Re: [PATCH] riscv: relocate R_RISCV_CALL_PLT in kexec_file

Conor Dooley
2023-03-21T15:24:36Z

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On Tue, Mar 21, 2023 at 04:03:49PM +0100, Torsten Duwe wrote:
> 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?

It's not been all that longer than a week & you're in patchwork so you
won't be forgotten, but I noticed a complaint when I went looking on
patchwork about your fixes tag:

Commit: f28b81e30b4b ("riscv: relocate R_RISCV_CALL_PLT in kexec_file")
Fixes tag: fixes: 838b3e28488f702 ("Load purgatory in kexec_file")
Has these problem(s):
- Subject does not match target commit subject
Just use
git log -1 --format='Fixes: %h ("%s")'

The fixes tag should be:
Fixes: 838b3e28488f ("RISC-V: Load purgatory in kexec_file")

Note the capital F & the missed RISC-V: prefix, checkpatch should have
complained about this.
Checkpatch also complains that your suse email in the Signoff doesn't
match the lst.de email that you used to send the patch (IOW you're
missing a From: header that send-email would add).

Could you fix those things up please & I suppose you can take the
opportunity to make the changes that Li Zhengyu suggested to the commit
message itself at the same time.

Thanks,
Conor.

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