1
| .word __bss_start @ r2
| .word _end @ r3
| .word _start @ r5
| .word _image_size @ r6
| .word _got_start @ r7
| .word _got_end @ r8
| .word decompress_stack_end @ sp
| .size LC0, . - LC0
|
| print_string:
| #ifdef CONFIG_DEBUG_OCD
| 2001: ldb.w r1, [r0]+, #1
| csub.a r1, #0
| bne 2002f
| mov pc, lr
| 2002:
| movc r2, p1.c0, #0
| cand.a r2, #2
| bne 2002b
| movc p1.c1, r1, #1
| csub.a r1, #'\n'
| cmoveq r1, #'\r'
| beq 2002b
| b 2001b
| #else
| mov pc, lr
| #endif
|
| __error_overwrite:
| adr r0, str_error
| b.l print_string
| 2001: nop8
| b 2001b
| str_error: .asciz "\nError: Kernel address OVERWRITE\n"
| .align
|
| .ltorg
|
| .align 4
| .section ".stack", "aw", %nobits
| decompress_stack: .space 4096
| decompress_stack_end:
|
|
