Our genvdso tool performs some rather paranoid checking that the VDSO
library isn't attempting to make use of a GOT by constraining the number
of entries that the GOT is allowed to contain to the minimum 2 entries
that are always generated by binutils.
Unfortunately lld prior to revision 334390 generates a third entry,
which is unused & thus harmless but falls foul of genvdso's checks &
causes the build to fail.
Since we already check that the VDSO contains no relocations it seems
reasonable to presume that it also doesn't contain use of a GOT, which
would involve relocations. Thus rather than attempting to work around
this issue by allowing 3 GOT entries when using lld, simply remove the
GOT checks which seem overly paranoid.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/vdso/genvdso.h | 51 ----------------------------------------
1 file changed, 51 deletions(-)
diff --git a/arch/mips/vdso/genvdso.h b/arch/mips/vdso/genvdso.h
index 94334727059a..611b06f01a3c 100644
--- a/arch/mips/vdso/genvdso.h
+++ b/arch/mips/vdso/genvdso.h
@@ -15,8 +15,6 @@ static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
ELF(Shdr) *shdr;
char *shstrtab, *name;
uint16_t sh_count, sh_entsize, i;
- unsigned int local_gotno, symtabno, gotsym;
- ELF(Dyn) *dyn = NULL;
shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
sh_count = swap_uint16(ehdr->e_shnum);
@@ -41,9 +39,6 @@ static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
"%s: '%s' contains relocation sections\n",
program_name, path);
return false;
- case SHT_DYNAMIC:
- dyn = vdso + FUNC(swap_uint)(shdr->sh_offset);
- break;
}
/* Check for existing sections. */
@@ -61,52 +56,6 @@ static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
}
}
- /*
- * Ensure the GOT has no entries other than the standard 2, for the same
- * reason we check that there's no relocation sections above.
- * The standard two entries are:
- * - Lazy resolver
- * - Module pointer
- */
- if (dyn) {
- local_gotno = symtabno = gotsym = 0;
-
- while (FUNC(swap_uint)(dyn->d_tag) != DT_NULL) {
- switch (FUNC(swap_uint)(dyn->d_tag)) {
- /*
- * This member holds the number of local GOT entries.
- */
- case DT_MIPS_LOCAL_GOTNO:
- local_gotno = FUNC(swap_uint)(dyn->d_un.d_val);
- break;
- /*
- * This member holds the number of entries in the
- * .dynsym section.
- */
- case DT_MIPS_SYMTABNO:
- symtabno = FUNC(swap_uint)(dyn->d_un.d_val);
- break;
- /*
- * This member holds the index of the first dynamic
- * symbol table entry that corresponds to an entry in
- * the GOT.
- */
- case DT_MIPS_GOTSYM:
- gotsym = FUNC(swap_uint)(dyn->d_un.d_val);
- break;
- }
-
- dyn++;
- }
-
- if (local_gotno > 2 || symtabno - gotsym) {
- fprintf(stderr,
- "%s: '%s' contains unexpected GOT entries\n",
- program_name, path);
- return false;
- }
- }
-
return true;
}
--
2.18.0
