Re: [PATCH] riscv: relocate R_RISCV_CALL_PLT in kexec_file

Torsten Duwe
2023-03-21T15:04:15Z

On Mon, 13 Mar 2023 11:13:17 +0800
Li Zhengyu <lizhengyu3@huawei.com> wrote:

> On Fri, 10 Mar 2023 19:27:03 +0100, Torsten Duwe <duwe@lst.de> wrote:
> > Depending on the toolchain (here: gcc-12, binutils-2.40) the
> > relocation entries for function calls are no longer R_RISCV_CALL, but
> > R_RISCV_CALL_PLT. When trying kexec_load_file on such kernels, it will
> > fail with
> >
> > kexec_image: Unknown rela relocation: 19
> > kexec_image: Error loading purgatory ret=-8
> >
> > The binary code at the call site remains the same, so tell
> > arch_kexec_apply_relocations_add() to handle _PLT alike.
>
> R_RISCV_CALL has already been deprecated, and replaced by R_RISCV_CALL_PLT.
>
> See Enum 18-19 in Table 3. Relocation types from
> https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc
> .
>
> It was deprecated in ("Deprecated R_RISCV_CALL, prefer
> R_RISCV_CALL_PLT")
> https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a0dced85018d7a0ec17023c9389cbd70b1dbc1b0
>
> >
> > fixes: 838b3e28488f702 ("Load purgatory in kexec_file")
> > Signed-off-by: Torsten Duwe <duwe@suse.de>
> > Cc: stable@vger.kernel.org
> >
> > ---
> > --- a/arch/riscv/kernel/elf_kexec.c
> > +++ b/arch/riscv/kernel/elf_kexec.c
> > @@ -425,6 +425,7 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
> > * sym, instead of searching the whole relsec.
> > */
> > case R_RISCV_PCREL_HI20:
> > + case R_RISCV_CALL_PLT:
> > case R_RISCV_CALL:
> > *(u64 *)loc = CLEAN_IMM(UITYPE, *(u64 *)loc) |
> > ENCODE_UJTYPE_IMM(val - addr);
> >
> > .
>
> Palmer, please apply these references to the commit message.
>
> Reviewed-by: Li Zhengyu <lizhengyu3@huawei.com>
>

Ping?