diff options
Diffstat (limited to 'arch/unicore32/boot/compressed/head.S')
| -rw-r--r-- | arch/unicore32/boot/compressed/head.S | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/arch/unicore32/boot/compressed/head.S b/arch/unicore32/boot/compressed/head.S new file mode 100644 index 00000000000..fbd1e374c68 --- /dev/null +++ b/arch/unicore32/boot/compressed/head.S @@ -0,0 +1,204 @@ +/* + * 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: |