For future rework of try_to_wake_up() we'd like to push part of that
function onto the CPU the task is actually going to run on.

In order to do so we need a generic callback from the existing scheduler IPI.

This patch introduces such a generic callback: scheduler_ipi() and
implements it as a NOP.

BenH notes: PowerPC might use this IPI on offline CPUs under rare conditions!
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Reviewed-by: NFrank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.744338123@chello.nl

In order to safely work around anomaly 05000491, we have to execute IFLUSH
from L1 instruction sram.  The trouble with multi-core systems is that all
L1 sram is visible only to the active core.  So we can't just place the
functions into L1 and call it directly.  We need to setup a jump table and
place the entry point in external memory.  This will call the right func
based on the active core.

In the process, convert from the manual relocation of a small bit of code
into Core B's L1 to the more general framework we already have in place
for loading arbitrary pieces of code into L1.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

The smp_processor_id() API requires that preempt be disabled when calling
it, so make sure it is when we go to send messages to other processors.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Defer bfin_setup_caches(cpu) to avoid unexpected faults due to the cpu
state not yet being fully initialized.
Signed-off-by: Nsteven miao <realmz6@gmail.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Currently, sending an interprocessor interrupt (IPI) requires building up
a message dynamically which means memory allocation.  But often times, we
will want to send an IPI in low level contexts where allocation is not
possible which may lead to a panic().  So create a per-cpu static array
for the message queue and use that instead.

Further, while we have two supplemental interrupts, we are currently only
using one of them.  So use the second one for the most common IPI message
of all -- smp_send_reschedule().  This avoids ugly contention for locks
which in turn would require an IPI message ...

In general, this improves SMP performance, and in some cases allows the
SMP port to work in places it wouldn't before.  Such as the PREEMPT_RT
state where the slab is protected by a per-cpu spin lock.  If the slab
kmalloc/kfree were to put the task to sleep, and that task was actually
the IPI handler, then the system falls down yet again.

After running some various stress tests on the system, the static limit
of 5 messages seems to work.  On the off chance even this overflows, we
simply panic(), and we can review that scenario to see if the limit needs
to be increased a bit more.
Signed-off-by: NYi Li <yi.li@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

This function takes an irq_handler_t function, but the prototype in
the header doesn't match the function definition.  This is due to the
smp headers needing to avoid circular dependencies.  So change the
function to take a simple pointer.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

The cpu maps are defines provided by common linux/cpumask.h, not local
variables.  So stop exporting them locally and include the right header
for their definition.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

This functions are implicitly called by core functions like cpu_relax(),
and since those functions may be called early on before common code has
initialized the per-cpu data area, we need to tweak the stats gathering.
Now the statistics are maintained in common bss which makes these funcs
safe to use as soon as the C runtime env is setup.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

SMP systems require per-cpu local clock event devices in order to enable
HRT support.  One a BF561, we can use local core timer for this purpose.
Originally, there was one global core-timer clock event device set up for
core A.

To accomplish this feat, we need to split the gptimer0/core timer logic
so that each is a standalone clock event.  There is no requirement that
we only have one clock event source anyways.  Once we have this, we just
define per-cpu clock event devices for each local core timer.
Signed-off-by: NYi Li <yi.li@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Sometimes a SMP system will randomly panic at boot.  This is due to caches
being out of sync when one core tries to signal the other.  So when one
core calls another via IPI, flush the data caches.
Signed-off-by: NYi Li <yi.li@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

When testing PREEMPT_RT kernel on BF561-EZKit, the kernel blocks while
booting.  When the kernel initializes the ethernet driver, it sleeps and
never wakes up.

The issue happens when the kernel waits for a timer for Core B to timeout
(the timers are per-cpu based: static DEFINE_PER_CPU(struct tvec_base *,
tvec_bases) = &boot_tvec_bases).

However, the ksoftirqd thread for Core B (note, the ksoftirqd thread is
also per-cpu based) cannot work properly, and the timers for Core B never
times out.

When ksoftirqd() for the first time runs on core B, it is possible core A
is still initializing core B (see smp_init() -> cpu_up() -> __cpu_up()).
So the "cpu_is_offline()" check may return true and ksoftirqd moves to
"wait_to_die".

So delay the core b start up until the per-cpu timers have been set up
fully.
Signed-off-by: NYi Li <yi.li@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

To set zeroes the sizeof the struct should be used rather
than sizeof the pointer, kzalloc does that.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Bill Gatliff & David Brownell pointed out we were missing some
copyrights, and licensing terms in some of the files in
./arch/blackfin, so this fixes things, and cleans them up.

It also removes:
 - verbose GPL text(refer to the top level ./COPYING file)
 - file names (you are looking at the file)
 - bug url (it's in the ./MAINTAINERS file)
 - "or later" on GPL-2, when we did not have that right

It also allows some Blackfin-specific assembly files to be under a BSD
like license (for people to use them outside of Linux).
Signed-off-by: NRobin Getz <robin.getz@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Check that the result of kmalloc is not NULL before passing it to other
functions.

In the first two cases, the new code returns -ENOMEM, which seems
compatible with what is done for similar functions for other architectures.

In the last two cases, the new code fails silently, ie just returns,
because the function has void return type.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression *x;
identifier f;
constant char *C;
@@

x = \(kmalloc\|kcalloc\|kzalloc\)(...);
... when != x == NULL
    when != x != NULL
    when != (x || ...)
(
kfree(x)
|
f(...,C,...,x,...)
|
*f(...,x,...)
|
*x->f
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

On Blackfin SMP, a per-cpu loops_per_jiffy is pointless since both cores
always run at the same CCLK.  In addition, the current implementation has
flaws since the main consumer for loops_per_jiffy (asm/delay.h) uses the
global kernel loops_per_jiffy and not the per_cpu one.  So punt all of the
per-cpu handling and go back to the global shared one.
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

When a low priority interrupt (like ethernet) is triggered between 2 high
priority IPI messages, a deadlock in disable_irq() is hit by the second
IPI handler.  This is because the second IPI message is queued within the
first IPI handler, but the handler doesn't process all messages, and new
ones are inserted rather than appended.  So now we process all the pending
messages, and append new ones to the pending list.

URL: http://blackfin.uclinux.org/gf/tracker/5226Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

The KGDB code uses this when switching processors to make sure the icache
is in a valid state.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

The Per-processor Data Area isn't actually reserved by this function, and
all it ended up doing was issuing a printk(), so punt it.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

For systems where the core cycles are not a usable tick source (like SMP
or cycles gets updated), enable gptimer0 as an alternative.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Add some notes for anomaly 05000120 to make sure we work around it.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Blackfin arch: fix bug - kgdb fails to continue after setting breakpoint on bf561-ezkit kernel with smp patch

Free spinlock before call IPI handlers.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>


Header from folded patch 'blackfin_arch__fix_bug_-_kgdb_fails_to_continue_after_setting_breakpoint_on_bf561-ezkit_kernel_with_smp_patch-1':

Blackfin arch: fix bug - kgdb fails to continue after setting breakpoint on bf561-ezkit kernel with smp patch

Don't test l1 code in SMP kernel.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>

[Mike Frysinger <vapier.adi@gmail.com>:
 - handle bf531/bf532/bf534/bf536 variants in ipipe.h
 - cleanup IPIPE logic for bfin_set_irq_handler()
 - cleanup ipipe asm code a bit and add missing ENDPROC()
 - simplify IPIPE code in trap_c
 - unify some of the IPIPE code and fix style
 - simplify DO_IRQ_L1 handling with ipipe code
 - revert IRQ_SW_INT# addition from ipipe merge
 - remove duplicate get_{c,s}clk() prototypes
]
Signed-off-by: NYi Li <yi.li@analog.com>
Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>

rename irq_flags to bfin_irq_flags to avoid namespace
collision with common code
Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>

Blackfin dual core BF561 processor can support SMP like features.
https://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:smp-like

In this patch, we provide SMP extend to Blackfin header files
and machine common code
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>