1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * arch/alpha/kernel/head.S
4 *
5 * initial boot stuff.. At this point, the bootloader has already
6 * switched into OSF/1 PAL-code, and loaded us at the correct address
7 * (START_ADDR).  So there isn't much left for us to do: just set up
8 * the kernel global pointer and jump to the kernel entry-point.
9 */
10
11#include <linux/init.h>
12#include <asm/asm-offsets.h>
13#include <asm/pal.h>
14#include <asm/setup.h>
15
16__HEAD
17.globl _stext
18	.set noreorder
19	.globl	__start
20	.ent	__start
21_stext:
22__start:
23	.prologue 0
24	br	$27,1f
251:	ldgp	$29,0($27)
26	/* We need to get current_task_info loaded up...  */
27	lda	$8,init_thread_union
28	/* ... and find our stack ... */
29	lda	$30,0x4000 - SIZEOF_PT_REGS($8)
30	/* ... and then we can start the kernel.  */
31	jsr	$26,start_kernel
32	call_pal PAL_halt
33	.end __start
34
35#ifdef CONFIG_SMP
36	.align 3
37	.globl	__smp_callin
38	.ent	__smp_callin
39	/* On entry here from SRM console, the HWPCB of the per-cpu
40	   slot for this processor has been loaded.  We've arranged
41	   for the UNIQUE value for this process to contain the PCBB
42	   of the target idle task.  */
43__smp_callin:
44	.prologue 1
45	ldgp	$29,0($27)	# First order of business, load the GP.
46
47	call_pal PAL_rduniq	# Grab the target PCBB.
48	mov	$0,$16		# Install it.
49	call_pal PAL_swpctx
50
51	lda	$8,0x3fff	# Find "current".
52	bic	$30,$8,$8
53
54	jsr	$26,smp_callin
55	call_pal PAL_halt
56	.end __smp_callin
57#endif /* CONFIG_SMP */
58
59	#
60	# The following two functions are needed for supporting SRM PALcode
61	# on the PC164 (at least), since that PALcode manages the interrupt
62	# masking, and we cannot duplicate the effort without causing problems
63	#
64
65	.align 3
66	.globl	cserve_ena
67	.ent	cserve_ena
68cserve_ena:
69	.prologue 0
70	bis	$16,$16,$17
71	lda	$16,52($31)
72	call_pal PAL_cserve
73	ret	($26)
74	.end	cserve_ena
75
76	.align 3
77	.globl	cserve_dis
78	.ent	cserve_dis
79cserve_dis:
80	.prologue 0
81	bis	$16,$16,$17
82	lda	$16,53($31)
83	call_pal PAL_cserve
84	ret	($26)
85	.end	cserve_dis
86
87	#
88	# It is handy, on occasion, to make halt actually just loop.
89	# Putting it here means we dont have to recompile the whole
90	# kernel.
91	#
92
93	.align 3
94	.globl	halt
95	.ent	halt
96halt:
97	.prologue 0
98	call_pal PAL_halt
99	.end	halt
100