[PATCH v2 1/5] RISC-V: Fix local GOT and reloc size calculation for TLS.
Nelson Chu
nelson@rivosinc.com
Wed Feb 21 07:04:05 GMT 2024
Committed this one first after passing the gcc/binutils regressions of
riscv-gnu-toolchain.
Nelson
On Wed, Feb 21, 2024 at 8:49 AM Nelson Chu <nelson@rivosinc.com> wrote:
> Oops I lost this one. This seems to fix the redundant dynamic
> R_RISCV_NONE in .rela.dyn if using --no-pie for tls gd and ie, so looks
> good to me.
>
> Btw, I just noticed that I also reviewed four of the TLS patches since my
> mail box looks weird and only shows the old patches, so I lost this one and
> others... I will see the remaining stuff.
>
> Thanks
> Nelson
>
> On Fri, Sep 1, 2023 at 1:13 AM Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
> wrote:
>
>> The previous code did not account correctly for two cases:
>> * A TLS symbol can be referenced with multiple TLS types (although rare),
>> in which case it only allocated the maximum slot size among the types,
>> instead of the sum.
>> * TLS relocations are only needed for DLLs, unlike normal symbols which
>> requires relocations for all PIE code.
>>
>> Modify the logic to account for the two cases.
>>
>> bfd/
>> * elfnn-riscv.c (riscv_elf_size_dynamic_sections): Handle relocation
>> sizing for TLS and non-TLS symbols differently, with the former
>> requiring relocs on DLL while the latter requiring on PIE.
>> Allocate GOT slots and relocation slots for each TLS type separately,
>> accounting for the possibility of a TLS variable getting referenced by
>> multiple symbols.
>> ld/
>> * testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
>> * testsuite/ld-riscv-elf/tls*: New testcase for TLS GD and IE, with
>> symbols referred by both types and global and local symbols.
>> ---
>> v2: Add tests for GD and IE, testing both global and local symbols.
>> Both -shared and -no-pie are tested.
>>
>> bfd/elfnn-riscv.c | 27 ++++++++++++++++-----
>> ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 8 +++++++
>> ld/testsuite/ld-riscv-elf/tls.d | 15 ++++++++++++
>> ld/testsuite/ld-riscv-elf/tls.s | 28 ++++++++++++++++++++++
>> ld/testsuite/ld-riscv-elf/tlsbin.d | 7 ++++++
>> ld/testsuite/ld-riscv-elf/tlslib.s | 6 +++++
>> 6 files changed, 85 insertions(+), 6 deletions(-)
>> create mode 100644 ld/testsuite/ld-riscv-elf/tls.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/tls.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/tlsbin.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/tlslib.s
>>
>> diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
>> index 09aa7be225e..02b46835cc7 100644
>> --- a/bfd/elfnn-riscv.c
>> +++ b/bfd/elfnn-riscv.c
>> @@ -1562,12 +1562,27 @@ riscv_elf_size_dynamic_sections (bfd *output_bfd,
>> struct bfd_link_info *info)
>> if (*local_got > 0)
>> {
>> *local_got = s->size;
>> - s->size += RISCV_ELF_WORD_BYTES;
>> - if (*local_tls_type & GOT_TLS_GD)
>> - s->size += RISCV_ELF_WORD_BYTES;
>> - if (bfd_link_pic (info)
>> - || (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE)))
>> - srel->size += sizeof (ElfNN_External_Rela);
>> + if (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE))
>> + {
>> + if (*local_tls_type & GOT_TLS_GD)
>> + {
>> + s->size += 2 * RISCV_ELF_WORD_BYTES;
>> + if (bfd_link_dll (info))
>> + srel->size += sizeof (ElfNN_External_Rela);
>> + }
>> + if (*local_tls_type & GOT_TLS_IE)
>> + {
>> + s->size += RISCV_ELF_WORD_BYTES;
>> + if (bfd_link_dll (info))
>> + srel->size += sizeof (ElfNN_External_Rela);
>> + }
>> + }
>> + else
>> + {
>> + s->size += RISCV_ELF_WORD_BYTES;
>> + if (bfd_link_pic (info))
>> + srel->size += sizeof (ElfNN_External_Rela);
>> + }
>> }
>> else
>> *local_got = (bfd_vma) -1;
>> diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> index 947a266ba72..adb4ee75e4a 100644
>> --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> @@ -317,4 +317,12 @@ if [istarget "riscv*-*-*"] {
>> run_dump_test "pcrel-reloc-rel-pie"
>> run_dump_test "pcrel-reloc-abs-nopie"
>> run_dump_test "pcrel-reloc-abs-pie"
>> +
>> + run_ld_link_tests {
>> + { "Build shared library for TLS runtime"
>> + "-shared" "" "" {tlslib.s}
>> + {} "tlslib.so" }
>> + }
>> + run_dump_test "tls"
>> + run_dump_test "tlsbin"
>> }
>> diff --git a/ld/testsuite/ld-riscv-elf/tls.d
>> b/ld/testsuite/ld-riscv-elf/tls.d
>> new file mode 100644
>> index 00000000000..0e2ab5683ad
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/tls.d
>> @@ -0,0 +1,15 @@
>> +#source: tls.s
>> +#ld: --shared tmpdir/tlslib.so
>> +#readelf: -Wr
>> +
>> +Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 5 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_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
>> +
>> +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+ __tls_get_addr \+ 0
>> \ No newline at end of file
>> diff --git a/ld/testsuite/ld-riscv-elf/tls.s
>> b/ld/testsuite/ld-riscv-elf/tls.s
>> new file mode 100644
>> index 00000000000..79e9bc20374
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/tls.s
>> @@ -0,0 +1,28 @@
>> + .section .tbss,"awT",@nobits
>> + .global sg1
>> +sg1:
>> + .zero 4
>> +sl1:
>> + .zero 4
>> +
>> + .text
>> + .globl _start
>> + .type _start,@function
>> +_start:
>> + /* GD, global var */
>> + la.tls.gd a0,sg1
>> + call __tls_get_addr
>> +
>> + /* IE, global var */
>> + la.tls.ie a0,sg1
>> + add a0,a0,tp
>> +
>> + /* GD, local var */
>> + la.tls.gd a0,sl1
>> + call __tls_get_addr
>> +
>> + /* IE, local var */
>> + la.tls.ie a0,sl1
>> + add a0,a0,tp
>> +
>> + ret
>> diff --git a/ld/testsuite/ld-riscv-elf/tlsbin.d
>> b/ld/testsuite/ld-riscv-elf/tlsbin.d
>> new file mode 100644
>> index 00000000000..12a4d0ea703
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/tlsbin.d
>> @@ -0,0 +1,7 @@
>> +#source: tls.s
>> +#ld: -no-pie tmpdir/tlslib.so
>> +#readelf: -Wr
>> +
>> +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
>> \ No newline at end of file
>> diff --git a/ld/testsuite/ld-riscv-elf/tlslib.s
>> b/ld/testsuite/ld-riscv-elf/tlslib.s
>> new file mode 100644
>> index 00000000000..17c770786d0
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/tlslib.s
>> @@ -0,0 +1,6 @@
>> + .text
>> + /* Dummy. */
>> + .globl __tls_get_addr
>> + .type __tls_get_addr,@function
>> +__tls_get_addr:
>> + ret
>> --
>> 2.42.0
>>
>>
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