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Date:   Mon, 26 Feb 2018 10:21:02 +0900
From:   AKASHI Takahiro <takahiro.akashi@linaro.org>
To:     Dave Young <dyoung@redhat.com>
Cc:     Philipp Rudo <prudo@linux.vnet.ibm.com>,
        linux-s390@vger.kernel.org,
        Heiko Carstens <heiko.carstens@de.ibm.com>, x86@kernel.org,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 00/17] Add kexec_file_load support to s390
Message-ID: <20180226012100.GA6019@linaro.org>
Mail-Followup-To: AKASHI Takahiro <takahiro.akashi@linaro.org>,
        Dave Young <dyoung@redhat.com>,
        Philipp Rudo <prudo@linux.vnet.ibm.com>, linux-s390@vger.kernel.org,
        Heiko Carstens <heiko.carstens@de.ibm.com>, x86@kernel.org,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vivek Goyal <vgoyal@redhat.com>
References: <20180212100754.55121-1-prudo@linux.vnet.ibm.com>
 <20180214073543.GA12328@dhcp-128-65.nay.redhat.com>
 <20180214105449.1325bfbe@ThinkPad>
 <20180223083405.GA29498@dhcp-128-65.nay.redhat.com>
 <20180223110143.1747fb3f@ThinkPad>
 <20180224015956.GA11191@dhcp-128-65.nay.redhat.com>
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On Sat, Feb 24, 2018 at 09:59:56AM +0800, Dave Young wrote:
> On 02/23/18 at 11:01am, Philipp Rudo wrote:
> > Hi Dave
> > 
> > On Fri, 23 Feb 2018 16:34:05 +0800
> > Dave Young <dyoung@redhat.com> wrote:
> > 
> > > On 02/14/18 at 10:54am, Philipp Rudo wrote:
> > > > Hi Dave,
> > > > 
> > > > I just browsed AKASHI's patches (v7). The way I see it the common code changes
> > > > are on different areas of kexec_file and shouldn't get in conflict. Only in the
> > > > arch code (s390 and arm64) some function calls might need an update. But I have
> > > > to take a closer look on the patches first.  
> > > 
> > > I'm tring both in local branch with both series (V8 from AKASHI and this series),
> > > but there are indeed some conflicts, may because AKASHI factored out some arch
> > > code from ppc/x86 to common code.
> > 
> > I feared this would happen.  I didn't have time to look at AKASHI's v8
> > yesterday but hope to find some today. How do you think i should handle
> > conflicts with his patches? I don't think it is wise to include the changes
> > into my patches as that would make AKASHI's patches a prereq for mine. Is adding
> > one (multiple?) fixup patches on top of my series ok for you?
> 
> Arch code need arch maintainer to review, maybe either of you can send
> the common part first before the arch code, eg. AKASHI can split the common
>  cleanup patches and post them as a separate series, after these prep
> series are reviewed then other patches can be refreshed based on it.
> 
> Seems in AKASHI's series, only patch 2, 3 ,4 ,5 is needed if split out
> as a common change series.

Yeah, all of those are touching kernel/kexec_file.c and in turn
they can conflict if being applied with 390 patches, but none of changes
that I made on kexec_file.c are overlapped with Phillips', I suppose
that merging these two patch sets is rather straightforward.

@Phillips: I hope that your patch#14 and #17 be aligned with my patch#3
as it is factoring out arch_kexec_{image_probe, image_load, verify_sig}()
and arch_kimage_file_post_load_cleanup().

Thanks,
-Takahiro AKASHI

> What do you think? 
> > 
> > Thanks
> > Philipp
> > 
> > > > 
> > > > @AKASHI: Welcome to the list. While browsing I couldn't find any
> > > > arch_apply_relocation function for arm64. These require the biggest changes in
> > > > my patch set. Did I just miss it or does arm64 work differently?
> > > > 
> > > > @Dave: Happy holiday  
> > > 
> > > Thank you!
> > > 
> > > > 
> > > > Thanks
> > > > Philipp
> > > > 
> > > > On Wed, 14 Feb 2018 15:35:43 +0800
> > > > Dave Young <dyoung@redhat.com> wrote:
> > > >   
> > > > > Hi Philipp,
> > > > > 
> > > > > I added AKASHI in cc, he posted arm64 kexec_file series previously.
> > > > > I would like to read both series especially the general part, but
> > > > > maybe at the end of this month because of a holiday..
> > > > > 
> > > > > From the patch log the cleanup looks nice, but still need read the
> > > > > details.
> > > > > 
> > > > > On 02/12/18 at 11:07am, Philipp Rudo wrote:  
> > > > > > Hi everybody
> > > > > > 
> > > > > > resending the series as there was no reaction, yet. Furthermore i was told
> > > > > > that Andrew and the x86 list should also be CCed, so welcome.
> > > > > > 
> > > > > > No changes made to the patches since first time i sent them. The patches
> > > > > > apply to the current master (v4.16-rc1).
> > > > > > 
> > > > > > Thanks
> > > > > > Philipp
> > > > > > 
> > > > > > ---
> > > > > > 
> > > > > > this series adds the kexec_file_load system call to s390. Before the system
> > > > > > call is added there are some preparations/clean ups to common
> > > > > > kexec_file_load. In detail this series contains:
> > > > > > 
> > > > > > Patch #1&2: Minor cleanups/fixes.
> > > > > > 
> > > > > > Patch #3-9: Clean up the purgatory load/relocation code. Especially remove
> > > > > > the mis-use of the purgatory_info->sechdrs->sh_offset field, currently
> > > > > > holding a pointer into either kexec_purgatory (ro) or purgatory_buf (rw)
> > > > > > depending on the section. With these patches the section address will be
> > > > > > calculated verbosely and sh_offset will contain the offset of the section
> > > > > > in the stripped purgatory binary (purgatory_buf).
> > > > > > 
> > > > > > Patch #10: Allows architectures to set the purgaory load address. This
> > > > > > patch is important for s390 as the kernel and purgatory have to be loaded
> > > > > > to fixed addresses. In current code this is impossible as the purgatory
> > > > > > load is opaque to the architecture.
> > > > > > 
> > > > > > Patch #11: Moves x86 purgatories sha implementation to common lib/
> > > > > > directory.
> > > > > > 
> > > > > > Patches #12-17 finally adds the kexec_file_load system call to s390.
> > > > > > 
> > > > > > Please note that I had to touch arch code for x86 and power a little. In
> > > > > > theory this should not change the behavior but I don't have a way to test
> > > > > > it. Cross-compiling with defconfig(*) works fine for both.
> > > > > > 
> > > > > > Thanks
> > > > > > Philipp
> > > > > > 
> > > > > > (*) On x86 with the orc unwinder turned off. objtool SEGFAULTs on s390...
> > > > > > 
> > > > > > Philipp Rudo (17):
> > > > > >   kexec_file: Silence compile warnings
> > > > > >   kexec_file: Remove checks in kexec_purgatory_load
> > > > > >   kexec_file: Make purgatory_info->ehdr const
> > > > > >   kexec_file: Search symbols in read-only kexec_purgatory
> > > > > >   kexec_file: Use read-only sections in arch_kexec_apply_relocations*
> > > > > >   kexec_file: Split up __kexec_load_puragory
> > > > > >   kexec_file: Simplify kexec_purgatory_setup_sechdrs 1
> > > > > >   kexec_file: Simplify kexec_purgatory_setup_sechdrs 2
> > > > > >   kexec_file: Remove mis-use of sh_offset field
> > > > > >   kexec_file: Allow archs to set purgatory load address
> > > > > >   kexec_file: Move purgatories sha256 to common code
> > > > > >   s390/kexec_file: Prepare setup.h for kexec_file_load
> > > > > >   s390/kexec_file: Add purgatory
> > > > > >   s390/kexec_file: Add kexec_file_load system call
> > > > > >   s390/kexec_file: Add image loader
> > > > > >   s390/kexec_file: Add crash support to image loader
> > > > > >   s390/kexec_file: Add ELF loader
> > > > > > 
> > > > > >  arch/powerpc/kernel/kexec_elf_64.c             |   9 +-
> > > > > >  arch/s390/Kbuild                               |   1 +
> > > > > >  arch/s390/Kconfig                              |   4 +
> > > > > >  arch/s390/include/asm/kexec.h                  |  23 ++
> > > > > >  arch/s390/include/asm/purgatory.h              |  17 ++
> > > > > >  arch/s390/include/asm/setup.h                  |  40 ++-
> > > > > >  arch/s390/kernel/Makefile                      |   1 +
> > > > > >  arch/s390/kernel/asm-offsets.c                 |   5 +
> > > > > >  arch/s390/kernel/compat_wrapper.c              |   1 +
> > > > > >  arch/s390/kernel/kexec_elf.c                   | 149 ++++++++++
> > > > > >  arch/s390/kernel/kexec_image.c                 |  78 +++++
> > > > > >  arch/s390/kernel/machine_kexec_file.c          | 291 +++++++++++++++++++
> > > > > >  arch/s390/kernel/syscalls/syscall.tbl          |   1 +
> > > > > >  arch/s390/purgatory/Makefile                   |  37 +++
> > > > > >  arch/s390/purgatory/head.S                     | 279 ++++++++++++++++++
> > > > > >  arch/s390/purgatory/purgatory.c                |  42 +++
> > > > > >  arch/x86/kernel/kexec-bzimage64.c              |   8 +-
> > > > > >  arch/x86/kernel/machine_kexec_64.c             |  66 ++---
> > > > > >  arch/x86/purgatory/Makefile                    |   3 +
> > > > > >  arch/x86/purgatory/purgatory.c                 |   2 +-
> > > > > >  include/linux/kexec.h                          |  38 +--
> > > > > >  {arch/x86/purgatory => include/linux}/sha256.h |  10 +-
> > > > > >  kernel/kexec_file.c                            | 375 ++++++++++++-------------
> > > > > >  {arch/x86/purgatory => lib}/sha256.c           |   4 +-
> > > > > >  24 files changed, 1200 insertions(+), 284 deletions(-)
> > > > > >  create mode 100644 arch/s390/include/asm/purgatory.h
> > > > > >  create mode 100644 arch/s390/kernel/kexec_elf.c
> > > > > >  create mode 100644 arch/s390/kernel/kexec_image.c
> > > > > >  create mode 100644 arch/s390/kernel/machine_kexec_file.c
> > > > > >  create mode 100644 arch/s390/purgatory/Makefile
> > > > > >  create mode 100644 arch/s390/purgatory/head.S
> > > > > >  create mode 100644 arch/s390/purgatory/purgatory.c
> > > > > >  rename {arch/x86/purgatory => include/linux}/sha256.h (63%)
> > > > > >  rename {arch/x86/purgatory => lib}/sha256.c (99%)
> > > > > > 
> > > > > > -- 
> > > > > > 2.13.5
> > > > > > 
> > > > > > 
> > > > > > _______________________________________________
> > > > > > kexec mailing list
> > > > > > kexec@lists.infradead.org
> > > > > > http://lists.infradead.org/mailman/listinfo/kexec    
> > > > > 
> > > > > Thanks
> > > > > Dave
> > > > >   
> > > >   
> > > 
> > > _______________________________________________
> > > kexec mailing list
> > > kexec@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/kexec
> > > 
> >