[PATCH 00/10] allow BFLT executables on systems with a MMU

From: Nicolas Pitre
Date: Tue Jul 12 2016 - 17:43:28 EST


This series provides the necessary changes to allow "flat" executable
binaries meant for no-MMU systems to actually run on systems with a 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.

Tested on ARM only with a busybox build.


arch/arm/include/asm/flat.h | 5 +-
arch/m68k/include/asm/flat.h | 5 +-
arch/sh/include/asm/flat.h | 5 +-
arch/xtensa/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 +
9 files changed, 274 insertions(+), 194 deletions(-)