x86, vdso: Use <tools/le_byteshift.h> for littleendian access

There are no standard functions for littleendian data (unlike
bigendian data.)  Thus, use <tools/le_byteshift.h> to access
littleendian data members.  Those are fairly inefficient, but it
doesn't matter for this purpose (and can be optimized later.)  This
avoids portability problems.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/20140606140017.afb7f91142f66cb3dd13c186@linux-foundation.org

diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 895d4b1..9769df0 100644 (file)
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -59,6 +59,7 @@ VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
        $(call if_changed,vdso)
 
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include
 hostprogs-y                    += vdso2c
 
 quiet_cmd_vdso2c = VDSO2C  $@

diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c
index deabaf5..450ac6e 100644 (file)
--- a/arch/x86/vdso/vdso2c.c
+++ b/arch/x86/vdso/vdso2c.c
@@ -11,6 +11,8 @@
 #include <sys/mman.h>
 #include <sys/types.h>
 
+#include <tools/le_byteshift.h>
+
 #include <linux/elf.h>
 #include <linux/types.h>
 
@@ -56,12 +58,12 @@ static void fail(const char *format, ...)
  */
 #define GLE(x, bits, ifnot)                                            \
        __builtin_choose_expr(                                          \
-               (sizeof(x) == bits/8),                                  \
-               (__typeof__(x))le##bits##toh(x), ifnot)
+               (sizeof(*(x)) == bits/8),                               \
+               (__typeof__(*(x)))get_unaligned_le##bits(x), ifnot)
 
-extern void bad_get_le(uint64_t);
+extern void bad_get_le(void);
 #define LAST_LE(x)                                                     \
-       __builtin_choose_expr(sizeof(x) == 1, (x), bad_get_le(x))
+       __builtin_choose_expr(sizeof(*(x)) == 1, *(x), bad_get_le())
 
 #define GET_LE(x)                                                      \
        GLE(x, 64, GLE(x, 32, GLE(x, 16, LAST_LE(x))))

diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h
index d1e99e1..8a07463 100644 (file)
--- a/arch/x86/vdso/vdso2c.h
+++ b/arch/x86/vdso/vdso2c.h
@@ -18,27 +18,27 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
        const char *secstrings;
        uint64_t syms[NSYMS] = {};
 
-       Elf_Phdr *pt = (Elf_Phdr *)(addr + GET_LE(hdr->e_phoff));
+       Elf_Phdr *pt = (Elf_Phdr *)(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) {
+       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)
+                       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))
+                       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);
+                       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) +
-                               GET_LE(pt[i].p_memsz);
+               } 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) +
+                               GET_LE(&pt[i].p_memsz);
                }
        }
        if (!found_load)
@@ -47,24 +47,24 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
 
        /* 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);
+                    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_RELENT || tag == DT_TEXTREL)
                        fail("vdso image contains dynamic relocations\n");
        }
 
        /* Walk the section table */
-       secstrings_hdr = addr + GET_LE(hdr->e_shoff) +
-               GET_LE(hdr->e_shentsize)*GET_LE(hdr->e_shstrndx);
-       secstrings = 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) +
-                       GET_LE(hdr->e_shentsize) * i;
-               if (GET_LE(sh->sh_type) == SHT_SYMTAB)
+       secstrings_hdr = addr + GET_LE(&hdr->e_shoff) +
+               GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx);
+       secstrings = 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) +
+                       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),
+               if (!strcmp(secstrings + GET_LE(&sh->sh_name),
                            ".altinstructions"))
                        alt_sec = sh;
        }
@@ -72,25 +72,25 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
        if (!symtab_hdr)
                fail("no symbol table\n");
 
-       strtab_hdr = addr + GET_LE(hdr->e_shoff) +
-               GET_LE(hdr->e_shentsize) * GET_LE(symtab_hdr->sh_link);
+       strtab_hdr = 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 < 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) +
-                       GET_LE(symtab_hdr->sh_entsize) * i;
-               const char *name = addr + GET_LE(strtab_hdr->sh_offset) +
-                       GET_LE(sym->st_name);
+               Elf_Sym *sym = addr + GET_LE(&symtab_hdr->sh_offset) +
+                       GET_LE(&symtab_hdr->sh_entsize) * i;
+               const char *name = addr + GET_LE(&strtab_hdr->sh_offset) +
+                       GET_LE(&sym->st_name);
                for (k = 0; k < NSYMS; k++) {
                        if (!strcmp(name, required_syms[k])) {
                                if (syms[k]) {
                                        fail("duplicate symbol %s\n",
                                             required_syms[k]);
                                }
-                               syms[k] = GET_LE(sym->st_value);
+                               syms[k] = GET_LE(&sym->st_value);
                        }
                }
        }
@@ -150,9 +150,9 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
        fprintf(outfile, "\t},\n");
        if (alt_sec) {
                fprintf(outfile, "\t.alt = %lu,\n",
-                       (unsigned long)GET_LE(alt_sec->sh_offset));
+                       (unsigned long)GET_LE(&alt_sec->sh_offset));
                fprintf(outfile, "\t.alt_len = %lu,\n",
-                       (unsigned long)GET_LE(alt_sec->sh_size));
+                       (unsigned long)GET_LE(&alt_sec->sh_size));
        }
        for (i = 0; i < NSYMS; i++) {
                if (syms[i])