arch/sparc/vdso/vdso2c.h

   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
  11 static 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
  21         ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr;
  22         ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
  23         ELF(Dyn) *dyn = 0, *dyn_end = 0;
  24         INT_BITS syms[NSYMS] = {};
  25
  26         ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
  27
  28         /* Walk the segment table. */
  29         for (i = 0; i < GET_BE(&hdr->e_phnum); i++) {
  30                 if (GET_BE(&pt[i].p_type) == PT_LOAD) {
  31                         if (found_load)
  32                                 fail("multiple PT_LOAD segs\n");
  33
  34                         if (GET_BE(&pt[i].p_offset) != 0 ||
  35                             GET_BE(&pt[i].p_vaddr) != 0)
  36                                 fail("PT_LOAD in wrong place\n");
  37
  38                         if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz))
  39                                 fail("cannot handle memsz != filesz\n");
  40
  41                         load_size = GET_BE(&pt[i].p_memsz);
  42                         found_load = 1;
  43                 } else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) {
  44                         dyn = raw_addr + GET_BE(&pt[i].p_offset);
  45                         dyn_end = raw_addr + GET_BE(&pt[i].p_offset) +
  46                                 GET_BE(&pt[i].p_memsz);
  47                 }
  48         }
  49         if (!found_load)
  50                 fail("no PT_LOAD seg\n");
  51
  52         if (stripped_len < load_size)
  53                 fail("stripped input is too short\n");
  54
  55         /* Walk the dynamic table */
  56         for (i = 0; dyn + i < dyn_end &&
  57                      GET_BE(&dyn[i].d_tag) != DT_NULL; i++) {
  58                 typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag);
  59                 typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val);
  60
  61                 if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0))
  62                         fail("vdso image contains dynamic relocations\n");
  63         }
  64
  65         /* Walk the section table */
  66         for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
  67                 ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
  68                         GET_BE(&hdr->e_shentsize) * i;
  69                 if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
  70                         symtab_hdr = sh;
  71         }
  72
  73         if (!symtab_hdr)
  74                 fail("no symbol table\n");
  75
  76         strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
  77                 GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link);
  78
  79         /* Walk the symbol table */
  80         for (i = 0;
  81              i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize);
  82              i++) {
  83                 int k;
  84
  85                 ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) +
  86                         GET_BE(&symtab_hdr->sh_entsize) * i;
  87                 const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) +
  88                         GET_BE(&sym->st_name);
  89
  90                 for (k = 0; k < NSYMS; k++) {
  91                         if (!strcmp(name, required_syms[k].name)) {
  92                                 if (syms[k]) {
  93                                         fail("duplicate symbol %s\n",
  94                                              required_syms[k].name);
  95                                 }
  96
  97                                 /*
  98                                  * Careful: we use negative addresses, but
  99                                  * st_value is unsigned, so we rely
 100                                  * on syms[k] being a signed type of the
 101                                  * correct width.
 102                                  */
 103                                 syms[k] = GET_BE(&sym->st_value);
 104                         }
 105                 }
 106         }
 107
 108         /* Validate mapping addresses. */
 109         if (syms[sym_vvar_start] % 8192)
 110                 fail("vvar_begin must be a multiple of 8192\n");
 111
 112         if (!name) {
 113                 fwrite(stripped_addr, stripped_len, 1, outfile);
 114                 return;
 115         }
 116
 117         mapping_size = (stripped_len + 8191) / 8192 * 8192;
 118
 119         fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
 120         fprintf(outfile, "#include <linux/cache.h>\n");
 121         fprintf(outfile, "#include <asm/vdso.h>\n");
 122         fprintf(outfile, "\n");
 123         fprintf(outfile,
 124                 "static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {",
 125                 mapping_size);
 126         for (j = 0; j < stripped_len; j++) {
 127                 if (j % 10 == 0)
 128                         fprintf(outfile, "\n\t");
 129                 fprintf(outfile, "0x%02X, ",
 130                         (int)((unsigned char *)stripped_addr)[j]);
 131         }
 132         fprintf(outfile, "\n};\n\n");
 133
 134         fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
 135         fprintf(outfile, "\t.data = raw_data,\n");
 136         fprintf(outfile, "\t.size = %lu,\n", mapping_size);
 137         for (i = 0; i < NSYMS; i++) {
 138                 if (required_syms[i].export && syms[i])
 139                         fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
 140                                 required_syms[i].name, (int64_t)syms[i]);
 141         }
 142         fprintf(outfile, "};\n");
 143 }