[PATCH] RISC-V: PR27566, consider ELF_MAXPAGESIZE/COMMONPAGESIZE for gp relaxations.
Nelson Chu
nelson@rivosinc.com
Thu Dec 5 01:19:13 GMT 2024
Hi guys, I have heard recently that this patch can fix the truncated errors
for gcc testsuites, which defines symbols to rodata but the values outside
the section size, especially when using newlib. So ping and will commit it
to fix the problem if no one objects before this week.
Thanks
Nelson
On Fri, May 12, 2023 at 5:16 PM Nelson Chu <nelson@rivosinc.com> wrote:
> For default linker script, if a symbol's value outsides the bounds of the
> defined section, then it may cross the data segment alignment, so we should
> reserve more size about MAXPAGESIZE and COMMONPAGESIZE when doing gp
> relaxations. Otherwise we may meet the truncated errors since the data
> segment alignment might move the section forward.
>
> bfd/
> * elfnn-riscv.c (_bfd_riscv_relax_lui): Consider MAXPAGESIZE and
> COMMONPAGESIZE if the symbol's value outsides the bounds of the
> defined section.
> (_bfd_riscv_relax_pc): Likewise.
> ld/
> * testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
> * testsuite/ld-riscv-elf/relax-data-segment-align*: New testcase
> for pr27566. Without this patch, the rv32 binutils will meet
> truncated errors for this testcase.
> ---
> bfd/elfnn-riscv.c | 29 +++++++++++++++++--
> ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 1 +
> .../ld-riscv-elf/relax-data-segment-align.d | 8 +++++
> .../ld-riscv-elf/relax-data-segment-align.s | 16 ++++++++++
> 4 files changed, 52 insertions(+), 2 deletions(-)
> create mode 100644 ld/testsuite/ld-riscv-elf/relax-data-segment-align.d
> create mode 100644 ld/testsuite/ld-riscv-elf/relax-data-segment-align.s
>
> diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
> index a23b91ac15c..26f965945d3 100644
> --- a/bfd/elfnn-riscv.c
> +++ b/bfd/elfnn-riscv.c
> @@ -4512,6 +4512,9 @@ _bfd_riscv_relax_lui (bfd *abfd,
> bfd_vma gp = htab->params->relax_gp
> ? riscv_global_pointer_value (link_info)
> : 0;
> + bfd_vma data_segment_alignment = link_info->relro
> + ? ELF_MAXPAGESIZE + ELF_COMMONPAGESIZE
> + : ELF_MAXPAGESIZE;
> int use_rvc = elf_elfheader (abfd)->e_flags & EF_RISCV_RVC;
>
> BFD_ASSERT (rel->r_offset + 4 <= sec->size);
> @@ -4536,6 +4539,16 @@ _bfd_riscv_relax_lui (bfd *abfd,
> htab->max_alignment_for_gp = max_alignment;
> }
> }
> +
> + /* PR27566, for default linker script, if a symbol's value outsides
> the
> + bounds of the defined section, then it may cross the data segment
> + alignment, so we should reserve more size about MAXPAGESIZE and
> + COMMONPAGESIZE, since the data segment alignment might move the
> + section forward. */
> + if (symval < sec_addr (sym_sec)
> + || symval > (sec_addr (sym_sec) + sym_sec->size))
> + max_alignment = data_segment_alignment > max_alignment
> + ? data_segment_alignment : max_alignment;
> }
>
> /* Is the reference in range of x0 or gp?
> @@ -4580,8 +4593,7 @@ _bfd_riscv_relax_lui (bfd *abfd,
> && ELFNN_R_TYPE (rel->r_info) == R_RISCV_HI20
> && VALID_CITYPE_LUI_IMM (RISCV_CONST_HIGH_PART (symval))
> && VALID_CITYPE_LUI_IMM (RISCV_CONST_HIGH_PART (symval)
> - + (link_info->relro ? 2 * ELF_MAXPAGESIZE
> - : ELF_MAXPAGESIZE)))
> + + data_segment_alignment))
> {
> /* Replace LUI with C.LUI if legal (i.e., rd != x0 and rd !=
> x2/sp). */
> bfd_vma lui = bfd_getl32 (contents + rel->r_offset);
> @@ -4726,6 +4738,9 @@ _bfd_riscv_relax_pc (bfd *abfd ATTRIBUTE_UNUSED,
> bfd_vma gp = htab->params->relax_gp
> ? riscv_global_pointer_value (link_info)
> : 0;
> + bfd_vma data_segment_alignment = link_info->relro
> + ? ELF_MAXPAGESIZE + ELF_COMMONPAGESIZE
> + : ELF_MAXPAGESIZE;
>
> BFD_ASSERT (rel->r_offset + 4 <= sec->size);
>
> @@ -4800,6 +4815,16 @@ _bfd_riscv_relax_pc (bfd *abfd ATTRIBUTE_UNUSED,
> htab->max_alignment_for_gp = max_alignment;
> }
> }
> +
> + /* PR27566, for default linker script, if a symbol's value outsides
> the
> + bounds of the defined section, then it may cross the data segment
> + alignment, so we should reserve more size about MAXPAGESIZE and
> + COMMONPAGESIZE, since the data segment alignment might move the
> + section forward. */
> + if (symval < sec_addr (sym_sec)
> + || symval > (sec_addr (sym_sec) + sym_sec->size))
> + max_alignment = data_segment_alignment > max_alignment
> + ? data_segment_alignment : max_alignment;
> }
>
> /* Is the reference in range of x0 or gp?
> diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
> b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
> index 9e103b283f7..713e741c8af 100644
> --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
> +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
> @@ -172,6 +172,7 @@ if [istarget "riscv*-*-*"] {
> run_dump_test "attr-merge-priv-spec-failed-06"
> run_dump_test "attr-phdr"
> run_dump_test "relax-max-align-gp"
> + run_dump_test "relax-data-segment-align"
> run_ld_link_tests [list \
> [list "Weak reference 32" "-T weakref.ld
> -m[riscv_choose_ilp32_emul]" "" \
> "-march=rv32i -mabi=ilp32" {weakref32.s} \
> diff --git a/ld/testsuite/ld-riscv-elf/relax-data-segment-align.d
> b/ld/testsuite/ld-riscv-elf/relax-data-segment-align.d
> new file mode 100644
> index 00000000000..22aeb4c3f90
> --- /dev/null
> +++ b/ld/testsuite/ld-riscv-elf/relax-data-segment-align.d
> @@ -0,0 +1,8 @@
> +#source: relax-data-segment-align.s
> +#ld:
> +#objdump: -d
> +
> +#failif
> +#...
> +.*gp.*
> +#...
> diff --git a/ld/testsuite/ld-riscv-elf/relax-data-segment-align.s
> b/ld/testsuite/ld-riscv-elf/relax-data-segment-align.s
> new file mode 100644
> index 00000000000..98718922fb5
> --- /dev/null
> +++ b/ld/testsuite/ld-riscv-elf/relax-data-segment-align.s
> @@ -0,0 +1,16 @@
> + .text
> + .globl _start
> +_start:
> + .rept 6000
> + lla a0, symbol
> + .endr
> +
> + .section .rodata
> + .set symbol, . + 4598
> + .fill 100, 4, 1
> +
> + .data
> + .align 3
> + .rept 860
> + .long 0x1000
> + .endr
> --
> 2.39.2 (Apple Git-143)
>
>
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