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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/alpha/kernel/head.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/*

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 * arch/alpha/kernel/head.S

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 *

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 * initial boot stuff.. At this point, the bootloader has already

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 * switched into OSF/1 PAL-code, and loaded us at the correct address

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 * (START_ADDR).  So there isn't much left for us to do: just set up

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 * the kernel global pointer and jump to the kernel entry-point.

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 */

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#include <linux/init.h>

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#include <asm/asm-offsets.h>

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#include <asm/pal.h>

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#include <asm/setup.h>

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__HEAD

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.globl _stext

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	.set noreorder

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	.globl	__start

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	.ent	__start

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_stext:

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__start:

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	.prologue 0

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	br	$27,1f

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1:	ldgp	$29,0($27)

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	/* We need to get current_task_info loaded up...  */

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	lda	$8,init_thread_union

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	/* ... and find our stack ... */

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	lda	$30,0x4000 - SIZEOF_PT_REGS($8)

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	/* ... and then we can start the kernel.  */

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	jsr	$26,start_kernel

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	call_pal PAL_halt

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	.end __start

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#ifdef CONFIG_SMP

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	.align 3

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	.globl	__smp_callin

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	.ent	__smp_callin

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	/* On entry here from SRM console, the HWPCB of the per-cpu

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	   slot for this processor has been loaded.  We've arranged

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	   for the UNIQUE value for this process to contain the PCBB

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	   of the target idle task.  */

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__smp_callin:

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	.prologue 1

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	ldgp	$29,0($27)	# First order of business, load the GP.

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	call_pal PAL_rduniq	# Grab the target PCBB.

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	mov	$0,$16		# Install it.

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	call_pal PAL_swpctx

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	lda	$8,0x3fff	# Find "current".

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	bic	$30,$8,$8

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	jsr	$26,smp_callin

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	call_pal PAL_halt

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	.end __smp_callin

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#endif /* CONFIG_SMP */

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	#

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	# The following two functions are needed for supporting SRM PALcode

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	# on the PC164 (at least), since that PALcode manages the interrupt

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	# masking, and we cannot duplicate the effort without causing problems

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	#

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	.align 3

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	.globl	cserve_ena

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	.ent	cserve_ena

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cserve_ena:

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	.prologue 0

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	bis	$16,$16,$17

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	lda	$16,52($31)

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	call_pal PAL_cserve

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	ret	($26)

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	.end	cserve_ena

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	.align 3

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	.globl	cserve_dis

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	.ent	cserve_dis

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cserve_dis:

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	.prologue 0

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	bis	$16,$16,$17

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	lda	$16,53($31)

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	call_pal PAL_cserve

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	ret	($26)

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	.end	cserve_dis

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	#

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	# It is handy, on occasion, to make halt actually just loop. 

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	# Putting it here means we dont have to recompile the whole

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	# kernel.

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	#

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	.align 3

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	.globl	halt

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	.ent	halt

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halt:

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	.prologue 0

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	call_pal PAL_halt

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	.end	halt

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