1 /*-
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #define __ELF_WORD_SIZE 64
28 #include <sys/param.h>
29 #include <sys/exec.h>
30 #include <sys/linker.h>
31 #ifdef DEBUG
32 #include <machine/_inttypes.h>
33 #endif
34 #include <vm/vm.h>
35 #include <vm/pmap.h>
36 #include <machine/elf.h>
37 #include <machine/segments.h>
38 #include <stand.h>
39
40 #include "bootstrap.h"
41 #include "libuserboot.h"
42
43 static int elf64_exec(struct preloaded_file *amp);
44 static int elf64_obj_exec(struct preloaded_file *amp);
45
46 struct file_format amd64_elf = { elf64_loadfile, elf64_exec };
47 struct file_format amd64_elf_obj = { elf64_obj_loadfile, elf64_obj_exec };
48
49 #define GUEST_NULL_SEL 0
50 #define GUEST_CODE_SEL 1
51 #define GUEST_DATA_SEL 2
52 #define GUEST_GDTR_LIMIT (3 * 8 - 1)
53
54 static void
setup_freebsd_gdt(struct user_segment_descriptor * gdt)55 setup_freebsd_gdt(struct user_segment_descriptor *gdt)
56 {
57 gdt[GUEST_NULL_SEL] = (struct user_segment_descriptor) { 0 };
58 gdt[GUEST_CODE_SEL] = (struct user_segment_descriptor) {
59 .sd_p = 1, .sd_long = 1, .sd_type = SDT_MEME
60 };
61 gdt[GUEST_DATA_SEL] = (struct user_segment_descriptor) {
62 .sd_p = 1, .sd_type = SDT_MEMRO
63 };
64 }
65
66 /*
67 * There is an ELF kernel and one or more ELF modules loaded.
68 * We wish to start executing the kernel image, so make such
69 * preparations as are required, and do so.
70 */
71 static int
elf64_exec(struct preloaded_file * fp)72 elf64_exec(struct preloaded_file *fp)
73 {
74 struct file_metadata *md;
75 Elf_Ehdr *ehdr;
76 vm_offset_t modulep, kernend;
77 int err;
78 int i;
79 uint32_t stack[1024];
80 pml4_entry_t PT4[512];
81 pdp_entry_t PT3[512];
82 pd_entry_t PT2[512];
83 struct user_segment_descriptor gdt[3];
84
85 if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL)
86 return(EFTYPE);
87 ehdr = (Elf_Ehdr *)&(md->md_data);
88
89 err = bi_load64(fp->f_args, &modulep, &kernend);
90 if (err != 0)
91 return(err);
92
93 bzero(PT4, PAGE_SIZE);
94 bzero(PT3, PAGE_SIZE);
95 bzero(PT2, PAGE_SIZE);
96
97 /*
98 * Build a scratch stack at physical 0x1000, page tables:
99 * PT4 at 0x2000,
100 * PT3 at 0x3000,
101 * PT2 at 0x4000,
102 * gdtr at 0x5000,
103 */
104
105 /*
106 * This is kinda brutal, but every single 1GB VM memory segment
107 * points to the same first 1GB of physical memory. But it is
108 * more than adequate.
109 */
110 for (i = 0; i < 512; i++) {
111 /* Each slot of the level 4 pages points to the same level 3 page */
112 PT4[i] = (pml4_entry_t) 0x3000;
113 PT4[i] |= PG_V | PG_RW;
114
115 /* Each slot of the level 3 pages points to the same level 2 page */
116 PT3[i] = (pdp_entry_t) 0x4000;
117 PT3[i] |= PG_V | PG_RW;
118
119 /* The level 2 page slots are mapped with 2MB pages for 1GB. */
120 PT2[i] = i * (2 * 1024 * 1024);
121 PT2[i] |= PG_V | PG_RW | PG_PS;
122 }
123
124 #ifdef DEBUG
125 printf("Start @ %#"PRIx64" ...\n", ehdr->e_entry);
126 #endif
127
128 dev_cleanup();
129
130 stack[0] = 0; /* return address */
131 stack[1] = modulep;
132 stack[2] = kernend;
133 CALLBACK(copyin, stack, 0x1000, sizeof(stack));
134 CALLBACK(copyin, PT4, 0x2000, sizeof(PT4));
135 CALLBACK(copyin, PT3, 0x3000, sizeof(PT3));
136 CALLBACK(copyin, PT2, 0x4000, sizeof(PT2));
137 CALLBACK(setreg, 4, 0x1000);
138
139 CALLBACK(setmsr, MSR_EFER, EFER_LMA | EFER_LME);
140 CALLBACK(setcr, 4, CR4_PAE | CR4_VMXE);
141 CALLBACK(setcr, 3, 0x2000);
142 CALLBACK(setcr, 0, CR0_PG | CR0_PE | CR0_NE);
143
144 setup_freebsd_gdt(gdt);
145 CALLBACK(copyin, gdt, 0x5000, sizeof(gdt));
146 CALLBACK(setgdt, 0x5000, sizeof(gdt));
147
148 CALLBACK(exec, ehdr->e_entry);
149
150 panic("exec returned");
151 }
152
153 static int
elf64_obj_exec(struct preloaded_file * fp)154 elf64_obj_exec(struct preloaded_file *fp)
155 {
156
157 return (EFTYPE);
158 }
159