Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: NHuang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\<event\>/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )
Suggested-by: NStephane Eranian <eranian@google.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NPaul Mackerras <paulus@samba.org>
Reviewed-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add basic performance counter support to the FRV arch.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement atomic64_t and its ops for FRV.  Tested with the following patch:

	diff --git a/arch/frv/kernel/setup.c b/arch/frv/kernel/setup.c
	index 55e4fab..086d50d 100644
	--- a/arch/frv/kernel/setup.c
	+++ b/arch/frv/kernel/setup.c
	@@ -746,6 +746,52 @@ static void __init parse_cmdline_early(char *cmdline)

	 } /* end parse_cmdline_early() */

	+static atomic64_t xxx;
	+
	+static void test_atomic64(void)
	+{
	+	atomic64_set(&xxx, 0x12300000023LL);
	+
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0x12300000023LL);
	+	mb();
	+	if (atomic64_inc_return(&xxx) != 0x12300000024LL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0x12300000024LL);
	+	mb();
	+	if (atomic64_sub_return(0x36900000050LL, &xxx) != -0x2460000002cLL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != -0x2460000002cLL);
	+	mb();
	+	if (atomic64_dec_return(&xxx) != -0x2460000002dLL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != -0x2460000002dLL);
	+	mb();
	+	if (atomic64_add_return(0x36800000001LL, &xxx) != 0x121ffffffd4LL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0x121ffffffd4LL);
	+	mb();
	+	if (atomic64_cmpxchg(&xxx, 0x123456789abcdefLL, 0x121ffffffd4LL) != 0x121ffffffd4LL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0x121ffffffd4LL);
	+	mb();
	+	if (atomic64_cmpxchg(&xxx, 0x121ffffffd4LL, 0x123456789abcdefLL) != 0x121ffffffd4LL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0x123456789abcdefLL);
	+	mb();
	+	if (atomic64_xchg(&xxx, 0xabcdef123456789LL) != 0x123456789abcdefLL)
	+		BUG();
	+	mb();
	+	BUG_ON(atomic64_read(&xxx) != 0xabcdef123456789LL);
	+	mb();
	+}
	+
	 /*****************************************************************************/
	 /*
	  *
	@@ -845,6 +891,8 @@ void __init setup_arch(char **cmdline_p)
	 //	asm volatile("movgs %0,timerd" :: "r"(10000000));
	 //	__set_HSR(0, __get_HSR(0) | HSR0_ETMD);

	+	test_atomic64();
	+
	 } /* end setup_arch() */

	 #if 0

Note that this doesn't cover all the trivial wrappers, but does cover all the
substantial implementations.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Export a number of features required to build all the modules.  It also
implements the following simple features:

 (*) csum_partial_copy_from_user() for MMU as well as no-MMU.

 (*) __ucmpdi2().

so that they can be exported too.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus 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!