xref: /linux/arch/loongarch/kernel/head.S (revision 6a069876eb1402478900ee0eb7d7fe276bb1f4e3)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 */
5#include <linux/init.h>
6#include <linux/threads.h>
7
8#include <asm/addrspace.h>
9#include <asm/asm.h>
10#include <asm/asmmacro.h>
11#include <asm/bug.h>
12#include <asm/regdef.h>
13#include <asm/loongarch.h>
14#include <asm/stackframe.h>
15
16#ifdef CONFIG_EFI_STUB
17
18#include "efi-header.S"
19
20	__HEAD
21
22_head:
23	.word	IMAGE_DOS_SIGNATURE	/* "MZ", MS-DOS header */
24	.org	0x8
25	.dword	_kernel_entry		/* Kernel entry point (physical address) */
26	.dword	_kernel_asize		/* Kernel image effective size */
27	.quad	PHYS_LINK_KADDR		/* Kernel image load offset from start of RAM */
28	.org	0x38			/* 0x20 ~ 0x37 reserved */
29	.long	LINUX_PE_MAGIC
30	.long	pe_header - _head	/* Offset to the PE header */
31
32pe_header:
33	__EFI_PE_HEADER
34
35SYM_DATA(kernel_asize, .long _kernel_asize);
36SYM_DATA(kernel_fsize, .long _kernel_fsize);
37
38#endif
39
40	__REF
41
42	.align 12
43
44SYM_CODE_START(kernel_entry)			# kernel entry point
45	UNWIND_HINT_END_OF_STACK
46
47	SETUP_TWINS
48	SETUP_MODES	t0
49	JUMP_VIRT_ADDR	t0, t1
50	SETUP_DMWINS	t0
51
52	la.pcrel	t0, __bss_start		# clear .bss
53	LONG_S		zero, t0, 0
54	la.pcrel	t1, __bss_stop - LONGSIZE
551:
56	PTR_ADDI	t0, t0, LONGSIZE
57	LONG_S		zero, t0, 0
58	bne		t0, t1, 1b
59
60	la.pcrel	t0, fw_arg0
61	PTR_S		a0, t0, 0		# firmware arguments
62	la.pcrel	t0, fw_arg1
63	PTR_S		a1, t0, 0
64	la.pcrel	t0, fw_arg2
65	PTR_S		a2, t0, 0
66
67#ifdef CONFIG_PAGE_SIZE_4KB
68	LONG_LI		t0, 0
69	LONG_LI		t1, CSR_STFILL
70	csrxchg		t0, t1, LOONGARCH_CSR_IMPCTL1
71#endif
72	/* KSave3 used for percpu base, initialized as 0 */
73	csrwr		zero, PERCPU_BASE_KS
74	/* GPR21 used for percpu base (runtime), initialized as 0 */
75	move		u0, zero
76
77	la.pcrel	tp, init_thread_union
78	/* Set the SP after an empty pt_regs.  */
79	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)
80	PTR_ADD		sp, sp, tp
81	set_saved_sp	sp, t0, t1
82
83#ifdef CONFIG_RELOCATABLE
84
85	bl		relocate_kernel
86
87#ifdef CONFIG_RANDOMIZE_BASE
88	/* Repoint the sp into the new kernel */
89	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)
90	PTR_ADD		sp, sp, tp
91	set_saved_sp	sp, t0, t1
92
93	/* Jump to the new kernel: new_pc = current_pc + random_offset */
94	pcaddi		t0, 0
95	PTR_ADD		t0, t0, a0
96	jirl		zero, t0, 0xc
97#endif /* CONFIG_RANDOMIZE_BASE */
98
99#endif /* CONFIG_RELOCATABLE */
100
101#ifdef CONFIG_KASAN
102	bl		kasan_early_init
103#endif
104
105	bl		start_kernel
106	ASM_BUG()
107
108SYM_CODE_END(kernel_entry)
109
110#ifdef CONFIG_SMP
111
112/*
113 * SMP slave cpus entry point.	Board specific code for bootstrap calls this
114 * function after setting up the stack and tp registers.
115 */
116SYM_CODE_START(smpboot_entry)
117	UNWIND_HINT_END_OF_STACK
118
119	SETUP_TWINS
120	SETUP_MODES	t0
121	JUMP_VIRT_ADDR	t0, t1
122	SETUP_DMWINS	t0
123
124#ifdef CONFIG_PAGE_SIZE_4KB
125	LONG_LI		t0, 0
126	LONG_LI		t1, CSR_STFILL
127	csrxchg		t0, t1, LOONGARCH_CSR_IMPCTL1
128#endif
129	/* Enable PG */
130	li.w		t0, 0xb0		# PLV=0, IE=0, PG=1
131	csrwr		t0, LOONGARCH_CSR_CRMD
132	li.w		t0, 0x04		# PLV=0, PIE=1, PWE=0
133	csrwr		t0, LOONGARCH_CSR_PRMD
134	li.w		t0, 0x00		# FPE=0, SXE=0, ASXE=0, BTE=0
135	csrwr		t0, LOONGARCH_CSR_EUEN
136
137	la.pcrel	t0, cpuboot_data
138	ld.d		sp, t0, CPU_BOOT_STACK
139	ld.d		tp, t0, CPU_BOOT_TINFO
140
141	bl		start_secondary
142	ASM_BUG()
143
144SYM_CODE_END(smpboot_entry)
145
146#endif /* CONFIG_SMP */
147