205 lines
4.1 KiB
ArmAsm
205 lines
4.1 KiB
ArmAsm
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/*
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* linux/arch/unicore32/boot/compressed/head.S
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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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>
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#define csub cmpsub
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#define cand cmpand
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#define nop8 nop; nop; nop; nop; nop; nop; nop; nop
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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
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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
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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
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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
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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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/*
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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
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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
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*/
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b __error_overwrite
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/*
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* We're not in danger of overwriting ourselves.
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* Do this the simple way.
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*/
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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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/*
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* Clean and flush the cache to maintain consistency.
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*/
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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
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/*
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* Turn off the Cache and MMU.
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*/
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mov r0, #0 @ disable i/d cache and MMU
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movc p0.c1, r0, #0
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nop8
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mov r0, #0 @ must be zero
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ldw r4, =KERNEL_IMAGE_START
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mov pc, r4 @ call kernel
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.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
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print_string:
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#ifdef CONFIG_DEBUG_OCD
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2001: ldb.w r1, [r0]+, #1
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csub.a r1, #0
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bne 2002f
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mov pc, lr
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2002:
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movc r2, p1.c0, #0
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cand.a r2, #2
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bne 2002b
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movc p1.c1, r1, #1
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csub.a r1, #'\n'
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cmoveq r1, #'\r'
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beq 2002b
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b 2001b
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#else
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mov pc, lr
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#endif
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__error_overwrite:
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adr r0, str_error
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b.l print_string
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2001: nop8
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b 2001b
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str_error: .asciz "\nError: Kernel address OVERWRITE\n"
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.align
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.ltorg
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.align 4
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.section ".stack", "aw", %nobits
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decompress_stack: .space 4096
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decompress_stack_end:
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