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>
drivers/video/fbmem.c:1567: warning: 'video_setup' defined but not used
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
No need for a file argument. If we'd really need it it's in vma->vm_file
already. gbefb and sgivwfb used to set vma->vm_file to the file argument, but
the kernel alrady did that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The ioctl and file arguments to ->fb_mmap are totally unused and there's not
reason a driver should need them.
Also update the ->fb_compat_ioctl prototype to be the same as ->fb_mmap.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While the code in fbmem.c allows for hooking read/write access to
non-linear frame buffers by means of fb_read and fb_write in struct fb_ops,
I could not find a way tho access the actual frame buffer memory from
within these routines. I therefore had to patch fbmem.c, to be able to
retrieve a pointer to struct fb_info from the 'file' argument to these
functions.
The second hunk of the patch is not strictly required, I only did that for
symmetry reasons (and the code is somewhat shorter).
Signed-off-by: Thomas Koeller <thomas@koeller.dyndns.org>
Acked-by: "Antonino A. Daplas" <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make fb_read() and fb_write() return 0 (EOF) instead of -ENOSPC if reading at
or past the end of the framebuffer. This fixes user space apps hanging if
info->fix.smem_len == 0.
Whitespace changes.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Fix fb_pan_display rejecting yoffsets that are valid if panning mode
is ywrap.
- Add more robust error checking in fb_pan_display specially since this
function is accessible by userland apps.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This code fixes a tiny problem with the recent fbcon rotation changes:
fb_prepare_logo doesn't check the return value of fb_find_logo and that
causes a crash for my while booting.
Obvious & working & tested fix is here.
Signed-off-by: Jasper Spaans <jasper@vs19.net>
Acked-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The frame buffer layer already had some code dealing with compat ioctls, this
patch moves over the remaining code from fs/compat_ioctl.c
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add ability to set rotation via sysfs. The attributes are located in
/sys/class/graphics/fb[n] and accepts 0 - unrotated; 1 - clockwise; 2 - upside
down; 3 - counterclockwise.
The attributes are:
con_rotate (r/w) - set rotation of the active console
con_rotate_all (w) - set rotation of all consoles
rotate (r/w) - set rotation of the framebuffer, if supported.
Currently, none of the drivers support this.
This is probably temporary, since con_rotate and con_rotate_all are
console-specific and has no business being under the fb device. However,
until the console layer acquires it's own sysfs class, these attributes will
temporarily reside here.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add support for rotating and positioning of the logo. Rotation and position
depends on 'int rotate' parameter added to fb_prepare_logo() and
fb_show_logo().
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the phys_mem_access_prot() function to take a pfn instead of an
address. This allows mmap64() to work on /dev/mem for addresses above 4G
on 32-bit architectures. We start with a pfn in mmap_mem(), so there's no
need to convert to an address; in fact, it's actively bad, since the
conversion can overflow when the address is above 4G.
Similarly fix the ppc32 page_is_ram() function to avoid a conversion to an
address by directly comparing to max_pfn. Working with max_pfn instead of
high_memory fixes page_is_ram() to give the right answer for highmem pages.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The previous patch adding the ability to nest struct class_device
changed the paramaters to the call class_device_create(). This patch
fixes up all in-kernel users of the function.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The function bit_putcs() in drivers/video/console/bitblit.c is becoming large.
Break it up into its component functions (bit_putcs_unaligned and
bit_putcs_aligned).
Incorporated fb_pad_aligned_buffer() optimization by Roman Zippel.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The Coordinated Video Timings (CVT) is the latest standard approved by VESA
concerning video timings generation. It addresses the limitation of GTF which
is designed mainly for CRT displays. CRT's have a high blanking requirement
(as much as 25% of the horizontal frame length) which artificially increases
the pixelclock. Digital displays, on the other hand, needs to conserve the
pixelclock as much as possible. The GTF also does not take into account the
different aspect ratios in its calculation.
The new function added is fb_find_mode_cvt(). It is called by fb_find_mode()
if it recognizes a mode option string formatted for CVT. The format is:
<xres>x<yres>[M][R][-<bpp>][<at-sign><refresh>][i][m]
The 'M' tells the function to calculate using CVT. On it's own, it will
compute a timing for CRT displays at 60Hz. If the 'R' is specified, 'reduced
blanking' computation will be used, best for flatpanels. The 'i' and the 'm'
is for 'interlaced mode' and 'with margins' respectively.
To determine if CVT was used, check for dmesg for something like this:
CVT Mode - <pix>M<n>[-R], ie: .480M3-R (800x600 reduced blanking)
where: pix - product of xres and yres, in MB
M - is a CVT mode
n - the aspect ratio (3 - 4:3; 4 - 5:4; 9 - 16:9, 15:9; A - 16:10)
-R - reduced blanking
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, fbcon assumes that the visual FB_VISUAL_MONO* is always 1 bit.
According to Geert, there are old hardware where it's possible to have
monochrome at 8-bit, but has only 2 colors, black - 0x00 and white - 0xff.
Fix color handlers (fb_get_color_depth, and get_color) for this special case.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add capability to fbdev to listen to the FB_ACTIVATE_ALL flag. If set, it
notifies fbcon that all consoles must be set to the current var.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Reported by: Pavel Kysilka (Bugzilla Bug 5059)
The intelfb driver does not keep resolution set with fbset after
switching to anot console and back.
Steps to reproduce:
initial options: tty1,tty2 - 1024x768-60
1) tty1 - fbset after booting (1024x768-60)
2) tty1 - fbset 800x600-100
tty1: 800x600-100
3) swith to tty2, swith to tty1
tty1: 1024x768-60 (the same resolution as default from kernel booting)
This bug is caused by intelfb unintentionally destroying info->flags in
set_par(). Therefore the flag, FBINFO_MISC_USEREVENT used to notify
fbcon of a mode change was cleared causing the above problem. This bug
though is not intelfb specific, as other drivers may also be affected.
The fix is to save info->flags in a local variable before calling any
of the driver hooks. A more definitive fix (for post 2.6.13) is to
separate info->flags into one that is set by the driver and another that
is set by core fbdev/fbcon.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Do not use memcpy in fb_pad_aligned_buffer. It is suboptimal because only
a few bytes are moved at a time. Replace with a for-loop.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fbdev is missing unregister_chrdev() on unload.
Signed-off-by: Jon Smirl <jonsmirl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Several drivers miss filling in the access_align field. So this patch has
them fill it in.
Signed-off-by: James Simmons <jsimmons@www.infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Shrink the stack when calling the drawing alignment functions.
Signed-off-by: James Simmons <jsimmons@www.infradead.org>
Cc: "Antonino A. Daplas" <adaplas@hotpop.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since no one is using the inbuf, outbuf of struct fb_pixmap I removed their
use in the framebuffer console. The idea is instead move the pixmap
functionality below the accelerated functions intead of on top as the way
it is now. If there is no objection please apply. This is against Linus
latestr GIT tree. Thank you.
Signed-off-by: James Simmons <jsimmons@www.infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch makes some needlessly global identifiers static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Arjan van de Ven <arjanv@infradead.org>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I have recompiled Linux kernel 2.6.11.5 documentation for me and our
university students again. The documentation could be extended for more
sources which are equipped by structured comments for recent 2.6 kernels. I
have tried to proceed with that task. I have done that more times from 2.6.0
time and it gets boring to do same changes again and again. Linux kernel
compiles after changes for i386 and ARM targets. I have added references to
some more files into kernel-api book, I have added some section names as well.
So please, check that changes do not break something and that categories are
not too much skewed.
I have changed kernel-doc to accept "fastcall" and "asmlinkage" words reserved
by kernel convention. Most of the other changes are modifications in the
comments to make kernel-doc happy, accept some parameters description and do
not bail out on errors. Changed <pid> to @pid in the description, moved some
#ifdef before comments to correct function to comments bindings, etc.
You can see result of the modified documentation build at
http://cmp.felk.cvut.cz/~pisa/linux/lkdb-2.6.11.tar.gz
Some more sources are ready to be included into kernel-doc generated
documentation. Sources has been added into kernel-api for now. Some more
section names added and probably some more chaos introduced as result of quick
cleanup work.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Martin Waitz <tali@admingilde.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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!
