1/*
2 * relocate_kernel.S - put the kernel image in place to boot
3 * Copyright (C) 2002-2004 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.h>
11#include <asm/kexec.h>
12
13/*
14 * Must be relocatable PIC code callable as a C function
15 */
16
17#define PTR(x) (x << 2)
18#define PAGE_ALIGNED (1 << PAGE_SHIFT)
19#define PAGE_ATTR 0x63 /* _PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY */
20#define PAE_PGD_ATTR 0x01 /* _PAGE_PRESENT */
21
22	.text
23	.align PAGE_ALIGNED
24	.globl relocate_kernel
25relocate_kernel:
26	movl	8(%esp), %ebp /* list of pages */
27
28#ifdef CONFIG_X86_PAE
29	/* map the control page at its virtual address */
30
31	movl	PTR(VA_PGD)(%ebp), %edi
32	movl	PTR(VA_CONTROL_PAGE)(%ebp), %eax
33	andl	$0xc0000000, %eax
34	shrl	$27, %eax
35	addl	%edi, %eax
36
37	movl	PTR(PA_PMD_0)(%ebp), %edx
38	orl	$PAE_PGD_ATTR, %edx
39	movl	%edx, (%eax)
40
41	movl	PTR(VA_PMD_0)(%ebp), %edi
42	movl	PTR(VA_CONTROL_PAGE)(%ebp), %eax
43	andl	$0x3fe00000, %eax
44	shrl	$18, %eax
45	addl	%edi, %eax
46
47	movl	PTR(PA_PTE_0)(%ebp), %edx
48	orl	$PAGE_ATTR, %edx
49	movl	%edx, (%eax)
50
51	movl	PTR(VA_PTE_0)(%ebp), %edi
52	movl	PTR(VA_CONTROL_PAGE)(%ebp), %eax
53	andl	$0x001ff000, %eax
54	shrl	$9, %eax
55	addl	%edi, %eax
56
57	movl	PTR(PA_CONTROL_PAGE)(%ebp), %edx
58	orl	$PAGE_ATTR, %edx
59	movl	%edx, (%eax)
60
61	/* identity map the control page at its physical address */
62
63	movl	PTR(VA_PGD)(%ebp), %edi
64	movl	PTR(PA_CONTROL_PAGE)(%ebp), %eax
65	andl	$0xc0000000, %eax
66	shrl	$27, %eax
67	addl	%edi, %eax
68
69	movl	PTR(PA_PMD_1)(%ebp), %edx
70	orl	$PAE_PGD_ATTR, %edx
71	movl	%edx, (%eax)
72
73	movl	PTR(VA_PMD_1)(%ebp), %edi
74	movl	PTR(PA_CONTROL_PAGE)(%ebp), %eax
75	andl	$0x3fe00000, %eax
76	shrl	$18, %eax
77	addl	%edi, %eax
78
79	movl	PTR(PA_PTE_1)(%ebp), %edx
80	orl	$PAGE_ATTR, %edx
81	movl	%edx, (%eax)
82
83	movl	PTR(VA_PTE_1)(%ebp), %edi
84	movl	PTR(PA_CONTROL_PAGE)(%ebp), %eax
85	andl	$0x001ff000, %eax
86	shrl	$9, %eax
87	addl	%edi, %eax
88
89	movl	PTR(PA_CONTROL_PAGE)(%ebp), %edx
90	orl	$PAGE_ATTR, %edx
91	movl	%edx, (%eax)
92#else
93	/* map the control page at its virtual address */
94
95	movl	PTR(VA_PGD)(%ebp), %edi
96	movl	PTR(VA_CONTROL_PAGE)(%ebp), %eax
97	andl	$0xffc00000, %eax
98	shrl	$20, %eax
99	addl	%edi, %eax
100
101	movl	PTR(PA_PTE_0)(%ebp), %edx
102	orl	$PAGE_ATTR, %edx
103	movl	%edx, (%eax)
104
105	movl	PTR(VA_PTE_0)(%ebp), %edi
106	movl	PTR(VA_CONTROL_PAGE)(%ebp), %eax
107	andl	$0x003ff000, %eax
108	shrl	$10, %eax
109	addl	%edi, %eax
110
111	movl	PTR(PA_CONTROL_PAGE)(%ebp), %edx
112	orl	$PAGE_ATTR, %edx
113	movl	%edx, (%eax)
114
115	/* identity map the control page at its physical address */
116
117	movl	PTR(VA_PGD)(%ebp), %edi
118	movl	PTR(PA_CONTROL_PAGE)(%ebp), %eax
119	andl	$0xffc00000, %eax
120	shrl	$20, %eax
121	addl	%edi, %eax
122
123	movl	PTR(PA_PTE_1)(%ebp), %edx
124	orl	$PAGE_ATTR, %edx
125	movl	%edx, (%eax)
126
127	movl	PTR(VA_PTE_1)(%ebp), %edi
128	movl	PTR(PA_CONTROL_PAGE)(%ebp), %eax
129	andl	$0x003ff000, %eax
130	shrl	$10, %eax
131	addl	%edi, %eax
132
133	movl	PTR(PA_CONTROL_PAGE)(%ebp), %edx
134	orl	$PAGE_ATTR, %edx
135	movl	%edx, (%eax)
136#endif
137
138relocate_new_kernel:
139	/* read the arguments and say goodbye to the stack */
140	movl  4(%esp), %ebx /* page_list */
141	movl  8(%esp), %ebp /* list of pages */
142	movl  12(%esp), %edx /* start address */
143	movl  16(%esp), %ecx /* cpu_has_pae */
144
145	/* zero out flags, and disable interrupts */
146	pushl $0
147	popfl
148
149	/* get physical address of control page now */
150	/* this is impossible after page table switch */
151	movl	PTR(PA_CONTROL_PAGE)(%ebp), %edi
152
153	/* switch to new set of page tables */
154	movl	PTR(PA_PGD)(%ebp), %eax
155	movl	%eax, %cr3
156
157	/* setup a new stack at the end of the physical control page */
158	lea	4096(%edi), %esp
159
160	/* jump to identity mapped page */
161	movl    %edi, %eax
162	addl    $(identity_mapped - relocate_kernel), %eax
163	pushl   %eax
164	ret
165
166identity_mapped:
167	/* store the start address on the stack */
168	pushl   %edx
169
170	/* Set cr0 to a known state:
171	 * 31 0 == Paging disabled
172	 * 18 0 == Alignment check disabled
173	 * 16 0 == Write protect disabled
174	 * 3  0 == No task switch
175	 * 2  0 == Don't do FP software emulation.
176	 * 0  1 == Proctected mode enabled
177	 */
178	movl	%cr0, %eax
179	andl	$~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
180	orl	$(1<<0), %eax
181	movl	%eax, %cr0
182
183	/* clear cr4 if applicable */
184	testl	%ecx, %ecx
185	jz	1f
186	/* Set cr4 to a known state:
187	 * Setting everything to zero seems safe.
188	 */
189	movl	%cr4, %eax
190	andl	$0, %eax
191	movl	%eax, %cr4
192
193	jmp 1f
1941:
195
196	/* Flush the TLB (needed?) */
197	xorl	%eax, %eax
198	movl	%eax, %cr3
199
200	/* Do the copies */
201	movl	%ebx, %ecx
202	jmp	1f
203
2040:	/* top, read another word from the indirection page */
205	movl	(%ebx), %ecx
206	addl	$4, %ebx
2071:
208	testl	$0x1,   %ecx  /* is it a destination page */
209	jz	2f
210	movl	%ecx,	%edi
211	andl	$0xfffff000, %edi
212	jmp     0b
2132:
214	testl	$0x2,	%ecx  /* is it an indirection page */
215	jz	2f
216	movl	%ecx,	%ebx
217	andl	$0xfffff000, %ebx
218	jmp     0b
2192:
220	testl   $0x4,   %ecx /* is it the done indicator */
221	jz      2f
222	jmp     3f
2232:
224	testl   $0x8,   %ecx /* is it the source indicator */
225	jz      0b	     /* Ignore it otherwise */
226	movl    %ecx,   %esi /* For every source page do a copy */
227	andl    $0xfffff000, %esi
228
229	movl    $1024, %ecx
230	rep ; movsl
231	jmp     0b
232
2333:
234
235	/* To be certain of avoiding problems with self-modifying code
236	 * I need to execute a serializing instruction here.
237	 * So I flush the TLB, it's handy, and not processor dependent.
238	 */
239	xorl	%eax, %eax
240	movl	%eax, %cr3
241
242	/* set all of the registers to known values */
243	/* leave %esp alone */
244
245	xorl	%eax, %eax
246	xorl	%ebx, %ebx
247	xorl    %ecx, %ecx
248	xorl    %edx, %edx
249	xorl    %esi, %esi
250	xorl    %edi, %edi
251	xorl    %ebp, %ebp
252	ret
253