For NUMA optimization and some other algorithms it is useful to have a fast
to get the current CPU and node numbers in user space.
x86-64 added a fast way to do this in a vsyscall. This adds a generic
syscall for other architectures to make it a generic portable facility.
I expect some of them will also implement it as a faster vsyscall.
The cache is an optimization for the x86-64 vsyscall optimization. Since
what the syscall returns is an approximation anyways and user space
often wants very fast results it can be cached for some time. The norma
methods to get this information in user space are relatively slow
The vsyscall is in a better position to manage the cache because it has direct
access to a fast time stamp (jiffies). For the generic syscall optimization
it doesn't help much, but enforce a valid argument to keep programs
portable
I only added an i386 syscall entry for now. Other architectures can follow
as needed.
AK: Also added some cleanups from Andrew Morton
Signed-off-by: Andi Kleen <ak@suse.de>
AK: This redoes the changes I temporarily reverted.
Intel now has support for Architectural Performance Monitoring Counters
( Refer to IA-32 Intel Architecture Software Developer's Manual
http://www.intel.com/design/pentium4/manuals/253669.htm ). This
feature is present starting from Intel Core Duo and Intel Core Solo processors.
What this means is, the performance monitoring counters and some performance
monitoring events are now defined in an architectural way (using cpuid).
And there will be no need to check for family/model etc for these architectural
events.
Below is the patch to use this performance counters in nmi watchdog driver.
Patch handles both i386 and x86-64 kernels.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Making NMI suspend/resume work with SMP. We use CPU hotplug to offline
APs in SMP suspend/resume. Only BSP executes sysdev's .suspend/.resume
method. APs should follow CPU hotplug code path.
And:
+From: Don Zickus <dzickus@redhat.com>
Makes the start/stop paths of nmi watchdog more robust to handle the
suspend/resume cases more gracefully.
AK: I merged the two patches together
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Adds a new /proc/sys/kernel/nmi call that will enable/disable the nmi
watchdog.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Removes the un/set_nmi_callback and reserve/release_lapic_nmi functions as
they are no longer needed. The various subsystems are modified to register
with the die_notifier instead.
Also includes compile fixes by Andrew Morton.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This patch cleans up the NMI interrupt path. Instead of being gated by if
the 'nmi callback' is set, the interrupt handler now calls everyone who is
registered on the die_chain and additionally checks the nmi watchdog,
reseting it if enabled. This allows more subsystems to hook into the NMI if
they need to (without being block by set_nmi_callback).
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This patch includes the changes to make the nmi watchdog on i386 SMP aware.
A bunch of code was moved around to make it simpler to read. In addition,
it is now possible to determine if a particular NMI was the result of the
watchdog or not. This feature allows the kernel to filter out unknown NMIs
easier.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Adds basic infrastructure to allow subsystems to reserve performance
counters on the x86 chips. Only UP kernels are supported in this patch to
make reviewing easier. The SMP portion makes a lot more changes.
Think of this as a locking mechanism where each bit represents a different
counter. In addition, each subsystem should also reserve an appropriate
event selection register that will correspond to the performance counter it
will be using (this is mainly neccessary for the Pentium 4 chips as they
break the 1:1 relationship to performance counters).
This will help prevent subsystems like oprofile from interfering with the
nmi watchdog.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
There are some machines around (large xSeries or Unisys ES7000) that
need physical IO-APIC destination mode to access all of their IO
devices. This currently doesn't work in UP kernels as used in
distribution installers.
This patch allows to compile even UP kernels as GENERICARCH which
allows to use physical or clustered APIC mode.
Signed-off-by: Andi Kleen <ak@suse.de>
They all contain the same thing. Instead, have a single generic one in
include/asm-generic, and permit an arch to override as needed.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
(And reset it on new thread creation)
It turns out that eflags is important to save and restore not just
because of iopl, but due to the magic bits like the NT bit, which we
don't want leaking between different threads.
Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This brings i386 asm/unistd.h into consistency with other architectures by not
exporting functionality which is not necessary.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The header file <linux/pfn.h> doesn't exist in userspace and probably
shouldn't -- but it's used unconditionally in <asm-i386/setup.h>. Protect it
with #ifdef __KERNEL__ and move setup.h from $(header-y) to $(unifdef-y) in
Kbuild accordingly.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some files which don't exist in userspace were being included unconditionally
in asm-i386/elf.h. Move the offending #includes down a few lines so that
they're protected by #ifdef __KERNEL__
In fact, we probably want to kill off all userspace use of asm/elf.h -- but we
aren't there yet, so we should at least make it possible to include it for
now.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Because <linux/linkage.h> doesn't exist in userspace, it should be only
included from within #ifdef __KERNEL__. Move the corresponding #include
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Vitezslav Samel <samel@mail.cz> reports that an HP DL380 g4 fails using the
default arch due to the ISA bus having an ID of 32.
It would have worked OK with the generic arch - for some reason the default
arch doesn't support as many busses.
So bump that up to support 256 busses, but leave it at 32 if we're building a
tiny system to save a bit of memory.
Cc: Vitezslav Samel <samel@mail.cz>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Commit 8c74932779 ("i386: Remove
alternative_smp") did not actually compile on x86 with CONFIG_SMP.
This fixes the __build_read/write_lock helpers. I've boot tested on
SMP.
[ Andi: "Oops, I think that was a quilt unrefreshed patch. Sorry. I
fixed those before testing, but then still send out the old patch." ]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
