On Tue, Nov 28, 2023 at 4:51 PM Tatsuyuki Ishi wrote: > Only relocation handling for now; relaxation is not implemented yet. > > bfd/ > * elfnn-riscv.c (riscv_elf_check_relocs): Record GOT reference and > paired relocation for TLSDESC_HI20. > (riscv_elf_adjust_dynamic_symbol): Allocate GOT and reloc slots for > TLSDESC symbols. > (riscv_elf_size_dynamic_sections): Likewise but for local symbols. > (tlsdescoff): New helper to determine static addend for R_TLSDESC. > (riscv_elf_relocate_section): Ignore TLSDESC_CALL reloc for now (it is > relaxation only). > Handle TLSDESC_{LOAD,ADD}_LO12 as paired pcrel relocs. > For TLS GOT slot generation, generalize the logic to handle any > combination of (GD, IE, TLSDESC). > Add TLSDESC Rela generation. > * ld/testsuite/ld-riscv-elf/tls*: Add TLSDESC instruction sequences > next to the existing GD and IE sequences. Update expectations. > --- > bfd/elfnn-riscv.c | 91 +++++++++++++++++++++++++++--- > ld/testsuite/ld-riscv-elf/tls.d | 4 +- > ld/testsuite/ld-riscv-elf/tls.s | 14 +++++ > ld/testsuite/ld-riscv-elf/tlsbin.d | 5 ++ > 4 files changed, 104 insertions(+), 10 deletions(-) > > diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c > index d5190538503..8f63998aa5a 100644 > --- a/bfd/elfnn-riscv.c > +++ b/bfd/elfnn-riscv.c > @@ -163,6 +163,7 @@ struct riscv_elf_link_hash_entry > #define GOT_TLS_GD 2 > #define GOT_TLS_IE 4 > #define GOT_TLS_LE 8 > +#define GOT_TLSDESC 16 > char tls_type; > }; > > @@ -300,6 +301,7 @@ riscv_is_insn_reloc (const reloc_howto_type *howto) > #define GOT_ENTRY_SIZE RISCV_ELF_WORD_BYTES > #define TLS_GD_GOT_ENTRY_SIZE (RISCV_ELF_WORD_BYTES * 2) > #define TLS_IE_GOT_ENTRY_SIZE RISCV_ELF_WORD_BYTES > +#define TLSDESC_GOT_ENTRY_SIZE (RISCV_ELF_WORD_BYTES * 2) > /* Reserve two entries of GOTPLT for ld.so, one is used for PLT resolver, > the other is used for link map. Other targets also reserve one more > entry used for runtime profile? */ > @@ -855,6 +857,12 @@ riscv_elf_check_relocs (bfd *abfd, struct > bfd_link_info *info, > return false; > break; > > + case R_RISCV_TLSDESC_HI20: > + if (!riscv_elf_record_got_reference (abfd, info, h, r_symndx) > + || !riscv_elf_record_tls_type (abfd, h, r_symndx, > GOT_TLSDESC)) > + return false; > + break; > + > case R_RISCV_CALL: > case R_RISCV_CALL_PLT: > /* These symbol requires a procedure linkage table entry. > @@ -1313,7 +1321,7 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, > void *inf) > s = htab->elf.sgot; > h->got.offset = s->size; > dyn = htab->elf.dynamic_sections_created; > - if (tls_type & (GOT_TLS_GD | GOT_TLS_IE)) > + if (tls_type & (GOT_TLS_GD | GOT_TLS_IE | GOT_TLSDESC)) > { > int indx = 0; > bool need_reloc = false; > @@ -1334,6 +1342,14 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, > void *inf) > if (need_reloc) > htab->elf.srelgot->size += sizeof (ElfNN_External_Rela); > } > + > + /* TLSDESC needs one dynamic reloc and two GOT slots. */ > + if (tls_type & GOT_TLSDESC) > + { > + s->size += TLSDESC_GOT_ENTRY_SIZE; > + /* TLSDESC always use dynamic relocs. */ > + htab->elf.srelgot->size += sizeof (ElfNN_External_Rela); > + } } > else > { > @@ -1561,7 +1577,7 @@ riscv_elf_size_dynamic_sections (bfd *output_bfd, > struct bfd_link_info *info) > if (*local_got > 0) > { > *local_got = s->size; > - if (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE)) > + if (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE | > GOT_TLSDESC)) > { > if (*local_tls_type & GOT_TLS_GD) > { > @@ -1575,6 +1591,11 @@ riscv_elf_size_dynamic_sections (bfd *output_bfd, > struct bfd_link_info *info) > if (bfd_link_dll (info)) > srel->size += sizeof (ElfNN_External_Rela); > } > + if (*local_tls_type & GOT_TLSDESC) > + { > + s->size += TLSDESC_GOT_ENTRY_SIZE; > + srel->size += sizeof (ElfNN_External_Rela); > + } > The code base seems different from the upstream code. > } > else > { > @@ -1725,6 +1746,17 @@ tpoff (struct bfd_link_info *info, bfd_vma address) > return address - elf_hash_table (info)->tls_sec->vma - TP_OFFSET; > } > > +/* Return the relocation value for a static TLSDESC relocation. */ > + > +static bfd_vma > +tlsdescoff (struct bfd_link_info *info, bfd_vma address) > +{ > + /* If tls_sec is NULL, we should have signalled an error already. */ > + if (elf_hash_table (info)->tls_sec == NULL) > + return 0; > + return address - elf_hash_table (info)->tls_sec->vma; > +} > + > /* Return the global pointer's value, or 0 if it is not in use. */ > > static bfd_vma > @@ -1774,6 +1806,7 @@ perform_relocation (const reloc_howto_type *howto, > case R_RISCV_GOT_HI20: > case R_RISCV_TLS_GOT_HI20: > case R_RISCV_TLS_GD_HI20: > + case R_RISCV_TLSDESC_HI20: > if (ARCH_SIZE > 32 && !VALID_UTYPE_IMM (RISCV_CONST_HIGH_PART > (value))) > return bfd_reloc_overflow; > value = ENCODE_UTYPE_IMM (RISCV_CONST_HIGH_PART (value)); > @@ -1784,6 +1817,8 @@ perform_relocation (const reloc_howto_type *howto, > case R_RISCV_TPREL_LO12_I: > case R_RISCV_TPREL_I: > case R_RISCV_PCREL_LO12_I: > + case R_RISCV_TLSDESC_LOAD_LO12: > + case R_RISCV_TLSDESC_ADD_LO12: > value = ENCODE_ITYPE_IMM (value); > break; > > @@ -2202,8 +2237,8 @@ riscv_elf_relocate_section (bfd *output_bfd, > bfd_vma relocation; > bfd_reloc_status_type r = bfd_reloc_ok; > const char *name = NULL; > - bfd_vma off, ie_off; > - bool unresolved_reloc, is_ie = false; > + bfd_vma off, ie_off, desc_off; > + bool unresolved_reloc, is_ie = false, is_desc = false; > bfd_vma pc = sec_addr (input_section) + rel->r_offset; > int r_type = ELFNN_R_TYPE (rel->r_info), tls_type; > reloc_howto_type *howto = riscv_elf_rtype_to_howto (input_bfd, > r_type); > @@ -2506,6 +2541,7 @@ riscv_elf_relocate_section (bfd *output_bfd, > case R_RISCV_NONE: > case R_RISCV_RELAX: > case R_RISCV_TPREL_ADD: > + case R_RISCV_TLSDESC_CALL: > case R_RISCV_COPY: > case R_RISCV_JUMP_SLOT: > case R_RISCV_RELATIVE: > @@ -2827,6 +2863,15 @@ riscv_elf_relocate_section (bfd *output_bfd, > relocation = dtpoff (info, relocation); > break; > > + case R_RISCV_TLSDESC_LOAD_LO12: > + case R_RISCV_TLSDESC_ADD_LO12: > + if (riscv_record_pcrel_lo_reloc (&pcrel_relocs, relocation, rel, > + input_section, info, howto, > + contents)) > + continue; > + r = bfd_reloc_overflow; > + break; > + > According to the spec, we probably can add a check here to make sure the addend must be zero, otherwise report dangerous relocation, just similar to what pcrel_lo did. > case R_RISCV_32: > /* Non ABS symbol should be blocked in check_relocs. */ > if (ARCH_SIZE > 32) > @@ -2892,11 +2937,16 @@ riscv_elf_relocate_section (bfd *output_bfd, > } > break; > > + case R_RISCV_TLSDESC_HI20: > + is_desc = true; > + goto tls; > + > case R_RISCV_TLS_GOT_HI20: > is_ie = true; > - /* Fall through. */ > + goto tls; > > case R_RISCV_TLS_GD_HI20: > + tls: > if (h != NULL) > { > off = h->got.offset; > @@ -2909,12 +2959,16 @@ riscv_elf_relocate_section (bfd *output_bfd, > } > > tls_type = _bfd_riscv_elf_tls_type (input_bfd, h, r_symndx); > - BFD_ASSERT (tls_type & (GOT_TLS_IE | GOT_TLS_GD)); > + BFD_ASSERT (tls_type & (GOT_TLS_IE | GOT_TLS_GD | GOT_TLSDESC)); > /* If this symbol is referenced by both GD and IE TLS, the IE > reference's GOT slot follows the GD reference's slots. */ > ie_off = 0; > if ((tls_type & GOT_TLS_GD) && (tls_type & GOT_TLS_IE)) > - ie_off = TLS_GD_GOT_ENTRY_SIZE; > + ie_off += TLS_GD_GOT_ENTRY_SIZE; > + > + desc_off = ie_off; > + if (tls_type & GOT_TLS_IE) > + desc_off += TLS_IE_GOT_ENTRY_SIZE; Is it possible that we only link GD and DESC, but without IE? > if ((off & 1) != 0) > off &= ~1; > @@ -2996,10 +3050,29 @@ riscv_elf_relocate_section (bfd *output_bfd, > htab->elf.sgot->contents + off + ie_off); > } > } > + > + if (tls_type & GOT_TLSDESC) > + { > + /* TLSDESC is always handled by the dynamic linker and > always need > + * a relocation. */ > + bfd_put_NN (output_bfd, 0, > + htab->elf.sgot->contents + off + desc_off); > + outrel.r_offset = sec_addr (htab->elf.sgot) > + + off + desc_off; > + outrel.r_addend = 0; > + if (indx == 0) > + outrel.r_addend = tlsdescoff (info, relocation); > + outrel.r_info = ELFNN_R_INFO (indx, R_RISCV_TLSDESC); > + riscv_elf_append_rela (output_bfd, htab->elf.srelgot, > &outrel); > + } > } > > BFD_ASSERT (off < (bfd_vma) -2); > - relocation = sec_addr (htab->elf.sgot) + off + (is_ie ? ie_off : > 0); > + relocation = sec_addr (htab->elf.sgot) + off; > + if (is_ie) > + relocation += ie_off; > + else if (is_desc) > + relocation += desc_off; > if (!riscv_record_pcrel_hi_reloc (&pcrel_relocs, pc, > relocation, r_type, > false)) > @@ -3219,7 +3292,7 @@ riscv_elf_finish_dynamic_symbol (bfd *output_bfd, > } > > if (h->got.offset != (bfd_vma) -1 > - && !(riscv_elf_hash_entry (h)->tls_type & (GOT_TLS_GD | GOT_TLS_IE)) > + && !(riscv_elf_hash_entry (h)->tls_type & (GOT_TLS_GD | GOT_TLS_IE > | GOT_TLSDESC)) > && !UNDEFWEAK_NO_DYNAMIC_RELOC (info, h)) > { > asection *sgot; > diff --git a/ld/testsuite/ld-riscv-elf/tls.d > b/ld/testsuite/ld-riscv-elf/tls.d > index e7f20309bf1..6cf008ac7a0 100644 > --- a/ld/testsuite/ld-riscv-elf/tls.d > +++ b/ld/testsuite/ld-riscv-elf/tls.d > @@ -2,13 +2,15 @@ > #ld: --shared tmpdir/tlslib.so > #readelf: -Wr > > -Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 5 entries: > +Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 7 entries: > +Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend > [0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPMOD64 +0 > [0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_TPREL64 +4 > +[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLSDESC +4 > [0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPMOD64 +0+ sg1 \+ 0 > [0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPREL64 +0+ sg1 \+ 0 > [0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_TPREL64 +0+ sg1 \+ 0 > +[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLSDESC +0+ sg1 \+ 0 > > Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry: > +Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend > diff --git a/ld/testsuite/ld-riscv-elf/tls.s > b/ld/testsuite/ld-riscv-elf/tls.s > index 79e9bc20374..7cbf5ea6c72 100644 > --- a/ld/testsuite/ld-riscv-elf/tls.s > +++ b/ld/testsuite/ld-riscv-elf/tls.s > @@ -17,6 +17,13 @@ _start: > la.tls.ie a0,sg1 > add a0,a0,tp > > + /* GD (TLSDESC), global var */ > +.desc1: > + auipc a0, %tlsdesc_hi(sg1) > + lw t0, %tlsdesc_load_lo(.desc1)(a0) > + addi a0, a0, %tlsdesc_add_lo(.desc1) > + jalr t0, t0, %tlsdesc_call(.desc1) > + > /* GD, local var */ > la.tls.gd a0,sl1 > call __tls_get_addr > @@ -25,4 +32,11 @@ _start: > la.tls.ie a0,sl1 > add a0,a0,tp > > + /* GD (TLSDESC), local var */ > +.desc2: > + auipc a0, %tlsdesc_hi(sl1) > + lw t0, %tlsdesc_load_lo(.desc2)(a0) > + addi a0, a0, %tlsdesc_add_lo(.desc2) > + jalr t0, t0, %tlsdesc_call(.desc2) > + > ret > diff --git a/ld/testsuite/ld-riscv-elf/tlsbin.d > b/ld/testsuite/ld-riscv-elf/tlsbin.d > index cdcd51a9199..79b7ade405e 100644 > --- a/ld/testsuite/ld-riscv-elf/tlsbin.d > +++ b/ld/testsuite/ld-riscv-elf/tlsbin.d > @@ -2,6 +2,11 @@ > #ld: -no-pie tmpdir/tlslib.so > #readelf: -Wr > > +Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 2 entries: > + +Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend > +[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLSDESC +4 > +[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLSDESC +0 > + > Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry: > +Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend > [0-9a-f]+ +[0-9a-f]+ R_RISCV_JUMP_SLOT +[0-9a-f]+ __tls_get_addr \+ 0 > -- > 2.43.0 > >