xref: /linux/arch/loongarch/kernel/head.S (revision 0e0073eb1b60f4ec6faecea034a6772fe1409a88)
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/regdef.h>
12#include <asm/loongarch.h>
13#include <asm/stackframe.h>
14
15#ifdef CONFIG_EFI_STUB
16
17#include "efi-header.S"
18
19	__HEAD
20
21_head:
22	.word	MZ_MAGIC		/* "MZ", MS-DOS header */
23	.org	0x3c			/* 0x04 ~ 0x3b reserved */
24	.long	pe_header - _head	/* Offset to the PE header */
25
26pe_header:
27	__EFI_PE_HEADER
28
29SYM_DATA(kernel_asize, .long _end - _text);
30SYM_DATA(kernel_fsize, .long _edata - _text);
31SYM_DATA(kernel_offset, .long kernel_offset - _text);
32
33#endif
34
35	__REF
36
37	.align 12
38
39SYM_CODE_START(kernel_entry)			# kernel entry point
40
41	/* Config direct window and set PG */
42	li.d		t0, CSR_DMW0_INIT	# UC, PLV0, 0x8000 xxxx xxxx xxxx
43	csrwr		t0, LOONGARCH_CSR_DMWIN0
44	li.d		t0, CSR_DMW1_INIT	# CA, PLV0, 0x9000 xxxx xxxx xxxx
45	csrwr		t0, LOONGARCH_CSR_DMWIN1
46
47	/* We might not get launched at the address the kernel is linked to,
48	   so we jump there.  */
49	la.abs		t0, 0f
50	jr		t0
510:
52	/* Enable PG */
53	li.w		t0, 0xb0		# PLV=0, IE=0, PG=1
54	csrwr		t0, LOONGARCH_CSR_CRMD
55	li.w		t0, 0x04		# PLV=0, PIE=1, PWE=0
56	csrwr		t0, LOONGARCH_CSR_PRMD
57	li.w		t0, 0x00		# FPE=0, SXE=0, ASXE=0, BTE=0
58	csrwr		t0, LOONGARCH_CSR_EUEN
59
60	la		t0, __bss_start		# clear .bss
61	st.d		zero, t0, 0
62	la		t1, __bss_stop - LONGSIZE
631:
64	addi.d		t0, t0, LONGSIZE
65	st.d		zero, t0, 0
66	bne		t0, t1, 1b
67
68	la		t0, fw_arg0
69	st.d		a0, t0, 0		# firmware arguments
70	la		t0, fw_arg1
71	st.d		a1, t0, 0
72	la		t0, fw_arg2
73	st.d		a2, t0, 0
74
75	/* KSave3 used for percpu base, initialized as 0 */
76	csrwr		zero, PERCPU_BASE_KS
77	/* GPR21 used for percpu base (runtime), initialized as 0 */
78	move		u0, zero
79
80	la		tp, init_thread_union
81	/* Set the SP after an empty pt_regs.  */
82	PTR_LI		sp, (_THREAD_SIZE - 32 - PT_SIZE)
83	PTR_ADD		sp, sp, tp
84	set_saved_sp	sp, t0, t1
85	PTR_ADDI	sp, sp, -4 * SZREG	# init stack pointer
86
87	bl		start_kernel
88
89SYM_CODE_END(kernel_entry)
90
91#ifdef CONFIG_SMP
92
93/*
94 * SMP slave cpus entry point.	Board specific code for bootstrap calls this
95 * function after setting up the stack and tp registers.
96 */
97SYM_CODE_START(smpboot_entry)
98	li.d		t0, CSR_DMW0_INIT	# UC, PLV0
99	csrwr		t0, LOONGARCH_CSR_DMWIN0
100	li.d		t0, CSR_DMW1_INIT	# CA, PLV0
101	csrwr		t0, LOONGARCH_CSR_DMWIN1
102
103	la.abs		t0, 0f
104	jr		t0
1050:
106	/* Enable PG */
107	li.w		t0, 0xb0		# PLV=0, IE=0, PG=1
108	csrwr		t0, LOONGARCH_CSR_CRMD
109	li.w		t0, 0x04		# PLV=0, PIE=1, PWE=0
110	csrwr		t0, LOONGARCH_CSR_PRMD
111	li.w		t0, 0x00		# FPE=0, SXE=0, ASXE=0, BTE=0
112	csrwr		t0, LOONGARCH_CSR_EUEN
113
114	la.abs		t0, cpuboot_data
115	ld.d		sp, t0, CPU_BOOT_STACK
116	ld.d		tp, t0, CPU_BOOT_TINFO
117
118	bl		start_secondary
119SYM_CODE_END(smpboot_entry)
120
121#endif /* CONFIG_SMP */
122
123SYM_ENTRY(kernel_entry_end, SYM_L_GLOBAL, SYM_A_NONE)
124