4 files changed, 126 insertions, 229 deletions

diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 61b04fe36e66..5a4affe025e8 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -10,7 +10,7 @@ VDSO32-$(CONFIG_X86_32)		:= y
 VDSO32-$(CONFIG_COMPAT)         := y
 
 # files to link into the vdso
-vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vdso-fakesections.o
+vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
 
 # files to link into kernel
 obj-y                           += vma.o
@@ -37,7 +37,8 @@ vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
 obj-y += $(vdso_img_objs)
 targets += $(vdso_img_cfiles)
 targets += $(vdso_img_sodbg)
-.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c)
+.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
+        $(vdso_img-y:%=$(obj)/vdso%.so)
 
 export CPPFLAGS_vdso.lds += -P -C
 
@@ -54,10 +55,10 @@ hostprogs-y			+= vdso2c
 
 quiet_cmd_vdso2c = VDSO2C  $@
 define cmd_vdso2c
-        $(obj)/vdso2c $< $@
+        $(obj)/vdso2c $< $(<:%.dbg=%) $@
 endef
 
-$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso2c FORCE
+$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
         $(call if_changed,vdso2c)
 
 #
@@ -113,6 +114,10 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE
 
 targets += vdsox32.lds $(vobjx32s-y)
 
+$(obj)/%.so: OBJCOPYFLAGS := -S
+$(obj)/%.so: $(obj)/%.so.dbg
+        $(call if_changed,objcopy)
+
 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
         $(call if_changed,vdso)
 
@@ -134,7 +139,7 @@ override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 
 targets += vdso32/vdso32.lds
 targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
-targets += vdso32/vclock_gettime.o vdso32/vdso-fakesections.o
+targets += vdso32/vclock_gettime.o
 
 $(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
 
@@ -156,7 +161,6 @@ $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
                                  $(obj)/vdso32/vdso32.lds \
                                  $(obj)/vdso32/vclock_gettime.o \
-                                 $(obj)/vdso32/vdso-fakesections.o \
                                  $(obj)/vdso32/note.o \
                                  $(obj)/vdso32/%.o
         $(call if_changed,vdso)
diff --git a/arch/x86/vdso/vdso-fakesections.c b/arch/x86/vdso/vdso-fakesections.c
deleted file mode 100644
index aa5fbfab20a5..000000000000
--- a/arch/x86/vdso/vdso-fakesections.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Copyright 2014 Andy Lutomirski
- * Subject to the GNU Public License, v.2
- *
- * String table for loadable section headers.  See vdso2c.h for why
- * this exists.
- */
-
-const char fake_shstrtab[] __attribute__((section(".fake_shstrtab"))) =
-        ".hash\0"
-        ".dynsym\0"
-        ".dynstr\0"
-        ".gnu.version\0"
-        ".gnu.version_d\0"
-        ".dynamic\0"
-        ".rodata\0"
-        ".fake_shstrtab\0"  /* Yay, self-referential code. */
-        ".note\0"
-        ".eh_frame_hdr\0"
-        ".eh_frame\0"
-        ".text";
diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c
index 22c54d04bced..8627db24a7f6 100644
--- a/arch/x86/vdso/vdso2c.c
+++ b/arch/x86/vdso/vdso2c.c
@@ -1,3 +1,53 @@
+/*
+ * vdso2c - A vdso image preparation tool
+ * Copyright (c) 2014 Andy Lutomirski and others
+ * Licensed under the GPL v2
+ *
+ * vdso2c requires stripped and unstripped input.  It would be trivial
+ * to fully strip the input in here, but, for reasons described below,
+ * we need to write a section table.  Doing this is more or less
+ * equivalent to dropping all non-allocatable sections, but it's
+ * easier to let objcopy handle that instead of doing it ourselves.
+ * If we ever need to do something fancier than what objcopy provides,
+ * it would be straightforward to add here.
+ *
+ * We're keep a section table for a few reasons:
+ *
+ * The Go runtime had a couple of bugs: it would read the section
+ * table to try to figure out how many dynamic symbols there were (it
+ * shouldn't have looked at the section table at all) and, if there
+ * were no SHT_SYNDYM section table entry, it would use an
+ * uninitialized value for the number of symbols.  An empty DYNSYM
+ * table would work, but I see no reason not to write a valid one (and
+ * keep full performance for old Go programs).  This hack is only
+ * needed on x86_64.
+ *
+ * The bug was introduced on 2012-08-31 by:
+ * https://code.google.com/p/go/source/detail?r=56ea40aac72b
+ * and was fixed on 2014-06-13 by:
+ * https://code.google.com/p/go/source/detail?r=fc1cd5e12595
+ *
+ * Binutils has issues debugging the vDSO: it reads the section table to
+ * find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which
+ * would break build-id if we removed the section table.  Binutils
+ * also requires that shstrndx != 0.  See:
+ * https://sourceware.org/bugzilla/show_bug.cgi?id=17064
+ *
+ * elfutils might not look for PT_NOTE if there is a section table at
+ * all.  I don't know whether this matters for any practical purpose.
+ *
+ * For simplicity, rather than hacking up a partial section table, we
+ * just write a mostly complete one.  We omit non-dynamic symbols,
+ * though, since they're rather large.
+ *
+ * Once binutils gets fixed, we might be able to drop this for all but
+ * the 64-bit vdso, since build-id only works in kernel RPMs, and
+ * systems that update to new enough kernel RPMs will likely update
+ * binutils in sync.  build-id has never worked for home-built kernel
+ * RPMs without manual symlinking, and I suspect that no one ever does
+ * that.
+ */
+
 #include <inttypes.h>
 #include <stdint.h>
 #include <unistd.h>
@@ -61,7 +111,8 @@ static void fail(const char *format, ...)
         va_start(ap, format);
         fprintf(stderr, "Error: ");
         vfprintf(stderr, format, ap);
-        unlink(outfilename);
+        if (outfilename)
+                unlink(outfilename);
         exit(1);
         va_end(ap);
 }
@@ -114,30 +165,53 @@ extern void bad_put_le(void);
 #include "vdso2c.h"
 #undef ELF_BITS
 
-static void go(void *addr, size_t len, FILE *outfile, const char *name)
+static void go(void *raw_addr, size_t raw_len,
+               void *stripped_addr, size_t stripped_len,
+               FILE *outfile, const char *name)
 {
-        Elf64_Ehdr *hdr = (Elf64_Ehdr *)addr;
+        Elf64_Ehdr *hdr = (Elf64_Ehdr *)raw_addr;
 
         if (hdr->e_ident[EI_CLASS] == ELFCLASS64) {
-                go64(addr, len, outfile, name);
+                go64(raw_addr, raw_len, stripped_addr, stripped_len,
+                     outfile, name);
         } else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) {
-                go32(addr, len, outfile, name);
+                go32(raw_addr, raw_len, stripped_addr, stripped_len,
+                     outfile, name);
         } else {
                 fail("unknown ELF class\n");
         }
 }
 
+static void map_input(const char *name, void **addr, size_t *len, int prot)
+{
+        off_t tmp_len;
+
+        int fd = open(name, O_RDONLY);
+        if (fd == -1)
+                err(1, "%s", name);
+
+        tmp_len = lseek(fd, 0, SEEK_END);
+        if (tmp_len == (off_t)-1)
+                err(1, "lseek");
+        *len = (size_t)tmp_len;
+
+        *addr = mmap(NULL, tmp_len, prot, MAP_PRIVATE, fd, 0);
+        if (*addr == MAP_FAILED)
+                err(1, "mmap");
+
+        close(fd);
+}
+
 int main(int argc, char **argv)
 {
-        int fd;
-        off_t len;
-        void *addr;
+        size_t raw_len, stripped_len;
+        void *raw_addr, *stripped_addr;
         FILE *outfile;
         char *name, *tmp;
         int namelen;
 
-        if (argc != 3) {
-                printf("Usage: vdso2c INPUT OUTPUT\n");
+        if (argc != 4) {
+                printf("Usage: vdso2c RAW_INPUT STRIPPED_INPUT OUTPUT\n");
                 return 1;
         }
 
@@ -145,7 +219,7 @@ int main(int argc, char **argv)
          * Figure out the struct name.  If we're writing to a .so file,
          * generate raw output insted.
          */
-        name = strdup(argv[2]);
+        name = strdup(argv[3]);
         namelen = strlen(name);
         if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) {
                 name = NULL;
@@ -161,26 +235,18 @@ int main(int argc, char **argv)
                                 *tmp = '_';
         }
 
-        fd = open(argv[1], O_RDONLY);
-        if (fd == -1)
-                err(1, "%s", argv[1]);
-
-        len = lseek(fd, 0, SEEK_END);
-        if (len == (off_t)-1)
-                err(1, "lseek");
-
-        addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
-        if (addr == MAP_FAILED)
-                err(1, "mmap");
+        map_input(argv[1], &raw_addr, &raw_len, PROT_READ);
+        map_input(argv[2], &stripped_addr, &stripped_len, PROT_READ);
 
-        outfilename = argv[2];
+        outfilename = argv[3];
         outfile = fopen(outfilename, "w");
         if (!outfile)
                 err(1, "%s", argv[2]);
 
-        go(addr, (size_t)len, outfile, name);
+        go(raw_addr, raw_len, stripped_addr, stripped_len, outfile, name);
 
-        munmap(addr, len);
+        munmap(raw_addr, raw_len);
+        munmap(stripped_addr, stripped_len);
         fclose(outfile);
 
         return 0;
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h
index 2da32fbc46da..fd57829b30d8 100644
--- a/arch/x86/vdso/vdso2c.h
+++ b/arch/x86/vdso/vdso2c.h
@@ -4,128 +4,14 @@
  * are built for 32-bit userspace.
  */
 
-/*
- * We're writing a section table for a few reasons:
- *
- * The Go runtime had a couple of bugs: it would read the section
- * table to try to figure out how many dynamic symbols there were (it
- * shouldn't have looked at the section table at all) and, if there
- * were no SHT_SYNDYM section table entry, it would use an
- * uninitialized value for the number of symbols.  An empty DYNSYM
- * table would work, but I see no reason not to write a valid one (and
- * keep full performance for old Go programs).  This hack is only
- * needed on x86_64.
- *
- * The bug was introduced on 2012-08-31 by:
- * https://code.google.com/p/go/source/detail?r=56ea40aac72b
- * and was fixed on 2014-06-13 by:
- * https://code.google.com/p/go/source/detail?r=fc1cd5e12595
- *
- * Binutils has issues debugging the vDSO: it reads the section table to
- * find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which
- * would break build-id if we removed the section table.  Binutils
- * also requires that shstrndx != 0.  See:
- * https://sourceware.org/bugzilla/show_bug.cgi?id=17064
- *
- * elfutils might not look for PT_NOTE if there is a section table at
- * all.  I don't know whether this matters for any practical purpose.
- *
- * For simplicity, rather than hacking up a partial section table, we
- * just write a mostly complete one.  We omit non-dynamic symbols,
- * though, since they're rather large.
- *
- * Once binutils gets fixed, we might be able to drop this for all but
- * the 64-bit vdso, since build-id only works in kernel RPMs, and
- * systems that update to new enough kernel RPMs will likely update
- * binutils in sync.  build-id has never worked for home-built kernel
- * RPMs without manual symlinking, and I suspect that no one ever does
- * that.
- */
-struct BITSFUNC(fake_sections)
-{
-        ELF(Shdr) *table;
-        unsigned long table_offset;
-        int count, max_count;
-
-        int in_shstrndx;
-        unsigned long shstr_offset;
-        const char *shstrtab;
-        size_t shstrtab_len;
-
-        int out_shstrndx;
-};
-
-static unsigned int BITSFUNC(find_shname)(struct BITSFUNC(fake_sections) *out,
-                                          const char *name)
-{
-        const char *outname = out->shstrtab;
-        while (outname - out->shstrtab < out->shstrtab_len) {
-                if (!strcmp(name, outname))
-                        return (outname - out->shstrtab) + out->shstr_offset;
-                outname += strlen(outname) + 1;
-        }
-
-        if (*name)
-                printf("Warning: could not find output name \"%s\"\n", name);
-        return out->shstr_offset + out->shstrtab_len - 1;  /* Use a null. */
-}
-
-static void BITSFUNC(init_sections)(struct BITSFUNC(fake_sections) *out)
-{
-        if (!out->in_shstrndx)
-                fail("didn't find the fake shstrndx\n");
-
-        memset(out->table, 0, out->max_count * sizeof(ELF(Shdr)));
-
-        if (out->max_count < 1)
-                fail("we need at least two fake output sections\n");
-
-        PUT_LE(&out->table[0].sh_type, SHT_NULL);
-        PUT_LE(&out->table[0].sh_name, BITSFUNC(find_shname)(out, ""));
-
-        out->count = 1;
-}
-
-static void BITSFUNC(copy_section)(struct BITSFUNC(fake_sections) *out,
-                                   int in_idx, const ELF(Shdr) *in,
-                                   const char *name)
-{
-        uint64_t flags = GET_LE(&in->sh_flags);
-
-        bool copy = flags & SHF_ALLOC &&
-                (GET_LE(&in->sh_size) ||
-                 (GET_LE(&in->sh_type) != SHT_RELA &&
-                  GET_LE(&in->sh_type) != SHT_REL)) &&
-                strcmp(name, ".altinstructions") &&
-                strcmp(name, ".altinstr_replacement");
-
-        if (!copy)
-                return;
-
-        if (out->count >= out->max_count)
-                fail("too many copied sections (max = %d)\n", out->max_count);
-
-        if (in_idx == out->in_shstrndx)
-                out->out_shstrndx = out->count;
-
-        out->table[out->count] = *in;
-        PUT_LE(&out->table[out->count].sh_name,
-               BITSFUNC(find_shname)(out, name));
-
-        /* elfutils requires that a strtab have the correct type. */
-        if (!strcmp(name, ".fake_shstrtab"))
-                PUT_LE(&out->table[out->count].sh_type, SHT_STRTAB);
-
-        out->count++;
-}
-
-static void BITSFUNC(go)(void *addr, size_t len,
+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 data_size;
-        ELF(Ehdr) *hdr = (ELF(Ehdr) *)addr;
+        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,
@@ -134,9 +20,7 @@ static void BITSFUNC(go)(void *addr, size_t len,
         const char *secstrings;
         INT_BITS syms[NSYMS] = {};
 
-        struct BITSFUNC(fake_sections) fake_sections = {};
-
-        ELF(Phdr) *pt = (ELF(Phdr) *)(addr + GET_LE(&hdr->e_phoff));
+        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++) {
@@ -154,14 +38,16 @@ static void BITSFUNC(go)(void *addr, size_t len,
                         load_size = GET_LE(&pt[i].p_memsz);
                         found_load = 1;
                 } else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) {
-                        dyn = addr + GET_LE(&pt[i].p_offset);
-                        dyn_end = addr + GET_LE(&pt[i].p_offset) +
+                        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");
-        data_size = (load_size + 4095) / 4096 * 4096;
+
+        if (stripped_len < load_size)
+                fail("stripped input is too short\n");
 
         /* Walk the dynamic table */
         for (i = 0; dyn + i < dyn_end &&
@@ -173,11 +59,11 @@ static void BITSFUNC(go)(void *addr, size_t len,
         }
 
         /* Walk the section table */
-        secstrings_hdr = addr + GET_LE(&hdr->e_shoff) +
+        secstrings_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
                 GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx);
-        secstrings = addr + GET_LE(&secstrings_hdr->sh_offset);
+        secstrings = raw_addr + GET_LE(&secstrings_hdr->sh_offset);
         for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
-                ELF(Shdr) *sh = addr + GET_LE(&hdr->e_shoff) +
+                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;
@@ -190,7 +76,7 @@ static void BITSFUNC(go)(void *addr, size_t len,
         if (!symtab_hdr)
                 fail("no symbol table\n");
 
-        strtab_hdr = addr + GET_LE(&hdr->e_shoff) +
+        strtab_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
                 GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link);
 
         /* Walk the symbol table */
@@ -198,9 +84,9 @@ static void BITSFUNC(go)(void *addr, size_t len,
              i < GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize);
              i++) {
                 int k;
-                ELF(Sym) *sym = addr + GET_LE(&symtab_hdr->sh_offset) +
+                ELF(Sym) *sym = raw_addr + GET_LE(&symtab_hdr->sh_offset) +
                         GET_LE(&symtab_hdr->sh_entsize) * i;
-                const char *name = addr + GET_LE(&strtab_hdr->sh_offset) +
+                const char *name = raw_addr + GET_LE(&strtab_hdr->sh_offset) +
                         GET_LE(&sym->st_name);
 
                 for (k = 0; k < NSYMS; k++) {
@@ -219,48 +105,7 @@ static void BITSFUNC(go)(void *addr, size_t len,
                                 syms[k] = GET_LE(&sym->st_value);
                         }
                 }
-
-                if (!strcmp(name, "fake_shstrtab")) {
-                        ELF(Shdr) *sh;
-
-                        fake_sections.in_shstrndx = GET_LE(&sym->st_shndx);
-                        fake_sections.shstrtab = addr + GET_LE(&sym->st_value);
-                        fake_sections.shstrtab_len = GET_LE(&sym->st_size);
-                        sh = addr + GET_LE(&hdr->e_shoff) +
-                                GET_LE(&hdr->e_shentsize) *
-                                fake_sections.in_shstrndx;
-                        fake_sections.shstr_offset = GET_LE(&sym->st_value) -
-                                GET_LE(&sh->sh_addr);
-                }
-        }
-
-        /* Build the output section table. */
-        if (!syms[sym_VDSO_FAKE_SECTION_TABLE_START] ||
-            !syms[sym_VDSO_FAKE_SECTION_TABLE_END])
-                fail("couldn't find fake section table\n");
-        if ((syms[sym_VDSO_FAKE_SECTION_TABLE_END] -
-             syms[sym_VDSO_FAKE_SECTION_TABLE_START]) % sizeof(ELF(Shdr)))
-                fail("fake section table size isn't a multiple of sizeof(Shdr)\n");
-        fake_sections.table = addr + syms[sym_VDSO_FAKE_SECTION_TABLE_START];
-        fake_sections.table_offset = syms[sym_VDSO_FAKE_SECTION_TABLE_START];
-        fake_sections.max_count = (syms[sym_VDSO_FAKE_SECTION_TABLE_END] -
-                                   syms[sym_VDSO_FAKE_SECTION_TABLE_START]) /
-                sizeof(ELF(Shdr));
-
-        BITSFUNC(init_sections)(&fake_sections);
-        for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
-                ELF(Shdr) *sh = addr + GET_LE(&hdr->e_shoff) +
-                        GET_LE(&hdr->e_shentsize) * i;
-                BITSFUNC(copy_section)(&fake_sections, i, sh,
-                                       secstrings + GET_LE(&sh->sh_name));
         }
-        if (!fake_sections.out_shstrndx)
-                fail("didn't generate shstrndx?!?\n");
-
-        PUT_LE(&hdr->e_shoff, fake_sections.table_offset);
-        PUT_LE(&hdr->e_shentsize, sizeof(ELF(Shdr)));
-        PUT_LE(&hdr->e_shnum, fake_sections.count);
-        PUT_LE(&hdr->e_shstrndx, fake_sections.out_shstrndx);
 
         /* Validate mapping addresses. */
         for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) {
@@ -281,10 +126,12 @@ static void BITSFUNC(go)(void *addr, size_t len,
                 fail("vvar_begin must be a multiple of 4096\n");
 
         if (!name) {
-                fwrite(addr, load_size, 1, outfile);
+                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");
@@ -292,20 +139,21 @@ static void BITSFUNC(go)(void *addr, size_t len,
         fprintf(outfile, "\n");
         fprintf(outfile,
                 "static unsigned char raw_data[%lu] __page_aligned_data = {",
-                data_size);
-        for (j = 0; j < load_size; j++) {
+                mapping_size);
+        for (j = 0; j < stripped_len; j++) {
                 if (j % 10 == 0)
                         fprintf(outfile, "\n\t");
-                fprintf(outfile, "0x%02X, ", (int)((unsigned char *)addr)[j]);
+                fprintf(outfile, "0x%02X, ",
+                        (int)((unsigned char *)stripped_addr)[j]);
         }
         fprintf(outfile, "\n};\n\n");
 
         fprintf(outfile, "static struct page *pages[%lu];\n\n",
-                data_size / 4096);
+                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", data_size);
+        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");