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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * relocate_kernel.S - put the kernel image in place to boot
4 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
5 */
6
7#include <linux/linkage.h>
8#include <asm/page_types.h>
9#include <asm/kexec.h>
10#include <asm/processor-flags.h>
11#include <asm/pgtable_types.h>
12
13/*
14 * Must be relocatable PIC code callable as a C function
15 */
16
17#define PTR(x) (x << 3)
18#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
19
20/*
21 * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
22 * ~ control_page + PAGE_SIZE are used as data storage and stack for
23 * jumping back
24 */
25#define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
26
27/* Minimal CPU state */
28#define RSP DATA(0x0)
29#define CR0 DATA(0x8)
30#define CR3 DATA(0x10)
31#define CR4 DATA(0x18)
32
33/* other data */
34#define CP_PA_TABLE_PAGE DATA(0x20)
35#define CP_PA_SWAP_PAGE DATA(0x28)
36#define CP_PA_BACKUP_PAGES_MAP DATA(0x30)
37
38 .text
39 .align PAGE_SIZE
40 .code64
41 .globl relocate_kernel
42relocate_kernel:
43 /*
44 * %rdi indirection_page
45 * %rsi page_list
46 * %rdx start address
47 * %rcx preserve_context
48 * %r8 sme_active
49 */
50
51 /* Save the CPU context, used for jumping back */
52 pushq %rbx
53 pushq %rbp
54 pushq %r12
55 pushq %r13
56 pushq %r14
57 pushq %r15
58 pushf
59
60 movq PTR(VA_CONTROL_PAGE)(%rsi), %r11
61 movq %rsp, RSP(%r11)
62 movq %cr0, %rax
63 movq %rax, CR0(%r11)
64 movq %cr3, %rax
65 movq %rax, CR3(%r11)
66 movq %cr4, %rax
67 movq %rax, CR4(%r11)
68
69 /* Save CR4. Required to enable the right paging mode later. */
70 movq %rax, %r13
71
72 /* zero out flags, and disable interrupts */
73 pushq $0
74 popfq
75
76 /* Save SME active flag */
77 movq %r8, %r12
78
79 /*
80 * get physical address of control page now
81 * this is impossible after page table switch
82 */
83 movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
84
85 /* get physical address of page table now too */
86 movq PTR(PA_TABLE_PAGE)(%rsi), %r9
87
88 /* get physical address of swap page now */
89 movq PTR(PA_SWAP_PAGE)(%rsi), %r10
90
91 /* save some information for jumping back */
92 movq %r9, CP_PA_TABLE_PAGE(%r11)
93 movq %r10, CP_PA_SWAP_PAGE(%r11)
94 movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
95
96 /* Switch to the identity mapped page tables */
97 movq %r9, %cr3
98
99 /* setup a new stack at the end of the physical control page */
100 lea PAGE_SIZE(%r8), %rsp
101
102 /* jump to identity mapped page */
103 addq $(identity_mapped - relocate_kernel), %r8
104 pushq %r8
105 ret
106
107identity_mapped:
108 /* set return address to 0 if not preserving context */
109 pushq $0
110 /* store the start address on the stack */
111 pushq %rdx
112
113 /*
114 * Set cr0 to a known state:
115 * - Paging enabled
116 * - Alignment check disabled
117 * - Write protect disabled
118 * - No task switch
119 * - Don't do FP software emulation.
120 * - Proctected mode enabled
121 */
122 movq %cr0, %rax
123 andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax
124 orl $(X86_CR0_PG | X86_CR0_PE), %eax
125 movq %rax, %cr0
126
127 /*
128 * Set cr4 to a known state:
129 * - physical address extension enabled
130 * - 5-level paging, if it was enabled before
131 */
132 movl $X86_CR4_PAE, %eax
133 testq $X86_CR4_LA57, %r13
134 jz 1f
135 orl $X86_CR4_LA57, %eax
1361:
137 movq %rax, %cr4
138
139 jmp 1f
1401:
141
142 /* Flush the TLB (needed?) */
143 movq %r9, %cr3
144
145 /*
146 * If SME is active, there could be old encrypted cache line
147 * entries that will conflict with the now unencrypted memory
148 * used by kexec. Flush the caches before copying the kernel.
149 */
150 testq %r12, %r12
151 jz 1f
152 wbinvd
1531:
154
155 movq %rcx, %r11
156 call swap_pages
157
158 /*
159 * To be certain of avoiding problems with self-modifying code
160 * I need to execute a serializing instruction here.
161 * So I flush the TLB by reloading %cr3 here, it's handy,
162 * and not processor dependent.
163 */
164 movq %cr3, %rax
165 movq %rax, %cr3
166
167 /*
168 * set all of the registers to known values
169 * leave %rsp alone
170 */
171
172 testq %r11, %r11
173 jnz 1f
174 xorl %eax, %eax
175 xorl %ebx, %ebx
176 xorl %ecx, %ecx
177 xorl %edx, %edx
178 xorl %esi, %esi
179 xorl %edi, %edi
180 xorl %ebp, %ebp
181 xorl %r8d, %r8d
182 xorl %r9d, %r9d
183 xorl %r10d, %r10d
184 xorl %r11d, %r11d
185 xorl %r12d, %r12d
186 xorl %r13d, %r13d
187 xorl %r14d, %r14d
188 xorl %r15d, %r15d
189
190 ret
191
1921:
193 popq %rdx
194 leaq PAGE_SIZE(%r10), %rsp
195 call *%rdx
196
197 /* get the re-entry point of the peer system */
198 movq 0(%rsp), %rbp
199 call 1f
2001:
201 popq %r8
202 subq $(1b - relocate_kernel), %r8
203 movq CP_PA_SWAP_PAGE(%r8), %r10
204 movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
205 movq CP_PA_TABLE_PAGE(%r8), %rax
206 movq %rax, %cr3
207 lea PAGE_SIZE(%r8), %rsp
208 call swap_pages
209 movq $virtual_mapped, %rax
210 pushq %rax
211 ret
212
213virtual_mapped:
214 movq RSP(%r8), %rsp
215 movq CR4(%r8), %rax
216 movq %rax, %cr4
217 movq CR3(%r8), %rax
218 movq CR0(%r8), %r8
219 movq %rax, %cr3
220 movq %r8, %cr0
221 movq %rbp, %rax
222
223 popf
224 popq %r15
225 popq %r14
226 popq %r13
227 popq %r12
228 popq %rbp
229 popq %rbx
230 ret
231
232 /* Do the copies */
233swap_pages:
234 movq %rdi, %rcx /* Put the page_list in %rcx */
235 xorl %edi, %edi
236 xorl %esi, %esi
237 jmp 1f
238
2390: /* top, read another word for the indirection page */
240
241 movq (%rbx), %rcx
242 addq $8, %rbx
2431:
244 testb $0x1, %cl /* is it a destination page? */
245 jz 2f
246 movq %rcx, %rdi
247 andq $0xfffffffffffff000, %rdi
248 jmp 0b
2492:
250 testb $0x2, %cl /* is it an indirection page? */
251 jz 2f
252 movq %rcx, %rbx
253 andq $0xfffffffffffff000, %rbx
254 jmp 0b
2552:
256 testb $0x4, %cl /* is it the done indicator? */
257 jz 2f
258 jmp 3f
2592:
260 testb $0x8, %cl /* is it the source indicator? */
261 jz 0b /* Ignore it otherwise */
262 movq %rcx, %rsi /* For ever source page do a copy */
263 andq $0xfffffffffffff000, %rsi
264
265 movq %rdi, %rdx
266 movq %rsi, %rax
267
268 movq %r10, %rdi
269 movl $512, %ecx
270 rep ; movsq
271
272 movq %rax, %rdi
273 movq %rdx, %rsi
274 movl $512, %ecx
275 rep ; movsq
276
277 movq %rdx, %rdi
278 movq %r10, %rsi
279 movl $512, %ecx
280 rep ; movsq
281
282 lea PAGE_SIZE(%rax), %rsi
283 jmp 0b
2843:
285 ret
286
287 .globl kexec_control_code_size
288.set kexec_control_code_size, . - relocate_kernel
1/*
2 * relocate_kernel.S - put the kernel image in place to boot
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8
9#include <linux/linkage.h>
10#include <asm/page_types.h>
11#include <asm/kexec.h>
12#include <asm/processor-flags.h>
13#include <asm/pgtable_types.h>
14
15/*
16 * Must be relocatable PIC code callable as a C function
17 */
18
19#define PTR(x) (x << 3)
20#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
21
22/*
23 * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
24 * ~ control_page + PAGE_SIZE are used as data storage and stack for
25 * jumping back
26 */
27#define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
28
29/* Minimal CPU state */
30#define RSP DATA(0x0)
31#define CR0 DATA(0x8)
32#define CR3 DATA(0x10)
33#define CR4 DATA(0x18)
34
35/* other data */
36#define CP_PA_TABLE_PAGE DATA(0x20)
37#define CP_PA_SWAP_PAGE DATA(0x28)
38#define CP_PA_BACKUP_PAGES_MAP DATA(0x30)
39
40 .text
41 .align PAGE_SIZE
42 .code64
43 .globl relocate_kernel
44relocate_kernel:
45 /*
46 * %rdi indirection_page
47 * %rsi page_list
48 * %rdx start address
49 * %rcx preserve_context
50 */
51
52 /* Save the CPU context, used for jumping back */
53 pushq %rbx
54 pushq %rbp
55 pushq %r12
56 pushq %r13
57 pushq %r14
58 pushq %r15
59 pushf
60
61 movq PTR(VA_CONTROL_PAGE)(%rsi), %r11
62 movq %rsp, RSP(%r11)
63 movq %cr0, %rax
64 movq %rax, CR0(%r11)
65 movq %cr3, %rax
66 movq %rax, CR3(%r11)
67 movq %cr4, %rax
68 movq %rax, CR4(%r11)
69
70 /* zero out flags, and disable interrupts */
71 pushq $0
72 popfq
73
74 /*
75 * get physical address of control page now
76 * this is impossible after page table switch
77 */
78 movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
79
80 /* get physical address of page table now too */
81 movq PTR(PA_TABLE_PAGE)(%rsi), %r9
82
83 /* get physical address of swap page now */
84 movq PTR(PA_SWAP_PAGE)(%rsi), %r10
85
86 /* save some information for jumping back */
87 movq %r9, CP_PA_TABLE_PAGE(%r11)
88 movq %r10, CP_PA_SWAP_PAGE(%r11)
89 movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
90
91 /* Switch to the identity mapped page tables */
92 movq %r9, %cr3
93
94 /* setup a new stack at the end of the physical control page */
95 lea PAGE_SIZE(%r8), %rsp
96
97 /* jump to identity mapped page */
98 addq $(identity_mapped - relocate_kernel), %r8
99 pushq %r8
100 ret
101
102identity_mapped:
103 /* set return address to 0 if not preserving context */
104 pushq $0
105 /* store the start address on the stack */
106 pushq %rdx
107
108 /*
109 * Set cr0 to a known state:
110 * - Paging enabled
111 * - Alignment check disabled
112 * - Write protect disabled
113 * - No task switch
114 * - Don't do FP software emulation.
115 * - Proctected mode enabled
116 */
117 movq %cr0, %rax
118 andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax
119 orl $(X86_CR0_PG | X86_CR0_PE), %eax
120 movq %rax, %cr0
121
122 /*
123 * Set cr4 to a known state:
124 * - physical address extension enabled
125 */
126 movl $X86_CR4_PAE, %eax
127 movq %rax, %cr4
128
129 jmp 1f
1301:
131
132 /* Flush the TLB (needed?) */
133 movq %r9, %cr3
134
135 movq %rcx, %r11
136 call swap_pages
137
138 /*
139 * To be certain of avoiding problems with self-modifying code
140 * I need to execute a serializing instruction here.
141 * So I flush the TLB by reloading %cr3 here, it's handy,
142 * and not processor dependent.
143 */
144 movq %cr3, %rax
145 movq %rax, %cr3
146
147 /*
148 * set all of the registers to known values
149 * leave %rsp alone
150 */
151
152 testq %r11, %r11
153 jnz 1f
154 xorl %eax, %eax
155 xorl %ebx, %ebx
156 xorl %ecx, %ecx
157 xorl %edx, %edx
158 xorl %esi, %esi
159 xorl %edi, %edi
160 xorl %ebp, %ebp
161 xorl %r8d, %r8d
162 xorl %r9d, %r9d
163 xorl %r10d, %r10d
164 xorl %r11d, %r11d
165 xorl %r12d, %r12d
166 xorl %r13d, %r13d
167 xorl %r14d, %r14d
168 xorl %r15d, %r15d
169
170 ret
171
1721:
173 popq %rdx
174 leaq PAGE_SIZE(%r10), %rsp
175 call *%rdx
176
177 /* get the re-entry point of the peer system */
178 movq 0(%rsp), %rbp
179 call 1f
1801:
181 popq %r8
182 subq $(1b - relocate_kernel), %r8
183 movq CP_PA_SWAP_PAGE(%r8), %r10
184 movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
185 movq CP_PA_TABLE_PAGE(%r8), %rax
186 movq %rax, %cr3
187 lea PAGE_SIZE(%r8), %rsp
188 call swap_pages
189 movq $virtual_mapped, %rax
190 pushq %rax
191 ret
192
193virtual_mapped:
194 movq RSP(%r8), %rsp
195 movq CR4(%r8), %rax
196 movq %rax, %cr4
197 movq CR3(%r8), %rax
198 movq CR0(%r8), %r8
199 movq %rax, %cr3
200 movq %r8, %cr0
201 movq %rbp, %rax
202
203 popf
204 popq %r15
205 popq %r14
206 popq %r13
207 popq %r12
208 popq %rbp
209 popq %rbx
210 ret
211
212 /* Do the copies */
213swap_pages:
214 movq %rdi, %rcx /* Put the page_list in %rcx */
215 xorl %edi, %edi
216 xorl %esi, %esi
217 jmp 1f
218
2190: /* top, read another word for the indirection page */
220
221 movq (%rbx), %rcx
222 addq $8, %rbx
2231:
224 testb $0x1, %cl /* is it a destination page? */
225 jz 2f
226 movq %rcx, %rdi
227 andq $0xfffffffffffff000, %rdi
228 jmp 0b
2292:
230 testb $0x2, %cl /* is it an indirection page? */
231 jz 2f
232 movq %rcx, %rbx
233 andq $0xfffffffffffff000, %rbx
234 jmp 0b
2352:
236 testb $0x4, %cl /* is it the done indicator? */
237 jz 2f
238 jmp 3f
2392:
240 testb $0x8, %cl /* is it the source indicator? */
241 jz 0b /* Ignore it otherwise */
242 movq %rcx, %rsi /* For ever source page do a copy */
243 andq $0xfffffffffffff000, %rsi
244
245 movq %rdi, %rdx
246 movq %rsi, %rax
247
248 movq %r10, %rdi
249 movl $512, %ecx
250 rep ; movsq
251
252 movq %rax, %rdi
253 movq %rdx, %rsi
254 movl $512, %ecx
255 rep ; movsq
256
257 movq %rdx, %rdi
258 movq %r10, %rsi
259 movl $512, %ecx
260 rep ; movsq
261
262 lea PAGE_SIZE(%rax), %rsi
263 jmp 0b
2643:
265 ret
266
267 .globl kexec_control_code_size
268.set kexec_control_code_size, . - relocate_kernel