sound/oss/sonicvibes.c:421: error: static declaration of hweight32 follows non-static declaration
include/asm-generic/bitops/hweight.h:6: error: previous declaration of hweight32 was here
Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch defines constant_fls() instead of removed generic_fls().
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Build fix for user mode linux.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix warning messages triggered by bitops code consolidation patches.
cxn_bitmap is the array of unsigned long. '&' is unnesesary for the argument
of *_bit() routins.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It's about to go away.
Cc: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change all instances of EXPORT_SYMBOL() in the core EDAC module to
EXPORT_SYMBOL_GPL().
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Add entries to MAINTAINERS list for EDAC-E752X, EDAC-E7XXX, and
EDAC-R82600 chipset drivers
- Fix MAINTAINERS entry for EDAC-CORE so it uses tabs rather than
spaces to indent. This is consistent with how the other entries are
formatted.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Patch from Dave Jiang <djiang@mvista.com>: Fix EDAC e752x driver so it
outputs sysbus-specific error message when sysbus error detected.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix spelling errors in EDAC documentation.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Cosmetic indentation/formatting cleanup for EDAC code. Make sure we
are using tabs rather than spaces to indent, etc.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix EDAC code so EXPORT_SYMBOL comes after the function that is being
exported. This is to maintain consistency with the rest of the kernel.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Add x86 dependency in drivers/edac/Kconfig for all current
platform-specific modules.
- Add PCI dependency to Radisys 82600 driver
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Fix code so we always hold mem_ctls_mutex while we are stepping
through the list of mem_ctl_info structures. Otherwise bad things
may happen if one task is stepping through the list while another
task is modifying it. We may eventually want to use reference
counting to manage the mem_ctl_info structures. In the meantime we
may as well fix this bug.
- Don't disable interrupts while we are walking the list of
mem_ctl_info structures in check_mc_devices(). This is unnecessary.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- After we unregister a kobject, wait for our kobject release method
to call complete(). This causes us to wait until the kobject
reference count reaches 0. Otherwise, a task accessing the EDAC
sysfs interface can hold the reference count above 0 until after the
EDAC module has been unloaded. When the reference count finally
drops to 0, this will result in an attempt to call our release
method inside the EDAC module after the module has already been
unloaded.
This isn't the best fix, since a process can get stuck sleeping forever
uninterruptibly if the user does the following:
rmmod my_module < /sys/my_sysfs/file
I'll go back and implement a better fix later. However this should
be ok for now.
- Call edac_remove_sysfs_mci_device() from edac_mc_del_mc() rather
than from edac_mc_free(). Since edac_mc_add_mc() calls
edac_create_sysfs_mci_device(), edac_mc_del_mc() should call
edac_remove_sysfs_mci_device().
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Remove calls to kobject_init(). These are unnecessary because
kobject_register() calls kobject_init().
- Remove extra calls to kobject_put(). When we call
kobject_unregister(), this releases our reference to the kobject.
The extra calls to kobject_put() may cause the reference count to
drop to 0 while a kobject is still in use.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is part 2 of a 2-part patch set.
Fix edac_mc_add_mc() so it cleans up properly if call to
edac_create_sysfs_mci_device() fails.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is part 1 of a 2-part patch set. The code changes are split into
two parts to make the patches more readable.
Move complete_mc_list_del() and del_mc_from_global_list() so we can
call del_mc_from_global_list() from edac_mc_add_mc() without forward
declarations. Perhaps using forward declarations would be better?
I'm doing things this way because the rest of the code is missing
them.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix xxx_probe1() functions so they call xxx_get_error_info() functions
to clear initial errors. This is simpler and cleaner than duplicating
the low-level code for accessing PCI config space.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix minor logic bug in e7xxx_remove_one().
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Fix i82875p_probe1() so it calls pci_get_device() instead of
pci_find_device().
- Fix i82875p_probe1() so it cleans up properly on failure.
- Fix i82875p_init() so it cleans up properly on failure.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Fix i82860_init() so it cleans up properly on failure.
- Fix i82860_exit() so it cleans up properly.
- Fix typo in comment (i.e. www.redhat.com.com).
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Add ctl_dev field to "struct e752x_dev_info". Then we can eliminate
ugly switch statement from e752x_probe1().
- Remove code from e752x_probe1() that clears initial PCI bus parity
errors. The core EDAC module already does this.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Eliminate unnecessary calls to pci_dev_get() and pci_dev_put() from
amd76x driver.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Perform the following name substitutions on all source files:
sed 's/BS_MOD_STR/EDAC_MOD_STR/g'
sed 's/bs_thread_info/edac_thread_info/g'
sed 's/bs_thread/edac_thread/g'
sed 's/bs_xstr/edac_xstr/g'
sed 's/bs_str/edac_str/g'
The names that start with BS_ or bs_ are artifacts of when the code
was called "bluesmoke".
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This implements the following idea:
On Monday 30 January 2006 19:22, Eric W. Biederman wrote:
> One piece missing from this conversation is the issue that we need errors
> in a uniform format. That is why edac_mc has helper functions.
>
> However there will always be errors that don't fit any particular model.
> Could we add a edac_printk(dev, ); That is similar to dev_printk but
> prints out an EDAC header and the device on which the error was found?
> Letting the rest of the string be user specified.
>
> For actual control that interface may be to blunt, but at least for people
> looking in the logs it allows all of the errors to be detected and
> harvested.
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch was originally posted by Christoph Hellwig (see
http://lkml.org/lkml/2006/2/14/331):
"Christoph Hellwig" <hch@lst.de> wrote:
> Use the kthread_ API instead of opencoding lots of hairy code for kernel
> thread creation and teardown, including tasklist_lock abuse.
>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Peterson <dsp@llnl.gov>
Cc: <dave_peterson@pobox.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes coverity id #2. the if (i==0) is pretty useless, since we
assing i=0, just the line before.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the connection-specific module "usb_gigaset", the hardware
driver for Gigaset base stations connected via the M105 USB DECT adapter. It
contains the code for handling probe/disconnect, AT command/response
transmission, and call setup and termination, as well as handling asynchronous
data transfers, PPP framing, byte stuffing, and flow control.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the payload data handler for the connection-specific module
"bas_gigaset". It contains the code for handling isochronous data transfers,
HDLC framing and flow control.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the main source file of the connection-specific module
"bas_gigaset", the hardware driver for Gigaset base stations connected
directly to the computer via USB. It contains the code for handling
probe/disconnect, AT command/response transmission, and call setup and
termination.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the procfs interface to the gigaset module. The procfs
interface provides access to status information and statistics about the
Gigaset devices. If the drivers are built with the debugging option it also
allows to change the amount of debugging output on the fly.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the tty interface to the gigaset module. The tty interface
provides direct access to the AT command set of the Gigaset devices.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the isdn4linux subsystem interface to the gigaset module. The
isdn4linux subsystem interface handles requests from and notifications to the
isdn4linux subsystem.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the event layer to the gigaset module. The event layer
serializes events from hardware, userspace, and other kernel subsystems.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
This patch adds the common include file for the Siemens Gigaset drivers,
providing definitions used by all of the Gigaset ISDN driver source files. It
also adds the main source file of the gigaset module which manages common
functions not specific to the type of connection to the device.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And: Tilman Schmidt <tilman@imap.cc>
The following patches add drivers for the Siemens Gigaset 3070 family of ISDN
DECT PABXes connected via USB, either directly or over a DECT link using a
Gigaset M105 or compatible DECT data adapter. The devices are integrated as
ISDN adapters within the isdn4linux framework, supporting incoming and
outgoing voice and data connections, and also as tty devices providing access
to device specific AT commands.
Supported devices include models 3070, 3075, 4170, 4175, SX205, SX255, and
SX353 from the Siemens Gigaset product family, as well as the technically
identical models 45isdn and 721X from the Deutsche Telekom Sinus series.
Supported DECT adapters are the Gigaset M105 data and the technically
identical Gigaset USB Adapter DECT, Sinus 45 data 2, and Sinus 721 data (but
not the Gigaset M34 and Sinus 702 data which advertise themselves as CDC-ACM
devices).
These drivers have been developed over the last four years within the
SourceForge project http://sourceforge.net/projects/gigaset307x/. They are
being used successfully in several installations for dial-in Internet access
and for voice call switching with Asterisk.
This is our second attempt at submitting these drivers, taking into account
the comments we received to our first submission on 2005-12-11.
The patch set adds three kernel modules:
- a common module "gigaset" encapsulating the common logic for
controlling the PABX and the interfaces to userspace and the
isdn4linux subsystem.
- a connection-specific module "bas_gigaset" which handles
communication with the PABX over a direct USB connection.
- a connection-specific module "usb_gigaset" which does the same
for a DECT connection using the Gigaset M105 USB DECT adapter.
We also have a module "ser_gigaset" which supports the Gigaset M101 RS232 DECT
adapter, but we didn't judge it fit for inclusion in the kernel, as it does
direct programming of a i8250 serial port. It should probably be rewritten as
a serial line discipline but so far we lack the neccessary knowledge about
writing a line discipline for that.
The drivers have been working with kernel releases 2.2 and 2.4 as well as 2.6,
and although we took efforts to remove the compatibility code for this
submission, it probably still shows in places. Please make allowances.
This patch:
Prepare the kernel build infrastructure for addition of the Gigaset ISDN
drivers. It creates a Makefile and Kconfig file for the Gigaset driver and
hooks them into those of the isdn4linux subsystem. It also adds a MAINTAINERS
entry for the driver.
This patch depends on patches 2 to 9 of the present set, as without the actual
source files, activating the options added here will cause the kernel build to
fail.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide proper kprobes fault handling, if a user-specified pre/post handlers
tries to access user address space, through copy_from_user(), get_user() etc.
The user-specified fault handler gets called only if the fault occurs while
executing user-specified handlers. In such a case user-specified handler is
allowed to fix it first, later if the user-specifed fault handler does not fix
it, we try to fix it by calling fix_exception().
The user-specified handler will not be called if the fault happens when single
stepping the original instruction, instead we reset the current probe and
allow the system page fault handler to fix it up.
I could not test this patch for sparc64.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide proper kprobes fault handling, if a user-specified pre/post handlers
tries to access user address space, through copy_from_user(), get_user() etc.
The user-specified fault handler gets called only if the fault occurs while
executing user-specified handlers. In such a case user-specified handler is
allowed to fix it first, later if the user-specifed fault handler does not fix
it, we try to fix it by calling fix_exception().
The user-specified handler will not be called if the fault happens when single
stepping the original instruction, instead we reset the current probe and
allow the system page fault handler to fix it up.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Acked-by: Anil S Keshavamurthy<anil.s.keshavamurthy@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide proper kprobes fault handling, if a user-specified pre/post handlers
tries to access user address space, through copy_from_user(), get_user() etc.
The user-specified fault handler gets called only if the fault occurs while
executing user-specified handlers. In such a case user-specified handler is
allowed to fix it first, later if the user-specifed fault handler does not fix
it, we try to fix it by calling fix_exception().
The user-specified handler will not be called if the fault happens when single
stepping the original instruction, instead we reset the current probe and
allow the system page fault handler to fix it up.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide proper kprobes fault handling, if a user-specified pre/post handlers
tries to access user address space, through copy_from_user(), get_user() etc.
The user-specified fault handler gets called only if the fault occurs while
executing user-specified handlers. In such a case user-specified handler is
allowed to fix it first, later if the user-specifed fault handler does not fix
it, we try to fix it by calling fix_exception().
The user-specified handler will not be called if the fault happens when single
stepping the original instruction, instead we reset the current probe and
allow the system page fault handler to fix it up.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide proper kprobes fault handling, if a user-specified pre/post handlers
tries to access user address space, through copy_from_user(), get_user() etc.
The user-specified fault handler gets called only if the fault occurs while
executing user-specified handlers. In such a case user-specified handler is
allowed to fix it first, later if the user-specifed fault handler does not fix
it, we try to fix it by calling fix_exception().
The user-specified handler will not be called if the fault happens when single
stepping the original instruction, instead we reset the current probe and
allow the system page fault handler to fix it up.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently kprobe handler traps only happen in kernel space, so function
kprobe_exceptions_notify should skip traps which happen in user space.
This patch modifies this, and it is based on 2.6.16-rc4.
Signed-off-by: bibo mao <bibo.mao@intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>
Cc: <hiramatu@sdl.hitachi.co.jp>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When kretprobe probes the schedule() function, if the probed process exits
then schedule() will never return, so some kretprobe instances will never
be recycled.
In this patch the parent process will recycle retprobe instances of the
probed function and there will be no memory leak of kretprobe instances.
Signed-off-by: bibo mao <bibo.mao@intel.com>
Cc: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In normal operation, kretprobe makes a target function return to trampoline
code. A kprobe (called trampoline_probe) has been inserted in the trampoline
code. When the kernel hits this kprobe, it calls kretprobe's handler and it
returns to the original return address.
Kretprobe-booster removes the trampoline_probe. It allows the trampoline code
to call kretprobe's handler directly instead of invoking kprobe. The
trampoline code returns to the original return address.
(changelog from Chuck Ebbert <76306.1226@compuserve.com> - thanks ;))
Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Current kprobe copies the original instruction at the probe point and replaces
it with a breakpoint instruction (int3). When the kernel hits the probe
point, kprobe handler is invoked. And the copied instruction is single-step
executed on the copied buffer (not on the original address) by kprobe. After
that, the kprobe checks registers and modify it (if need) as if the
instructions was executed on the original address.
My proposal is based on the fact there are many instructions which do NOT
require the register modification after the single-step execution. When the
copied instruction is a kind of them, kprobe just jumps back to the next
instruction after single-step execution. If so, why don't we execute those
instructions directly?
With kprobe-booster patch, kprobes will execute a copied instruction directly
and (if need) jump back to original code. This direct execution is executed
when the kprobe don't have both post_handler and break_handler, and the copied
instruction can be executed directly.
I sorted instructions which can be executed directly or not;
- Call instructions are NG(can not be executed directly).
We should correct the return address pushed into top of stack.
- Indirect instructions except for absolute indirect-jumps
are NG. Those instructions changes EIP randomly. We should
check EIP and correct it.
- Instructions that change EIP beyond the range of the
instruction buffer are NG.
- Instructions that change EIP to tail 5 bytes of the
instruction buffer (it is the size of a jump instruction).
We must write a jump instruction which backs to original
kernel code in the instruction buffer.
- Break point instruction is NG. We should not touch EIP and
pass to other handlers.
- Absolute direct/indirect jumps are OK.- Conditional Jumps are NG.
- Halt and software-interruptions are NG. Because it will stay on
the instruction buffer of kprobes.
- Prefixes are NG.
- Unknown/reserved opcode is NG.
- Other 1 byte instructions are OK. But those instructions need a
jump back code.
- 2 bytes instructions are mapped sparsely. So, in this release,
this patch don't boost those instructions.
>From Intel's IA-32 opcode map described in IA-32 Intel Architecture Software
Developer's Manual Vol.2 B, I determined that following opcodes are not
boostable.
- 0FH (2byte escape)
- 70H - 7FH (Jump on condition)
- 9AH (Call) and 9CH (Pushf)
- C0H-C1H (Grp 2: includes reserved opcode)
- C6H-C7H (Grp11: includes reserved opcode)
- CCH-CEH (Software-interrupt)
- D0H-D3H (Grp2: includes reserved opcode)
- D6H (Reserved)
- D8H-DFH (Coprocessor)
- E0H-E3H (loop/conditional jump)
- E8H (Call)
- F0H-F3H (Prefixes and reserved)
- F4H (Halt)
- F6H-F7H (Grp3: includes reserved opcode)
- FEH-FFH(Grp4,5: includes reserved opcode)
Kprobe-booster checks whether target instruction can be boosted (can be
executed directly) at arch_copy_kprobe() function. If the target instruction
can be boosted, it clears "boostable" flag. If not, it sets "boostable" flag
-1. This is disabled status. In resume_execution() function, If "boostable"
flag is cleared, kprobe-booster measures the size of the target instruction
and sets "boostable" flag 1.
In kprobe_handler(), kprobe checks the "boostable" flag. If the flag is 1, it
resets current kprobe and executes instruction buffer directly instead of
single stepping.
When unregistering a boosted kprobe, it calls synchronize_sched()
after "int3" is removed. So we can ensure followings after
the synchronize_sched() called.
- interrupt handlers are finished on all CPUs.
- instruction buffer is not executed on all CPUs.
And we can release the boosted kprobe safely.
And also, on preemptible kernel, the booster is not enabled where the kernel
preemption is enabled. So, there are no preempted threads on the instruction
buffer.
The description of kretprobe-booster:
====================================
In the normal operation, kretprobe make a target function return to trampoline
code. And a kprobe (called trampoline_probe) have been inserted at the
trampoline code. When the kernel hits this kprobe, it calls kretprobe's
handler and it returns to original return address.
Kretprobe-booster patch removes the trampoline_probe. It allows the
trampoline code to call kretprobe's handler directly instead of invoking
kprobe. And tranpoline code returns to original return address.
This new trampoline code stores and restores registers, so the kretprobe
handler is still able to access those registers.
Current kprobe has about 1.3 usec/probe(*) overhead, and kprobe-booster patch
reduces it to 0.6 usec/probe(*). Also current kretprobe has about 2.0
usec/probe(*) overhead. Kprobe-booster patch reduces it to 1.3 usec/probe(*),
and the combination of both kprobe-booster patch and kretprobe-booster patch
reduces it to 0.9 usec/probe(*).
I expect the combination of both patches can reduce half of a probing
overhead.
Performance numbers strongly depend on the processor model.
Andrew Morton wrote:
> These preempt tricks look rather nasty. Can you please describe what the
> problem is, precisely? And how this code avoids it? Perhaps we can find
> something cleaner.
The problem is how to remove the copied instructions of the
kprobe *safely* on the preemptable kernel (CONFIG_PREEMPT=y).
Kprobes basically executes the following actions;
(1)int3
(2)preempt_disable()
(3)kprobe_prehandler()
(4)copied instructioin(single step)
(5)kprobe_posthandler()
(6)preempt_enable()
(7)return to the original code
During the execution of copied instruction, preemption is
disabled (from step (2) to (6)).
When unregistering the probes, Kprobe waits for RCU
quiescent state by using synchronize_sched() after removing
int3 instruction.
Thus we can ensure the copied instruction is not executed.
On the other hand, kprobe-booster executes the following actions;
(1)int3
(2)preempt_disable()
(3)kprobe_prehandler()
(4)preempt_enable() <-- this one is added by my patch
(5)copied instruction(direct execution)
(6)jmp back to the original code
The problem is that we have no way to prevent preemption on
step (5) or (6). We cannot call preempt_disable() after step (6),
because there are no rooms to do that. Thus, some other
processes may be preempted at step(5) or (6) on preemptable kernel.
And I couldn't find the easy way to ensure that other processes'
stack do *not* have the address of them. (I thought some way
to do that, but those are very costly.)
So currently, I simply boost the kprobe only when the probe
point is already preemption disabled.
> Also, the patch adds a preempt_enable() but I don't see a corresponding
> preempt_disable(). Am I missing something?
It is corresponding to the preempt_disable() in the top of
kprobe_handler().
I copied the code of kprobe_handler() here:
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable(); <-- HERE
kcb = get_kprobe_ctlblk();
Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up kprobe's resume_execute() for i386 arch.
Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The nanosleep cleanup allows to remove the data field of hrtimer. The
callback function can use container_of() to get it's own data. Since the
hrtimer structure is anyway embedded in other structures, this adds no
overhead.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
nsec_t predates ktime_t and has mostly been superseded by it. In the few
places that are left it's better to make it explicit that we're dealing with
64 bit values here.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that it_real_value is gone, the last user of DEFINE_KTIME and
ktime_to_clock_t are also gone, so remove it before someone starts using it
again.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
