Anton Vorontsov [Tue, 22 Jul 2008 10:21:07 +0000 (11:21 +0100)]
serial: 8250: fix shared interrupts issues with SMP and RT kernels
With SMP kernels _irqsave spinlock disables only local interrupts, while
the shared serial interrupt could be assigned to the CPU that is not
currently starting up the serial port.
This might cause issues because serial8250_startup() routine issues
IRQ-triggering operations before registering the port in the IRQ chain
(though, this is fine to do and done explicitly because we don't want to
process any interrupts on the port startup).
With RT kernels and preemptable hardirqs, _irqsave spinlock does not
disable local hardirqs, and the bug could be reproduced much easily:
After this, all serial ports on the given IRQ are non-functional.
To fix the issue we should explicitly disable shared IRQ before
issuing any IRQ-triggering operations.
I also changed spin_lock_irqsave to the ordinary spin_lock, since it
seems to be safe: chain does not contain new port (yet), thus nobody
will interfere us from the ISRs.
Alan Cox [Tue, 22 Jul 2008 10:18:03 +0000 (11:18 +0100)]
tty: rework break handling
Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Alan Cox [Tue, 22 Jul 2008 10:17:53 +0000 (11:17 +0100)]
tty: Mark unconverted drivers as BROKEN
Nobody seems to use these drivers anyway so if they want them they can
fix them up. I don't have the needed info to add break_ctl support to them.
Send patches if you don't like it.
Alan Cox [Tue, 22 Jul 2008 10:17:16 +0000 (11:17 +0100)]
specialix: Code cleanups
Go through the inlines and other oddments that are iffy. Remove various bits
of dead code and bogus debug. Turn the crtsdts compile time option into a
runtime switch.
Alan Cox [Tue, 22 Jul 2008 10:09:07 +0000 (11:09 +0100)]
usb_serial: API all change
USB serial likes to use port->tty back pointers for the real work it does and
to do so without any actual locking. Unfortunately when you consider hangup
events, hangup/parallel reopen or even worse hangup followed by parallel close
events the tty->port and port->tty pointers are not guaranteed to be the same
as port->tty is the active tty while tty->port is the port the tty may or
may not still be attached to.
So rework the entire API to pass the tty struct. For console cases we need
to pass both for now. This shows up multiple drivers that immediately crash
with USB console some of which have been fixed in the process.
Longer term we need a proper tty as console abstraction
When a kernel was rebuilt, the previous Module.markers was not cleared.
It caused markers with different format strings to appear as duplicates
when a markers was changed. This problem is present since
scripts/mod/modpost.c started to generate Module.markers, commit b2e3e658b344c6bcfb8fb694100ab2f2b5b2edb0
It therefore applies to 2.6.25, 2.6.26 and linux-next.
I merely merged the patches from Roland, Wenji and Takashi here.
David Brownell [Mon, 21 Jul 2008 21:21:34 +0000 (14:21 -0700)]
gpio: pcf857x: add lock and handle more chips
Two small updates to the pcf857x driver: (a) the max732[89] chips are
also second sources for the pcf8574/a, and (b) add a mutex to prevent
trashing the cached state. Adding the lock is effectively a bugfix,
although it seems unlikely that anyone would have run into the issue it
protects against.
John Reiser [Mon, 21 Jul 2008 21:21:32 +0000 (14:21 -0700)]
execve filename: document and export via auxiliary vector
The Linux kernel puts the filename argument of execve() into the new
address space. Many developers are surprised to learn this. Those who
know and could use it, object "But it's not documented."
Those who want to use it dislike the expression
(char *)(1+ strlen(env[-1+ n_env]) + env[-1+ n_env])
because it requires locating the last original environment variable,
and assumes that the filename follows the characters.
This patch documents the insertion of the filename, and makes it easier
to find by adding a new tag AT_EXECFN in the ElfXX_auxv_t; see <elf.h>.
In many cases readlink("/proc/self/exe",) gives the same answer. But if
all the original pages get unmapped, then the kernel erases the symlink
for /proc/self/exe. This can happen when a program decompressor does a
good job of cleaning up after uncompressing directly to memory, so that
the address space of the target program looks the same as if compression
had never happened. One example is http://upx.sourceforge.net .
One notable use of the underlying concept (what path containED the
executable) is glibc expanding $ORIGIN in DT_RUNPATH. In practice for
the near term, it may be a good idea for user-mode code to use both
/proc/self/exe and AT_EXECFN as fall-back methods for each other.
/proc/self/exe can fail due to unmapping, AT_EXECFN can fail because it
won't be present on non-new systems. The auxvec or {AT_EXECFN}.d_val
also can get overwritten, although in nearly all cases this would be the
result of a bug.
The runtime cost is one NEW_AUX_ENT using two words of stack space. The
underlying value is maintained already as bprm->exec; setup_arg_pages()
in fs/exec.c slides it for stack_shift, etc.
Jan Kratochvil [Tue, 22 Jul 2008 12:00:47 +0000 (14:00 +0200)]
x86: fix crash due to missing debugctlmsr on AMD K6-3
currently if you use PTRACE_SINGLEBLOCK on AMD K6-3 (i586) it will crash.
Kernel now wrongly assumes existing DEBUGCTLMSR MSR register there.
Removed the assumption also for some other non-K6 CPUs but I am not sure there
(but it can only bring small inefficiency there if my assumption is wrong).
Based on info from Roland McGrath, Chuck Ebbert and Mikulas Patocka.
More info at:
https://bugzilla.redhat.com/show_bug.cgi?id=456175
Rusty Russell [Wed, 23 Jul 2008 00:24:28 +0000 (19:24 -0500)]
modules: Take a shortcut for checking if an address is in a module
This patch keeps track of the boundaries of module allocation, in
order to speed up module_text_address().
Inspired by Arjan's version, which required arch-specific defines:
Various pieces of the kernel (lockdep, latencytop, etc) tend
to store backtraces, sometimes at a relatively high
frequency. In itself this isn't a big performance deal (after
all you're using diagnostics features), but there have been
some complaints from people who have over 100 modules loaded
that this is a tad too slow.
This is due to the new backtracer code which looks at every
slot on the stack to see if it's a kernel/module text address,
so that's 1024 slots. 1024 times 100 modules... that's a lot
of list walking.
module.c and module.h conatains code for finding
exported symbols which are declared with EXPORT_UNUSED_SYMBOL,
and this code is compiled in even if CONFIG_UNUSED_SYMBOLS is not set
and thus there can be no EXPORT_UNUSED_SYMBOLs in modules anyway
(because EXPORT_UNUSED_SYMBOL(x) are compiled out to nothing then).
Richard Kennedy [Wed, 23 Jul 2008 00:24:26 +0000 (19:24 -0500)]
module: reorder struct module to save space on 64 bit builds
reorder struct module to save space on 64 bit builds.
saves 1 cacheline_size (128 on default x86_64 & 64 on AMD
Opteron/athlon) when CONFIG_MODULE_UNLOAD=y.
Rusty Russell [Wed, 23 Jul 2008 00:24:25 +0000 (19:24 -0500)]
module: generic each_symbol iterator function
Introduce an each_symbol() iterator to avoid duplicating the knowledge
about the 5 different sections containing symbols. Currently only
used by find_symbol(), but will be used by symbol_put_addr() too.
Rusty Russell [Wed, 23 Jul 2008 00:24:25 +0000 (19:24 -0500)]
module: don't use stop_machine for waiting rmmod
rmmod has a little-used "-w" option, meaning that instead of failing if the
module is in use, it should block until the module becomes unused.
In this case, we don't need to use stop_machine: Max Krasnyansky
indicated that would be useful for SystemTap which loads/unloads new
modules frequently.
Rusty, in his peevish way, complained that macros defining constants
should have a name which somewhat accurately reflects the actual
purpose of the constant.
Aside from the fact that PTE_MASK gives no clue as to what's actually
being masked, and is misleadingly similar to the functionally entirely
different PMD_MASK, PUD_MASK and PGD_MASK, I don't really see what the
problem is.
But if this patch silences the incessent noise, then it will have
achieved its goal (TODO: write test-case).
Rusty Russell [Tue, 22 Jul 2008 05:40:46 +0000 (15:40 +1000)]
x86: fix pte_flags() to only return flags, fix lguest (updated)
(Jeremy said:
rusty: use PTE_MASK
rusty: use PTE_MASK
rusty: use PTE_MASK
When I asked:
jsgf: does that include the NX flag?
He responded eloquently:
rusty: use PTE_MASK
rusty: use PTE_MASK
yes, it's the official constant of masking flags out of ptes
)
Change a15af1c9ea2750a9ff01e51615c45950bad8221b 'x86/paravirt: add
pte_flags to just get pte flags' removed lguest's private pte_flags()
in favor of a generic one.
Unfortunately, the generic one doesn't filter out the non-flags bits:
this results in lguest creating corrupt shadow page tables and blowing
up host memory.
Since noone is supposed to use the pfn part of pte_flags(), it seems
safest to always do the filtering.
David Altobelli [Wed, 2 Jul 2008 15:38:53 +0000 (09:38 -0600)]
HP iLO driver
A driver for the HP iLO/iLO2 management processor, which allows userspace
programs to query the management processor. Programs can open a channel
to the device (/dev/hpilo/dXccbN), and use this to send/receive queries.
The O_EXCL open flag is used to indicate that a particular channel cannot
be shared between processes. This driver will replace various packages
HP has shipped, including hprsm and hp-ilo.
sysdev: Pass the attribute to the low level sysdev show/store function
This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.
I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.
I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.
Cornelia Huck [Tue, 10 Jun 2008 09:09:08 +0000 (11:09 +0200)]
driver core: Suppress sysfs warnings for device_rename().
driver core: Suppress sysfs warnings for device_rename().
Renaming network devices to an already existing name is not
something we want sysfs to print a scary warning for, since the
callers can deal with this correctly. So let's introduce
sysfs_create_link_nowarn() which gets rid of the common warning.
Wang Chen [Tue, 24 Jun 2008 08:59:02 +0000 (16:59 +0800)]
kobject: Transmit return value of call_usermodehelper() to caller
kobject_uevent_env() drops the return value of call_usermodehelper().
It will make upper caller, such as dm_send_uevents(), to lose error
information.
BTW, Previously kobject_uevent_env() transmitted return of
call_usermodehelper() to callers, but
commit 5f123fbd80f4f788554636f02bf73e40f914e0d6
"[PATCH] merge kobject_uevent and kobject_hotplug" removed it.
The first paragraph of this document implies that user space developers
shouldn't use sysfs at all, but then it goes on to describe rules that
developers should follow when accessing sysfs. Not only is this somewhat
self-contradictory, it has been shown to discourage developers from using
established sysfs interfaces.
A note of caution is more appropriate than a blanket "sysfs will never
be stable" assertion.
debugfs_remove_recursive() will remove a dentry and all its children.
Drivers can use this to zap their whole debugfs tree so that they don't
need to keep track of every single debugfs dentry they created.
It may fail to remove the whole tree in certain cases:
sh-3.2# rmmod atmel-mci < /sys/kernel/debug/mmc0/ios/clock
mmc0: card b368 removed
atmel_mci atmel_mci.0: Lost dma0chan1, falling back to PIO
sh-3.2# ls /sys/kernel/debug/mmc0/
ios
But I'm not sure if that case can be handled in any sane manner.
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