diff options
Diffstat (limited to 'kernel/arch/x86/vdso/vdso2c.h')
| -rw-r--r-- | kernel/arch/x86/vdso/vdso2c.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/kernel/arch/x86/vdso/vdso2c.h b/kernel/arch/x86/vdso/vdso2c.h new file mode 100644 index 000000000..022498755 --- /dev/null +++ b/kernel/arch/x86/vdso/vdso2c.h @@ -0,0 +1,175 @@ +/* + * This file is included twice from vdso2c.c. It generates code for 32-bit + * and 64-bit vDSOs. We need both for 64-bit builds, since 32-bit vDSOs + * are 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; + ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr; + int i; + unsigned long j; + ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr, + *alt_sec = NULL; + ELF(Dyn) *dyn = 0, *dyn_end = 0; + const char *secstrings; + INT_BITS syms[NSYMS] = {}; + + ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_LE(&hdr->e_phoff)); + + /* Walk the segment table. */ + for (i = 0; i < GET_LE(&hdr->e_phnum); i++) { + if (GET_LE(&pt[i].p_type) == PT_LOAD) { + if (found_load) + fail("multiple PT_LOAD segs\n"); + + if (GET_LE(&pt[i].p_offset) != 0 || + GET_LE(&pt[i].p_vaddr) != 0) + fail("PT_LOAD in wrong place\n"); + + if (GET_LE(&pt[i].p_memsz) != GET_LE(&pt[i].p_filesz)) + fail("cannot handle memsz != filesz\n"); + + load_size = GET_LE(&pt[i].p_memsz); + found_load = 1; + } else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) { + dyn = raw_addr + GET_LE(&pt[i].p_offset); + dyn_end = raw_addr + GET_LE(&pt[i].p_offset) + + GET_LE(&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_LE(&dyn[i].d_tag) != DT_NULL; i++) { + typeof(dyn[i].d_tag) tag = GET_LE(&dyn[i].d_tag); + if (tag == DT_REL || tag == DT_RELSZ || tag == DT_RELA || + tag == DT_RELENT || tag == DT_TEXTREL) + fail("vdso image contains dynamic relocations\n"); + } + + /* Walk the section table */ + secstrings_hdr = raw_addr + GET_LE(&hdr->e_shoff) + + GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx); + secstrings = raw_addr + GET_LE(&secstrings_hdr->sh_offset); + for (i = 0; i < GET_LE(&hdr->e_shnum); i++) { + ELF(Shdr) *sh = raw_addr + GET_LE(&hdr->e_shoff) + + GET_LE(&hdr->e_shentsize) * i; + if (GET_LE(&sh->sh_type) == SHT_SYMTAB) + symtab_hdr = sh; + + if (!strcmp(secstrings + GET_LE(&sh->sh_name), + ".altinstructions")) + alt_sec = sh; + } + + if (!symtab_hdr) + fail("no symbol table\n"); + + strtab_hdr = raw_addr + GET_LE(&hdr->e_shoff) + + GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link); + + /* Walk the symbol table */ + for (i = 0; + i < GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize); + i++) { + int k; + ELF(Sym) *sym = raw_addr + GET_LE(&symtab_hdr->sh_offset) + + GET_LE(&symtab_hdr->sh_entsize) * i; + const char *name = raw_addr + GET_LE(&strtab_hdr->sh_offset) + + GET_LE(&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_LE(&sym->st_value); + } + } + } + + /* Validate mapping addresses. */ + for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) { + INT_BITS symval = syms[special_pages[i]]; + + if (!symval) + continue; /* The mapping isn't used; ignore it. */ + + if (symval % 4096) + fail("%s must be a multiple of 4096\n", + required_syms[i].name); + if (symval + 4096 < syms[sym_vvar_start]) + fail("%s underruns vvar_start\n", + required_syms[i].name); + if (symval + 4096 > 0) + fail("%s is on the wrong side of the vdso text\n", + required_syms[i].name); + } + if (syms[sym_vvar_start] % 4096) + fail("vvar_begin must be a multiple of 4096\n"); + + if (!name) { + fwrite(stripped_addr, stripped_len, 1, outfile); + return; + } + + mapping_size = (stripped_len + 4095) / 4096 * 4096; + + fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n"); + fprintf(outfile, "#include <linux/linkage.h>\n"); + fprintf(outfile, "#include <asm/page_types.h>\n"); + fprintf(outfile, "#include <asm/vdso.h>\n"); + fprintf(outfile, "\n"); + fprintf(outfile, + "static unsigned char raw_data[%lu] __page_aligned_data = {", + 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, "static struct page *pages[%lu];\n\n", + mapping_size / 4096); + + fprintf(outfile, "const struct vdso_image %s = {\n", name); + fprintf(outfile, "\t.data = raw_data,\n"); + fprintf(outfile, "\t.size = %lu,\n", mapping_size); + fprintf(outfile, "\t.text_mapping = {\n"); + fprintf(outfile, "\t\t.name = \"[vdso]\",\n"); + fprintf(outfile, "\t\t.pages = pages,\n"); + fprintf(outfile, "\t},\n"); + if (alt_sec) { + fprintf(outfile, "\t.alt = %lu,\n", + (unsigned long)GET_LE(&alt_sec->sh_offset)); + fprintf(outfile, "\t.alt_len = %lu,\n", + (unsigned long)GET_LE(&alt_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"); +} |