[PATCH v2 1/5] RISC-V: Fix local GOT and reloc size calculation for TLS.
Nelson Chu
nelson@rivosinc.com
Wed Feb 21 00:49:25 GMT 2024
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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