ppc476 linker workaround shared lib fixes
When building a shared lib from non-PIC objects, we'll get dynamic text relocations. These need to move with any insns we move. Otherwise the dynamic reloc will modify the branch, resulting in crashes and other unpleasant behaviour. Also, ld -r --ppc476-workaround used with sufficiently aligned PIC objects needs a fix for emitted REL16 relocs. bfd/ * elf64-ppc.c (ppc_elf_relocate_section): Move dynamic text relocs with insns moved by --ppc476-workaround. Correct output of REL16 relocs. ld/testsuite/ * ld-powerpc/ppc476-shared.s, * ld-powerpc/ppc476-shared.lnk, * ld-powerpc/ppc476-shared.d, * ld-powerpc/ppc476-shared2.d: New tests. * ld-powerpc/powerpc.exp: Run them.
This commit is contained in:
Alan Modra
parent
bdd2d2b7e6
commit
f8b447819b
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@ -1,3 +1,9 @@
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2015-06-05 Alan Modra <amodra@gmail.com>
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* elf64-ppc.c (ppc_elf_relocate_section): Move dynamic text
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relocs with insns moved by --ppc476-workaround. Correct
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output of REL16 relocs.
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2015-06-01 Jiong Wang <jiong.wang@arm.com>
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* elfnn-aarch64.c (aarch64_reloc_got_type): Support
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@ -9608,6 +9608,8 @@ ppc_elf_relocate_section (bfd *output_bfd,
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&& rel->r_offset >= offset
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&& rel->r_offset < offset + 4)
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{
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asection *sreloc;
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/* If the insn we are patching had a reloc, adjust the
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reloc r_offset so that the reloc applies to the moved
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location. This matters for -r and --emit-relocs. */
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@ -9620,6 +9622,56 @@ ppc_elf_relocate_section (bfd *output_bfd,
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relend[-1] = tmp;
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}
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relend[-1].r_offset += patch_off - offset;
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/* Adjust REL16 addends too. */
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switch (ELF32_R_TYPE (relend[-1].r_info))
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{
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case R_PPC_REL16:
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case R_PPC_REL16_LO:
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case R_PPC_REL16_HI:
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case R_PPC_REL16_HA:
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relend[-1].r_addend += patch_off - offset;
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break;
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default:
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break;
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}
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/* If we are building a PIE or shared library with
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non-PIC objects, perhaps we had a dynamic reloc too?
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If so, the dynamic reloc must move with the insn. */
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sreloc = elf_section_data (input_section)->sreloc;
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if (sreloc != NULL)
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{
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bfd_byte *slo, *shi, *srelend;
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bfd_vma soffset;
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slo = sreloc->contents;
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shi = srelend
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= slo + sreloc->reloc_count * sizeof (Elf32_External_Rela);
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soffset = (offset + input_section->output_section->vma
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+ input_section->output_offset);
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while (slo < shi)
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{
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bfd_byte *srel = slo + (shi - slo) / 2;
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bfd_elf32_swap_reloca_in (output_bfd, srel, &outrel);
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if (outrel.r_offset < soffset)
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slo = srel + 1;
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else if (outrel.r_offset > soffset + 3)
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shi = srel;
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else
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{
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bfd_byte *nextr = srel + sizeof (Elf32_External_Rela);
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if (nextr != srelend)
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{
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memmove (srel, nextr, srelend - nextr);
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srel = srelend - sizeof (Elf32_External_Rela);
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}
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outrel.r_offset += patch_off - offset;
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bfd_elf32_swap_reloca_out (output_bfd, &outrel, srel);
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break;
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}
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}
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}
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}
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else
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rel = NULL;
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@ -1,3 +1,11 @@
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2015-06-05 Alan Modra <amodra@gmail.com>
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* ld-powerpc/ppc476-shared.s,
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* ld-powerpc/ppc476-shared.lnk,
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* ld-powerpc/ppc476-shared.d,
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* ld-powerpc/ppc476-shared2.d: New tests.
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* ld-powerpc/powerpc.exp: Run them.
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2015-06-02 Jiong Wang <jiong.wang@arm.com>
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* ld-aarch64/emit-relocs-313.s: Use gotpage_lo15.
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@ -325,3 +325,6 @@ run_dump_test "attr-gnu-12-11"
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run_dump_test "attr-gnu-12-21"
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run_dump_test "vle-multiseg-6"
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run_dump_test "ppc476-shared"
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run_dump_test "ppc476-shared2"
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@ -0,0 +1,30 @@
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#source: ppc476-shared.s
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#as: -a32
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#ld: -melf32ppc -q -shared --ppc476-workaround -T ppc476-shared.lnk
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#objdump: -dr
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#target: powerpc*-*-*
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.*: file format .*
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Disassembly of section \.text:
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0+fffc <\.text>:
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fffc: (48 01 00 04|04 00 01 48) b 20000 .*
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10000: (38 63 00 00|00 00 63 38) addi r3,r3,0
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1000[02]: R_PPC_ADDR16_LO .bss
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\.\.\.
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1fff0: (42 9f 00 05|05 00 9f 42) bcl .*
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1fff4: (7d 28 02 a6|a6 02 28 7d) mflr r9
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1fff8: (3d 29 00 00|00 00 29 3d) addis r9,r9,0
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1fff[8a]: R_PPC_REL16_HA .bss\+0x[46]
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1fffc: (48 00 00 14|14 00 00 48) b 20010 .*
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20000: (3c 60 00 00|00 00 60 3c) lis r3,0
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2000[02]: R_PPC_ADDR16_HA .bss
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20004: (4b fe ff fc|fc ff fe 4b) b 10000 .*
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20008: (48 00 00 02|02 00 00 48) ba 0 .*
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2000c: (48 00 00 02|02 00 00 48) ba 0 .*
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20010: (39 29 01 00|00 01 29 39) addi r9,r9,256
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2001[02]: R_PPC_REL16_LO .bss\+0x1[ce]
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20014: (4b ff ff ec|ec ff ff 4b) b 20000 .*
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20018: (48 00 00 02|02 00 00 48) ba 0 .*
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2001c: (48 00 00 02|02 00 00 48) ba 0 .*
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@ -0,0 +1,6 @@
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SECTIONS
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{
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. = 0xfffc;
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.text : { *(.text) }
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.bss : { *(.bss) }
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}
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@ -0,0 +1,13 @@
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.text
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lis 3,x@ha
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addi 3,3,x@l
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.org 0xfff4
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bcl 20,31,.+4
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0:
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mflr 9
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addis 9,9,x-0b@ha
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addi 9,9,x-0b@l
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.section .bss,"aw",@nobits
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x: .space 4
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@ -0,0 +1,12 @@
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#source: ppc476-shared.s
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#as: -a32
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#ld: -melf32ppc -shared --ppc476-workaround -T ppc476-shared.lnk
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#objdump: -R
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#target: powerpc*-*-*
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.*: file format .*
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DYNAMIC RELOCATION RECORDS
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OFFSET TYPE VALUE
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0001000[02] R_PPC_ADDR16_LO \.text\+0x000200f4
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0002000[02] R_PPC_ADDR16_HA \.text\+0x000200f4
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