Messages in this thread | | | Date | Tue, 17 May 2022 17:25:59 +0800 | From | Baoquan He <> | Subject | Re: [PATCH] kexec_file: Drop pr_err in weak implementations of arch_kexec_apply_relocations[_add] |
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On 04/25/22 at 11:11pm, Naveen N. Rao wrote: > kexec_load_purgatory() can fail for many reasons - there is no need to > print an error when encountering unsupported relocations. > > This solves a build issue on powerpc with binutils v2.36 and newer [1]. > Since commit d1bcae833b32f1 ("ELF: Don't generate unused section > symbols") [2], binutils started dropping section symbols that it thought
I am not familiar with binutils, while wondering if this exists in other ARCHes except of ppc. Arm64 doesn't have the ARCH override either, do we have problem with it?
> were unused. This isn't an issue in general, but with kexec_file.c, gcc > is placing kexec_arch_apply_relocations[_add] into a separate > .text.unlikely section and the section symbol ".text.unlikely" is being > dropped. Due to this, recordmcount is unable to find a non-weak symbol
But arch_kexec_apply_relocations_add is weak symbol on ppc.
> in .text.unlikely to generate a relocation record against. Dropping > pr_err() calls results in these functions being left in .text section,
Why dropping pr_err() can make arch_kexec_apply_relocations_add put in .text?
> enabling recordmcount to emit a proper relocation record. > > [1] https://github.com/linuxppc/issues/issues/388 > [2] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1 > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > kernel/kexec_file.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index 8347fc158d2b96..55d144c58b5278 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -121,7 +121,6 @@ int __weak > arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section, > const Elf_Shdr *relsec, const Elf_Shdr *symtab) > { > - pr_err("RELA relocation unsupported.\n"); > return -ENOEXEC; > } > > @@ -138,7 +137,6 @@ int __weak > arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section, > const Elf_Shdr *relsec, const Elf_Shdr *symtab) > { > - pr_err("REL relocation unsupported.\n"); > return -ENOEXEC; > } > > > base-commit: 83d8a0d166119de813cad27ae7d61f54f9aea707 > -- > 2.35.1 >
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