From 9abc968f910ddf4cd06e17770c9053586d0a9258 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 6 Nov 2003 14:30:11 +0000 Subject: [PATCH] * elf32-ppc.c (ppc_elf_install_value): Delete. (shared_stub_entry, stub_entry): Make them arrays of ints. Remove initial branch. (ppc_elf_relax_section): Write one branch around all trampolines instead. Correct bogus R_PPC_PLTREL24 handling. Correct branch range check. Only use shared_stub_entry when shared. Test that branches can reach stubs. Write trampolines out at end so that just one realloc is used. Handle little-endian mode. Move relevant code from ppc_elf_install_value to here. (ppc_elf_relocate_section): Move code handling RELAX32 from ppc_elf_install_value to here. --- bfd/ChangeLog | 14 ++ bfd/elf32-ppc.c | 370 ++++++++++++++++++++++-------------------------- 2 files changed, 187 insertions(+), 197 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 5a343eac457..b45ea437928 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,17 @@ +2003-11-07 Alan Modra + + * elf32-ppc.c (ppc_elf_install_value): Delete. + (shared_stub_entry, stub_entry): Make them arrays of ints. + Remove initial branch. + (ppc_elf_relax_section): Write one branch around all trampolines + instead. Correct bogus R_PPC_PLTREL24 handling. Correct + branch range check. Only use shared_stub_entry when shared. + Test that branches can reach stubs. Write trampolines out at + end so that just one realloc is used. Handle little-endian + mode. Move relevant code from ppc_elf_install_value to here. + (ppc_elf_relocate_section): Move code handling RELAX32 from + ppc_elf_install_value to here. + 2003-11-06 Alan Modra * elf32-ppc.c (ppc_elf_howto_raw); Add entry for R_PPC_RELAX32PC. diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c index e0957098258..e2de01e2647 100644 --- a/bfd/elf32-ppc.c +++ b/bfd/elf32-ppc.c @@ -1532,32 +1532,32 @@ static reloc_howto_type ppc_elf_howto_raw[] = { FALSE), /* pcrel_offset */ /* Phony relocs to handle branch stubs. */ - HOWTO (R_PPC_RELAX32, /* type */ - 0, /* rightshift */ - 0, /* size */ + HOWTO (R_PPC_RELAX32, /* type */ + 0, /* rightshift */ + 0, /* size */ 0, /* bitsize */ FALSE, /* pc_relative */ 0, /* bitpos */ complain_overflow_dont, /* complain_on_overflow */ bfd_elf_generic_reloc, /* special_function */ - "R_PPC_RELAX32", /* name */ + "R_PPC_RELAX32", /* name */ FALSE, /* partial_inplace */ 0, /* src_mask */ - 0, /* dst_mask */ + 0, /* dst_mask */ FALSE), /* pcrel_offset */ - HOWTO (R_PPC_RELAX32PC, /* type */ - 0, /* rightshift */ - 0, /* size */ + HOWTO (R_PPC_RELAX32PC, /* type */ + 0, /* rightshift */ + 0, /* size */ 0, /* bitsize */ FALSE, /* pc_relative */ 0, /* bitpos */ complain_overflow_dont, /* complain_on_overflow */ bfd_elf_generic_reloc, /* special_function */ - "R_PPC_RELAX32PC", /* name */ + "R_PPC_RELAX32PC", /* name */ FALSE, /* partial_inplace */ 0, /* src_mask */ - 0, /* dst_mask */ + 0, /* dst_mask */ FALSE), /* pcrel_offset */ /* GNU extension to record C++ vtable hierarchy. */ @@ -1625,84 +1625,26 @@ ppc_elf_howto_init (void) } } -static bfd_reloc_status_type -ppc_elf_install_value (bfd *abfd, - bfd_byte *hit_addr, - bfd_vma v, - unsigned int r_type) -{ - bfd_vma t0, t1; -#ifdef BFD_HOST_U_64_BIT - BFD_HOST_U_64_BIT val = (BFD_HOST_U_64_BIT) v; -#else - bfd_vma val = v; -#endif - - switch (r_type) - { - case R_PPC_RELAX32: - case R_PPC_RELAX32PC: - t0 = bfd_get_32 (abfd, hit_addr); - t1 = bfd_get_32 (abfd, hit_addr + 4); - - /* We're clearing the bits for R_PPC_ADDR16_HA - and R_PPC_ADDR16_LO here. */ - t0 &= ~0xffff; - t1 &= ~0xffff; - - /* t0 is HA, t1 is lo */ - t0 |= ((val + 0x8000) >> 16) & 0xffff; - t1 |= val & 0xffff; - - bfd_put_32 (abfd, t0, hit_addr); - bfd_put_32 (abfd, t1, hit_addr + 4); - break; +#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0])) - case R_PPC_REL24: - case R_PPC_LOCAL24PC: - case R_PPC_PLTREL24: - t0 = bfd_get_32 (abfd, hit_addr); - t0 &= ~0x3fffffc; - t0 |= val & 0x3fffffc; - bfd_put_32 (abfd, t0, hit_addr); - break; - - case R_PPC_REL14: - case R_PPC_REL14_BRTAKEN: - case R_PPC_REL14_BRNTAKEN: - t0 = bfd_get_32 (abfd, hit_addr); - t0 &= ~0xfffc; - t0 |= val & 0xfffc; - bfd_put_32 (abfd, t0, hit_addr); - break; - - default: - return bfd_reloc_notsupported; - } - - return bfd_reloc_ok; -} - -static const bfd_byte shared_stub_entry[] = +static const int shared_stub_entry[] = { - 0x48, 0x00, 0x00, 0x24, /* b .+36 */ - 0x7c, 0x08, 0x02, 0xa6, /* mflr 0 */ - 0x42, 0x9f, 0x00, 0x05, /* bcl 20, 31, .Lxxx */ - 0x7d, 0x68, 0x02, 0xa6, /* mflr 11 */ - 0x3d, 0x6b, 0x00, 0x00, /* addis 11, 11, (xxx-.Lxxx)@ha */ - 0x39, 0x6b, 0x00, 0x18, /* addi 11, 11, (xxx-.Lxxx)@l */ - 0x7c, 0x08, 0x03, 0xa6, /* mtlr 0 */ - 0x7d, 0x69, 0x03, 0xa6, /* mtctr 11 */ - 0x4e, 0x80, 0x04, 0x20, /* bctr */ + 0x7c0802a6, /* mflr 0 */ + 0x429f0005, /* bcl 20, 31, .Lxxx */ + 0x7d6802a6, /* mflr 11 */ + 0x3d6b0000, /* addis 11, 11, (xxx-.Lxxx)@ha */ + 0x396b0018, /* addi 11, 11, (xxx-.Lxxx)@l */ + 0x7c0803a6, /* mtlr 0 */ + 0x7d6903a6, /* mtctr 11 */ + 0x4e800420, /* bctr */ }; -static const bfd_byte stub_entry[] = +static const int stub_entry[] = { - 0x48, 0x00, 0x00, 0x14, /* b .+20 */ - 0x3d, 0x60, 0x00, 0x00, /* lis 11,xxx@ha */ - 0x39, 0x6b, 0x00, 0x00, /* addi 11,11,xxx@l */ - 0x7d, 0x69, 0x03, 0xa6, /* mtctr 11 */ - 0x4e, 0x80, 0x04, 0x20, /* bctr */ + 0x3d600000, /* lis 11,xxx@ha */ + 0x396b0000, /* addi 11,11,xxx@l */ + 0x7d6903a6, /* mtctr 11 */ + 0x4e800420, /* bctr */ }; @@ -1726,9 +1668,9 @@ ppc_elf_relax_section (bfd *abfd, Elf_Internal_Rela *internal_relocs = NULL; Elf_Internal_Rela *irel, *irelend; struct one_fixup *fixups = NULL; - bfd_boolean changed_contents = FALSE; - bfd_boolean changed_relocs = FALSE; + bfd_boolean changed; struct ppc_elf_link_hash_table *ppc_info; + bfd_size_type trampoff; *again = FALSE; @@ -1743,6 +1685,10 @@ ppc_elf_relax_section (bfd *abfd, if (isec->_cooked_size == 0) isec->_cooked_size = isec->_raw_size; + trampoff = (isec->_cooked_size + 3) & (bfd_vma) -4; + /* Space for a branch around any trampolines. */ + trampoff += 4; + symtab_hdr = &elf_tdata (abfd)->symtab_hdr; /* Get a copy of the native relocations. */ @@ -1772,21 +1718,26 @@ ppc_elf_relax_section (bfd *abfd, for (irel = internal_relocs; irel < irelend; irel++) { unsigned long r_type = ELF32_R_TYPE (irel->r_info); - bfd_vma symaddr, reladdr, trampoff, toff, roff; + bfd_vma symaddr, reladdr, toff, roff; asection *tsec; - bfd_size_type amt; struct one_fixup *f; size_t insn_offset = 0; - bfd_vma max_branch_offset; + bfd_vma max_branch_offset, val; + bfd_byte *hit_addr; + unsigned long t0; switch (r_type) { case R_PPC_REL24: case R_PPC_LOCAL24PC: + case R_PPC_PLTREL24: + max_branch_offset = 1 << 25; + break; + case R_PPC_REL14: case R_PPC_REL14_BRTAKEN: case R_PPC_REL14_BRNTAKEN: - case R_PPC_PLTREL24: + max_branch_offset = 1 << 15; break; default: @@ -1824,7 +1775,7 @@ ppc_elf_relax_section (bfd *abfd, } else { - /* Need dynamic symbol handling. */ + /* Global symbol handling. */ unsigned long indx; struct elf_link_hash_entry *h; @@ -1835,62 +1786,34 @@ ppc_elf_relax_section (bfd *abfd, || h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; - if (r_type == R_PPC_PLTREL24) + if (r_type == R_PPC_PLTREL24 + && ppc_info->plt != NULL + && h->plt.offset != (bfd_vma) -1) { - Elf_Internal_Sym *isym; - - if (h->plt.offset == (bfd_vma) -1 - || ppc_info->plt == NULL) - { - - /* Read this BFD's local symbols. */ - if (isymbuf == NULL) - { - isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents; - if (isymbuf == NULL) - isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr, - symtab_hdr->sh_info, 0, - NULL, NULL, NULL); - if (isymbuf == 0) - goto error_return; - } - isym = isymbuf + ELF32_R_SYM (irel->r_info); - - if (isym->st_shndx == SHN_UNDEF) - /* We can't do anthing with undefined symbols. */ - continue; - else if (isym->st_shndx == SHN_ABS) - tsec = bfd_abs_section_ptr; - else if (isym->st_shndx == SHN_COMMON) - tsec = bfd_com_section_ptr; - else - tsec = h->root.u.def.section; - - toff = h->root.u.def.value; - } - else - { - tsec = ppc_info->plt; - toff = h->plt.offset; - } + tsec = ppc_info->plt; + toff = h->plt.offset; } - else if (h->root.type == bfd_link_hash_undefined - || h->root.type == bfd_link_hash_undefweak) - continue; - - else + else if (h->root.type == bfd_link_hash_defined + || h->root.type == bfd_link_hash_defweak) { tsec = h->root.u.def.section; toff = h->root.u.def.value; } + else + continue; } + /* If the branch and target are in the same section, you have + no hope of adding stubs. We'll error out later should the + branch overflow. */ + if (tsec == isec) + continue; + + toff += irel->r_addend; if (tsec->sec_info_type == ELF_INFO_TYPE_MERGE) toff = _bfd_merged_section_offset (abfd, &tsec, elf_section_data (tsec)->sec_info, - toff + irel->r_addend, 0); - else - toff += irel->r_addend; + toff, 0); symaddr = tsec->output_section->vma + tsec->output_offset + toff; @@ -1898,70 +1821,41 @@ ppc_elf_relax_section (bfd *abfd, reladdr = (isec->output_section->vma + isec->output_offset - + roff) & (bfd_vma) -4; + + roff); /* If the branch is in range, no need to do anything. */ - max_branch_offset = 1 << 25; - if (r_type != R_PPC_REL24 - && r_type != R_PPC_LOCAL24PC - && r_type != R_PPC_PLTREL24) - max_branch_offset = 1 << 15; - - if ((bfd_vma) (symaddr - reladdr) + max_branch_offset - <= 2 * max_branch_offset) + if (symaddr - reladdr + max_branch_offset < 2 * max_branch_offset) continue; - /* If the branch and target are in the same section, you have - no hope. We'll error out later. */ - if (tsec == isec) - continue; - - /* Look for an existing fixup to this address. - ??? What if the existing fixup is for a non-pic stub, and the - new one requires a pic stub? This presumably could happen with - a static link and a mix of R_PPC_LOCAL24PC and R_PPC_REL24 - relocs to a symbol needing long branch stubs. - ??? Why do we require R_PPC_LOCAL24PC and branches to the plt - to have a shared branch stub? Shared branch stubs should only - be needed when info->shared. */ + /* Look for an existing fixup to this address. */ for (f = fixups; f ; f = f->next) if (f->tsec == tsec && f->toff == toff) break; if (f == NULL) { - const bfd_byte *stub; size_t size; unsigned long stub_rtype; - if (link_info->shared - || tsec == ppc_info->plt - || r_type == R_PPC_LOCAL24PC) + val = trampoff - roff; + if (val >= max_branch_offset) + /* Oh dear, we can't reach a trampoline. Don't try to add + one. We'll report an error later. */ + continue; + + if (link_info->shared) { - stub = shared_stub_entry; - size = sizeof (shared_stub_entry); - insn_offset = 16; + size = 4 * ARRAY_SIZE (shared_stub_entry); + insn_offset = 12; stub_rtype = R_PPC_RELAX32PC; } else { - stub = stub_entry; - size = sizeof (stub_entry); - insn_offset = 4; + size = 4 * ARRAY_SIZE (stub_entry); + insn_offset = 0; stub_rtype = R_PPC_RELAX32; } - /* Resize the current section to make room for the new branch. */ - trampoff = (isec->_cooked_size + 3) & (bfd_vma) - 4; - amt = trampoff + size; - contents = bfd_realloc (contents, amt); - if (contents == NULL) - abort (); - - isec->_cooked_size = amt; - - memcpy (contents + trampoff, stub, size); - /* Hijack the old relocation. Since we need two relocations for this use a "composite" reloc. */ irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info), @@ -1975,31 +1869,95 @@ ppc_elf_relax_section (bfd *abfd, f->toff = toff; f->trampoff = trampoff; fixups = f; + + trampoff += size; } else { + val = f->trampoff - roff; + if (val >= max_branch_offset) + continue; + /* Nop out the reloc, since we're finalizing things here. */ irel->r_info = ELF32_R_INFO (0, R_PPC_NONE); } - /* Fix up the existing branch to hit the trampoline. Hope like - hell this doesn't overflow too. */ - if (ppc_elf_install_value (abfd, contents + roff, - f->trampoff - (roff & (bfd_vma) -3) + 4, - r_type) != bfd_reloc_ok) - abort (); + /* Fix up the existing branch to hit the trampoline. */ + hit_addr = contents + roff; + switch (r_type) + { + case R_PPC_REL24: + case R_PPC_LOCAL24PC: + case R_PPC_PLTREL24: + t0 = bfd_get_32 (abfd, hit_addr); + t0 &= ~0x3fffffc; + t0 |= val & 0x3fffffc; + bfd_put_32 (abfd, t0, hit_addr); + break; - changed_contents = TRUE; - changed_relocs = TRUE; + case R_PPC_REL14: + case R_PPC_REL14_BRTAKEN: + case R_PPC_REL14_BRNTAKEN: + t0 = bfd_get_32 (abfd, hit_addr); + t0 &= ~0xfffc; + t0 |= val & 0xfffc; + bfd_put_32 (abfd, t0, hit_addr); + break; + } } - /* Clean up. */ - while (fixups) + /* Write out the trampolines. */ + changed = fixups != NULL; + if (fixups != NULL) { - struct one_fixup *f = fixups; - fixups = fixups->next; - free (f); + const int *stub; + bfd_byte *dest; + bfd_vma val; + int i, size; + + do + { + struct one_fixup *f = fixups; + fixups = fixups->next; + free (f); + } + while (fixups); + + contents = bfd_realloc (contents, trampoff); + if (contents == NULL) + goto error_return; + + isec->_cooked_size = (isec->_cooked_size + 3) & (bfd_vma) -4; + /* Branch around the trampolines. */ + val = trampoff - isec->_cooked_size + 0x48000000; + dest = contents + isec->_cooked_size; + isec->_cooked_size = trampoff; + bfd_put_32 (abfd, val, dest); + dest += 4; + + if (link_info->shared) + { + stub = shared_stub_entry; + size = ARRAY_SIZE (shared_stub_entry); + } + else + { + stub = stub_entry; + size = ARRAY_SIZE (stub_entry); + } + + i = 0; + while (dest < contents + trampoff) + { + bfd_put_32 (abfd, stub[i], dest); + i++; + if (i == size) + i = 0; + dest += 4; + } + BFD_ASSERT (i == 0); } + if (isymbuf != NULL && symtab_hdr->contents != (unsigned char *) isymbuf) { @@ -2015,7 +1973,7 @@ ppc_elf_relax_section (bfd *abfd, if (contents != NULL && elf_section_data (isec)->this_hdr.contents != contents) { - if (!changed_contents && !link_info->keep_memory) + if (!changed && !link_info->keep_memory) free (contents); else { @@ -2026,13 +1984,13 @@ ppc_elf_relax_section (bfd *abfd, if (elf_section_data (isec)->relocs != internal_relocs) { - if (!changed_relocs) + if (!changed) free (internal_relocs); else elf_section_data (isec)->relocs = internal_relocs; } - *again = changed_contents || changed_relocs; + *again = changed; return TRUE; error_return: @@ -4739,7 +4697,7 @@ ppc_elf_relocate_section (bfd *output_bfd, symtab_hdr, relocation, sec, unresolved_reloc, info, warned); - + sym_name = h->root.root.string; } @@ -5462,8 +5420,26 @@ ppc_elf_relocate_section (bfd *output_bfd, + rel->r_offset - 4); /* Fall thru */ case R_PPC_RELAX32: - ppc_elf_install_value (output_bfd, contents + rel->r_offset, - relocation + addend, r_type); + { + unsigned long t0; + unsigned long t1; + + t0 = bfd_get_32 (output_bfd, contents + rel->r_offset); + t1 = bfd_get_32 (output_bfd, contents + rel->r_offset + 4); + + /* We're clearing the bits for R_PPC_ADDR16_HA + and R_PPC_ADDR16_LO here. */ + t0 &= ~0xffff; + t1 &= ~0xffff; + + /* t0 is HA, t1 is LO */ + relocation += addend; + t0 |= ((relocation + 0x8000) >> 16) & 0xffff; + t1 |= relocation & 0xffff; + + bfd_put_32 (output_bfd, t0, contents + rel->r_offset); + bfd_put_32 (output_bfd, t1, contents + rel->r_offset + 4); + } continue; /* Indirect .sdata relocation. */ -- 2.30.2