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Diffstat (limited to 'arch/arm26/boot/compressed/head.S')
| -rw-r--r-- | arch/arm26/boot/compressed/head.S | 517 |
1 files changed, 517 insertions, 0 deletions
diff --git a/arch/arm26/boot/compressed/head.S b/arch/arm26/boot/compressed/head.S new file mode 100644 index 00000000000..0307804a607 --- /dev/null +++ b/arch/arm26/boot/compressed/head.S @@ -0,0 +1,517 @@ +/* + * linux/arch/arm26/boot/compressed/head.S + * + * Copyright (C) 1996-2002 Russell King + * + * 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/config.h> +#include <linux/linkage.h> + +/* + * Debugging stuff + * + * Note that these macros must not contain any code which is not + * 100% relocatable. Any attempt to do so will result in a crash. + * Please select one of the following when turning on debugging. + */ + + .macro kputc,val + mov r0, \val + bl putc + .endm + + .macro kphex,val,len + mov r0, \val + mov r1, #\len + bl phex + .endm + + .macro debug_reloc_start + .endm + + .macro debug_reloc_end + .endm + + .section ".start", #alloc, #execinstr +/* + * sort out different calling conventions + */ + .align +start: + .type start,#function + .rept 8 + mov r0, r0 + .endr + + b 1f + .word 0x016f2818 @ Magic numbers to help the loader + .word start @ absolute load/run zImage address + .word _edata @ zImage end address +1: mov r7, r1 @ save architecture ID + mov r8, #0 @ save r0 + teqp pc, #0x0c000003 @ turn off interrupts + + .text + adr r0, LC0 + ldmia r0, {r1, r2, r3, r4, r5, r6, ip, sp} + subs r0, r0, r1 @ calculate the delta offset + + teq r0, #0 @ if delta is zero, we're + beq not_relocated @ running at the address we + @ were linked at. + + add r2, r2, r0 @ different address, so we + add r3, r3, r0 @ need to fix up various + add r5, r5, r0 @ pointers. + add r6, r6, r0 + add ip, ip, r0 + add sp, sp, r0 + +1: ldr r1, [r6, #0] @ relocate entries in the GOT + add r1, r1, r0 @ table. This fixes up the + str r1, [r6], #4 @ C references. + cmp r6, ip + blo 1b + +not_relocated: mov r0, #0 +1: str r0, [r2], #4 @ clear bss + str r0, [r2], #4 + str r0, [r2], #4 + str r0, [r2], #4 + cmp r2, r3 + blo 1b + + bl cache_on + + 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 + * r2 = end of malloc space (and therefore this image) + * We basically want: + * r4 >= r2 -> OK + * r4 + image length <= r5 -> OK + */ + cmp r4, r2 + bhs wont_overwrite + add r0, r4, #4096*1024 @ 4MB largest kernel size + cmp r0, r5 + bls wont_overwrite + + mov r5, r2 @ decompress after malloc space + mov r0, r5 + mov r3, r7 + bl decompress_kernel + + add r0, r0, #127 + bic r0, r0, #127 @ align the kernel length +/* + * r0 = decompressed kernel length + * r1-r3 = unused + * r4 = kernel execution address + * r5 = decompressed kernel start + * r6 = processor ID + * r7 = architecture ID + * r8-r14 = unused + */ + add r1, r5, r0 @ end of decompressed kernel + adr r2, reloc_start + ldr r3, LC1 + add r3, r2, r3 +1: ldmia r2!, {r8 - r13} @ copy relocation code + stmia r1!, {r8 - r13} + ldmia r2!, {r8 - r13} + stmia r1!, {r8 - r13} + cmp r2, r3 + blo 1b + + bl cache_clean_flush + add pc, r5, r0 @ call relocation code + +/* + * We're not in danger of overwriting ourselves. Do this the simple way. + * + * r4 = kernel execution address + * r7 = architecture ID + */ +wont_overwrite: mov r0, r4 + mov r3, r7 + bl decompress_kernel + b call_kernel + + .type LC0, #object +LC0: .word LC0 @ r1 + .word __bss_start @ r2 + .word _end @ r3 + .word _load_addr @ r4 + .word _start @ r5 + .word _got_start @ r6 + .word _got_end @ ip + .word user_stack+4096 @ sp +LC1: .word reloc_end - reloc_start + .size LC0, . - LC0 + +/* + * Turn on the cache. We need to setup some page tables so that we + * can have both the I and D caches on. + * + * We place the page tables 16k down from the kernel execution address, + * and we hope that nothing else is using it. If we're using it, we + * will go pop! + * + * On entry, + * r4 = kernel execution address + * r6 = processor ID + * r7 = architecture number + * r8 = run-time address of "start" + * On exit, + * r1, r2, r3, r8, r9, r12 corrupted + * This routine must preserve: + * r4, r5, r6, r7 + */ + .align 5 +cache_on: mov r3, #8 @ cache_on function + b call_cache_fn + +__setup_mmu: sub r3, r4, #16384 @ Page directory size + bic r3, r3, #0xff @ Align the pointer + bic r3, r3, #0x3f00 +/* + * Initialise the page tables, turning on the cacheable and bufferable + * bits for the RAM area only. + */ + mov r0, r3 + mov r8, r0, lsr #18 + mov r8, r8, lsl #18 @ start of RAM + add r9, r8, #0x10000000 @ a reasonable RAM size + mov r1, #0x12 + orr r1, r1, #3 << 10 + add r2, r3, #16384 +1: cmp r1, r8 @ if virt > start of RAM + orrhs r1, r1, #0x0c @ set cacheable, bufferable + cmp r1, r9 @ if virt > end of RAM + bichs r1, r1, #0x0c @ clear cacheable, bufferable + str r1, [r0], #4 @ 1:1 mapping + add r1, r1, #1048576 + teq r0, r2 + bne 1b +/* + * If ever we are running from Flash, then we surely want the cache + * to be enabled also for our execution instance... We map 2MB of it + * so there is no map overlap problem for up to 1 MB compressed kernel. + * If the execution is in RAM then we would only be duplicating the above. + */ + mov r1, #0x1e + orr r1, r1, #3 << 10 + mov r2, pc, lsr #20 + orr r1, r1, r2, lsl #20 + add r0, r3, r2, lsl #2 + str r1, [r0], #4 + add r1, r1, #1048576 + str r1, [r0] + mov pc, lr + +__armv4_cache_on: + mov r12, lr + bl __setup_mmu + mov r0, #0 + mcr p15, 0, r0, c7, c10, 4 @ drain write buffer + mcr p15, 0, r0, c8, c7, 0 @ flush I,D TLBs + mrc p15, 0, r0, c1, c0, 0 @ read control reg + orr r0, r0, #0x1000 @ I-cache enable + orr r0, r0, #0x0030 + b __common_cache_on + +__arm6_cache_on: + mov r12, lr + bl __setup_mmu + mov r0, #0 + mcr p15, 0, r0, c7, c0, 0 @ invalidate whole cache v3 + mcr p15, 0, r0, c5, c0, 0 @ invalidate whole TLB v3 + mov r0, #0x30 +__common_cache_on: +#ifndef DEBUG + orr r0, r0, #0x000d @ Write buffer, mmu +#endif + mov r1, #-1 + mcr p15, 0, r3, c2, c0, 0 @ load page table pointer + mcr p15, 0, r1, c3, c0, 0 @ load domain access control + mcr p15, 0, r0, c1, c0, 0 @ load control register + mov pc, r12 + +/* + * All code following this line is relocatable. It is relocated by + * the above code to the end of the decompressed kernel image and + * executed there. During this time, we have no stacks. + * + * r0 = decompressed kernel length + * r1-r3 = unused + * r4 = kernel execution address + * r5 = decompressed kernel start + * r6 = processor ID + * r7 = architecture ID + * r8-r14 = unused + */ + .align 5 +reloc_start: add r8, r5, r0 + debug_reloc_start + mov r1, r4 +1: + .rept 4 + ldmia r5!, {r0, r2, r3, r9 - r13} @ relocate kernel + stmia r1!, {r0, r2, r3, r9 - r13} + .endr + + cmp r5, r8 + blo 1b + debug_reloc_end + +call_kernel: bl cache_clean_flush + bl cache_off + mov r0, #0 + mov r1, r7 @ restore architecture number + mov pc, r4 @ call kernel + +/* + * Here follow the relocatable cache support functions for the + * various processors. This is a generic hook for locating an + * entry and jumping to an instruction at the specified offset + * from the start of the block. Please note this is all position + * independent code. + * + * r1 = corrupted + * r2 = corrupted + * r3 = block offset + * r6 = corrupted + * r12 = corrupted + */ + +call_cache_fn: adr r12, proc_types + mrc p15, 0, r6, c0, c0 @ get processor ID +1: ldr r1, [r12, #0] @ get value + ldr r2, [r12, #4] @ get mask + eor r1, r1, r6 @ (real ^ match) + tst r1, r2 @ & mask + addeq pc, r12, r3 @ call cache function + add r12, r12, #4*5 + b 1b + +/* + * Table for cache operations. This is basically: + * - CPU ID match + * - CPU ID mask + * - 'cache on' method instruction + * - 'cache off' method instruction + * - 'cache flush' method instruction + * + * We match an entry using: ((real_id ^ match) & mask) == 0 + * + * Writethrough caches generally only need 'on' and 'off' + * methods. Writeback caches _must_ have the flush method + * defined. + */ + .type proc_types,#object +proc_types: + .word 0x41560600 @ ARM6/610 + .word 0xffffffe0 + b __arm6_cache_off @ works, but slow + b __arm6_cache_off + mov pc, lr +@ b __arm6_cache_on @ untested +@ b __arm6_cache_off +@ b __armv3_cache_flush + + .word 0x41007000 @ ARM7/710 + .word 0xfff8fe00 + b __arm7_cache_off + b __arm7_cache_off + mov pc, lr + + .word 0x41807200 @ ARM720T (writethrough) + .word 0xffffff00 + b __armv4_cache_on + b __armv4_cache_off + mov pc, lr + + .word 0x41129200 @ ARM920T + .word 0xff00fff0 + b __armv4_cache_on + b __armv4_cache_off + b __armv4_cache_flush + + .word 0x4401a100 @ sa110 / sa1100 + .word 0xffffffe0 + b __armv4_cache_on + b __armv4_cache_off + b __armv4_cache_flush + + .word 0x6901b110 @ sa1110 + .word 0xfffffff0 + b __armv4_cache_on + b __armv4_cache_off + b __armv4_cache_flush + + .word 0x69050000 @ xscale + .word 0xffff0000 + b __armv4_cache_on + b __armv4_cache_off + b __armv4_cache_flush + + .word 0 @ unrecognised type + .word 0 + mov pc, lr + mov pc, lr + mov pc, lr + + .size proc_types, . - proc_types + +/* + * Turn off the Cache and MMU. ARMv3 does not support + * reading the control register, but ARMv4 does. + * + * On entry, r6 = processor ID + * On exit, r0, r1, r2, r3, r12 corrupted + * This routine must preserve: r4, r6, r7 + */ + .align 5 +cache_off: mov r3, #12 @ cache_off function + b call_cache_fn + +__armv4_cache_off: + mrc p15, 0, r0, c1, c0 + bic r0, r0, #0x000d + mcr p15, 0, r0, c1, c0 @ turn MMU and cache off + mov r0, #0 + mcr p15, 0, r0, c7, c7 @ invalidate whole cache v4 + mcr p15, 0, r0, c8, c7 @ invalidate whole TLB v4 + mov pc, lr + +__arm6_cache_off: + mov r0, #0x00000030 @ ARM6 control reg. + b __armv3_cache_off + +__arm7_cache_off: + mov r0, #0x00000070 @ ARM7 control reg. + b __armv3_cache_off + +__armv3_cache_off: + mcr p15, 0, r0, c1, c0, 0 @ turn MMU and cache off + mov r0, #0 + mcr p15, 0, r0, c7, c0, 0 @ invalidate whole cache v3 + mcr p15, 0, r0, c5, c0, 0 @ invalidate whole TLB v3 + mov pc, lr + +/* + * Clean and flush the cache to maintain consistency. + * + * On entry, + * r6 = processor ID + * On exit, + * r1, r2, r3, r12 corrupted + * This routine must preserve: + * r0, r4, r5, r6, r7 + */ + .align 5 +cache_clean_flush: + mov r3, #16 + b call_cache_fn + +__armv4_cache_flush: + bic r1, pc, #31 + add r2, r1, #65536 @ 2x the largest dcache size +1: ldr r12, [r1], #32 @ s/w flush D cache + teq r1, r2 + bne 1b + + mcr p15, 0, r1, c7, c7, 0 @ flush I cache + mcr p15, 0, r1, c7, c10, 4 @ drain WB + mov pc, lr + +__armv3_cache_flush: + mov r1, #0 + mcr p15, 0, r0, c7, c0, 0 @ invalidate whole cache v3 + mov pc, lr + +/* + * Various debugging routines for printing hex characters and + * memory, which again must be relocatable. + */ +#ifdef DEBUG + .type phexbuf,#object +phexbuf: .space 12 + .size phexbuf, . - phexbuf + +phex: adr r3, phexbuf + mov r2, #0 + strb r2, [r3, r1] +1: subs r1, r1, #1 + movmi r0, r3 + bmi puts + and r2, r0, #15 + mov r0, r0, lsr #4 + cmp r2, #10 + addge r2, r2, #7 + add r2, r2, #'0' + strb r2, [r3, r1] + b 1b + +puts: loadsp r3 +1: ldrb r2, [r0], #1 + teq r2, #0 + moveq pc, lr +2: writeb r2 + mov r1, #0x00020000 +3: subs r1, r1, #1 + bne 3b + teq r2, #'\n' + moveq r2, #'\r' + beq 2b + teq r0, #0 + bne 1b + mov pc, lr +putc: + mov r2, r0 + mov r0, #0 + loadsp r3 + b 2b + +memdump: mov r12, r0 + mov r10, lr + mov r11, #0 +2: mov r0, r11, lsl #2 + add r0, r0, r12 + mov r1, #8 + bl phex + mov r0, #':' + bl putc +1: mov r0, #' ' + bl putc + ldr r0, [r12, r11, lsl #2] + mov r1, #8 + bl phex + and r0, r11, #7 + teq r0, #3 + moveq r0, #' ' + bleq putc + and r0, r11, #7 + add r11, r11, #1 + teq r0, #7 + bne 1b + mov r0, #'\n' + bl putc + cmp r11, #64 + blt 2b + mov pc, r10 +#endif + +reloc_end: + + .align + .section ".stack", "aw" +user_stack: .space 4096 |