cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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vdso2c.h (4135B)

      1/*
      2 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
      3 */
      4
      5/*
      6 * This file is included up to twice from vdso2c.c.  It generates code for
      7 * 32-bit and 64-bit vDSOs.  We will eventually need both for 64-bit builds,
      8 * since 32-bit vDSOs will then be built for 32-bit userspace.
      9 */
     10
     11static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
     12			 void *stripped_addr, size_t stripped_len,
     13			 FILE *outfile, const char *name)
     14{
     15	int found_load = 0;
     16	unsigned long load_size = -1;  /* Work around bogus warning */
     17	unsigned long mapping_size;
     18	int i;
     19	unsigned long j;
     20	ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr;
     21	ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
     22	ELF(Dyn) *dyn = 0, *dyn_end = 0;
     23	INT_BITS syms[NSYMS] = {};
     24
     25	ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
     26
     27	/* Walk the segment table. */
     28	for (i = 0; i < GET_BE(&hdr->e_phnum); i++) {
     29		if (GET_BE(&pt[i].p_type) == PT_LOAD) {
     30			if (found_load)
     31				fail("multiple PT_LOAD segs\n");
     32
     33			if (GET_BE(&pt[i].p_offset) != 0 ||
     34			    GET_BE(&pt[i].p_vaddr) != 0)
     35				fail("PT_LOAD in wrong place\n");
     36
     37			if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz))
     38				fail("cannot handle memsz != filesz\n");
     39
     40			load_size = GET_BE(&pt[i].p_memsz);
     41			found_load = 1;
     42		} else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) {
     43			dyn = raw_addr + GET_BE(&pt[i].p_offset);
     44			dyn_end = raw_addr + GET_BE(&pt[i].p_offset) +
     45				GET_BE(&pt[i].p_memsz);
     46		}
     47	}
     48	if (!found_load)
     49		fail("no PT_LOAD seg\n");
     50
     51	if (stripped_len < load_size)
     52		fail("stripped input is too short\n");
     53
     54	/* Walk the dynamic table */
     55	for (i = 0; dyn + i < dyn_end &&
     56		     GET_BE(&dyn[i].d_tag) != DT_NULL; i++) {
     57		typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag);
     58		typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val);
     59
     60		if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0))
     61			fail("vdso image contains dynamic relocations\n");
     62	}
     63
     64	/* Walk the section table */
     65	for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
     66		ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
     67			GET_BE(&hdr->e_shentsize) * i;
     68		if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
     69			symtab_hdr = sh;
     70	}
     71
     72	if (!symtab_hdr)
     73		fail("no symbol table\n");
     74
     75	strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
     76		GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link);
     77
     78	/* Walk the symbol table */
     79	for (i = 0;
     80	     i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize);
     81	     i++) {
     82		int k;
     83
     84		ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) +
     85			GET_BE(&symtab_hdr->sh_entsize) * i;
     86		const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) +
     87			GET_BE(&sym->st_name);
     88
     89		for (k = 0; k < NSYMS; k++) {
     90			if (!strcmp(name, required_syms[k].name)) {
     91				if (syms[k]) {
     92					fail("duplicate symbol %s\n",
     93					     required_syms[k].name);
     94				}
     95
     96				/*
     97				 * Careful: we use negative addresses, but
     98				 * st_value is unsigned, so we rely
     99				 * on syms[k] being a signed type of the
    100				 * correct width.
    101				 */
    102				syms[k] = GET_BE(&sym->st_value);
    103			}
    104		}
    105	}
    106
    107	/* Validate mapping addresses. */
    108	if (syms[sym_vvar_start] % 8192)
    109		fail("vvar_begin must be a multiple of 8192\n");
    110
    111	if (!name) {
    112		fwrite(stripped_addr, stripped_len, 1, outfile);
    113		return;
    114	}
    115
    116	mapping_size = (stripped_len + 8191) / 8192 * 8192;
    117
    118	fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
    119	fprintf(outfile, "#include <linux/cache.h>\n");
    120	fprintf(outfile, "#include <asm/vdso.h>\n");
    121	fprintf(outfile, "\n");
    122	fprintf(outfile,
    123		"static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {",
    124		mapping_size);
    125	for (j = 0; j < stripped_len; j++) {
    126		if (j % 10 == 0)
    127			fprintf(outfile, "\n\t");
    128		fprintf(outfile, "0x%02X, ",
    129			(int)((unsigned char *)stripped_addr)[j]);
    130	}
    131	fprintf(outfile, "\n};\n\n");
    132
    133	fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
    134	fprintf(outfile, "\t.data = raw_data,\n");
    135	fprintf(outfile, "\t.size = %lu,\n", mapping_size);
    136	for (i = 0; i < NSYMS; i++) {
    137		if (required_syms[i].export && syms[i])
    138			fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
    139				required_syms[i].name, (int64_t)syms[i]);
    140	}
    141	fprintf(outfile, "};\n");
    142}