P J P [Tue, 12 Nov 2013 23:10:22 +0000 (15:10 -0800)]
initramfs: read CONFIG_RD_ variables for initramfs compression
When expert configuration option(CONFIG_EXPERT) is enabled, menuconfig
offers a choice of compression algorithm to compress initial ramfs image;
This choice is stored into CONFIG_RD_* variables. But usr/Makefile uses
earlier INITRAMFS_COMPRESSION_* macros to build initial ramfs file. Since
none of them is defined, resulting 'initramfs_data.cpio' file remains
un-compressed.
This patch updates the Makefile to use CONFIG_RD_* variables and adds
support for LZ4 compression algorithm. Also updates the
'gen_initramfs_list.sh' script to check whether a selected compression
command is accessible or not. And fall-back to default gzip(1)
compression when it is not.
This patch proposes to make init failures more explicit.
Before this, the "No init found" message didn't help much. It could
sometimes be misleading and actually mean "No *working* init found".
This message could hide many different issues:
- no init program candidates found at all
- some init program candidates exist but can't be executed (missing
execute permissions, failed to load shared libraries, executable
compiled for an unknown architecture...)
This patch notifies the kernel user when a candidate init program is found
but can't be executed. In each failure situation, the error code is
displayed, to quickly find the root cause. "No init found" is also
replaced by "No working init found", which is more correct.
This will help embedded Linux developers (especially the newcomers),
regularly making and debugging new root filesystems.
Credits to Geert Uytterhoeven and Janne Karhunen for their improvement
suggestions.
P J P [Tue, 12 Nov 2013 23:10:20 +0000 (15:10 -0800)]
init/do_mounts_rd.c: fix NULL pointer dereference while loading initramfs
Make menuconfig allows one to choose compression format of an initial
ramdisk image. But this choice does not result in duly compressed initial
ramdisk image. Because - $ make install - does not pass on the selected
compression choice to the dracut(8) tool, which creates the initramfs
file. dracut(8) generates the image with the default compression, ie.
gzip(1).
If a user chose any other compression instead of gzip(1), it leads to a
crash due to NULL pointer dereference in crd_load(), caused by a NULL
function pointer returned by the 'decompress_method()' routine. Because
the initramfs image is gzip(1) compressed, whereas the kernel knows only
to decompress the chosen format and not gzip(1).
This patch replaces the crash by an explicit panic() call with an
appropriate error message. This shall prevent the kernel from
eventually panicking in: init/do_mounts.c: mount_block_root() with
-> panic("VFS: Unable to mount root fs on %s", b);
Jason Baron [Tue, 12 Nov 2013 23:10:18 +0000 (15:10 -0800)]
epoll: do not take global 'epmutex' for simple topologies
When calling EPOLL_CTL_ADD for an epoll file descriptor that is attached
directly to a wakeup source, we do not need to take the global 'epmutex',
unless the epoll file descriptor is nested. The purpose of taking the
'epmutex' on add is to prevent complex topologies such as loops and deep
wakeup paths from forming in parallel through multiple EPOLL_CTL_ADD
operations. However, for the simple case of an epoll file descriptor
attached directly to a wakeup source (with no nesting), we do not need to
hold the 'epmutex'.
This patch along with 'epoll: optimize EPOLL_CTL_DEL using rcu' improves
scalability on larger systems. Quoting Nathan Zimmer's mail on SPECjbb
performance:
"On the 16 socket run the performance went from 35k jOPS to 125k jOPS. In
addition the benchmark when from scaling well on 10 sockets to scaling
well on just over 40 sockets.
...
Currently the benchmark stops scaling at around 40-44 sockets but it seems like
I found a second unrelated bottleneck."
Jason Baron [Tue, 12 Nov 2013 23:10:16 +0000 (15:10 -0800)]
epoll: optimize EPOLL_CTL_DEL using rcu
Nathan Zimmer found that once we get over 10+ cpus, the scalability of
SPECjbb falls over due to the contention on the global 'epmutex', which is
taken in on EPOLL_CTL_ADD and EPOLL_CTL_DEL operations.
Patch #1 removes the 'epmutex' lock completely from the EPOLL_CTL_DEL path
by using rcu to guard against any concurrent traversals.
Patch #2 remove the 'epmutex' lock from EPOLL_CTL_ADD operations for
simple topologies. IE when adding a link from an epoll file descriptor to
a wakeup source, where the epoll file descriptor is not nested.
This patch (of 2):
Optimize EPOLL_CTL_DEL such that it does not require the 'epmutex' by
converting the file->f_ep_links list into an rcu one. In this way, we can
traverse the epoll network on the add path in parallel with deletes.
Since deletes can't create loops or worse wakeup paths, this is safe.
This patch in combination with the patch "epoll: Do not take global 'epmutex'
for simple topologies", shows a dramatic performance improvement in
scalability for SPECjbb.
Joe Perches [Tue, 12 Nov 2013 23:10:14 +0000 (15:10 -0800)]
checkpatch: don't require kernel style __attribute__ shortcuts in uapi paths
Avoid prescribing kernel styled shortcuts for gcc extensions of
__attribute__((foo)) in the uapi include paths.
Fix $realfile filename when using -f/--file to not remove first level
directory as if the filename was used in a -P1 patch. Only strip the
first level directory (typically a or b) for P1 patches.
Josh Triplett [Tue, 12 Nov 2013 23:10:12 +0000 (15:10 -0800)]
checkpatch.pl: check for the FSF mailing address
Kernel maintainers reject new instances of the GPL boilerplate paragraph
directing people to write to the FSF for a copy of the GPL, since the FSF
has moved in the past and may do so again.
Make this an error for new code, but just a --strict CHK in --file mode;
anyone interested in doing tree-wide cleanups of this form can enable this
test explicitly.
Joe Perches [Tue, 12 Nov 2013 23:10:06 +0000 (15:10 -0800)]
checkpatch: extend CamelCase types and ignore existing CamelCase uses in a patch
Extend the CamelCase words found to include structure members.
In https://lkml.org/lkml/2013/9/3/318 Sarah Sharp (mostly) wrote:
"In general, if checkpatch.pl complains about a variable a patch
introduces that's CamelCase, you should pay attention to it. Otherwise,
[] ignore it."
So, if checking a patch, scan the original patched file if it's available
and add any preexisting CamelCase types so reuses do not generate
CamelCase messages.
That also means Andrew's not so cruelly spurned anymore.
https://lkml.org/lkml/2013/2/22/426
Joe Perches [Tue, 12 Nov 2013 23:10:05 +0000 (15:10 -0800)]
checkpatch: report missing spaces around trigraphs with --strict
Spaces around trigraphs are specified by CodingStyle but checkpatch is
currently silent about them because there are many current instances
without them.
Make missing spaces around trigraphs a --strict message.
Oleg Nesterov [Tue, 12 Nov 2013 23:10:02 +0000 (15:10 -0800)]
list: change list_for_each_entry*() to use list_*_entry()
Now that we have list_{next,prev}_entry() we can change
list_for_each_entry*() and list_safe_reset_next() to use the new helpers
to improve the readability.
Oleg Nesterov [Tue, 12 Nov 2013 23:10:01 +0000 (15:10 -0800)]
list: introduce list_next_entry() and list_prev_entry()
Add two trivial helpers list_next_entry() and list_prev_entry(), they
can have a lot of users including list.h itself. In fact the 1st one is
already defined in events/core.c and bnx2x_sp.c, so the patch simply
moves the definition to list.h.
Johan Hovold [Tue, 12 Nov 2013 23:09:41 +0000 (15:09 -0800)]
backlight: atmel-pwm-bl: clean up probe error handling
Clean up probe error handling by checking parameters before any
allocations and removing an obsolete error label. Also remove unnecessary
reset of private gpio number.
Jingoo Han [Tue, 12 Nov 2013 23:09:04 +0000 (15:09 -0800)]
backlight: use dev_get_platdata()
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly. This is a cosmetic change to
make the code simpler and enhance the readability.
Jingoo Han [Tue, 12 Nov 2013 23:09:02 +0000 (15:09 -0800)]
backlight: lm3639: don't mix different enum types
Don't mix different enum types to fix the sparse warnings.
drivers/video/backlight/lm3639_bl.c:80:51: warning: mixing different enum types
drivers/video/backlight/lm3639_bl.c:80:51: int enum lm3639_fleds versus
drivers/video/backlight/lm3639_bl.c:80:51: int enum lm3639_bleds
drivers/video/backlight/lm3639_bl.c:82:51: warning: mixing different enum types
drivers/video/backlight/lm3639_bl.c:82:51: int enum lm3639_fleds versus
drivers/video/backlight/lm3639_bl.c:82:51: int enum lm3639_bleds
Daniel Jeong [Tue, 12 Nov 2013 23:08:58 +0000 (15:08 -0800)]
backlight: lm3630: apply chip revision
The LM3630 chip was revised by TI and chip name was also changed to
LM3630A. And register map, default values and initial sequences are
changed. The files, lm3630_bl.{c,h} are replaced by lm3630a_bl.{c,h} You
can find more information about LM3630A(datasheet, evm etc) at
http://www.ti.com/product/lm3630a
Milo Kim [Tue, 12 Nov 2013 23:08:57 +0000 (15:08 -0800)]
backlight: lp855x_bl: support new LP8555 device
LP8555 is one of the LP855x family devices.
This device needs pre_init_device() and post_init_device() driver
structure. It's same as LP8557, so the device configuration code is
shared with LP8557. Backlight outputs are generated from dual DC-DC boost
converters. It's configurable EPROM settings which are defined in the
platform data.
Driver documentation and device tree bindings are updated.
Jean Delvare [Tue, 12 Nov 2013 23:08:56 +0000 (15:08 -0800)]
MAINTAINERS: update Zwane Mwaikambo's e-mail address
Zwane Mwaikambo's @arm.linux.org.uk address no longer works. In February
2013 he asked for his gmail address to be used instead [1] so let's just
do that.
Jingoo Han [Tue, 12 Nov 2013 23:08:55 +0000 (15:08 -0800)]
MAINTAINERS: remove Richard Purdie as backlight maintainer
Remove Richard Purdie as backlight subsystem maintainer,
akpm: Richard is still responsive and is reviewing some of the patches,
but appears to agree that listing him as the maintainer is no longer
appropriate.
Ryan Mallon [Tue, 12 Nov 2013 23:08:51 +0000 (15:08 -0800)]
vsprintf: check real user/group id for %pK
Some setuid binaries will allow reading of files which have read
permission by the real user id. This is problematic with files which
use %pK because the file access permission is checked at open() time,
but the kptr_restrict setting is checked at read() time. If a setuid
binary opens a %pK file as an unprivileged user, and then elevates
permissions before reading the file, then kernel pointer values may be
leaked.
This happens for example with the setuid pppd application on Ubuntu 12.04:
This will only leak the pointer value from the first line, but other
setuid binaries may leak more information.
Fix this by adding a check that in addition to the current process having
CAP_SYSLOG, that effective user and group ids are equal to the real ids.
If a setuid binary reads the contents of a file which uses %pK then the
pointer values will be printed as NULL if the real user is unprivileged.
Update the sysctl documentation to reflect the changes, and also correct
the documentation to state the kptr_restrict=0 is the default.
This is a only temporary solution to the issue. The correct solution is
to do the permission check at open() time on files, and to replace %pK
with a function which checks the open() time permission. %pK uses in
printk should be removed since no sane permission check can be done, and
instead protected by using dmesg_restrict.
Kees Cook [Tue, 12 Nov 2013 23:08:49 +0000 (15:08 -0800)]
printk: report console names during cut-over
This reports the names of consoles as they're being disabled to help
identify which is which during cut-over. Helps answer the question
"which boot console actually got activated?" once the regular console is
running, mostly when debugging boot console failures.
Vineet Gupta [Tue, 12 Nov 2013 23:08:47 +0000 (15:08 -0800)]
sched: remove ARCH specific fpu_counter from task_struct
fpu_counter in task_struct was used only by sh/x86. Both of these now
carry it in ARCH specific thread_struct, hence this can now be removed
from generic task_struct, shrinking it slightly for other arches.
Vineet Gupta [Tue, 12 Nov 2013 23:08:46 +0000 (15:08 -0800)]
x86: move fpu_counter into ARCH specific thread_struct
Only a couple of arches (sh/x86) use fpu_counter in task_struct so it can
be moved out into ARCH specific thread_struct, reducing the size of
task_struct for other arches.
Vineet Gupta [Tue, 12 Nov 2013 23:08:45 +0000 (15:08 -0800)]
sh: move fpu_counter into ARCH specific thread_struct
Only a couple of arches (sh/x86) use fpu_counter in task_struct so it can
be moved out into ARCH specific thread_struct, reducing the size of
task_struct for other arches.
Compile tested sh defconfig + sh4-linux-gcc (4.6.3)
Commit 15d94b82565e ("reboot: move shutdown/reboot related functions to
kernel/reboot.c") moved all kexec-related functionality to
kernel/reboot.c, so kernel/sys.c no longer needs to include
<linux/kexec.h>.
projects / linux.git / log