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c145eaeae5
Mistakenly applied this to 2.6.31 all those years ago while doing
experiments on later kernels. Actually it depends on several other
patches which never got applied.
This reverts commit 9dda27bbe8.
Signed-off-by: Matt Sealey <matt@genesi-usa.com>
261 lines
6.5 KiB
ArmAsm
261 lines
6.5 KiB
ArmAsm
/*
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* linux/arch/arm/kernel/head-common.S
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*
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* Copyright (C) 1994-2002 Russell King
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* Copyright (c) 2003 ARM Limited
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define ATAG_CORE 0x54410001
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#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
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.type __switch_data, %object
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__switch_data:
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.long __mmap_switched
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.long __data_loc @ r4
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.long _data @ r5
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.long __bss_start @ r6
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.long _end @ r7
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.long processor_id @ r4
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.long __machine_arch_type @ r5
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.long __atags_pointer @ r6
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.long cr_alignment @ r7
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.long init_thread_union + THREAD_START_SP @ sp
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/*
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* The following fragment of code is executed with the MMU on in MMU mode,
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* and uses absolute addresses; this is not position independent.
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*
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* r0 = cp#15 control register
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* r1 = machine ID
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* r2 = atags pointer
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* r9 = processor ID
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*/
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__mmap_switched:
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adr r3, __switch_data + 4
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ldmia r3!, {r4, r5, r6, r7}
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cmp r4, r5 @ Copy data segment if needed
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1: cmpne r5, r6
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ldrne fp, [r4], #4
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strne fp, [r5], #4
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bne 1b
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mov fp, #0 @ Clear BSS (and zero fp)
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1: cmp r6, r7
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strcc fp, [r6],#4
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bcc 1b
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ldmia r3, {r4, r5, r6, r7, sp}
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str r9, [r4] @ Save processor ID
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str r1, [r5] @ Save machine type
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str r2, [r6] @ Save atags pointer
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bic r4, r0, #CR_A @ Clear 'A' bit
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stmia r7, {r0, r4} @ Save control register values
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b start_kernel
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ENDPROC(__mmap_switched)
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/*
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* Exception handling. Something went wrong and we can't proceed. We
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* ought to tell the user, but since we don't have any guarantee that
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* we're even running on the right architecture, we do virtually nothing.
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*
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* If CONFIG_DEBUG_LL is set we try to print out something about the error
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* and hope for the best (useful if bootloader fails to pass a proper
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* machine ID for example).
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*/
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__error_p:
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#ifdef CONFIG_DEBUG_LL
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adr r0, str_p1
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bl printascii
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mov r0, r9
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bl printhex8
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adr r0, str_p2
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bl printascii
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b __error
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str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x"
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str_p2: .asciz ").\n"
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.align
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#endif
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ENDPROC(__error_p)
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__error_a:
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#ifdef CONFIG_DEBUG_LL
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mov r4, r1 @ preserve machine ID
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adr r0, str_a1
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bl printascii
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mov r0, r4
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bl printhex8
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adr r0, str_a2
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bl printascii
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adr r3, 3f
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ldmia r3, {r4, r5, r6} @ get machine desc list
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sub r4, r3, r4 @ get offset between virt&phys
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add r5, r5, r4 @ convert virt addresses to
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add r6, r6, r4 @ physical address space
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1: ldr r0, [r5, #MACHINFO_TYPE] @ get machine type
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bl printhex8
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mov r0, #'\t'
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bl printch
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ldr r0, [r5, #MACHINFO_NAME] @ get machine name
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add r0, r0, r4
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bl printascii
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mov r0, #'\n'
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bl printch
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add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
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cmp r5, r6
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blo 1b
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adr r0, str_a3
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bl printascii
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b __error
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ENDPROC(__error_a)
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str_a1: .asciz "\nError: unrecognized/unsupported machine ID (r1 = 0x"
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str_a2: .asciz ").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
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str_a3: .asciz "\nPlease check your kernel config and/or bootloader.\n"
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.align
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#endif
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__error:
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#ifdef CONFIG_ARCH_RPC
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/*
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* Turn the screen red on a error - RiscPC only.
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*/
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mov r0, #0x02000000
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mov r3, #0x11
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orr r3, r3, r3, lsl #8
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orr r3, r3, r3, lsl #16
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str r3, [r0], #4
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str r3, [r0], #4
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str r3, [r0], #4
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str r3, [r0], #4
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#endif
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1: mov r0, r0
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b 1b
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ENDPROC(__error)
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/*
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* Read processor ID register (CP#15, CR0), and look up in the linker-built
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* supported processor list. Note that we can't use the absolute addresses
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* for the __proc_info lists since we aren't running with the MMU on
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* (and therefore, we are not in the correct address space). We have to
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* calculate the offset.
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*
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* r9 = cpuid
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* Returns:
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* r3, r4, r6 corrupted
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* r5 = proc_info pointer in physical address space
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* r9 = cpuid (preserved)
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*/
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__lookup_processor_type:
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adr r3, 3f
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ldmda r3, {r5 - r7}
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sub r3, r3, r7 @ get offset between virt&phys
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add r5, r5, r3 @ convert virt addresses to
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add r6, r6, r3 @ physical address space
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1: ldmia r5, {r3, r4} @ value, mask
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and r4, r4, r9 @ mask wanted bits
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teq r3, r4
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beq 2f
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add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list)
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cmp r5, r6
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blo 1b
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mov r5, #0 @ unknown processor
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2: mov pc, lr
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ENDPROC(__lookup_processor_type)
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/*
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* This provides a C-API version of the above function.
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*/
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ENTRY(lookup_processor_type)
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stmfd sp!, {r4 - r7, r9, lr}
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mov r9, r0
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bl __lookup_processor_type
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mov r0, r5
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ldmfd sp!, {r4 - r7, r9, pc}
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ENDPROC(lookup_processor_type)
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/*
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* Look in <asm/procinfo.h> and arch/arm/kernel/arch.[ch] for
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* more information about the __proc_info and __arch_info structures.
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*/
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.long __proc_info_begin
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.long __proc_info_end
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3: .long .
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.long __arch_info_begin
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.long __arch_info_end
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/*
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* Lookup machine architecture in the linker-build list of architectures.
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* Note that we can't use the absolute addresses for the __arch_info
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* lists since we aren't running with the MMU on (and therefore, we are
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* not in the correct address space). We have to calculate the offset.
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*
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* r1 = machine architecture number
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* Returns:
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* r3, r4, r6 corrupted
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* r5 = mach_info pointer in physical address space
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*/
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__lookup_machine_type:
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adr r3, 3b
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ldmia r3, {r4, r5, r6}
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sub r3, r3, r4 @ get offset between virt&phys
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add r5, r5, r3 @ convert virt addresses to
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add r6, r6, r3 @ physical address space
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1: ldr r3, [r5, #MACHINFO_TYPE] @ get machine type
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teq r3, r1 @ matches loader number?
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beq 2f @ found
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add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
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cmp r5, r6
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blo 1b
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mov r5, #0 @ unknown machine
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2: mov pc, lr
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ENDPROC(__lookup_machine_type)
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/*
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* This provides a C-API version of the above function.
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*/
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ENTRY(lookup_machine_type)
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stmfd sp!, {r4 - r6, lr}
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mov r1, r0
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bl __lookup_machine_type
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mov r0, r5
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ldmfd sp!, {r4 - r6, pc}
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ENDPROC(lookup_machine_type)
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/* Determine validity of the r2 atags pointer. The heuristic requires
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* that the pointer be aligned, in the first 16k of physical RAM and
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* that the ATAG_CORE marker is first and present. Future revisions
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* of this function may be more lenient with the physical address and
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* may also be able to move the ATAGS block if necessary.
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*
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* r8 = machinfo
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*
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* Returns:
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* r2 either valid atags pointer, or zero
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* r5, r6 corrupted
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*/
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__vet_atags:
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tst r2, #0x3 @ aligned?
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bne 1f
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ldr r5, [r2, #0] @ is first tag ATAG_CORE?
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subs r5, r5, #ATAG_CORE_SIZE
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bne 1f
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ldr r5, [r2, #4]
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ldr r6, =ATAG_CORE
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cmp r5, r6
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bne 1f
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mov pc, lr @ atag pointer is ok
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1: mov r2, #0
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mov pc, lr
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ENDPROC(__vet_atags)
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