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/*
* Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
*/
/*
* This file is included up to twice from vdso2c.c. It generates code for
* 32-bit and 64-bit vDSOs. We will eventually need both for 64-bit builds,
* since 32-bit vDSOs will then be built for 32-bit userspace.
*/
static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
void *stripped_addr, size_t stripped_len,
FILE *outfile, const char *name)
{
int found_load = 0;
unsigned long load_size = -1; /* Work around bogus warning */
unsigned long mapping_size;
int i;
unsigned long j;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
*patch_sec = NULL;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
ELF(Dyn) *dyn = 0, *dyn_end = 0;
const char *secstrings;
INT_BITS syms[NSYMS] = {};
ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
/* Walk the segment table. */
for (i = 0; i < GET_BE(&hdr->e_phnum); i++) {
if (GET_BE(&pt[i].p_type) == PT_LOAD) {
if (found_load)
fail("multiple PT_LOAD segs\n");
if (GET_BE(&pt[i].p_offset) != 0 ||
GET_BE(&pt[i].p_vaddr) != 0)
fail("PT_LOAD in wrong place\n");
if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz))
fail("cannot handle memsz != filesz\n");
load_size = GET_BE(&pt[i].p_memsz);
found_load = 1;
} else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) {
dyn = raw_addr + GET_BE(&pt[i].p_offset);
dyn_end = raw_addr + GET_BE(&pt[i].p_offset) +
GET_BE(&pt[i].p_memsz);
}
}
if (!found_load)
fail("no PT_LOAD seg\n");
if (stripped_len < load_size)
fail("stripped input is too short\n");
/* Walk the dynamic table */
for (i = 0; dyn + i < dyn_end &&
GET_BE(&dyn[i].d_tag) != DT_NULL; i++) {
typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag);
typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val);
if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0))
fail("vdso image contains dynamic relocations\n");
}
/* Walk the section table */
secstrings_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize)*GET_BE(&hdr->e_shstrndx);
secstrings = raw_addr + GET_BE(&secstrings_hdr->sh_offset);
for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize) * i;
if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
symtab_hdr = sh;
if (!strcmp(secstrings + GET_BE(&sh->sh_name),
".tick_patch"))
patch_sec = sh;
}
if (!symtab_hdr)
fail("no symbol table\n");
strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link);
/* Walk the symbol table */
for (i = 0;
i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize);
i++) {
int k;
ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) +
GET_BE(&symtab_hdr->sh_entsize) * i;
const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) +
GET_BE(&sym->st_name);
for (k = 0; k < NSYMS; k++) {
if (!strcmp(name, required_syms[k].name)) {
if (syms[k]) {
fail("duplicate symbol %s\n",
required_syms[k].name);
}
/*
* Careful: we use negative addresses, but
* st_value is unsigned, so we rely
* on syms[k] being a signed type of the
* correct width.
*/
syms[k] = GET_BE(&sym->st_value);
}
}
}
/* Validate mapping addresses. */
if (syms[sym_vvar_start] % 8192)
fail("vvar_begin must be a multiple of 8192\n");
if (!name) {
fwrite(stripped_addr, stripped_len, 1, outfile);
return;
}
mapping_size = (stripped_len + 8191) / 8192 * 8192;
fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
fprintf(outfile, "#include <linux/cache.h>\n");
fprintf(outfile, "#include <asm/vdso.h>\n");
fprintf(outfile, "\n");
fprintf(outfile,
"static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {",
mapping_size);
for (j = 0; j < stripped_len; j++) {
if (j % 10 == 0)
fprintf(outfile, "\n\t");
fprintf(outfile, "0x%02X, ",
(int)((unsigned char *)stripped_addr)[j]);
}
fprintf(outfile, "\n};\n\n");
fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
fprintf(outfile, "\t.data = raw_data,\n");
fprintf(outfile, "\t.size = %lu,\n", mapping_size);
if (patch_sec) {
fprintf(outfile, "\t.tick_patch = %lu,\n",
(unsigned long)GET_BE(&patch_sec->sh_offset));
fprintf(outfile, "\t.tick_patch_len = %lu,\n",
(unsigned long)GET_BE(&patch_sec->sh_size));
}
for (i = 0; i < NSYMS; i++) {
if (required_syms[i].export && syms[i])
fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
required_syms[i].name, (int64_t)syms[i]);
}
fprintf(outfile, "};\n");
}
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