From 4467f7ad7dbb0af5136fadb32dba37bc0388194f Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Mon, 6 Aug 2018 15:24:25 -0700 Subject: [PATCH] MIPS: genvdso: Remove GOT checks 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 Patchwork: https://patchwork.linux-mips.org/patch/20152/ Cc: James Hogan Cc: Ralf Baechle Cc: linux-mips@linux-mips.org --- 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; } -- 2.45.2