The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Use seq_file interface for proc output in sba_iommu. Also
clean up the bus root assignment, and give the proc files
a more logical name. Tested on my J6000.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Gut ccio-dma.c of the ugly proc append and snprintf cruft and
just use seq_printf instead. Tested on a K-class.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Clean up some of the messages printed by the superio driver
by defining a prefix instead of duplicating it in every message.
Also some small coding style cleanups.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Define a chassis_power_off routine that machines which have a way
to turn off the power supply can hook into. Formerly they were
using pm_power_off, which is now being used by generic code. Make
lasi.c use chassis_power_off instead of pm_power_off.
Note, all machines need to call machine_power_off so that the
switch can power off the machine, though halt -p may not necessarily
be able to work properly on the machine.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
pdc_stable v0.22, changes since v0.10:
o renamed root subsystem from 'pdc' to 'stable'
o split 'info' into several files, one per PDC field
o implemented 'autoboot' and 'autosearch' write calls to toggle
these flags
o grant read permission to all users on "safe" files
o more code cleanup (removed duplicate code)
o avoid bad stable storage clobbering by write locking critical sections
o print consistent data as well
o SMP cleanups
Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Helge,
o Convert a bunch of kmalloc/memset uses to kzalloc.
o pci.c: Add some __read_mostly annotations.
o pci.c: Move constant pci_post_reset_delay to asm/pci.h
o grfioctl.h: Add A4450A to comment of CRT_ID_VISUALIZE_EG.
o Add some consts to perf.c/perf_images.h
Matthew,
o sticore.c: Add some consts to suppress compile warnings.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
- Move capable() from sched.h to capability.h;
- Use <linux/capability.h> where capable() is used
(in include/, block/, ipc/, kernel/, a few drivers/,
mm/, security/, & sound/;
many more drivers/ to go)
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix Dino reporting on J2240. This particular machine thought it
had a Cujo. Also add J2240 Dino chip to the hp_hardware_list.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
pdc_stable 0.10:
As mentioned on LKML, pdc_stable wasn't checky enough on the return
values of some calls. This patch makes it more robust to errors when
registering objects in sysfs.
Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Deal with overlapping LBA MMIO resources,
rp3440 PDC BUG: PDC reports lmmio range for the last rope that overlaps
with the CPU HPA. Console output was:
...
Found devices:
1. Storm Peak Fast at 0xfffffffffe798000 [152] { 0, 0x0, 0x889, 0x00004 }
2. Storm Peak Fast at 0xfffffffffe799000 [153] { 0, 0x0, 0x889, 0x00004 }
...
FAILED: lba_fixup_bus() request for lmmio_space
[fffffffff0000000/fffffffffecffffe]
Output is now:
LBA: Truncating lmmio_space [fffffffff0000000/fffffffffecffffe] to
[fffffffff0000000,fffffffffe797fff]
My only concern with this patch is how C8000 (PAT PDC) will report
elmmio ranges when a gfx card is installed. I'll have to test this
another day.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Fix dino by using DINO_LOCAL_IRQS as the limit for gsc_find_local_irq()
instead of the irq itself.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Fix irq-off-by-one for Cirrus 6832 Cardbus on RDI Tadpole PARISC Laptop.
We just DECLARE_PCI_FIXUP_ENABLE as it is unlikely that this will be
found in any other parisc system.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Flag a whole bunch of things as __read_mostly on parisc. Also flag a few
branches as unlikely() and cleanup a bit of code.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Convert superio_init to use PCI_FIXUP_FINAL as ohci_pci being called
before superio_probe really makes a mess. superio_init will then fail
to register irq 20 (the "SuperIO" irq) and BUG() because ohci_pci has
stolen it before superio_fixup_irq can be moved USB to irq 1.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This really only adds them for the machines I can check SMP on, which
is CPU interrupts and IOSAPIC (so not any of the GSC based machines).
With this patch, irqbalanced can be used to maintain irq balancing.
Unfortunately, irqbalanced is a bit x86 centric, so it doesn't do an
incredibly good job, but it does work.
Signed-off-by: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
git commit 976ecd12b8 changed our locking
characteristics, and put the onus of spin_lock_init on superio.c.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2.6.12-rc1-pa6 use work queue in LED/LCD driver instead of tasklet.
Main advantage is it allows use of msleep() in the led_LCD_driver to
"atomically" perform two MMIO writes (CMD, then DATA).
Lead to nice cleanup of the main led_work_func() and led_LCD_driver().
Kudos to David for being persistent.
From: David Pye <dmp@davidmpye.dyndns.org>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Fix card-mode Dino crashes on 725 (and probably other Snake) systems.
Dino was coming up in fatal mode after a warm reboot. Resetting Dino
brings it out of fatal mode, so do that if the status register indicates
we're in fatal mode. Since this was never observed on any later systems,
I presume firmware does this for us on those.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Add debug statements in the cfg_read and cfg_write functions
Fix debug statements from the IRQ overhaul last winter
Rename dino_driver_callback() to dino_probe()
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
revert use of %%sr0 in fdc asm.
Thanks to Joel Soete for pointing out this oversight.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.14-rc2-pa3 fdc/lci should be %r0 instead 0 for index (PA 1.1 compliance)
From: Joel Soete <soete.joel@tiscali.be>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Explain why we need insert_resource() instead of request_resource().
Fundementally, this is more convoluted for ccio driver because of
o legacy (HP-PB) transperant bridges.
o support for MMIO behind card-mode Dino (PCI)
o support for above bridges without ccio in the box
SBA driver doesn't have to worry about those issues.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Use insert_resource instead of request_resource now that the subdevices
will already have their resources claimed
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
re-enable use of "inline" for perf critical functions.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.12-rc4-pa5 fix sign extension of MMIO range
Fixes the problem of claiming a range that is disabled on 64-bit kernel:
ccio_init_resource() claimed CCIO bus address space (ffffffff00000000,
ffffffffffffffff)
also removes use of __FILE__.
Tested on both 32 and 64-bit systems by Joel.
From: Joel Soete <soete.joel@tiscali.be>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.12-rc1-pa7 incorrect BUG_ON in ccio
ccio-dma.c line 1317 was preventing K-class with 4GB RAM from booting.
Any ccio machine with >=2GB of RAM would have (incorrectly) triggered this.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Convert to ioremap and __raw_read/write
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
revert use of %%sr0 in fdc asm.
Thanks to Joel Soete for pointing out this oversight.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.14-rc2-pa3 move "sync" outside the main loop that fills IO Pdir.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
remove explicit use of sr0 in fdc ops.
Thanks to Joel Soete for reminding me were I added those...
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.14-rc2-pa2 - make SBA more anal about invalidating pdir entries
Previous code cleared the valid flag a pdir entry but it did NOT
guarantee this change was visible to the PDIR before writing
the PCOM register. Ie the SBA could pick up a stale entry if
the write happened to hit the SBA before the cacheline was flushed
from the cache.
Long term, I think I want to make this a compile time flag.
Developement tree should enable anal pdir checking by default
and Debian can disable it with either a CONFIG option
or one-line patch. fdc/sync options can only negatively affect
performance though I haven't measure how much yet.
If someone can run netperf TCP_RR across gige and compare
-pa1 and -pa2, that would be sufficient.
Cleaned up the use of "fdc" to make sure it's using "kernel"
space id (specify sr0 but maps to sr4-7). It seems a bit fragile
to assume "sr1" gets loaded with KERNEL_SPACE which is how the
code works today.
Tested on 32 and 64-bit SMP kernels on j6k.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
remove PDC_NARROW from SBA and document history of PDC_NARROW a bit.
It will still show up in an older kernel's .config file.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
if/ifdef cleanups from Joel Soete.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
2.6.12-rc4-pa2 fix 32-bit support for Astro platforms
o Since my last SBA code change, SBA could allocate more than 1GB of IOVA
space on Astro boxes with more than 1GB of RAM when running 32-bit kernel.
This is bad since IOMMU can only talk to the first 1GB at most.
Kudos to jejb for quickly spotting that bug.
o jejb also noted SBA should *always* reject DMA masks > 32-bits since
DMA-mapping.txt indicates caller should try again with 32-bits.
o off-by-one error when comparing the mask to IOVA space size.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Convert pa_dev->hpa from an unsigned long to a struct resource.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Fix up users of ->hpa to use ->hpa.start instead.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Make /sys/bus/parisc/drivers look better by cleaning up parisc_driver
names.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Fix parse_tree_node. much more needs to be done to fix this file.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Make drivers.c compile based on a patch from Pat Mochel.
From: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Fix drivers.c to create new device tree nodes when no match is found.
Signed-off-by: Richard Hirst <rhirst@parisc-linux.org>
Do a proper depth-first search returning parents before children, using the
new klist infrastructure.
Signed-off-by: Richard Hirst <rhirst@parisc-linux.org>
Fixed parisc_device traversal so that pdc_stable works again
Fixed check_dev so it doesn't dereference a parisc_device until it
has verified the bus type
Signed-off-by: Randolph Chung <tausq@parisc-linux.org>
Convert pa_dev->hpa from an unsigned long to a struct resource.
Use insert_resource() instead of request_mem_region().
Request resources at bus walk time instead of driver probe time.
Don't release the resources as we don't have any hotplug parisc_device
support yet.
Add parisc_pathname() to conveniently get the textual representation
of the hwpath used in sysfs.
Inline the remnants of claim_device() into its caller.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
I noticed that some of the STI regions weren't showing up in iomem.
Reading the STI spec indicated that all STI devices occupy at least 32MB.
So check for STI HPAs and give them 32MB instead of 4kB.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.
1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().
There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition. I've marked it as such so that we remember to fix it.
This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch contains the most trivial from Rusty's trivial patches:
- spelling fixes
- remove duplicate includes
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This converts the final 20 DEFINE_SPINLOCK holdouts. (another 580 places
are already using DEFINE_SPINLOCK). Build tested on x86.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When you hot-plug a (root) bridge hierarchy, it may have p2p bridges and
devices attached to it that have not been configured by firmware. In this
case, we need to configure the devices before starting them. This patch
separates device start from device scan so that we can introduce the
configuration step in the middle.
I kept the existing semantics for pci_scan_bus() since there are a huge number
of callers to that function.
Also, I have no way of testing the changes I made to the parisc files, so this
needs review by those folks. Sorry for the massive cross-post, this touches
files in many different places.
Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
