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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#ifdef CONFIG_USE_OF
97#if defined(CONFIG_MIPS_RAW_APPENDED_DTB) || \
98	defined(CONFIG_MIPS_ELF_APPENDED_DTB)
99
100	PTR_LA		t2, __appended_dtb
101
102#ifdef CONFIG_CPU_BIG_ENDIAN
103	li		t1, 0xd00dfeed
104#else  /* !CONFIG_CPU_BIG_ENDIAN */
105	li		t1, 0xedfe0dd0
106#endif /* !CONFIG_CPU_BIG_ENDIAN */
107	lw		t0, (t2)
108	beq		t0, t1, dtb_found
109#endif /* CONFIG_MIPS_RAW_APPENDED_DTB || CONFIG_MIPS_ELF_APPENDED_DTB */
110	li		t1, -2
111	move		t2, a1
112	beq		a0, t1, dtb_found
113
114#ifdef CONFIG_BUILTIN_DTB
115	PTR_LA	t2, __dtb_start
116	PTR_LA	t1, __dtb_end
117	bne		t1, t2, dtb_found
118#endif /* CONFIG_BUILTIN_DTB */
119
120	li		t2, 0
121dtb_found:
122#endif /* CONFIG_USE_OF */
123	PTR_LA		t0, __bss_start		# clear .bss
124	LONG_S		zero, (t0)
125	PTR_LA		t1, __bss_stop - LONGSIZE
1261:
127	PTR_ADDIU	t0, LONGSIZE
128	LONG_S		zero, (t0)
129	bne		t0, t1, 1b
130
131	LONG_S		a0, fw_arg0		# firmware arguments
132	LONG_S		a1, fw_arg1
133	LONG_S		a2, fw_arg2
134	LONG_S		a3, fw_arg3
135
136#ifdef CONFIG_USE_OF
137	LONG_S		t2, fw_passed_dtb
138#endif
139
140	MTC0		zero, CP0_CONTEXT	# clear context register
141#ifdef CONFIG_64BIT
142	MTC0		zero, CP0_XCONTEXT
143#endif
144	PTR_LA		$28, init_thread_union
145	/* Set the SP after an empty pt_regs.  */
146	PTR_LI		sp, _THREAD_SIZE - 32 - PT_SIZE
147	PTR_ADDU	sp, $28
148	back_to_back_c0_hazard
149	set_saved_sp	sp, t0, t1
150	PTR_SUBU	sp, 4 * SZREG		# init stack pointer
151
152#ifdef CONFIG_RELOCATABLE
153	/* Copy kernel and apply the relocations */
154	jal		relocate_kernel
155
156	/* Repoint the sp into the new kernel image */
157	PTR_LI		sp, _THREAD_SIZE - 32 - PT_SIZE
158	PTR_ADDU	sp, $28
159	set_saved_sp	sp, t0, t1
160	PTR_SUBU	sp, 4 * SZREG		# init stack pointer
161
162	/*
163	 * relocate_kernel returns the entry point either
164	 * in the relocated kernel or the original if for
165	 * some reason relocation failed - jump there now
166	 * with instruction hazard barrier because of the
167	 * newly sync'd icache.
168	 */
169	jr.hb		v0
170#else  /* !CONFIG_RELOCATABLE */
171	j		start_kernel
172#endif /* !CONFIG_RELOCATABLE */
173	END(kernel_entry)
174
175#ifdef CONFIG_SMP
176/*
177 * SMP slave cpus entry point.	Board specific code for bootstrap calls this
178 * function after setting up the stack and gp registers.
179 */
180NESTED(smp_bootstrap, 16, sp)
181	smp_slave_setup
182	setup_c0_status_sec
183	j	start_secondary
184	END(smp_bootstrap)
185#endif /* CONFIG_SMP */
186