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Re: [PULL REQUEST] [PATCH v2 00/10] allow BFLT executables on systems with a MMU

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Hi Nicolas,

On 18/07/16 13:31, Nicolas Pitre wrote:
> This series provides the necessary changes to allow "flat" executable
> binaries meant for no-MMU systems to actually run on systems with a MMU.
> 
> This can also be found in the following git repo:
> 
> 	git://git.linaro.org/people/nicolas.pitre/linux binfmt_flat_with_mmu
> 
> *Why?*
> 
> Because developing and testing natively on a large system with lots of
> RAM makes it so much more convenient to use all the existing profiling
> tools and debugging facilities that a kernel with lots of RAM can give.
> And incidentally, those systems with lots of RAM all have a MMU.
> 
> *Why not use elf_fdpic?*
> 
> The flat executable format is simple with very small footprint
> overhead, either in the executables themselves or kernel support.
> This makes the flat format more suitable than elf_fdpic for very small
> single-user-app embedded systems.
> 
> And while elf_fdpic binaries can run on MMU systems, flat binaries still
> couldn't, which just felt wrong.
> 
> So here it is.  The no-MMU support should remain unaffected. Please consider
> for pulling.
> 
> Tested on ARM only with a busybox build.

Tested on m68k (ColdFire specifically) and everything compiles
cleanly and works as before.

I tried running a flat binary on an MMU ColdFire system and
that crashed out with a SIGSEGV. I haven't debugged any further
than that yet.

I had a look over the patches and I didn't see any specific
problems. So from me:

Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>

When I get a minute I'll dig a little into that bflat running
on MMU problem on ColdFire.

Regards
Greg



> Changes since v1:
> 
> - Removed SuperH and Xtensa from the Kconfig rule as they fail to build
>   due to lack of get/put_unaligned_user().
> 
> - Clarified some commit logs a bit.
> 
> diffstat:
> 
>  arch/arm/include/asm/flat.h  |   5 +-
>  arch/m68k/include/asm/flat.h |   5 +-
>  fs/Kconfig.binfmt            |   3 +-
>  fs/binfmt_elf_fdpic.c        |  38 +---
>  fs/binfmt_flat.c             | 372 +++++++++++++++++++++--------------
>  fs/exec.c                    |  33 ++++
>  include/linux/binfmts.h      |   2 +
>  7 files changed, 268 insertions(+), 190 deletions(-)
> 
> 

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[PULL REQUEST] [PATCH v2 00/10] allow BFLT executables on systems with a MMU Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
  [PATCH v2 07/10] binfmt_flat: use clear_user() rather than memset() to clear .bss Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
  [PATCH v2 02/10] elf_fdpic_transfer_args_to_stack(): make it generic Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
  [PATCH v2 03/10] binfmt_flat: use generic transfer_args_to_stack() Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
  [PATCH v2 06/10] binfmt_flat: use proper user space accessors with old relocs code Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
  [PATCH v2 01/10] binfmt_flat: assorted cleanups Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:40 +0200
    Re: [PATCH v2 01/10] binfmt_flat: assorted cleanups Greg Ungerer <gerg@linux-m68k.org> - 2016-07-19 07:10 +0200
      Re: [PATCH v2 01/10] binfmt_flat: assorted cleanups Geert Uytterhoeven <geert@linux-m68k.org> - 2016-07-19 08:50 +0200
        Re: [PATCH v2 01/10] binfmt_flat: assorted cleanups Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-20 06:20 +0200
          Re: [PATCH v2 01/10] binfmt_flat: assorted cleanups Geert Uytterhoeven <geert@linux-m68k.org> - 2016-07-20 09:00 +0200
            Re: [PATCH v2 01/10] binfmt_flat: assorted cleanups Greg Ungerer <gerg@linux-m68k.org> - 2016-07-20 09:20 +0200
  [PATCH v2 09/10] binfmt_flat: add MMU-specific support Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:50 +0200
  [PATCH v2 04/10] binfmt_flat: clean up create_flat_tables() and stack accesses Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:50 +0200
  [PATCH v2 08/10] binfmt_flat: update libraries' data segment pointer with userspace accessors Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-18 05:50 +0200
  Re: [PULL REQUEST] [PATCH v2 00/10] allow BFLT executables on systems  with a MMU Greg Ungerer <gerg@linux-m68k.org> - 2016-07-19 09:30 +0200

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