iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
1,102,925 Commits 104 Branches 1,843 Tags 5.7 GiB
09a018176b
Commit Graph

9 Commits

Author SHA1 Message Date
David Hildenbrand
bbcd53c960 drivers/char: remove /dev/kmem for good 
Patch series "drivers/char: remove /dev/kmem for good".

Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and
memory ballooning, I started questioning the existence of /dev/kmem.

Comparing it with the /proc/kcore implementation, it does not seem to be
able to deal with things like

a) Pages unmapped from the direct mapping (e.g., to be used by secretmem)
  -> kern_addr_valid(). virt_addr_valid() is not sufficient.

b) Special cases like gart aperture memory that is not to be touched
  -> mem_pfn_is_ram()

Unless I am missing something, it's at least broken in some cases and might
fault/crash the machine.

Looks like its existence has been questioned before in 2005 and 2010 [1],
after ~11 additional years, it might make sense to revive the discussion.

CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by
mistake?).  All distributions disable it: in Ubuntu it has been disabled
for more than 10 years, in Debian since 2.6.31, in Fedora at least
starting with FC3, in RHEL starting with RHEL4, in SUSE starting from
15sp2, and OpenSUSE has it disabled as well.

1) /dev/kmem was popular for rootkits [2] before it got disabled
   basically everywhere. Ubuntu documents [3] "There is no modern user of
   /dev/kmem any more beyond attackers using it to load kernel rootkits.".
   RHEL documents in a BZ [5] "it served no practical purpose other than to
   serve as a potential security problem or to enable binary module drivers
   to access structures/functions they shouldn't be touching"

2) /proc/kcore is a decent interface to have a controlled way to read
   kernel memory for debugging puposes. (will need some extensions to
   deal with memory offlining/unplug, memory ballooning, and poisoned
   pages, though)

3) It might be useful for corner case debugging [1]. KDB/KGDB might be a
   better fit, especially, to write random memory; harder to shoot
   yourself into the foot.

4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems
   to be incompatible with 64bit [1]. For educational purposes,
   /proc/kcore might be used to monitor value updates -- or older
   kernels can be used.

5) It's broken on arm64, and therefore, completely disabled there.

Looks like it's essentially unused and has been replaced by better
suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's
just remove it.

[1] https://lwn.net/Articles/147901/
[2] https://www.linuxjournal.com/article/10505
[3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled
[4] https://sourceforge.net/projects/kme/
[5] https://bugzilla.redhat.com/show_bug.cgi?id=154796

Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Alexander A. Klimov" <grandmaster@al2klimov.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: huang ying <huang.ying.caritas@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: James Troup <james.troup@canonical.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <kasong@redhat.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: openrisc@lists.librecores.org
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Pavel Machek (CIP)" <pavel@denx.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: sparclinux@vger.kernel.org
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Theodore Dubois <tblodt@icloud.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: William Cohen <wcohen@redhat.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-05-07 00:26:34 -07:00
Krzysztof Kozlowski
3508aae9b5 ARM: configs: Cleanup old Kconfig options 
CONFIG_MMC_BLOCK_BOUNCE is gone since commit c3dccb74be ("mmc: core:
Delete bounce buffer Kconfig option").

CONFIG_LBDAF is gone since commit 72deb455b5 ("block: remove
CONFIG_LBDAF").

CONFIG_IOSCHED_DEADLINE and CONFIG_IOSCHED_CFQ are gone since
commit f382fb0bce ("block: remove legacy IO schedulers").

The IOSCHED_DEADLINE was replaced by MQ_IOSCHED_DEADLINE and it will be
now enabled by default (along with MQ_IOSCHED_KYBER).

The IOSCHED_BFQ seems to replace IOSCHED_CFQ so select it in configs
previously choosing the latter.

CONFIG_CROSS_COMPILE is gone since commit f1089c92da ("kbuild: remove
CONFIG_CROSS_COMPILE support").

Link: https://lore.kernel.org/r/20200130195525.4525-2-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>
 2020-02-09 03:44:58 -08:00
Eric W. Biederman
61a47c1ad3 sysctl: Remove the sysctl system call 
This system call has been deprecated almost since it was introduced, and
in a survey of the linux distributions I can no longer find any of them
that enable CONFIG_SYSCTL_SYSCALL.  The only indication that I can find
that anyone might care is that a few of the defconfigs in the kernel
enable CONFIG_SYSCTL_SYSCALL.  However this appears in only 31 of 414
defconfigs in the kernel, so I suspect this symbols presence is simply
because it is harmless to include rather than because it is necessary.

As there appear to be no users of the sysctl system call, remove the
code.  As this removes one of the few uses of the internal kernel mount
of proc I hope this allows for even more simplifications of the proc
filesystem.

Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Anders Berg <anders.berg@lsi.com>
Cc: Apelete Seketeli <apelete@seketeli.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chee Nouk Phoon <cnphoon@altera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christian Ruppert <christian.ruppert@abilis.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hongliang Tao <taohl@lemote.com>
Cc: Hua Yan <yanh@lemote.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <blogic@openwrt.org>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: Jun Nie <jun.nie@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Kevin Wells <kevin.wells@nxp.com>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Noam Camus <noamc@ezchip.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Pierrick Hascoet <pierrick.hascoet@abilis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Roland Stigge <stigge@antcom.de>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Scott Telford <stelford@cadence.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Tanmay Inamdar <tinamdar@apm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
 2019-11-26 13:03:56 -06:00
Krzysztof Kozlowski
6c48edcc95 ARM: configs: Remove useless UEVENT_HELPER_PATH 
Remove the CONFIG_UEVENT_HELPER_PATH because:
1. It is disabled since commit 1be01d4a57 ("driver: base: Disable
   CONFIG_UEVENT_HELPER by default") as its dependency (UEVENT_HELPER) was
   made default to 'n',
2. It is not recommended (help message: "This should not be used today
   [...] creates a high system load") and was kept only for ancient
   userland,
3. Certain userland specifically requests it to be disabled (systemd
   README: "Legacy hotplug slows down the system and confuses udev").

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
 2019-06-19 07:09:39 -07:00
Christoph Hellwig
72deb455b5 block: remove CONFIG_LBDAF 
Currently support for 64-bit sector_t and blkcnt_t is optional on 32-bit
architectures.  These types are required to support block device and/or
file sizes larger than 2 TiB, and have generally defaulted to on for
a long time.  Enabling the option only increases the i386 tinyconfig
size by 145 bytes, and many data structures already always use
64-bit values for their in-core and on-disk data structures anyway,
so there should not be a large change in dynamic memory usage either.

Dropping this option removes a somewhat weird non-default config that
has cause various bugs or compiler warnings when actually used.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2019-04-06 10:48:35 -06:00
Alexey Brodkin
3337d5cfe5 configs: get rid of obsolete CONFIG_ENABLE_WARN_DEPRECATED 
This Kconfig option was removed during v4.19 development in commit
771c035372 ("deprecate the '__deprecated' attribute warnings entirely
and for good") so there's no point to keep it in defconfigs any longer.

FWIW defconfigs were patched with:
--------------------------->8----------------------
find . -name *_defconfig -exec sed -i '/CONFIG_ENABLE_WARN_DEPRECATED/d' {} \;
--------------------------->8----------------------

Link: http://lkml.kernel.org/r/20190128152434.41969-1-abrodkin@synopsys.com
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-03-07 18:32:02 -08:00
Krzysztof Kozlowski
bd5f62605f ARM: defconfig: Cleanup from old Kconfig options 
Remove old, dead Kconfig options (in order appearing in this commit):
 - EXPERIMENTAL is gone since v3.9;
 - INET_LRO: commit 7bbf3cae65 ("ipv4: Remove inet_lro library");
 - MTD_CONCAT: commit f53fdebcc3 ("mtd: drop MTD_CONCAT from Kconfig entirely");
 - MTD_PARTITIONS: commit 6a8a98b22b ("mtd: kill CONFIG_MTD_PARTITIONS");
 - MTD_CHAR: commit 660685d9d1 ("mtd: merge mtdchar module with mtdcore");
 - NETDEV_1000 and NETDEV_10000: commit f860b0522f ("drivers/net:
   Kconfig and Makefile cleanup"); NET_ETHERNET should be replaced with
   just ETHERNET but that is separate change;
 - INOTIFY: commit 2dfc1cae4c ("inotify: remove inotify in kernel interface");
 - MISC_DEVICES: commit 7c5763b845 ("drivers: misc: Remove
   MISC_DEVICES config option");
 - HID_SUPPORT: commit 1f41a6a994 ("HID: Fix the generic Kconfig options");
 - BT_L2CAP and BT_SCO: commit f1e91e1640 ("Bluetooth: Always compile
   SCO and L2CAP in Bluetooth Core");
 - DEBUG_ERRORS: commit b025a3f836 ("ARM: 6876/1: Kconfig.debug:
   Remove unused CONFIG_DEBUG_ERRORS");
 - USB_DEVICE_CLASS: commit 007bab9132 ("USB: remove CONFIG_USB_DEVICE_CLASS");
 - RCU_CPU_STALL_DETECTOR: commit a00e0d714f ("rcu: Remove conditional
   compilation for RCU CPU stall warnings");
 - SYSCTL_SYSCALL_CHECK: commit 7c60c48f58 ("sysctl: Improve the
   sysctl sanity checks");
 - IP_NF_QUEUE: commit 3dd6664fac ("netfilter: remove unused "config IP_NF_QUEUE"");
 - IP_NF_TARGET_ULOG: commit d4da843e6f ("netfilter: kill remnants of ulog targets");
 - IP6_NF_QUEUE: commit d16cf20e2f ("netfilter: remove ip_queue support");
 - IP6_NF_TARGET_LOG: commit 6939c33a75 ("netfilter: merge ipt_LOG and
   ip6_LOG into xt_LOG");
 - USB_LED: commit a335aaf312 ("usb: misc: remove outdated USB LED driver");
 - MMC_UNSAFE_RESUME: commit 2501c9179d ("mmc: core: Use
   MMC_UNSAFE_RESUME as default behavior");
 - AUTOFS_FS: commit 561c5cf923 ("staging: Remove autofs3");
 - DISPLAY_SUPPORT: commit 5a6b5e02d6 ("fbdev: remove display subsystem");
 - CFG80211_REG_DEBUG: commit c799ba6eab ("cfg80211: remove
   CFG80211_REG_DEBUG");
 - VIDEO_OUTPUT_CONTROL: commit f167a64e9d ("video / output: Drop
   display output class support");
 - USB_LIBUSUAL: commit f61870ee6f ("usb: remove libusual");
 - CRYPTO_ZLIB: commit 110492183c ("crypto: compress - remove unused
   pcomp interface");
 - BLK_DEV_UB: commit 68a5059ecf ("block: remove the deprecated ub driver");

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
[for vexpress]
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
 2017-06-10 19:28:57 +02:00
Linus Walleij
332524eaf7 ARM: deconfig: fix the moxart defconfig 
The moxart defconfig wasn't even building a kernel for Moxart,
it was building a kernel for V4T on the nothing platform. Switch
to MULTI_V4 and keep the right drivers, update a few selections.
Now it (presumably) builds a minimalist Moxart kernel again.

Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
 2017-03-02 23:08:28 +01:00
Jonas Jensen
17723fd357 ARM: moxart: add MOXA ART SoC platform files 
The MOXA ART SoC is based on Faraday's FA526. This is a ARMv4 32-bit
192 MHz CPU with MMU and 16KB/8KB D/I-cache.

Add platform support for this SoC.

Also add UC-7112-LX as a machine.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>
 2013-12-22 11:57:38 -08:00