Messages in this thread | | | From | Nicolas Pitre <> | Subject | [PATCH v5 00/15] allow BFLT executables on systems with a MMU | Date | Sun, 24 Jul 2016 11:30:14 -0400 |
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This series provides the necessary changes to allow "flat" executable binaries meant for no-MMU systems to actually run on systems with a MMU. Also thrown in are various cleanups to binfmt_flat.c.
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, confirmed by Greg Ungerer. Tested with MMU on ARM and M68K.
Changes since v4:
- Isolated architecture specific changes in their own patches for easier review through their own path to mainline.
- Added needed m68k register fixup from Greg Ungerer.
Changes since v3:
- Small cosmetic changes to pr_*().
- Addressed most important checkpatch complaints on the whole source file and patches in this seris.
Changes since v2:
- Added protection against a corrupted header that could have caused nasty overflows etc. Suggested by Alan Cox.
- printk() modernization. Suggested by Greg Ungerer / Geert Uytterhoeven.
- Added Greg Ungerer's reviewed-by tag.
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 | 11 +- arch/m68k/include/asm/processor.h | 2 - fs/Kconfig.binfmt | 3 +- fs/binfmt_elf_fdpic.c | 38 +-- fs/binfmt_flat.c | 525 ++++++++++++++++++-------------- fs/exec.c | 33 ++ include/linux/binfmts.h | 2 + 8 files changed, 345 insertions(+), 274 deletions(-)
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