1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * relocate_kernel.S for kexec
4 * Created by <nschichan@corp.free.fr> on Thu Oct 12 17:49:57 2006
5 */
6
7#include <asm/asm.h>
8#include <asm/asmmacro.h>
9#include <asm/regdef.h>
10#include <asm/mipsregs.h>
11#include <asm/stackframe.h>
12#include <asm/addrspace.h>
13
14#include <kernel-entry-init.h>
15
16LEAF(relocate_new_kernel)
17	PTR_L a0,	arg0
18	PTR_L a1,	arg1
19	PTR_L a2,	arg2
20	PTR_L a3,	arg3
21
22	PTR_L		s0, kexec_indirection_page
23	PTR_L		s1, kexec_start_address
24
25process_entry:
26	PTR_L		s2, (s0)
27	PTR_ADDIU	s0, s0, SZREG
28
29	/*
30	 * In case of a kdump/crash kernel, the indirection page is not
31	 * populated as the kernel is directly copied to a reserved location
32	 */
33	beqz		s2, done
34
35	/* destination page */
36	and		s3, s2, 0x1
37	beq		s3, zero, 1f
38	and		s4, s2, ~0x1	/* store destination addr in s4 */
39	b		process_entry
40
411:
42	/* indirection page, update s0	*/
43	and		s3, s2, 0x2
44	beq		s3, zero, 1f
45	and		s0, s2, ~0x2
46	b		process_entry
47
481:
49	/* done page */
50	and		s3, s2, 0x4
51	beq		s3, zero, 1f
52	b		done
531:
54	/* source page */
55	and		s3, s2, 0x8
56	beq		s3, zero, process_entry
57	and		s2, s2, ~0x8
58	li		s6, (1 << _PAGE_SHIFT) / SZREG
59
60copy_word:
61	/* copy page word by word */
62	REG_L		s5, (s2)
63	REG_S		s5, (s4)
64	PTR_ADDIU	s4, s4, SZREG
65	PTR_ADDIU	s2, s2, SZREG
66	LONG_ADDIU	s6, s6, -1
67	beq		s6, zero, process_entry
68	b		copy_word
69	b		process_entry
70
71done:
72#ifdef CONFIG_SMP
73	/* kexec_flag reset is signal to other CPUs what kernel
74	   was moved to it's location. Note - we need relocated address
75	   of kexec_flag.  */
76
77	bal		1f
78 1:	move		t1,ra;
79	PTR_LA		t2,1b
80	PTR_LA		t0,kexec_flag
81	PTR_SUB		t0,t0,t2;
82	PTR_ADD		t0,t1,t0;
83	LONG_S		zero,(t0)
84#endif
85
86#ifdef CONFIG_CPU_CAVIUM_OCTEON
87	/* We need to flush I-cache before jumping to new kernel.
88	 * Unfortunately, this code is cpu-specific.
89	 */
90	.set push
91	.set noreorder
92	syncw
93	syncw
94	synci		0($0)
95	.set pop
96#else
97	sync
98#endif
99	/* jump to kexec_start_address */
100	j		s1
101	END(relocate_new_kernel)
102
103#ifdef CONFIG_SMP
104/*
105 * Other CPUs should wait until code is relocated and
106 * then start at entry (?) point.
107 */
108LEAF(kexec_smp_wait)
109	PTR_L		a0, s_arg0
110	PTR_L		a1, s_arg1
111	PTR_L		a2, s_arg2
112	PTR_L		a3, s_arg3
113	PTR_L		s1, kexec_start_address
114
115	/* Non-relocated address works for args and kexec_start_address ( old
116	 * kernel is not overwritten). But we need relocated address of
117	 * kexec_flag.
118	 */
119
120	bal		1f
1211:	move		t1,ra;
122	PTR_LA		t2,1b
123	PTR_LA		t0,kexec_flag
124	PTR_SUB		t0,t0,t2;
125	PTR_ADD		t0,t1,t0;
126
1271:	LONG_L		s0, (t0)
128	bne		s0, zero,1b
129
130#ifdef USE_KEXEC_SMP_WAIT_FINAL
131	kexec_smp_wait_final
132#else
133	sync
134#endif
135	j		s1
136	END(kexec_smp_wait)
137#endif
138
139#ifdef __mips64
140       /* all PTR's must be aligned to 8 byte in 64-bit mode */
141       .align  3
142#endif
143
144/* All parameters to new kernel are passed in registers a0-a3.
145 * kexec_args[0..3] are used to prepare register values.
146 */
147
148EXPORT(kexec_args)
149arg0:	PTR_WD		0x0
150arg1:	PTR_WD		0x0
151arg2:	PTR_WD		0x0
152arg3:	PTR_WD		0x0
153	.size	kexec_args,PTRSIZE*4
154
155#ifdef CONFIG_SMP
156/*
157 * Secondary CPUs may have different kernel parameters in
158 * their registers a0-a3. secondary_kexec_args[0..3] are used
159 * to prepare register values.
160 */
161EXPORT(secondary_kexec_args)
162s_arg0: PTR_WD		0x0
163s_arg1: PTR_WD		0x0
164s_arg2: PTR_WD		0x0
165s_arg3: PTR_WD		0x0
166	.size	secondary_kexec_args,PTRSIZE*4
167kexec_flag:
168	LONG		0x1
169
170#endif
171
172EXPORT(kexec_start_address)
173	PTR_WD		0x0
174	.size		kexec_start_address, PTRSIZE
175
176EXPORT(kexec_indirection_page)
177	PTR_WD		0
178	.size		kexec_indirection_page, PTRSIZE
179
180relocate_new_kernel_end:
181
182EXPORT(relocate_new_kernel_size)
183	PTR_WD		relocate_new_kernel_end - relocate_new_kernel
184	.size		relocate_new_kernel_size, PTRSIZE
185