linux-kernel - [PATCH v2 0/5] xen: avoid module usage in non-modular code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 21 Feb 2016 19:06:03 -0500
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	<linux-kernel@...r.kernel.org>
CC:	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Russell King <linux@....linux.org.uk>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<xen-devel@...ts.xenproject.org>
Subject: [PATCH v2 0/5] xen: avoid module usage in non-modular code

This series of commits is a part of a larger project to ensure
people don't reference modular support functions in non-modular
code.  Overall there was roughly 5k lines of dead code in the
kernel due to this.  So far we've fixed several areas, like tty,
x86, net, ... and we continue to work on other areas.

There are several reasons to not use module support for code that
can never be built as a module, but the big ones are:

 (1) it is easy to accidentally write unused module_exit and remove code
 (2) it can be misleading when reading the source, thinking it can be
      modular when the Makefile and/or Kconfig prohibit it
 (3) it requires the include of the module.h header file which in turn
     includes nearly everything else.
 (4) it gets copied/replicated into other code and spreads like weeds.

For the xen subsystem, there are just five commits:

First, we get rid of "include <linux/module.h>" instances that are
completely unnecessary.

Then #2 and #3 and #5 are basically trivial remapping to the
appropriate non-modular counterparts, meaning that there is no
runtime change here either.

The fourth hypervisor commit is similar, but also has removal of
some dead code associated with the module_exit function that will
never be called.  So the runtime should be the same, but the object
file will be different (reduced in size).

Patches created on linux-next and build tested for x86-64 and ARM64
allmodconfig.

---

[v2: manually inline one-liners in #4; update probe vs init fcn names
 in #5 ; both suggestions by Stefano ; add Reviewed tags to #1, #2, #3.
 Redid build testing on x86-64 and ARM64 to test for typos etc.  ]

Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: David Vrabel <david.vrabel@...rix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Russell King <linux@....linux.org.uk>
Cc: Stefano Stabellini <stefano.stabellini@...citrix.com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: xen-devel@...ts.xenproject.org

Paul Gortmaker (5):
  xen: audit usages of module.h ; remove unnecessary instances
  drivers/xen: make [xen-]ballon explicitly non-modular
  drivers/xen: make xenbus_dev_[front/back]end explicitly non-modular
  drivers/xen: make sys-hypervisor.c explicitly non-modular
  drivers/xen: make platform-pci.c explicitly non-modular

 arch/arm/include/asm/xen/hypercall.h     |  2 ++
 drivers/xen/balloon.c                    |  4 ----
 drivers/xen/events/events_2l.c           |  1 -
 drivers/xen/events/events_base.c         |  2 +-
 drivers/xen/events/events_fifo.c         |  1 -
 drivers/xen/features.c                   |  2 +-
 drivers/xen/grant-table.c                |  1 -
 drivers/xen/platform-pci.c               | 16 ++++++----------
 drivers/xen/sys-hypervisor.c             | 31 ++++---------------------------
 drivers/xen/xen-balloon.c                | 14 +++-----------
 drivers/xen/xen-pciback/conf_space.c     |  2 +-
 drivers/xen/xen-pciback/pciback_ops.c    |  2 +-
 drivers/xen/xen-pciback/xenbus.c         |  2 +-
 drivers/xen/xen-selfballoon.c            |  1 -
 drivers/xen/xenbus/xenbus_dev_backend.c  | 13 ++-----------
 drivers/xen/xenbus/xenbus_dev_frontend.c | 13 ++-----------
 drivers/xen/xenbus/xenbus_xs.c           |  1 -
 drivers/xen/xenfs/xensyms.c              |  1 -
 18 files changed, 24 insertions(+), 85 deletions(-)

-- 
2.6.1
Paul Gortmaker (5):
  xen: audit usages of module.h ; remove unnecessary instances
  drivers/xen: make [xen-]ballon explicitly non-modular
  drivers/xen: make xenbus_dev_[front/back]end explicitly non-modular
  drivers/xen: make sys-hypervisor.c explicitly non-modular
  drivers/xen: make platform-pci.c explicitly non-modular

 arch/arm/include/asm/xen/hypercall.h     |  2 ++
 drivers/xen/balloon.c                    |  4 ---
 drivers/xen/events/events_2l.c           |  1 -
 drivers/xen/events/events_base.c         |  2 +-
 drivers/xen/events/events_fifo.c         |  1 -
 drivers/xen/features.c                   |  2 +-
 drivers/xen/grant-table.c                |  1 -
 drivers/xen/platform-pci.c               | 22 +++++-------
 drivers/xen/sys-hypervisor.c             | 59 +++++---------------------------
 drivers/xen/xen-balloon.c                | 14 ++------
 drivers/xen/xen-pciback/conf_space.c     |  2 +-
 drivers/xen/xen-pciback/pciback_ops.c    |  2 +-
 drivers/xen/xen-pciback/xenbus.c         |  2 +-
 drivers/xen/xen-selfballoon.c            |  1 -
 drivers/xen/xenbus/xenbus_dev_backend.c  | 13 ++-----
 drivers/xen/xenbus/xenbus_dev_frontend.c | 13 ++-----
 drivers/xen/xenbus/xenbus_xs.c           |  1 -
 drivers/xen/xenfs/xensyms.c              |  1 -
 18 files changed, 31 insertions(+), 112 deletions(-)

-- 
2.6.1