1 /*
2 * Copyright (c) 2021 - 2022, Intel Corporation.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Intel Corporation nor the names of its
15 * contributors may be used to endorse or promote products
16 * derived from this software without specific prior written
17 * permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
25 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
26 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
28 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
30 * OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include <elf.h>
34 #include <stdint.h>
35 #include "stdlib.h"
36 #include "boot.h"
37
38 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
39 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
40
41
42 /**
43 * @brief Load elf pointed by ehdr, linked at link_addr, to load_addr.
44 *
45 * @param[in] ehdr A pointer to target ELF header.
46 * @param[in] load_addr The address to which the image will be loaded.
47 * @param[in] link_addr The address to which the image was linked.
48 *
49 * @return 0 on success, -1 on error.
50 */
elf_load(Elf32_Ehdr * ehdr,uint64_t load_addr,uint64_t link_addr)51 int elf_load(Elf32_Ehdr *ehdr, uint64_t load_addr, uint64_t link_addr)
52 {
53 int i;
54 uint64_t addr;
55 Elf32_Phdr *phdr;
56 Elf32_Phdr *pbase = (Elf32_Phdr *)((char *)ehdr + ehdr->e_phoff);
57
58 for (i = 0; i < ehdr->e_phnum; i++) {
59 phdr = (Elf32_Phdr *)((char *)pbase + i * ehdr->e_phentsize);
60 if ((phdr->p_type != PT_LOAD) || (phdr->p_memsz == 0) || (phdr->p_offset == 0)) {
61 continue;
62 }
63
64 if (phdr->p_filesz > phdr->p_memsz) {
65 return -1;
66 }
67
68 addr = (uint64_t)(load_addr + (phdr->p_paddr - link_addr));
69 memcpy((char *)addr, (const char *)((char *)ehdr + phdr->p_offset), phdr->p_filesz);
70
71 if (phdr->p_memsz > phdr->p_filesz) {
72 addr = (uint64_t)(load_addr + (phdr->p_paddr - link_addr + phdr->p_filesz));
73 (void)memset((void *)addr, 0x0, (phdr->p_memsz - phdr->p_filesz));
74 }
75 }
76
77 return 0;
78 }
79
80 /**
81 * @brief Calculate link address range of the elf image.
82 *
83 * @param[in] ehdr A pointer to target ELF header.
84 * @param[out] link_addr_low The lowest link address of all loadable section in ELF.
85 * @param[out] link_addr_high The highest reachable link address (link address plus memory size of that section) of all
86 * loadable section in ELF.
87 *
88 * @return 0 on success, -1 on error.
89 */
elf_calc_link_addr_range(Elf32_Ehdr * ehdr,uint64_t * link_addr_low,uint64_t * link_addr_high)90 int elf_calc_link_addr_range(Elf32_Ehdr *ehdr, uint64_t *link_addr_low, uint64_t *link_addr_high)
91 {
92 Elf32_Phdr *phdr;
93 Elf32_Phdr *pbase = (Elf32_Phdr *)((char *)ehdr + ehdr->e_phoff);
94
95 int i;
96 uint64_t ram_low = ~0;
97 uint64_t ram_high = 0;
98
99 for (i = 0; i < ehdr->e_phnum; i++) {
100 phdr = (Elf32_Phdr *)((char *)pbase + i * ehdr->e_phentsize);
101 if (phdr->p_type != PT_LOAD)
102 continue;
103
104 ram_low = MIN(ram_low, phdr->p_paddr);
105 ram_high = MAX(ram_high, ALIGN_UP(phdr->p_paddr + phdr->p_memsz, phdr->p_align));
106 }
107
108 *link_addr_low = ram_low;
109 *link_addr_high = ram_high;
110
111 return 0;
112 }
113
114 /**
115 * @brief Get entry point of ELF image.
116 *
117 * @param[in] ehdr A pointer to target ELF header.
118 *
119 * @return Entry point address of ELF image.
120 */
elf_get_entry(Elf32_Ehdr * ehdr)121 uint32_t elf_get_entry(Elf32_Ehdr *ehdr)
122 {
123 return ehdr->e_entry;
124 }
125
126 /**
127 * @brief Validate ELF header.
128 *
129 * @param[in] ehdr A pointer to target ELF header.
130 *
131 * @return 0 on success (valid elf), -1 on error.
132 */
validate_elf_header(Elf32_Ehdr * ehdr)133 int validate_elf_header(Elf32_Ehdr *ehdr)
134 {
135 if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
136 ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
137 ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
138 ehdr->e_ident[EI_MAG3] != ELFMAG3 ||
139 ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
140 Print(L"Image is not a valid arch-independent ELF\n");
141 return -1;
142 }
143
144 if (ehdr->e_ident[EI_CLASS] != ELFCLASS32 ||
145 ehdr->e_machine != EM_386 ||
146 ehdr->e_version != EV_CURRENT) {
147 Print(L"Image is not a valid arch-dependent ELF\n");
148 return -1;
149 }
150
151 if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
152 Print(L"This ELF is not of the right type\n");
153 return -1;
154 }
155
156 return 0;
157 }
158