Re: [PATCH v13 4/8] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c

[Mike Rapoport <rppt@kernel.org>]

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On Thu, Nov 12, 2020 at 04:17:01PM +0800, chenzhou wrote:
> Hi all,
> 
> 
> On 2020/11/11 21:20, kernel test robot wrote:
> > Hi Chen,
> >
> > Thank you for the patch! Perhaps something to improve:
> >
> > [auto build test WARNING on tip/master]
> > [also build test WARNING on linus/master v5.10-rc3 next-20201111]
> > [cannot apply to arm64/for-next/core tip/x86/core]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch]
> >
> > url:    https://github.com/0day-ci/linux/commits/Chen-Zhou/support-reserving-crashkernel-above-4G-on-arm64-kdump/20201031-154154
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 6f72faf4a32303c8bdc6491186b79391e9cf0c7e
> > config: i386-randconfig-r024-20201110 (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> > reproduce (this is a W=1 build):
> >         # https://github.com/0day-ci/linux/commit/0384057e2a51e71f42a0e1cb9d37555f4f37874e
> >         git remote add linux-review https://github.com/0day-ci/linux
> >         git fetch --no-tags linux-review Chen-Zhou/support-reserving-crashkernel-above-4G-on-arm64-kdump/20201031-154154
> >         git checkout 0384057e2a51e71f42a0e1cb9d37555f4f37874e
> >         # save the attached .config to linux build tree
> >         make W=1 ARCH=i386 
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All warnings (new ones prefixed by >>):
> >
> >    In file included from arch/x86/kernel/setup.c:39:
> >>> arch/x86/include/asm/kexec.h:77: warning: "vmcore_elf_check_arch_cross" redefined
> >       77 | # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> >          | 
> >    In file included from arch/x86/kernel/setup.c:9:
> >    include/linux/crash_dump.h:39: note: this is the location of the previous definition
> >       39 | #define vmcore_elf_check_arch_cross(x) 0
> >          | 
> The root cause is that some code under CONFIG_CRASH_CORE depend on CONFIG_KEXEC_CORE.
> 
> Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and reuse crashkernel
> parameter for fadump" removes dependency with CONFIG_KEXEC for crashkernel parameter
> and vmcoreinfo related code.
> This patch series introduce CONFIG_CRASH_CORE and move code related to vmcoreinfo and
> parsing of crashkernel parameter under this config, allowing code reuse without dependency
> on CONFIG_KEXEC.
> 
> But some functions and macros(in file asm/kexec.h) related with vmcoreinfo may also have
> this dependency on CONFIG_KEXEC/CONFIG_KEXEC_CORE.
> 
> For example, for x86_32, the macro vmcore_elf_check_arch_cross, if CONFIG_KEXEC_CORE
> is disabled, vmcore_elf_check_arch_cross will always return 0. I think this is wrong.
> # git grep -w vmcore_elf_check_arch_cross
> arch/x86/include/asm/kexec.h:# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> include/linux/crash_dump.h:#ifndef vmcore_elf_check_arch_cross
> include/linux/crash_dump.h:#define vmcore_elf_check_arch_cross(x) 0
> include/linux/crash_dump.h:#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
> 
> I want to move these dependency functions and macros from asm/kexec.h to asm/crash_dump.h(new file),
> is my understanding right or any suggestions about this?

I'd simply move vmcore_elf_check_arch_cross() from
arch/x86/include/asm/kexec.h to arch/x86/include/elf.h.
The latter is already included in linux/crash_dump.h.

> Thanks,
> Chen Zhou
> > vim +/vmcore_elf_check_arch_cross +77 arch/x86/include/asm/kexec.h
> >
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  75  
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  76  /* We can also handle crash dumps from 64 bit kernel. */
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30 @77  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  78  #else
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  79  /* Maximum physical address we can use pages from */
> > 577af55d802d9f arch/x86/include/asm/kexec.h Yinghai Lu      2013-01-24  80  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  81  /* Maximum address we can reach in physical address mode */
> > 577af55d802d9f arch/x86/include/asm/kexec.h Yinghai Lu      2013-01-24  82  # define KEXEC_DESTINATION_MEMORY_LIMIT (MAXMEM-1)
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  83  /* Maximum address we can use for the control pages */
> > 577af55d802d9f arch/x86/include/asm/kexec.h Yinghai Lu      2013-01-24  84  # define KEXEC_CONTROL_MEMORY_LIMIT     (MAXMEM-1)
> > 3c233d1334ffc8 include/asm-x86/kexec.h      Harvey Harrison 2008-01-30  85  
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
> 

-- 
Sincerely yours,
Mike.