1 /*
2 * 32bitbios_support.c - relocation of 32bit BIOS implementation
3 *
4 * Stefan Berger, stefanb@us.ibm.com
5 * Copyright (c) 2006, International Business Machines Corporation.
6 *
7 * Keir Fraser, keir@xensource.com
8 * Copyright (c) 2007, XenSource Inc.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms and conditions of the GNU General Public License,
12 * version 2, as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 *
19 * You should have received a copy of the GNU General Public License along with
20 * this program; If not, see <http://www.gnu.org/licenses/>.
21 */
22
23 #include <inttypes.h>
24 #include <elf.h>
25 #ifdef __sun__
26 #include <sys/machelf.h>
27 #endif
28
29 #include "util.h"
30 #include "config.h"
31
32 #include "../rombios/32bit/32bitbios_flat.h"
33
relocate_32bitbios(char * elfarray,uint32_t elfarraysize)34 static uint32_t relocate_32bitbios(char *elfarray, uint32_t elfarraysize)
35 {
36 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfarray;
37 Elf32_Shdr *shdr = (Elf32_Shdr *)&elfarray[ehdr->e_shoff];
38 uint32_t reloc_off, reloc_size;
39 char *highbiosarea;
40 int i;
41
42 /*
43 * Step 1. General elf cleanup, and compute total relocation size.
44 */
45 reloc_off = 0;
46 for ( i = 0; i < ehdr->e_shnum; i++ )
47 {
48 /* By default all section data points into elf image data array. */
49 shdr[i].sh_addr = (Elf32_Addr)&elfarray[shdr[i].sh_offset];
50
51 /* Fix up a corner case of address alignment. */
52 if ( shdr[i].sh_addralign == 0 )
53 shdr[i].sh_addralign = 1;
54
55 /* Any section which contains run-time data must be relocated. */
56 if ( shdr[i].sh_flags & SHF_ALLOC )
57 {
58 uint32_t mask = shdr[i].sh_addralign - 1;
59 reloc_off = (reloc_off + mask) & ~mask;
60 reloc_off += shdr[i].sh_size;
61 }
62 }
63
64 /*
65 * Step 2. Now we know the relocation size, allocate a chunk of high mem.
66 */
67 reloc_size = reloc_off;
68 printf("%d bytes of ROMBIOS high-memory extensions:\n", reloc_size);
69 highbiosarea = mem_alloc(reloc_size, 1024);
70 BUG_ON(highbiosarea == NULL);
71 printf(" Relocating to 0x%x-0x%x ... ",
72 (uint32_t)&highbiosarea[0],
73 (uint32_t)&highbiosarea[reloc_size]);
74
75 /*
76 * Step 3. Copy run-time data into the newly-allocated high-memory chunk.
77 */
78 reloc_off = 0;
79 for ( i = 0; i < ehdr->e_shnum; i++ )
80 {
81 uint32_t mask = shdr[i].sh_addralign - 1;
82
83 /* Nothing to do for non-run-time sections. */
84 if ( !(shdr[i].sh_flags & SHF_ALLOC) )
85 continue;
86
87 /* Copy from old location. */
88 reloc_off = (reloc_off + mask) & ~mask;
89 if ( shdr[i].sh_type == SHT_NOBITS )
90 memset(&highbiosarea[reloc_off], 0, shdr[i].sh_size);
91 else
92 memcpy(&highbiosarea[reloc_off], (void *)shdr[i].sh_addr,
93 shdr[i].sh_size);
94
95 /* Update address to new location. */
96 shdr[i].sh_addr = (Elf32_Addr)&highbiosarea[reloc_off];
97 reloc_off += shdr[i].sh_size;
98 }
99 BUG_ON(reloc_off != reloc_size);
100
101 /*
102 * Step 4. Perform relocations in high memory.
103 */
104 for ( i = 0; i < ehdr->e_shnum; i++ )
105 {
106 Elf32_Sym *syms, *sym;
107 Elf32_Rel *rels;
108 char *code;
109 uint32_t *loc, fix;
110 int j;
111
112 if ( shdr[i].sh_type == SHT_RELA )
113 printf("Unsupported section type SHT_RELA\n");
114
115 if ( shdr[i].sh_type != SHT_REL )
116 continue;
117
118 syms = (Elf32_Sym *)shdr[shdr[i].sh_link].sh_addr;
119 rels = (Elf32_Rel *)shdr[i].sh_addr;
120 code = (char *)shdr[shdr[i].sh_info].sh_addr;
121
122 for ( j = 0; j < shdr[i].sh_size / sizeof(Elf32_Rel); j++ )
123 {
124 sym = &syms[ELF32_R_SYM(rels[j].r_info)];
125 loc = (uint32_t *)&code[rels[j].r_offset];
126 fix = shdr[sym->st_shndx].sh_addr + sym->st_value;
127
128 switch ( ELF32_R_TYPE(rels[j].r_info) )
129 {
130 case R_386_PC32:
131 *loc += fix - (uint32_t)loc;
132 break;
133
134 case R_386_32:
135 *loc += fix;
136 break;
137 }
138 }
139 }
140
141 printf("done\n");
142
143 return (uint32_t)highbiosarea;
144 }
145
rombios_highbios_setup(void)146 uint32_t rombios_highbios_setup(void)
147 {
148 return relocate_32bitbios((char *)highbios_array, sizeof(highbios_array));
149 }
150
151 /*
152 * Local variables:
153 * mode: C
154 * c-file-style: "BSD"
155 * c-basic-offset: 4
156 * tab-width: 4
157 * indent-tabs-mode: nil
158 * End:
159 */
160