Re: [PATCH v2 2/5] ia64: reuse append_elf_note() and final_note() functions

[Hari Bathini]

On Saturday 03 December 2016 12:52 AM, Eric W. Biederman wrote:
> Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx> writes:
>
> > Hi Dave,
> >
> >
> > Thanks for the review.
> >
> >
> > On Thursday 01 December 2016 10:26 AM, Dave Young wrote:
> > > Hi Hari
> > >
> > > Personally I like V1 more, but split the patch 2 is easier for ia64
> > > people to reivew.  I did basic x86 testing, it runs ok.
> > >
> > > On 11/25/16 at 05:24pm, Hari Bathini wrote:
> > > > Get rid of multiple definitions of append_elf_note() & final_note()
> > > > functions. Reuse these functions compiled under CONFIG_CRASH_CORE.
> > > >
> > > > Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
> > > > ---
> > > >    arch/ia64/kernel/crash.c   |   22 ----------------------
> > > >    include/linux/crash_core.h |    4 ++++
> > > >    kernel/crash_core.c        |    6 +++---
> > > >    kernel/kexec_core.c        |   28 ----------------------------
> > > >    4 files changed, 7 insertions(+), 53 deletions(-)
> > > >
> > > > diff --git a/arch/ia64/kernel/crash.c b/arch/ia64/kernel/crash.c
> > > > index 2955f35..75859a0 100644
> > > > --- a/arch/ia64/kernel/crash.c
> > > > +++ b/arch/ia64/kernel/crash.c
> > > > @@ -27,28 +27,6 @@ static int kdump_freeze_monarch;
> > > >    static int kdump_on_init = 1;
> > > >    static int kdump_on_fatal_mca = 1;
> > > >    -static inline Elf64_Word
> > > > -*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
> > > > -		size_t data_len)
> > > > -{
> > > > -	struct elf_note *note = (struct elf_note *)buf;
> > > > -	note->n_namesz = strlen(name) + 1;
> > > > -	note->n_descsz = data_len;
> > > > -	note->n_type   = type;
> > > > -	buf += (sizeof(*note) + 3)/4;
> > > > -	memcpy(buf, name, note->n_namesz);
> > > > -	buf += (note->n_namesz + 3)/4;
> > > > -	memcpy(buf, data, data_len);
> > > > -	buf += (data_len + 3)/4;
> > > > -	return buf;
> > > > -}
> > > > -
> > > > -static void
> > > > -final_note(void *buf)
> > > > -{
> > > > -	memset(buf, 0, sizeof(struct elf_note));
> > > > -}
> > > > -
> > > The above IA64 version looks better than the functions in kexec_core.c
> > > about the Elf64_Word type usage and the simpler final_note function.
> > Hmmm.. Is void* better over Elf64_Word* to be agnostic of Elf32 or
> > Elf64 type?
> Both Elf64_Word and Elf32_Word result in a u32.  So I expect the right
> solution is to add a definition of Elf_Word to include/linux/elf.h
> and to make the buffer "Elf_Word *buf".
>
> That way we preserve the alignment knowledge, while making the code
> depend on 32bit or 64bit.
>
> Eric

Thanks for the review, Eric. Will address this in the next version.

As some recent changes in powerpc tree may cause merger conflicts,
I will wait for those changes to get into linus's tree and rebase the
next version on top of that..

Thanks
Hari