Implementation of kernel tracepoints. Inspired from the Linux Kernel
Markers. Allows complete typing verification by declaring both tracing
statement inline functions and probe registration/unregistration static
inline functions within the same macro "DEFINE_TRACE". No format string
is required. See the tracepoint Documentation and Samples patches for
usage examples.
Taken from the documentation patch :
"A tracepoint placed in code provides a hook to call a function (probe)
that you can provide at runtime. A tracepoint can be "on" (a probe is
connected to it) or "off" (no probe is attached). When a tracepoint is
"off" it has no effect, except for adding a tiny time penalty (checking
a condition for a branch) and space penalty (adding a few bytes for the
function call at the end of the instrumented function and adds a data
structure in a separate section). When a tracepoint is "on", the
function you provide is called each time the tracepoint is executed, in
the execution context of the caller. When the function provided ends its
execution, it returns to the caller (continuing from the tracepoint
site).
You can put tracepoints at important locations in the code. They are
lightweight hooks that can pass an arbitrary number of parameters, which
prototypes are described in a tracepoint declaration placed in a header
file."
Addition and removal of tracepoints is synchronized by RCU using the
scheduler (and preempt_disable) as guarantees to find a quiescent state
(this is really RCU "classic"). The update side uses rcu_barrier_sched()
with call_rcu_sched() and the read/execute side uses
"preempt_disable()/preempt_enable()".
We make sure the previous array containing probes, which has been
scheduled for deletion by the rcu callback, is indeed freed before we
proceed to the next update. It therefore limits the rate of modification
of a single tracepoint to one update per RCU period. The objective here
is to permit fast batch add/removal of probes on _different_
tracepoints.
Changelog :
- Use #name ":" #proto as string to identify the tracepoint in the
tracepoint table. This will make sure not type mismatch happens due to
connexion of a probe with the wrong type to a tracepoint declared with
the same name in a different header.
- Add tracepoint_entry_free_old.
- Change __TO_TRACE to get rid of the 'i' iterator.
Masami Hiramatsu <mhiramat@redhat.com> :
Tested on x86-64.
Performance impact of a tracepoint : same as markers, except that it
adds about 70 bytes of instructions in an unlikely branch of each
instrumented function (the for loop, the stack setup and the function
call). It currently adds a memory read, a test and a conditional branch
at the instrumentation site (in the hot path). Immediate values will
eventually change this into a load immediate, test and branch, which
removes the memory read which will make the i-cache impact smaller
(changing the memory read for a load immediate removes 3-4 bytes per
site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it
also saves the d-cache hit).
About the performance impact of tracepoints (which is comparable to
markers), even without immediate values optimizations, tests done by
Hideo Aoki on ia64 show no regression. His test case was using hackbench
on a kernel where scheduler instrumentation (about 5 events in code
scheduler code) was added.
Quoting Hideo Aoki about Markers :
I evaluated overhead of kernel marker using linux-2.6-sched-fixes git
tree, which includes several markers for LTTng, using an ia64 server.
While the immediate trace mark feature isn't implemented on ia64, there
is no major performance regression. So, I think that we don't have any
issues to propose merging marker point patches into Linus's tree from
the viewpoint of performance impact.
I prepared two kernels to evaluate. The first one was compiled without
CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS.
I downloaded the original hackbench from the following URL:
http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
I ran hackbench 5 times in each condition and calculated the average and
difference between the kernels.
The parameter of hackbench: every 50 from 50 to 800
The number of CPUs of the server: 2, 4, and 8
Below is the results. As you can see, major performance regression
wasn't found in any case. Even if number of processes increases,
differences between marker-enabled kernel and marker- disabled kernel
doesn't increase. Moreover, if number of CPUs increases, the differences
doesn't increase either.
Curiously, marker-enabled kernel is better than marker-disabled kernel
in more than half cases, although I guess it comes from the difference
of memory access pattern.
Linus Torvalds [Mon, 13 Oct 2008 16:54:35 +0000 (09:54 -0700)]
Merge phase #5 (misc) of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
Merges oprofile, timers/hpet, x86/traps, x86/time, and x86/core misc items.
* 'x86-core-v4-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (132 commits)
x86: change early_ioremap to use slots instead of nesting
x86: adjust dependencies for CONFIG_X86_CMOV
dumpstack: x86: various small unification steps, fix
x86: remove additional_cpus
x86: remove additional_cpus configurability
x86: improve UP kernel when CPU-hotplug and SMP is enabled
dumpstack: x86: various small unification steps
dumpstack: i386: make kstack= an early boot-param and add oops=panic
dumpstack: x86: use log_lvl and unify trace formatting
dumptrace: x86: consistently include loglevel, print stack switch
dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stack
dumpstack: x86: make printk_address equal
dumpstack: x86: move die_nmi to dumpstack_32.c
traps: x86: finalize unification of traps.c
traps: x86: make traps_32.c and traps_64.c equal
traps: x86: various noop-changes preparing for unification of traps_xx.c
traps: x86_64: use task_pid_nr(tsk) instead of tsk->pid in do_general_protection
traps: i386: expand clear_mem_error and remove from mach_traps.h
traps: x86_64: make io_check_error equal to the one on i386
traps: i386: use preempt_conditional_sti/cli in do_int3
...
David S. Miller [Mon, 13 Oct 2008 09:45:26 +0000 (10:45 +0100)]
serial: fix device name reporting when minor space is shared between drivers
The multiple drivers share the minor space occupied by a particular major
number, the actual index within the device name's space is indicated by
the tty_driver->name_base + uart_port->line
Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line
Use those to print the device names properly in such situations in
serial_core.c and 8250.c
Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:44:57 +0000 (10:44 +0100)]
tty: Remove lots of NULL checks
Many tty drivers contain 'can't happen' checks against NULL pointers passed
in by the tty layer. These have never been possible to occur. Even more
importantly if they ever do occur we want to know as it would be a serious
bug.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stephen Rothwell [Mon, 13 Oct 2008 09:44:33 +0000 (10:44 +0100)]
tty: Fallout from tty-move-canon-specials
Today's linux-next build (x86_64 allmodconfig) failed like this:
/drivers/char/tty_ioctl.c: In function 'change_termios':
drivers/isdn/capi/capi.c:1234: error: implicit declaration of function 'n_tty_ioctl'
drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl':
drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl'
Alan Cox [Mon, 13 Oct 2008 09:44:17 +0000 (10:44 +0100)]
tty: some ICANON magic is in the wrong places
Move the set up on ldisc change into the ldisc
Move the INQ/OUTQ cases into the driver not in shared ioctl code where it
gives bogus answers for other ldisc values
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:44:08 +0000 (10:44 +0100)]
tty: simplify ktermios allocation
Copy the simplification from the pty unix98 special case to the generic one.
This allows us to kill off driver->termios_locked entirely which is nice. We
have to whack bits of the cris driver as it meddles in places it shouldn't
providing its own arrays that were never used anyway.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:43:48 +0000 (10:43 +0100)]
pty: Fix allocation failure double free
The updating and moving around of the pty code added a bug where both the
helper and caller free the main tty struct (the pty driver must free the
o_tty pair itself however).
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When creating a new pty, save the pty's inode in the tty->driver_data.
Use this inode in pty_kill() to identify the devpts instance. Since
we now have the inode for the pty, we can skip get_node() lookup and
remove the unused get_node().
TODO:
- check if the mutex_lock is needed in pty_kill().
devpts_pty_new() is called when setting up a new pty and would not
will not have an existing dentry or inode for the pty. So don't bother
looking for an existing dentry - just create a new one.
Pass-in 'inode' or 'tty' parameter to devpts interfaces. With multiple
devpts instances, these parameters will be used in subsequent patches
to identify the instance of devpts mounted. The parameters also help
simplify devpts implementation.
Changelog[v3]:
- minor changes due to merge with ttydev updates
- rename parameters to emphasize they are ptmx or pts inodes
- pass-in tty_struct * to devpts_pty_kill() (this will help
cleanup the get_node() call in a subsequent patch)
Move tty_driver_lookup_tty() and tty_reopen() from tty_init_dev()
into tty_open() (one of the two callers of tty_init_dev()). These
calls are not really required in ptmx_open(), the other caller,
since ptmx_open() would be setting up a new tty.
Changelog[v2]:
- remove the lookup and reopen calls from ptmx_open
- merge with recent changes to ttydev tree
Alan Cox [Mon, 13 Oct 2008 09:42:19 +0000 (10:42 +0100)]
tty: More driver operations
We have the lookup operation abstracted which is nice for pty cleanup but
we really want to abstract the add/remove entries as well so that we can
pull the pty code out of the tty core and create a clear defined interface
for the tty driver table.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:41:42 +0000 (10:41 +0100)]
tty: Remove more special casing and out of place code
Carry on pushing code out of tty_io when it belongs to other drivers. I'm
not 100% happy with some of this and it will be worth revisiting some of the
exports later when the restructuring work is done.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:41:30 +0000 (10:41 +0100)]
tty: shutdown method
Right now there are various drivers that try to use tty->count to know when
they get the final close. Aristeau Rozanski showed while debugging the vt
sysfs race that this isn't entirely safe.
Instead of driver side tricks to work around this introduce a shutdown which
is called when the tty is being destructed. This also means that the shutdown
method is tied into the refcounting.
Use this to rework the console close/sysfs logic.
Remove lots of special case code from the tty core code. The pty code can now
have a shutdown() method that replaces the special case hackery in the tree
free up paths.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:41:16 +0000 (10:41 +0100)]
vt: remove bogus lock dropping
For hysterical raisins the vt layer drops and retakes locks in the write
method. This is a left over from the days when user/kernel data was passed
directly to the tty not pre-buffered.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:41:03 +0000 (10:41 +0100)]
pty: If the administrator creates a device for a ptmx slave we should not error
The open path for ptmx slaves is via the ptmx device. Opening them any
other way is not allowed. Vegard Nossum found that previously this was not
the case and mknod foo c 128 42; cat foo would produce nasty diagnostics
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:40:53 +0000 (10:40 +0100)]
tty: Fix abusers of current->sighand->tty
Various people outside the tty layer still stick their noses in behind the
scenes. We need to make sure they also obey the locking and referencing rules.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:40:43 +0000 (10:40 +0100)]
tty: Redo current tty locking
Currently it is sometimes locked by the tty mutex and sometimes by the
sighand lock. The latter is in fact correct and now we can hand back referenced
objects we can fix this up without problems around sleeping functions.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:40:07 +0000 (10:40 +0100)]
stallion: Use krefs
Use tty_port_init and krefs in the stallion drivers to protect us from devices
going away underneath us. As with the other drives some rearranging is done to
pass the tty structure down properly on the user side.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:39:58 +0000 (10:39 +0100)]
tty: kref usage for isicom and moxa
Rather than blindly keep taking krefs we reorder the code in a few places
to pass the tty down to the right place (which is important as from the user
side it is not the case that tty == port->tty in all situations). For the irq
and related paths use the krefs to stop the tty being freed under us.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:39:46 +0000 (10:39 +0100)]
tty: usb-serial krefs
Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.
Contains two err->dev_err changes merged together to fix clashes in the
-next tree.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:39:13 +0000 (10:39 +0100)]
tty: Make get_current_tty use a kref
We now return a kref covered tty reference. That ensures the tty structure
doesn't go away when you have a return from get_current_tty. This is not
enough to protect you from most of the resources being freed behind your
back - yet.
[Updated to include fixes for SELinux problems found by Andrew Morton and
an s390 leak found while debugging the former]
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:39:01 +0000 (10:39 +0100)]
tty: compare the tty winsize
We always use the real tty one for stuff so the pty one should not be
compared. As we propagate window changes to both it doesn't currently
matter but will when we tidy up the pty termios logic a bit more
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:38:18 +0000 (10:38 +0100)]
tty: Add termiox
We need a way to describe the various additional modes and flow control
features that random weird hardware shows up and software such as wine
wants to emulate as Windows supports them.
TCGETX/TCSETX and the termiox ioctl are a SYS5 extension that we might as
well adopt. This patches adds the structures and the basic ioctl interfaces
when the TCGETX etc defines are added for an architecture. Drivers wishing
to use this stuff need to add new methods.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:38:07 +0000 (10:38 +0100)]
tty: ipw need reworking
This came in via another tree and unfortunately is rather broken on
the tty side. Comment the apparent locking problems for someone who knows
the driver to look at.
Fix the termios and other ioctl handling. The driver was calling the wrong
methods for what it wanted to do but the right ones existed so its a simple
fix up.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:37:48 +0000 (10:37 +0100)]
tty: Cris has a nice RS485 ioctl so we should steal it
JP Tosoni observed:
"About a RS485 ioctl: could you consider the attached files which are
already in the Linux kernel (in include/asm-cris). They define a
TIOCSERSETRS485 (ioctl.h), and the data structure (rs485.h)
with allows to specify timings. Sounds just like what we want ?"
and he's right: sort of. Rework the structure to use flag bits and make the
time delay a fixed sized field so we don't get 32/64bit problems. Add the ioctls
to x86 so that people know what to add to their platform of choice.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:37:36 +0000 (10:37 +0100)]
tty: use krefs to protect driver module counts
The tty layer keeps driver module counts that are used so the driver knows
when it can be unloaded. For obvious reasons we want to tie that to the
refcounting properly.
At this point the driver side itself isn't refcounted nicely but we can do
that later and kref the drivers.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:36:40 +0000 (10:36 +0100)]
tty: move tioclinux from a special case
Right now we have ifdefs and hooks in the core ioctl handler for TIOCLINUX
and then test if its a console. This is brain dead. Instead call the
tioclinux helper from the relevant driver ioctl methods.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Miller [Mon, 13 Oct 2008 09:36:31 +0000 (10:36 +0100)]
serial: allow 8250 to be used on sparc
This requires three changes:
1) Remove !SPARC restriction in Kconfig.
2) Move Sparc specific serial drivers before 8250, so that serial
console devices don't change names on us, even if 8250 finds
devices.
3) Since the Sparc specific serial drivers try to use the
same major/minor device namespace as 8250, some coordination
is necessary. Use the sunserial_*() layer routines to allocate
minor number space within TTY_MAJOR when CONFIG_SPARC.
This has no effect on other platforms.
Thanks to Josip Rodin for bringing up this issue and testing
plus debugging various revisions of this patch.
Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Will Newton [Mon, 13 Oct 2008 09:36:21 +0000 (10:36 +0100)]
8250: remove a few inlines of dubious value
Remove some inlines from various functions that are called once, are too
big to inline, or are called only from slow path code. This saves around
300 bytes of code for me.
Signed-off-by: Will Newton <will.newton@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:36:11 +0000 (10:36 +0100)]
serial_8250: pci_enable_device fail is not fully handled
<rmk> talking about leaks - I noticed that the 'check return of
pci_enable_dev()' in the 8250 pci resume function finally made it in
despite my objections against it (causing stuff in higher levels to
leak).
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jason Wessel [Mon, 13 Oct 2008 09:35:51 +0000 (10:35 +0100)]
usb: fix pl2303 initialization
This patch removes the private check for the termios_initialized for
the pl2303 usb driver. It forced the baud to 9600 on the first call
to pl2303_set_termios()
Based on the tty changes in the 2.6.27 kernel, the termios passed to
the *_set_termios functions is always populated the first time.
This means there is no need to privately initialize the settings the
first time, and doing so will not allow the use of the kernel
parameter "console=ttyUSB0,115200" as an example.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Mon, 13 Oct 2008 09:35:33 +0000 (10:35 +0100)]
nozomi: Fix close on error
Nozomi assumes the close method isn't called if open errors. The tty layer
is different to other drives in this respect however. Pointed out by Denis J
Barrow.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Miller [Mon, 13 Oct 2008 09:35:23 +0000 (10:35 +0100)]
serial: Make uart_port's ioport "unsigned long".
Otherwise the top 32-bits of the resource value get chopped
off on 64-bit systems, and the resulting I/O accesses go to
random places.
Thanks to testing and debugging by Josip Rodin, which helped
track this down.
Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miloslav Trmac [Mon, 13 Oct 2008 09:35:15 +0000 (10:35 +0100)]
audit: Handle embedded NUL in TTY input auditing
Data read from a TTY can contain an embedded NUL byte (e.g. after
pressing Ctrl-2, or sent to a PTY). After the previous patch, the data
would be logged only up to the first NUL.
This patch modifies the AUDIT_TTY record to always use the hexadecimal
format, which does not terminate at the first NUL byte. The vast
majority of recorded TTY input data will contain either ' ' or '\n', so
the hexadecimal format would have been used anyway.
Akinobu Mita [Mon, 13 Oct 2008 09:35:05 +0000 (10:35 +0100)]
ip2: avoid add_timer with pending timer
add_timer() is not supposed to be called when the timer is pending.
ip2 driver attempts to avoid that condition by setting and resetting
a flag (TimerOn) in timer function. But there is some gap between
add_timer() and setting TimerOn.
This patch fix this problem by using mod_timer() and remove TimerOn
which has been unnecessary by this change.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jiri Slaby [Mon, 13 Oct 2008 09:34:56 +0000 (10:34 +0100)]
ip2: init/deinit cleanup
Cleanup of module_init/exit:
- mostly whitespace
- remove empty functions
- replace c++ comments
- remove useless prints (module loaded, unloaded)
- mark the calls as __exit and __init
- use break; and return; to save some indent levels after it
- note resource leakage
Jiri Slaby [Mon, 13 Oct 2008 09:34:27 +0000 (10:34 +0100)]
Char: merge ip2main and ip2base
It's pretty useless to have one setup() function separated along with
module_init() which only calls a function from ip2main anyway. Get rid
of ip2base.
Mike Frysinger [Mon, 13 Oct 2008 09:33:16 +0000 (10:33 +0100)]
Blackfin Serial Driver: move common variables out of serial headers and into the serial driver
move common variables out of serial headers and into the serial driver and
rename "nr_ports" to "nr_active_ports" so as to easily differentiate
between BFIN_UART_NR_PORTS (the # of available) and nr_ports (the # of enabled)
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Bryan Wu <cooloney@kernel.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Julia Lawall [Mon, 13 Oct 2008 09:31:49 +0000 (10:31 +0100)]
drivers/char/hvc_console.c: adjust call to put_tty_driver
The call to put_tty_driver is out of place and is applied to the wrong
argument.
The function enclosing the patched code calls alloc_tty_driver and stores
the result in drv. Subsequently, there are two occurrences of error
handling code, one making a goto to put_tty and one making a goto to
stop_thread. At the point of the first one the assignment hvc_driver = drv
has not yet been executed, and from inspecting the rest of the file it
seems that hvc_driver would be NULL. Thus the current call to
put_tty_driver is useless, and one applied to drv is needed. The goto
stop_thread is in the error handling code for a call to
tty_register_driver, but the error cases in tty_register_driver do not free
its argument, so it should be done here. Thus, I have moved the put_tty
label after the stop_thread label, so that put_tty_driver is called in both
cases.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r exists@
local idexpression x;
expression E,f;
position p1,p2,p3;
identifier l;
statement S;
@@
x = alloc_tty_driver@p1(...)
...
if (x == NULL) S
... when != E = x
when != put_tty_driver(x)
goto@p2 l;
... when != E = x
when != f(...,x,...)
when any
(
return \(0\|x\);
|
return@p3 ...;
)
alloc_tty_driver is called at the beginning of the function containing the
lines of code shown in the patch. Thus, put_tty_driver is needed before
returning in the error handling code.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@nr exists@
local idexpression x;
expression E,f;
position p1,p2,p3;
identifier l;
statement S;
@@
x = alloc_tty_driver@p1(...)
...
if (x == NULL) S
... when != E = x
when != put_tty_driver(x)
when != goto l;
(
return \(0\|x\);
|
return@p3 ...;
)
@script:python@
p1 << nr.p1;
p3 << nr.p3;
@@
print "%s: call on line %s not freed or saved before return on line %s" % (p1[0].file,p1[0].line,p3[0].line)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas Gleixner [Sun, 5 Oct 2008 15:51:52 +0000 (17:51 +0200)]
x86: remove additional_cpus
remove remainder of additional_cpus logic. We now just listen to the
disabled_cpus value like we did for years. disabled_cpus is always >=
0 so no need for an extra check.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ingo Molnar [Sun, 5 Oct 2008 15:12:36 +0000 (17:12 +0200)]
x86: remove additional_cpus configurability
additional_cpus=<x> parameter is dangerous and broken: for example
if we boot additional_cpus=-2 on a stock dual-core system it will
crash the box on bootup.
So reduce the maze of code a bit by removingthe user-configurability
angle.
- define STACKSLOTS_PER_LINE and use it
- define get_bp macro to hide the %%ebp/%%rbp difference
- i386: check task==NULL in dump_trace, like x86_64
- i386: show_trace(NULL, ...) uses current automatically
- x86_64: use [#%d] for die_counter, like i386
- whitespace and comments
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
dumptrace: x86: consistently include loglevel, print stack switch
- i386 and x86_64: always printk the 'data' parameter
- i386: announce stack switch (irq -> normal)
- i386: check if there is a stack switch before announcing it
There is a warning that 'context' might come out corrupt in early
boot. If this is true it should be fixed, not worked around.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
projects / linux-2.6-omap-h63xx.git / log