From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
Greg Ungerer <gerg@linux-m68k.org>
Subject: [PATCH v3 00/12] allow BFLT executables on systems with a MMU
Date: Wed, 20 Jul 2016 00:20:12 -0400 [thread overview]
Message-ID: <1468988424-32671-1-git-send-email-nicolas.pitre@linaro.org> (raw)
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, confirmed by
Greg Ungerer. Tested on ARM with MMU only with a busybox build.
Please consider for merging.
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 | 5 +-
fs/Kconfig.binfmt | 3 +-
fs/binfmt_elf_fdpic.c | 38 +---
fs/binfmt_flat.c | 453 +++++++++++++++++++++----------------
fs/exec.c | 33 +++
include/linux/binfmts.h | 2 +
7 files changed, 306 insertions(+), 233 deletions(-)
next reply other threads:[~2016-07-20 4:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 4:20 Nicolas Pitre [this message]
2016-07-20 4:20 ` [PATCH v3 01/12] binfmt_flat: assorted cleanups Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 02/12] binfmt_flat: convert printk invocations to their modern form Nicolas Pitre
2016-07-20 4:30 ` Joe Perches
2016-07-20 5:05 ` Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 03/12] binfmt_flat: prevent kernel dammage from corrupted executable headers Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 04/12] elf_fdpic_transfer_args_to_stack(): make it generic Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 05/12] binfmt_flat: use generic transfer_args_to_stack() Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 06/12] binfmt_flat: clean up create_flat_tables() and stack accesses Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 07/12] binfmt_flat: use proper user space accessors with relocs processing code Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 08/12] binfmt_flat: use proper user space accessors with old relocs code Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 09/12] binfmt_flat: use clear_user() rather than memset() to clear .bss Nicolas Pitre
2016-07-20 7:15 ` Greg Ungerer
2016-07-20 4:20 ` [PATCH v3 10/12] binfmt_flat: update libraries' data segment pointer with userspace accessors Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 11/12] binfmt_flat: add MMU-specific support Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 12/12] binfmt_flat: allow compressed flat binary format to work on MMU systems Nicolas Pitre
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