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android_kernel_motorola_sm6225/arch/arm/boot/compressed/head.S
Russell King f4619025a5 [ARM] Allow r2 to be passed through the decompressor to the kernel 
This is part of a patch from Marc Singer to allow r2 to be
passed to the kernel.  Marc's original comments follow:

This revised R2 (atags pointer) patch incorporates comments from Nico
Pitre and Ben Dooks. It modifies the head.S files such that the R2
value set by the bootloader is conveyed to the kernel startup code.
The kernel head.S heuristically validates the pointer. It will set R2
to zero if it believes the pointer is invalid. Presently, it requires
that the ATAGS list reside in the first 16KiB of physical RAM.
Relaxing this contraint may be both desirable as well as tricky.

Signed-off-by: Marc Singer <elf@buici.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-12 17:17:57 +00:00

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/*
* linux/arch/arm/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.
*/
#ifdef DEBUG
#if defined(CONFIG_DEBUG_ICEDCC)
.macro loadsp, rb
.endm
.macro writeb, ch, rb
mcr p14, 0, \ch, c0, c1, 0
.endm
#else
#include <asm/arch/debug-macro.S>
.macro writeb, ch, rb
senduart \ch, \rb
.endm
#if defined(CONFIG_ARCH_SA1100)
.macro loadsp, rb
mov \rb, #0x80000000 @ physical base address
#ifdef CONFIG_DEBUG_LL_SER3
add \rb, \rb, #0x00050000 @ Ser3
#else
add \rb, \rb, #0x00010000 @ Ser1
#endif
.endm
#elif defined(CONFIG_ARCH_IOP331)
.macro loadsp, rb
mov \rb, #0xff000000
orr \rb, \rb, #0x00ff0000
orr \rb, \rb, #0x0000f700 @ location of the UART
.endm
#elif defined(CONFIG_ARCH_S3C2410)
.macro loadsp, rb
mov \rb, #0x50000000
add \rb, \rb, #0x4000 * CONFIG_S3C2410_LOWLEVEL_UART_PORT
.endm
#else
.macro loadsp, rb
addruart \rb
.endm
#endif
#endif
#endif
.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 r9, 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, r2 @ save atags pointer
#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, r8, and r9.
*/
.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 are
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.
*/
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 = atags pointer
* r9-r14 = corrupted
*/
add r1, r5, r0 @ end of decompressed kernel
adr r2, reloc_start
ldr r3, LC1
add r3, r2, r3
1: ldmia r2!, {r9 - r14} @ copy relocation code
stmia r1!, {r9 - r14}
ldmia r2!, {r9 - r14}
stmia r1!, {r9 - r14}
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 zreladdr @ 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
#ifdef CONFIG_ARCH_RPC
.globl params
params: ldr r0, =params_phys
mov pc, lr
.ltorg
.align
#endif
/*
* 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 = atags pointer
* r9 = run-time address of "start" (???)
* On exit,
* r1, r2, r3, r9, r10, r12 corrupted
* This routine must preserve:
* r4, r5, r6, r7, r8
*/
.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 r9, r0, lsr #18
mov r9, r9, lsl #18 @ start of RAM
add r10, r9, #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, r10 @ 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, #0x5000 @ I-cache enable, RR cache replacement
orr r0, r0, #0x0030
bl __common_cache_on
mov r0, #0
mcr p15, 0, r0, c8, c7, 0 @ flush I,D TLBs
mov pc, r12
__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
bl __common_cache_on
mov r0, #0
mcr p15, 0, r0, c5, c0, 0 @ invalidate whole TLB v3
mov pc, r12
__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, lr
/*
* 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 = atags pointer
* r9-r14 = corrupted
*/
.align 5
reloc_start: add r9, r5, r0
debug_reloc_start
mov r1, r4
1:
.rept 4
ldmia r5!, {r0, r2, r3, r10 - r14} @ relocate kernel
stmia r1!, {r0, r2, r3, r10 - r14}
.endr
cmp r5, r9
blo 1b
debug_reloc_end
call_kernel: bl cache_clean_flush
bl cache_off
mov r0, #0 @ must be zero
mov r1, r7 @ restore architecture number
mov r2, r8 @ restore atags pointer
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 0x00000000 @ old ARM ID
.word 0x0000f000
mov pc, lr
mov pc, lr
mov pc, lr
.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 0x00007000 @ ARM7 IDs
.word 0x0000f000
mov pc, lr
mov pc, lr
mov pc, lr
@ Everything from here on will be the new ID system.
.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
@ These match on the architecture ID
.word 0x00020000 @ ARMv4T
.word 0x000f0000
b __armv4_cache_on
b __armv4_cache_off
b __armv4_cache_flush
.word 0x00050000 @ ARMv5TE
.word 0x000f0000
b __armv4_cache_on
b __armv4_cache_off
b __armv4_cache_flush
.word 0x00060000 @ ARMv5TEJ
.word 0x000f0000
b __armv4_cache_on
b __armv4_cache_off
b __armv4_cache_flush
.word 0x00070000 @ ARMv6
.word 0x000f0000
b __armv4_cache_on
b __armv4_cache_off
b __armv6_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, r11, r12 corrupted
* This routine must preserve:
* r0, r4, r5, r6, r7
*/
.align 5
cache_clean_flush:
mov r3, #16
b call_cache_fn
__armv6_cache_flush:
mov r1, #0
mcr p15, 0, r1, c7, c14, 0 @ clean+invalidate D
mcr p15, 0, r1, c7, c5, 0 @ invalidate I+BTB
mcr p15, 0, r1, c7, c15, 0 @ clean+invalidate unified
mcr p15, 0, r1, c7, c10, 4 @ drain WB
mov pc, lr
__armv4_cache_flush:
mov r2, #64*1024 @ default: 32K dcache size (*2)
mov r11, #32 @ default: 32 byte line size
mrc p15, 0, r3, c0, c0, 1 @ read cache type
teq r3, r6 @ cache ID register present?
beq no_cache_id
mov r1, r3, lsr #18
and r1, r1, #7
mov r2, #1024
mov r2, r2, lsl r1 @ base dcache size *2
tst r3, #1 << 14 @ test M bit
addne r2, r2, r2, lsr #1 @ +1/2 size if M == 1
mov r3, r3, lsr #12
and r3, r3, #3
mov r11, #8
mov r11, r11, lsl r3 @ cache line size in bytes
no_cache_id:
bic r1, pc, #63 @ align to longest cache line
add r2, r1, r2
1: ldr r3, [r1], r11 @ s/w flush D cache
teq r1, r2
bne 1b
mcr p15, 0, r1, c7, c5, 0 @ flush I cache
mcr p15, 0, r1, c7, c6, 0 @ flush D 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, r3
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
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