/* * linux/arch/armnommu/boot/compressed/head.S * * Copyright (C) 1996-2002 Russell King * Copyright (C) 2004 Hyok S. Choi (MPU support) * * 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 #include #include /* * 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 #ifdef DEBUG kputc #'\n' kphex r6, 8 /* processor id */ kputc #':' kphex r7, 8 /* architecture id */ kputc #':' mrc p15, 0, r0, c1, c0 kphex r0, 8 /* control reg */ kputc #'\n' kphex r5, 8 /* decompressed kernel start */ kputc #'-' kphex r8, 8 /* decompressed kernel end */ kputc #'>' kphex r4, 8 /* kernel execution address */ kputc #'\n' #endif .endm .macro debug_reloc_end #ifdef DEBUG kphex r5, 8 /* end of kernel */ kputc #'\n' mov r0, r4 bl memdump /* dump 256 bytes at start of kernel */ #endif .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 #ifndef __ARM_ARCH_2__ /* * Booting from Angel - need to enter SVC mode and disable * FIQs/IRQs (numeric definitions from angel arm.h source). * We only do this if we were in user mode on entry. */ mrs r2, cpsr @ get current mode tst r2, #3 @ not user? bne not_angel mov r0, #0x17 @ angel_SWIreason_EnterSVC swi 0x123456 @ angel_SWI_ARM not_angel: mrs r2, cpsr @ turn off interrupts to orr r2, r2, #0xc0 @ prevent angel from running msr cpsr_c, r2 #else teqp pc, #0x0c000003 @ turn off interrupts #endif /* * Note that some cache flushing and other stuff may * be needed here - is there an Angel SWI call for this? */ /* * some architecture specific code can be inserted * by the linker here, but it should preserve r7 and r8. */ .text adr r0, LC0 ldmia r0, {r1, r2, r3, r4, r5, r6, ip, sp} subs r0, r0, r1 @ calculate the delta offset @ if delta is zero, we're beq not_relocated @ running at the address we @ were linked at. /* * We're running at a different address. We need to fix * up various pointers: * r5 - zImage base address * r6 - GOT start * ip - GOT end */ add r5, r5, r0 add r6, r6, r0 add ip, ip, r0 #ifndef CONFIG_ZBOOT_ROM /* * If we're running fully PIC === CONFIG_ZBOOT_ROM = n, * 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. */ 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 #else /* * Relocate entries in the GOT table. We only relocate * the entries that are outside the (relocated) BSS region. */ 1: ldr r1, [r6, #0] @ relocate entries in the GOT cmp r1, r2 @ entry < bss_start || cmphs r3, r1 @ _end < entry addlo r1, r1, r0 @ table. This fixes up the str r1, [r6], #4 @ C references. cmp r6, ip blo 1b #endif 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 /* * The C runtime environment should now be setup * sufficiently. Turn the cache on, set up some * pointers, and start 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 * 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 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 /* * 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: #ifdef CONFIG_ARCH_S3C44B0 ldr r2, S3C44B0_PROCESSOR_TYPE str r2, [r6] ldr r2, S3C44B0_MACH_TYPE str r2, [r9] mov fp, #0 b 1f S3C44B0_PROCESSOR_TYPE: .long 0x44b07700 S3C44B0_MACH_TYPE: .long MACH_TYPE_S3C44B0 1: #endif mov r0, #0 mov r1, r7 @ restore architecture number mov pc, r4 @ call kernel /* * 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", "w" user_stack: .space 4096