cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

genvdso.h (3278B)

      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}