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  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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arch/unicore32/boot/compressed/head.S
 
1
/*
 
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 * linux/arch/unicore32/boot/compressed/head.S
 
3
 *
 
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 * Code specific to PKUnity SoC and UniCore ISA
 
5
 *
 
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 * Copyright (C) 2001-2010 GUAN Xue-tao
 
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 *
 
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 * This program is free software; you can redistribute it and/or modify
 
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 * it under the terms of the GNU General Public License version 2 as
 
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 * published by the Free Software Foundation.
 
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 */
 
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#include <linux/linkage.h>
 
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#include <mach/memory.h>
 
14
 
 
15
#define csub    cmpsub
 
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#define cand    cmpand
 
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#define nop8    nop; nop; nop; nop; nop; nop; nop; nop
 
18
 
 
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                .section ".start", #alloc, #execinstr
 
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                .text
 
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start:
 
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                .type   start,#function
 
23
 
 
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                /* Initialize ASR, PRIV mode and INTR off */
 
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                mov     r0, #0xD3
 
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                mov.a   asr, r0
 
27
 
 
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                adr     r0, LC0
 
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                ldm     (r1, r2, r3, r5, r6, r7, r8), [r0]+
 
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                ldw     sp, [r0+], #28
 
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                sub.a   r0, r0, r1              @ calculate the delta offset
 
32
 
 
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                /*
 
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                 * if delta is zero, we are running at the address
 
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                 * we were linked at.
 
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                 */
 
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                beq     not_relocated
 
38
 
 
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                /*
 
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                 * We're running at a different address.  We need to fix
 
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                 * up various pointers:
 
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                 *   r5 - zImage base address (_start)
 
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                 *   r7 - GOT start
 
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                 *   r8 - GOT end
 
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                 */
 
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                add     r5, r5, r0
 
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                add     r7, r7, r0
 
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                add     r8, r8, r0
 
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                /*
 
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                 * we need to fix up pointers into the BSS region.
 
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                 *   r2 - BSS start
 
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                 *   r3 - BSS end
 
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                 *   sp - stack pointer
 
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                 */
 
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                add     r2, r2, r0
 
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                add     r3, r3, r0
 
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                add     sp, sp, r0
 
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60
                /*
 
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                 * Relocate all entries in the GOT table.
 
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                 * This fixes up the C references.
 
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                 *   r7 - GOT start
 
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                 *   r8 - GOT end
 
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                 */
 
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1001:           ldw     r1, [r7+], #0
 
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                add     r1, r1, r0
 
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                stw.w   r1, [r7]+, #4
 
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                csub.a  r7, r8
 
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                bub     1001b
 
71
 
 
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not_relocated:
 
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                /*
 
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                 * Clear BSS region.
 
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                 *   r2 - BSS start
 
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                 *   r3 - BSS end
 
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                 */
 
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                mov     r0, #0
 
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1002:           stw.w   r0, [r2]+, #4
 
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                csub.a  r2, r3
 
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                bub     1002b
 
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                /*
 
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                 * Turn on the cache.
 
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                 */
 
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                mov     r0, #0
 
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                movc    p0.c5, r0, #28          @ cache invalidate all
 
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                nop8
 
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                movc    p0.c6, r0, #6           @ tlb invalidate all
 
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                nop8
 
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                mov     r0, #0x1c               @ en icache and wb dcache
 
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                movc    p0.c1, r0, #0
 
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                nop8
 
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                /*
 
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                 * Set up some pointers, for starting decompressing.
 
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                 */
 
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                mov     r1, sp                  @ malloc space above stack
 
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                add     r2, sp, #0x10000        @ 64k max
 
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                /*
 
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                 * Check to see if we will overwrite ourselves.
 
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                 *   r4 = final kernel address
 
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                 *   r5 = start of this image
 
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                 *   r6 = size of decompressed image
 
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                 *   r2 = end of malloc space (and therefore this image)
 
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                 * We basically want:
 
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                 *   r4 >= r2 -> OK
 
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                 *   r4 + image length <= r5 -> OK
 
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                 */
 
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                ldw     r4, =KERNEL_IMAGE_START
 
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                csub.a  r4, r2
 
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                bea     wont_overwrite
 
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                add     r0, r4, r6
 
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                csub.a  r0, r5
 
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                beb     wont_overwrite
 
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                /*
 
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                 * If overwrite, just print error message
 
122
                 */
 
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                b       __error_overwrite
 
124
 
 
125
                /*
 
126
                 * We're not in danger of overwriting ourselves.
 
127
                 * Do this the simple way.
 
128
                 */
 
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wont_overwrite:
 
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                /*
 
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                 * decompress_kernel:
 
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                 *   r0: output_start
 
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                 *   r1: free_mem_ptr_p
 
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                 *   r2: free_mem_ptr_end_p
 
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                 */
 
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                mov     r0, r4
 
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                b.l     decompress_kernel       @ C functions
 
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139
                /*
 
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                 * Clean and flush the cache to maintain consistency.
 
141
                 */
 
142
                mov     r0, #0
 
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                movc    p0.c5, r0, #14          @ flush dcache
 
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                nop8
 
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                movc    p0.c5, r0, #20          @ icache invalidate all
 
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                nop8
 
147
 
 
148
                /*
 
149
                 * Turn off the Cache and MMU.
 
150
                 */
 
151
                mov     r0, #0                  @ disable i/d cache and MMU
 
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                movc    p0.c1, r0, #0
 
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                nop8
 
154
 
 
155
                mov     r0, #0                  @ must be zero
 
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                ldw     r4, =KERNEL_IMAGE_START
 
157
                mov     pc, r4                  @ call kernel
 
158
 
 
159
 
 
160
                .align  2
 
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                .type   LC0, #object
 
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LC0:            .word   LC0                     @ r1
 
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                .word   __bss_start             @ r2
 
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                .word   _end                    @ r3
 
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                .word   _start                  @ r5
 
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                .word   _image_size             @ r6
 
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                .word   _got_start              @ r7
 
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                .word   _got_end                @ r8
 
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                .word   decompress_stack_end    @ sp
 
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                .size   LC0, . - LC0
 
171
 
 
172
print_string:
 
173
#ifdef CONFIG_DEBUG_OCD
 
174
2001:           ldb.w   r1, [r0]+, #1
 
175
                csub.a  r1, #0
 
176
                bne     2002f
 
177
                mov     pc, lr
 
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2002:
 
179
                movc    r2, p1.c0, #0
 
180
                cand.a  r2, #2
 
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                bne     2002b
 
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                movc    p1.c1, r1, #1
 
183
                csub.a  r1, #'\n'
 
184
                cmoveq  r1, #'\r'
 
185
                beq     2002b
 
186
                b       2001b
 
187
#else
 
188
                mov     pc, lr
 
189
#endif
 
190
 
 
191
__error_overwrite:
 
192
                adr     r0, str_error
 
193
                b.l     print_string
 
194
2001:           nop8
 
195
                b       2001b
 
196
str_error:      .asciz  "\nError: Kernel address OVERWRITE\n"
 
197
                .align
 
198
 
 
199
                .ltorg
 
200
 
 
201
                .align  4
 
202
                .section ".stack", "aw", %nobits
 
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decompress_stack:       .space  4096
 
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decompress_stack_end: