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