1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2015 Imagination Technologies
4 * Author: Alex Smith <alex.smith@imgtec.com>
5 */
6
7static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
8{
9	const ELF(Ehdr) *ehdr = vdso;
10	void *shdrs;
11	ELF(Shdr) *shdr;
12	char *shstrtab, *name;
13	uint16_t sh_count, sh_entsize, i;
14
15	shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
16	sh_count = swap_uint16(ehdr->e_shnum);
17	sh_entsize = swap_uint16(ehdr->e_shentsize);
18
19	shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
20	shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
21
22	for (i = 0; i < sh_count; i++) {
23		shdr = shdrs + (i * sh_entsize);
24		name = shstrtab + swap_uint32(shdr->sh_name);
25
26		/*
27		 * Ensure there are no relocation sections - ld.so does not
28		 * relocate the VDSO so if there are relocations things will
29		 * break.
30		 */
31		switch (swap_uint32(shdr->sh_type)) {
32		case SHT_REL:
33		case SHT_RELA:
34			fprintf(stderr,
35				"%s: '%s' contains relocation sections\n",
36				program_name, path);
37			return false;
38		}
39
40		/* Check for existing sections. */
41		if (strcmp(name, ".MIPS.abiflags") == 0) {
42			fprintf(stderr,
43				"%s: '%s' already contains a '.MIPS.abiflags' section\n",
44				program_name, path);
45			return false;
46		}
47
48		if (strcmp(name, ".mips_abiflags") == 0) {
49			strcpy(name, ".MIPS.abiflags");
50			shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS);
51			shdr->sh_entsize = shdr->sh_size;
52		}
53	}
54
55	return true;
56}
57
58static inline bool FUNC(get_symbols)(const char *path, void *vdso)
59{
60	const ELF(Ehdr) *ehdr = vdso;
61	void *shdrs, *symtab;
62	ELF(Shdr) *shdr;
63	const ELF(Sym) *sym;
64	char *strtab, *name;
65	uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
66	uint64_t offset;
67	uint32_t flags;
68
69	shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
70	sh_count = swap_uint16(ehdr->e_shnum);
71	sh_entsize = swap_uint16(ehdr->e_shentsize);
72
73	for (i = 0; i < sh_count; i++) {
74		shdr = shdrs + (i * sh_entsize);
75
76		if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
77			break;
78	}
79
80	if (i == sh_count) {
81		fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
82			path);
83		return false;
84	}
85
86	/* Get flags */
87	flags = swap_uint32(ehdr->e_flags);
88	if (elf_class == ELFCLASS64)
89		elf_abi = ABI_N64;
90	else if (flags & EF_MIPS_ABI2)
91		elf_abi = ABI_N32;
92	else
93		elf_abi = ABI_O32;
94
95	/* Get symbol table. */
96	symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
97	st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
98	st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
99
100	/* Get string table. */
101	shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
102	strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
103
104	/* Write offsets for symbols needed by the kernel. */
105	for (i = 0; vdso_symbols[i].name; i++) {
106		if (!(vdso_symbols[i].abis & elf_abi))
107			continue;
108
109		for (j = 0; j < st_count; j++) {
110			sym = symtab + (j * st_entsize);
111			name = strtab + swap_uint32(sym->st_name);
112
113			if (!strcmp(name, vdso_symbols[i].name)) {
114				offset = FUNC(swap_uint)(sym->st_value);
115
116				fprintf(out_file,
117					"\t.%s = 0x%" PRIx64 ",\n",
118					vdso_symbols[i].offset_name, offset);
119				break;
120			}
121		}
122
123		if (j == st_count) {
124			fprintf(stderr,
125				"%s: '%s' is missing required symbol '%s'\n",
126				program_name, path, vdso_symbols[i].name);
127			return false;
128		}
129	}
130
131	return true;
132}
133