1 /* $NetBSD: prekern.c,v 1.6 2022/08/21 14:05:52 mlelstv Exp $ */
2
3 /*
4 * Copyright (c) 2017 The NetBSD Foundation, Inc. All rights reserved.
5 *
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Maxime Villard.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32
33 #include "opt_realmem.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/cpu.h>
39 #include <sys/conf.h>
40
41 #include <uvm/uvm.h>
42 #include <machine/pmap.h>
43 #include <machine/pmap_private.h>
44 #include <machine/bootinfo.h>
45 #include <machine/cpufunc.h>
46
47 #include <x86/bootspace.h>
48
49 #include <dev/isa/isareg.h>
50 #include <machine/isa_machdep.h>
51
52 #define PREKERN_API_VERSION 2
53
54 struct prekern_args {
55 int version;
56 int boothowto;
57 void *bootinfo;
58 void *bootspace;
59 int esym;
60 int biosextmem;
61 int biosbasemem;
62 int cpuid_level;
63 uint32_t nox_flag;
64 uint64_t PDPpaddr;
65 vaddr_t atdevbase;
66 vaddr_t lwp0uarea;
67 paddr_t first_avail;
68 };
69
70 void main(void);
71 void init_slotspace(void);
72 void init_x86_64(paddr_t);
73
74 static void prekern_copy_args(struct prekern_args *);
75 static void prekern_unmap(void);
76 int start_prekern(struct prekern_args *);
77
78 static void
prekern_copy_args(struct prekern_args * pkargs)79 prekern_copy_args(struct prekern_args *pkargs)
80 {
81 extern int boothowto;
82 extern struct bootinfo bootinfo;
83 extern struct bootspace bootspace;
84 extern int esym;
85 extern int biosextmem;
86 extern int biosbasemem;
87 extern int cpuid_level;
88 extern uint32_t nox_flag;
89 extern uint64_t PDPpaddr;
90 extern vaddr_t lwp0uarea;
91
92 boothowto = pkargs->boothowto;
93 memcpy(&bootinfo, pkargs->bootinfo, sizeof(bootinfo));
94 memcpy(&bootspace, pkargs->bootspace, sizeof(bootspace));
95 esym = pkargs->esym;
96
97 #ifndef REALEXTMEM
98 biosextmem = pkargs->biosextmem;
99 #else
100 biosextmem = REALEXTMEM;
101 #endif
102
103 #ifndef REALBASEMEM
104 biosbasemem = pkargs->biosbasemem;
105 #else
106 biosbasemem = REALBASEMEM;
107 #endif
108
109 cpuid_level = pkargs->cpuid_level;
110 nox_flag = pkargs->nox_flag;
111 PDPpaddr = pkargs->PDPpaddr;
112 atdevbase = pkargs->atdevbase;
113 lwp0uarea = pkargs->lwp0uarea;
114 }
115
116 static void
prekern_unmap_pte(void)117 prekern_unmap_pte(void)
118 {
119 extern struct bootspace bootspace;
120 pd_entry_t *pdir = (pd_entry_t *)bootspace.pdir;
121
122 /* Unmap the prekern recursive PTE slot. */
123 pdir[509] = 0;
124 tlbflushg();
125 }
126
127 static void
prekern_unmap(void)128 prekern_unmap(void)
129 {
130 /* Unmap the prekern itself. */
131 L4_BASE[0] = 0;
132 tlbflushg();
133 }
134
135 /*
136 * The prekern jumps here.
137 */
138 int
start_prekern(struct prekern_args * pkargs)139 start_prekern(struct prekern_args *pkargs)
140 {
141 paddr_t first_avail;
142
143 if (pkargs->version != PREKERN_API_VERSION) {
144 return -1;
145 }
146
147 prekern_copy_args(pkargs);
148 first_avail = pkargs->first_avail;
149
150 prekern_unmap_pte();
151 init_slotspace();
152 init_x86_64(first_avail);
153 prekern_unmap();
154
155 main();
156
157 panic("main returned");
158
159 return 0;
160 }
161