xref: /openbmc/linux/arch/loongarch/kernel/head.S (revision d6344cc8)
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	MZ_MAGIC		/* "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
46	/* Config direct window and set PG */
47	li.d		t0, CSR_DMW0_INIT	# UC, PLV0, 0x8000 xxxx xxxx xxxx
48	csrwr		t0, LOONGARCH_CSR_DMWIN0
49	li.d		t0, CSR_DMW1_INIT	# CA, PLV0, 0x9000 xxxx xxxx xxxx
50	csrwr		t0, LOONGARCH_CSR_DMWIN1
51
52	JUMP_VIRT_ADDR	t0, t1
53
54	/* Enable PG */
55	li.w		t0, 0xb0		# PLV=0, IE=0, PG=1
56	csrwr		t0, LOONGARCH_CSR_CRMD
57	li.w		t0, 0x04		# PLV=0, PIE=1, PWE=0
58	csrwr		t0, LOONGARCH_CSR_PRMD
59	li.w		t0, 0x00		# FPE=0, SXE=0, ASXE=0, BTE=0
60	csrwr		t0, LOONGARCH_CSR_EUEN
61
62	la.pcrel	t0, __bss_start		# clear .bss
63	st.d		zero, t0, 0
64	la.pcrel	t1, __bss_stop - LONGSIZE
651:
66	addi.d		t0, t0, LONGSIZE
67	st.d		zero, t0, 0
68	bne		t0, t1, 1b
69
70	la.pcrel	t0, fw_arg0
71	st.d		a0, t0, 0		# firmware arguments
72	la.pcrel	t0, fw_arg1
73	st.d		a1, t0, 0
74	la.pcrel	t0, fw_arg2
75	st.d		a2, t0, 0
76
77	/* KSave3 used for percpu base, initialized as 0 */
78	csrwr		zero, PERCPU_BASE_KS
79	/* GPR21 used for percpu base (runtime), initialized as 0 */
80	move		u0, zero
81
82	la.pcrel	tp, init_thread_union
83	/* Set the SP after an empty pt_regs.  */
84	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)
85	PTR_ADD		sp, sp, tp
86	set_saved_sp	sp, t0, t1
87
88#ifdef CONFIG_RELOCATABLE
89
90	bl		relocate_kernel
91
92#ifdef CONFIG_RANDOMIZE_BASE
93	/* Repoint the sp into the new kernel */
94	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)
95	PTR_ADD		sp, sp, tp
96	set_saved_sp	sp, t0, t1
97
98	/* Jump to the new kernel: new_pc = current_pc + random_offset */
99	pcaddi		t0, 0
100	add.d		t0, t0, a0
101	jirl		zero, t0, 0xc
102#endif /* CONFIG_RANDOMIZE_BASE */
103
104#endif /* CONFIG_RELOCATABLE */
105
106#ifdef CONFIG_KASAN
107	bl		kasan_early_init
108#endif
109
110	bl		start_kernel
111	ASM_BUG()
112
113SYM_CODE_END(kernel_entry)
114
115#ifdef CONFIG_SMP
116
117/*
118 * SMP slave cpus entry point.	Board specific code for bootstrap calls this
119 * function after setting up the stack and tp registers.
120 */
121SYM_CODE_START(smpboot_entry)
122	li.d		t0, CSR_DMW0_INIT	# UC, PLV0
123	csrwr		t0, LOONGARCH_CSR_DMWIN0
124	li.d		t0, CSR_DMW1_INIT	# CA, PLV0
125	csrwr		t0, LOONGARCH_CSR_DMWIN1
126
127	JUMP_VIRT_ADDR	t0, t1
128
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
148SYM_ENTRY(kernel_entry_end, SYM_L_GLOBAL, SYM_A_NONE)
149