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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/powerpc/kernel/idle_book3e.S
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/*

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 * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <[email protected]>

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 *

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 * Generic idle routine for Book3E processors

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 *

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 * This program is free software; you can redistribute it and/or

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 * modify it under the terms of the GNU General Public License

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 * as published by the Free Software Foundation; either version

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 * 2 of the License, or (at your option) any later version.

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 */

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#include <linux/threads.h>

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#include <asm/reg.h>

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#include <asm/ppc_asm.h>

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#include <asm/asm-offsets.h>

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#include <asm/ppc-opcode.h>

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#include <asm/processor.h>

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#include <asm/thread_info.h>

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/* 64-bit version only for now */

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#ifdef CONFIG_PPC64

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_GLOBAL(book3e_idle)

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	/* Save LR for later */

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	mflr	r0

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	std	r0,16(r1)

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	/* Hard disable interrupts */

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	wrteei	0

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	/* Now check if an interrupt came in while we were soft disabled

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	 * since we may otherwise lose it (doorbells etc...). We know

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	 * that since PACAHARDIRQEN will have been cleared in that case.

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	 */

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	lbz	r3,PACAHARDIRQEN(r13)

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	cmpwi	cr0,r3,0

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	beqlr

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	/* Now we are going to mark ourselves as soft and hard enables in

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	 * order to be able to take interrupts while asleep. We inform lockdep

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	 * of that. We don't actually turn interrupts on just yet tho.

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	 */

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#ifdef CONFIG_TRACE_IRQFLAGS

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	stdu    r1,-128(r1)

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	bl	.trace_hardirqs_on

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#endif

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	li	r0,1

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	stb	r0,PACASOFTIRQEN(r13)

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	stb	r0,PACAHARDIRQEN(r13)

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	/* Interrupts will make use return to LR, so get something we want

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	 * in there

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	 */

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	bl	1f

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	/* Hard disable interrupts again */

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	wrteei	0

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	/* Mark them off again in the PACA as well */

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	li	r0,0

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	stb	r0,PACASOFTIRQEN(r13)

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	stb	r0,PACAHARDIRQEN(r13)

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	/* Tell lockdep about it */

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#ifdef CONFIG_TRACE_IRQFLAGS

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	bl	.trace_hardirqs_off

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	addi    r1,r1,128

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#endif

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	ld	r0,16(r1)

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	mtlr	r0

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	blr

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1:	/* Let's set the _TLF_NAPPING flag so interrupts make us return

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	 * to the right spot

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	*/

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	clrrdi	r11,r1,THREAD_SHIFT

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	ld	r10,TI_LOCAL_FLAGS(r11)

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	ori	r10,r10,_TLF_NAPPING

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	std	r10,TI_LOCAL_FLAGS(r11)

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	/* We can now re-enable hard interrupts and go to sleep */

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	wrteei	1

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1:	PPC_WAIT(0)

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	b	1b

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#endif /* CONFIG_PPC64 */

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