1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Kernel module loader for Hexagon |
4 | * |
5 | * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
6 | */ |
7 | |
8 | #include <asm/module.h> |
9 | #include <linux/elf.h> |
10 | #include <linux/module.h> |
11 | #include <linux/moduleloader.h> |
12 | #include <linux/vmalloc.h> |
13 | |
14 | #if 0 |
15 | #define DEBUGP printk |
16 | #else |
17 | #define DEBUGP(fmt , ...) |
18 | #endif |
19 | |
20 | /* |
21 | * module_frob_arch_sections - tweak got/plt sections. |
22 | * @hdr - pointer to elf header |
23 | * @sechdrs - pointer to elf load section headers |
24 | * @secstrings - symbol names |
25 | * @mod - pointer to module |
26 | */ |
27 | int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, |
28 | char *secstrings, |
29 | struct module *mod) |
30 | { |
31 | unsigned int i; |
32 | int found = 0; |
33 | |
34 | /* Look for .plt and/or .got.plt and/or .init.plt sections */ |
35 | for (i = 0; i < hdr->e_shnum; i++) { |
36 | DEBUGP("Section %d is %s\n" , i, |
37 | secstrings + sechdrs[i].sh_name); |
38 | if (strcmp(secstrings + sechdrs[i].sh_name, ".plt" ) == 0) |
39 | found = i+1; |
40 | if (strcmp(secstrings + sechdrs[i].sh_name, ".got.plt" ) == 0) |
41 | found = i+1; |
42 | if (strcmp(secstrings + sechdrs[i].sh_name, ".rela.plt" ) == 0) |
43 | found = i+1; |
44 | } |
45 | |
46 | /* At this time, we don't support modules comiled with -shared */ |
47 | if (found) { |
48 | printk(KERN_WARNING |
49 | "Module '%s' contains unexpected .plt/.got sections.\n" , |
50 | mod->name); |
51 | /* return -ENOEXEC; */ |
52 | } |
53 | |
54 | return 0; |
55 | } |
56 | |
57 | /* |
58 | * apply_relocate_add - perform rela relocations. |
59 | * @sechdrs - pointer to section headers |
60 | * @strtab - some sort of start address? |
61 | * @symindex - symbol index offset or something? |
62 | * @relsec - address to relocate to? |
63 | * @module - pointer to module |
64 | * |
65 | * Perform rela relocations. |
66 | */ |
67 | int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, |
68 | unsigned int symindex, unsigned int relsec, |
69 | struct module *module) |
70 | { |
71 | unsigned int i; |
72 | Elf32_Sym *sym; |
73 | uint32_t *location; |
74 | uint32_t value; |
75 | unsigned int nrelocs = sechdrs[relsec].sh_size / sizeof(Elf32_Rela); |
76 | Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; |
77 | Elf32_Word sym_info = sechdrs[relsec].sh_info; |
78 | Elf32_Sym *sym_base = (Elf32_Sym *) sechdrs[symindex].sh_addr; |
79 | void *loc_base = (void *) sechdrs[sym_info].sh_addr; |
80 | |
81 | DEBUGP("Applying relocations in section %u to section %u base=%p\n" , |
82 | relsec, sym_info, loc_base); |
83 | |
84 | for (i = 0; i < nrelocs; i++) { |
85 | |
86 | /* Symbol to relocate */ |
87 | sym = sym_base + ELF32_R_SYM(rela[i].r_info); |
88 | |
89 | /* Where to make the change */ |
90 | location = loc_base + rela[i].r_offset; |
91 | |
92 | /* `Everything is relative'. */ |
93 | value = sym->st_value + rela[i].r_addend; |
94 | |
95 | DEBUGP("%d: value=%08x loc=%p reloc=%d symbol=%s\n" , |
96 | i, value, location, ELF32_R_TYPE(rela[i].r_info), |
97 | sym->st_name ? |
98 | &strtab[sym->st_name] : "(anonymous)" ); |
99 | |
100 | switch (ELF32_R_TYPE(rela[i].r_info)) { |
101 | case R_HEXAGON_B22_PCREL: { |
102 | int dist = (int)(value - (uint32_t)location); |
103 | if ((dist < -0x00800000) || |
104 | (dist >= 0x00800000)) { |
105 | printk(KERN_ERR |
106 | "%s: %s: %08x=%08x-%08x %s\n" , |
107 | module->name, |
108 | "R_HEXAGON_B22_PCREL reloc out of range" , |
109 | dist, value, (uint32_t)location, |
110 | sym->st_name ? |
111 | &strtab[sym->st_name] : "(anonymous)" ); |
112 | return -ENOEXEC; |
113 | } |
114 | DEBUGP("B22_PCREL contents: %08X.\n" , *location); |
115 | *location &= ~0x01ff3fff; |
116 | *location |= 0x00003fff & dist; |
117 | *location |= 0x01ff0000 & (dist<<2); |
118 | DEBUGP("Contents after reloc: %08x\n" , *location); |
119 | break; |
120 | } |
121 | case R_HEXAGON_HI16: |
122 | value = (value>>16) & 0xffff; |
123 | fallthrough; |
124 | case R_HEXAGON_LO16: |
125 | *location &= ~0x00c03fff; |
126 | *location |= value & 0x3fff; |
127 | *location |= (value & 0xc000) << 8; |
128 | break; |
129 | case R_HEXAGON_32: |
130 | *location = value; |
131 | break; |
132 | case R_HEXAGON_32_PCREL: |
133 | *location = value - (uint32_t)location; |
134 | break; |
135 | case R_HEXAGON_PLT_B22_PCREL: |
136 | case R_HEXAGON_GOTOFF_LO16: |
137 | case R_HEXAGON_GOTOFF_HI16: |
138 | printk(KERN_ERR "%s: GOT/PLT relocations unsupported\n" , |
139 | module->name); |
140 | return -ENOEXEC; |
141 | default: |
142 | printk(KERN_ERR "%s: unknown relocation: %u\n" , |
143 | module->name, |
144 | ELF32_R_TYPE(rela[i].r_info)); |
145 | return -ENOEXEC; |
146 | } |
147 | } |
148 | return 0; |
149 | } |
150 | |