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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/* 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#include <asm/nospec-branch.h>
13#include <asm/unwind_hints.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
43SYM_CODE_START_NOALIGN(relocate_kernel)
44 UNWIND_HINT_EMPTY
45 /*
46 * %rdi indirection_page
47 * %rsi page_list
48 * %rdx start address
49 * %rcx preserve_context
50 * %r8 sme_active
51 */
52
53 /* Save the CPU context, used for jumping back */
54 pushq %rbx
55 pushq %rbp
56 pushq %r12
57 pushq %r13
58 pushq %r14
59 pushq %r15
60 pushf
61
62 movq PTR(VA_CONTROL_PAGE)(%rsi), %r11
63 movq %rsp, RSP(%r11)
64 movq %cr0, %rax
65 movq %rax, CR0(%r11)
66 movq %cr3, %rax
67 movq %rax, CR3(%r11)
68 movq %cr4, %rax
69 movq %rax, CR4(%r11)
70
71 /* Save CR4. Required to enable the right paging mode later. */
72 movq %rax, %r13
73
74 /* zero out flags, and disable interrupts */
75 pushq $0
76 popfq
77
78 /* Save SME active flag */
79 movq %r8, %r12
80
81 /*
82 * get physical address of control page now
83 * this is impossible after page table switch
84 */
85 movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
86
87 /* get physical address of page table now too */
88 movq PTR(PA_TABLE_PAGE)(%rsi), %r9
89
90 /* get physical address of swap page now */
91 movq PTR(PA_SWAP_PAGE)(%rsi), %r10
92
93 /* save some information for jumping back */
94 movq %r9, CP_PA_TABLE_PAGE(%r11)
95 movq %r10, CP_PA_SWAP_PAGE(%r11)
96 movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
97
98 /* Switch to the identity mapped page tables */
99 movq %r9, %cr3
100
101 /* setup a new stack at the end of the physical control page */
102 lea PAGE_SIZE(%r8), %rsp
103
104 /* jump to identity mapped page */
105 addq $(identity_mapped - relocate_kernel), %r8
106 pushq %r8
107 ret
108SYM_CODE_END(relocate_kernel)
109
110SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
111 UNWIND_HINT_EMPTY
112 /* set return address to 0 if not preserving context */
113 pushq $0
114 /* store the start address on the stack */
115 pushq %rdx
116
117 /*
118 * Set cr0 to a known state:
119 * - Paging enabled
120 * - Alignment check disabled
121 * - Write protect disabled
122 * - No task switch
123 * - Don't do FP software emulation.
124 * - Proctected mode enabled
125 */
126 movq %cr0, %rax
127 andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax
128 orl $(X86_CR0_PG | X86_CR0_PE), %eax
129 movq %rax, %cr0
130
131 /*
132 * Set cr4 to a known state:
133 * - physical address extension enabled
134 * - 5-level paging, if it was enabled before
135 */
136 movl $X86_CR4_PAE, %eax
137 testq $X86_CR4_LA57, %r13
138 jz 1f
139 orl $X86_CR4_LA57, %eax
1401:
141 movq %rax, %cr4
142
143 jmp 1f
1441:
145
146 /* Flush the TLB (needed?) */
147 movq %r9, %cr3
148
149 /*
150 * If SME is active, there could be old encrypted cache line
151 * entries that will conflict with the now unencrypted memory
152 * used by kexec. Flush the caches before copying the kernel.
153 */
154 testq %r12, %r12
155 jz 1f
156 wbinvd
1571:
158
159 movq %rcx, %r11
160 call swap_pages
161
162 /*
163 * To be certain of avoiding problems with self-modifying code
164 * I need to execute a serializing instruction here.
165 * So I flush the TLB by reloading %cr3 here, it's handy,
166 * and not processor dependent.
167 */
168 movq %cr3, %rax
169 movq %rax, %cr3
170
171 /*
172 * set all of the registers to known values
173 * leave %rsp alone
174 */
175
176 testq %r11, %r11
177 jnz 1f
178 xorl %eax, %eax
179 xorl %ebx, %ebx
180 xorl %ecx, %ecx
181 xorl %edx, %edx
182 xorl %esi, %esi
183 xorl %edi, %edi
184 xorl %ebp, %ebp
185 xorl %r8d, %r8d
186 xorl %r9d, %r9d
187 xorl %r10d, %r10d
188 xorl %r11d, %r11d
189 xorl %r12d, %r12d
190 xorl %r13d, %r13d
191 xorl %r14d, %r14d
192 xorl %r15d, %r15d
193
194 ret
195
1961:
197 popq %rdx
198 leaq PAGE_SIZE(%r10), %rsp
199 ANNOTATE_RETPOLINE_SAFE
200 call *%rdx
201
202 /* get the re-entry point of the peer system */
203 movq 0(%rsp), %rbp
204 leaq relocate_kernel(%rip), %r8
205 movq CP_PA_SWAP_PAGE(%r8), %r10
206 movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
207 movq CP_PA_TABLE_PAGE(%r8), %rax
208 movq %rax, %cr3
209 lea PAGE_SIZE(%r8), %rsp
210 call swap_pages
211 movq $virtual_mapped, %rax
212 pushq %rax
213 ret
214SYM_CODE_END(identity_mapped)
215
216SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
217 UNWIND_HINT_EMPTY
218 movq RSP(%r8), %rsp
219 movq CR4(%r8), %rax
220 movq %rax, %cr4
221 movq CR3(%r8), %rax
222 movq CR0(%r8), %r8
223 movq %rax, %cr3
224 movq %r8, %cr0
225 movq %rbp, %rax
226
227 popf
228 popq %r15
229 popq %r14
230 popq %r13
231 popq %r12
232 popq %rbp
233 popq %rbx
234 ret
235SYM_CODE_END(virtual_mapped)
236
237 /* Do the copies */
238SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
239 UNWIND_HINT_EMPTY
240 movq %rdi, %rcx /* Put the page_list in %rcx */
241 xorl %edi, %edi
242 xorl %esi, %esi
243 jmp 1f
244
2450: /* top, read another word for the indirection page */
246
247 movq (%rbx), %rcx
248 addq $8, %rbx
2491:
250 testb $0x1, %cl /* is it a destination page? */
251 jz 2f
252 movq %rcx, %rdi
253 andq $0xfffffffffffff000, %rdi
254 jmp 0b
2552:
256 testb $0x2, %cl /* is it an indirection page? */
257 jz 2f
258 movq %rcx, %rbx
259 andq $0xfffffffffffff000, %rbx
260 jmp 0b
2612:
262 testb $0x4, %cl /* is it the done indicator? */
263 jz 2f
264 jmp 3f
2652:
266 testb $0x8, %cl /* is it the source indicator? */
267 jz 0b /* Ignore it otherwise */
268 movq %rcx, %rsi /* For ever source page do a copy */
269 andq $0xfffffffffffff000, %rsi
270
271 movq %rdi, %rdx
272 movq %rsi, %rax
273
274 movq %r10, %rdi
275 movl $512, %ecx
276 rep ; movsq
277
278 movq %rax, %rdi
279 movq %rdx, %rsi
280 movl $512, %ecx
281 rep ; movsq
282
283 movq %rdx, %rdi
284 movq %r10, %rsi
285 movl $512, %ecx
286 rep ; movsq
287
288 lea PAGE_SIZE(%rax), %rsi
289 jmp 0b
2903:
291 ret
292SYM_CODE_END(swap_pages)
293
294 .globl kexec_control_code_size
295.set kexec_control_code_size, . - relocate_kernel