1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994, 1995 Waldorf Electronics
7 * Written by Ralf Baechle and Andreas Busse
8 * Copyright (C) 1994 - 99, 2003, 06 Ralf Baechle
9 * Copyright (C) 1996 Paul M. Antoine
10 * Modified for DECStation and hence R3000 support by Paul M. Antoine
11 * Further modifications by David S. Miller and Harald Koerfgen
12 * Copyright (C) 1999 Silicon Graphics, Inc.
13 * Kevin Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
14 * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
15 */
16#include <linux/init.h>
17#include <linux/threads.h>
18
19#include <asm/addrspace.h>
20#include <asm/asm.h>
21#include <asm/asmmacro.h>
22#include <asm/irqflags.h>
23#include <asm/regdef.h>
24#include <asm/mipsregs.h>
25#include <asm/stackframe.h>
26
27#include <kernel-entry-init.h>
28
29	/*
30	 * For the moment disable interrupts, mark the kernel mode and
31	 * set ST0_KX so that the CPU does not spit fire when using
32	 * 64-bit addresses.  A full initialization of the CPU's status
33	 * register is done later in per_cpu_trap_init().
34	 */
35	.macro	setup_c0_status set clr
36	.set	push
37	mfc0	t0, CP0_STATUS
38	or	t0, ST0_KERNEL_CUMASK|\set|0x1f|\clr
39	xor	t0, 0x1f|\clr
40	mtc0	t0, CP0_STATUS
41	.set	noreorder
42	sll	zero,3				# ehb
43	.set	pop
44	.endm
45
46	.macro	setup_c0_status_pri
47#ifdef CONFIG_64BIT
48	setup_c0_status ST0_KX 0
49#else
50	setup_c0_status 0 0
51#endif
52	.endm
53
54	.macro	setup_c0_status_sec
55#ifdef CONFIG_64BIT
56	setup_c0_status ST0_KX ST0_BEV
57#else
58	setup_c0_status 0 ST0_BEV
59#endif
60	.endm
61
62#ifndef CONFIG_NO_EXCEPT_FILL
63	/*
64	 * Reserved space for exception handlers.
65	 * Necessary for machines which link their kernels at KSEG0.
66	 */
67	.fill	0x400
68#endif
69
70EXPORT(_stext)
71
72#ifdef CONFIG_BOOT_RAW
73	/*
74	 * Give us a fighting chance of running if execution beings at the
75	 * kernel load address.	 This is needed because this platform does
76	 * not have a ELF loader yet.
77	 */
78FEXPORT(__kernel_entry)
79	j	kernel_entry
80#endif /* CONFIG_BOOT_RAW */
81
82	__REF
83
84NESTED(kernel_entry, 16, sp)			# kernel entry point
85
86	kernel_entry_setup			# cpu specific setup
87
88	setup_c0_status_pri
89
90	/* We might not get launched at the address the kernel is linked to,
91	   so we jump there.  */
92	PTR_LA	t0, 0f
93	jr	t0
940:
95
96	PTR_LA		t0, __bss_start		# clear .bss
97	LONG_S		zero, (t0)
98	PTR_LA		t1, __bss_stop - LONGSIZE
991:
100	PTR_ADDIU	t0, LONGSIZE
101	LONG_S		zero, (t0)
102	bne		t0, t1, 1b
103
104	LONG_S		a0, fw_arg0		# firmware arguments
105	LONG_S		a1, fw_arg1
106	LONG_S		a2, fw_arg2
107	LONG_S		a3, fw_arg3
108
109	MTC0		zero, CP0_CONTEXT	# clear context register
110#ifdef CONFIG_64BIT
111	MTC0		zero, CP0_XCONTEXT
112#endif
113	PTR_LA		$28, init_thread_union
114	/* Set the SP after an empty pt_regs.  */
115	PTR_LI		sp, _THREAD_SIZE - 32 - PT_SIZE
116	PTR_ADDU	sp, $28
117	back_to_back_c0_hazard
118	set_saved_sp	sp, t0, t1
119	PTR_SUBU	sp, 4 * SZREG		# init stack pointer
120
121#ifdef CONFIG_RELOCATABLE
122	/* Copy kernel and apply the relocations */
123	jal		relocate_kernel
124
125	/* Repoint the sp into the new kernel image */
126	PTR_LI		sp, _THREAD_SIZE - 32 - PT_SIZE
127	PTR_ADDU	sp, $28
128	set_saved_sp	sp, t0, t1
129	PTR_SUBU	sp, 4 * SZREG		# init stack pointer
130
131	/*
132	 * relocate_kernel returns the entry point either
133	 * in the relocated kernel or the original if for
134	 * some reason relocation failed - jump there now
135	 * with instruction hazard barrier because of the
136	 * newly sync'd icache.
137	 */
138	jr.hb		v0
139#else  /* !CONFIG_RELOCATABLE */
140	j		start_kernel
141#endif /* !CONFIG_RELOCATABLE */
142	END(kernel_entry)
143
144#ifdef CONFIG_SMP
145/*
146 * SMP slave cpus entry point.	Board specific code for bootstrap calls this
147 * function after setting up the stack and gp registers.
148 */
149NESTED(smp_bootstrap, 16, sp)
150	smp_slave_setup
151	setup_c0_status_sec
152	j	start_secondary
153	END(smp_bootstrap)
154#endif /* CONFIG_SMP */
155