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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/arm/kernel/fiqasm.S
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/*

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 *  linux/arch/arm/kernel/fiqasm.S

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 *

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 *  Derived from code originally in linux/arch/arm/kernel/fiq.c:

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 *

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 *  Copyright (C) 1998 Russell King

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 *  Copyright (C) 1998, 1999 Phil Blundell

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 *  Copyright (C) 2011, Linaro Limited

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 *

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 *  FIQ support written by Philip Blundell <[email protected]>, 1998.

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 *

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 *  FIQ support re-written by Russell King to be more generic

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 *

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 *  v7/Thumb-2 compatibility modifications by Linaro Limited, 2011.

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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/*

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 * Taking an interrupt in FIQ mode is death, so both these functions

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 * disable irqs for the duration.

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 */

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ENTRY(__set_fiq_regs)

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	mov	r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE

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	mrs	r1, cpsr

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	msr	cpsr_c, r2	@ select FIQ mode

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	mov	r0, r0		@ avoid hazard prior to ARMv4

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	ldmia	r0!, {r8 - r12}

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	ldr	sp, [r0], #4

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	ldr	lr, [r0]

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	msr	cpsr_c, r1	@ return to SVC mode

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	mov	r0, r0		@ avoid hazard prior to ARMv4

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	mov	pc, lr

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ENDPROC(__set_fiq_regs)

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ENTRY(__get_fiq_regs)

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	mov	r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE

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	mrs	r1, cpsr

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	msr	cpsr_c, r2	@ select FIQ mode

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	mov	r0, r0		@ avoid hazard prior to ARMv4

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	stmia	r0!, {r8 - r12}

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	str	sp, [r0], #4

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	str	lr, [r0]

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	msr	cpsr_c, r1	@ return to SVC mode

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	mov	r0, r0		@ avoid hazard prior to ARMv4

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	mov	pc, lr

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ENDPROC(__get_fiq_regs)

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