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Diffstat (limited to 'target/linux/generic/image/relocate/head.S')
| -rw-r--r-- | target/linux/generic/image/relocate/head.S | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/target/linux/generic/image/relocate/head.S b/target/linux/generic/image/relocate/head.S new file mode 100644 index 0000000..3e5b374 --- /dev/null +++ b/target/linux/generic/image/relocate/head.S @@ -0,0 +1,159 @@ +/* + * Kernel relocation stub for MIPS devices + * + * Copyright (C) 2015 Felix Fietkau <nbd@openwrt.org> + * + * Based on: + * + * LZMA compressed kernel loader for Atheros AR7XXX/AR9XXX based boards + * + * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org> + * + * Some parts of this code was based on the OpenWrt specific lzma-loader + * for the BCM47xx and ADM5120 based boards: + * Copyright (C) 2004 Manuel Novoa III (mjn3@codepoet.org) + * Copyright (C) 2005 by Oleg I. Vdovikin <oleg@cs.msu.su> + * + * 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 <asm/asm.h> +#include <asm/regdef.h> +#include "cp0regdef.h" +#include "cacheops.h" + +#define KSEG0 0x80000000 + + .macro ehb + sll zero, 3 + .endm + + .macro reset + li t0, 0xbe000034 + lw t1, 0(t0) + ori t1, 1 + sw t1, 0(t0) + .endm + + .text + +LEAF(startup) + .set noreorder + .set mips32 + + .fill 0x10000 + + mtc0 zero, CP0_WATCHLO # clear watch registers + mtc0 zero, CP0_WATCHHI + mtc0 zero, CP0_CAUSE # clear before writing status register + + mfc0 t0, CP0_STATUS + li t1, 0x1000001f + or t0, t1 + xori t0, 0x1f + mtc0 t0, CP0_STATUS + ehb + + mtc0 zero, CP0_COUNT + mtc0 zero, CP0_COMPARE + ehb + + la t0, __reloc_label # get linked address of label + bal __reloc_label # branch and link to label to + nop # get actual address +__reloc_label: + subu t0, ra, t0 # get reloc_delta + + /* Copy our code to the right place */ + la t1, _code_start # get linked address of _code_start + la t2, _code_end # get linked address of _code_end + + addu t4, t2, t0 # calculate actual address of _code_end + lw t5, 0(t4) # get extra data size + + add t2, t5 + add t2, 4 + + add t0, t1 # calculate actual address of _code_start + +__reloc_copy: + lw t3, 0(t0) + sw t3, 0(t1) + add t1, 4 + blt t1, t2, __reloc_copy + add t0, 4 + + /* flush cache */ + la t0, _code_start + la t1, _code_end + + li t2, ~(CONFIG_CACHELINE_SIZE - 1) + and t0, t2 + and t1, t2 + li t2, CONFIG_CACHELINE_SIZE + + b __flush_check + nop + +__flush_line: + cache Hit_Writeback_Inv_D, 0(t0) + cache Hit_Invalidate_I, 0(t0) + add t0, t2 + +__flush_check: + bne t0, t1, __flush_line + nop + + sync + + la t0, __reloc_back + j t0 + nop + +__reloc_back: + la t0, _code_end + add t0, 4 + + addu t1, t0, t5 + + li t2, KERNEL_ADDR + +__kernel_copy: + lw t3, 0(t0) + sw t3, 0(t2) + add t0, 4 + blt t0, t1, __kernel_copy + add t2, 4 + + /* flush cache */ + li t0, KERNEL_ADDR + addu t1, t0, t5 + + add t1, CONFIG_CACHELINE_SIZE - 1 + li t2, ~(CONFIG_CACHELINE_SIZE - 1) + and t0, t2 + and t1, t2 + li t2, CONFIG_CACHELINE_SIZE + + b __kernel_flush_check + nop + +__kernel_flush_line: + cache Hit_Writeback_Inv_D, 0(t0) + cache Hit_Invalidate_I, 0(t0) + add t0, t2 + +__kernel_flush_check: + bne t0, t1, __kernel_flush_line + nop + + sync + + li t0, KERNEL_ADDR + jr t0 + nop + + .set reorder +END(startup) |