Default kernel stack size on parisc is 16k.  During tests we found that the
kernel stack can easily grow beyond 13k, which leaves 3k left for irq
processing.

This patch adds the possibility to activate an additional stack of 16k per CPU
which is being used during irq processing.  This implementation does not yet
uses this irq stack for the irq bh handler.

The assembler code for call_on_stack was heavily cleaned up by John
David Anglin.

CC: John David Anglin <dave.anglin@bell.net>
Signed-off-by: NHelge Deller <deller@gmx.de>

Add the CONFIG_DEBUG_STACKOVERFLOW config option to enable checks to
detect kernel stack overflows.

Stack overflows can not be detected reliable since we do not want to
introduce too much overhead.

Instead, during irq processing in do_cpu_irq_mask() we check kernel
stack usage of the interrupted kernel process. Kernel threads can be
easily detected by checking the value of space register 7 (sr7) which
is zero when running inside the kernel.

Since THREAD_SIZE is 16k and PAGE_SIZE is 4k, reduce the alignment of
the init thread to the lower value (PAGE_SIZE) in the kernel
vmlinux.ld.S linker script.
Signed-off-by: NHelge Deller <deller@gmx.de>

People are playing odd games with IRQF_DISABLED, remove it.

Its not reliable, since shared interrupt lines could disable it for you,
and its possible and allowed for archs to disable IRQs to limit IRQ nesting.

Therefore, simply mandate that _ALL_ IRQ handlers are run with IRQs disabled.

[ This _should_ not break anything, since we've mandated that IRQ handlers
  _must_ be able to deal with this for a _long_ time ]

IRQ handlers should be fast, no if buts and any other exceptions. We also have
plenty instrumentation to find any offending IRQ latency sources.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NHelge Deller <deller@gmx.de>

The CPU irqs (timer and IPI) are not shared and only need to be claimed once.
A mismatch error occurs if they are claimed more than once.
Signed-off-by: NJohn David Anglin <dave.anglin@nrc-cnrc.gc.ca>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: NHelge Deller <deller@gmx.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Convert to the new function names. Scripted with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: linux-parisc@vger.kernel.org

1) As promised in the comment, the core does not copy cpumask anymore
   when the arch code returns -EINVAL

2) Get the per cpu information from irq_data
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: linux-parisc@vger.kernel.org

Convert all the parisc driver interrupt handlers (dino, eisa, gsc,
iosapic and superio) as well as the cpu interrupts.  Prepare
show_interrupts for GENERIC_HARDIRQS_NO_DEPRECATED and finally selects
that Kconfig option

[jejb: compile and testing fixes]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

The CHECK_IRQ_PER_CPU is wrong, it should be checking
irq_to_desc(irq)->status not just irq.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

The generic conversion eliminates the spurious no_ack and no_end
routines, converts all the cascaded handlers to handle_simple_irq() and
makes iosapic use a modified handle_percpu_irq() to become the same as
the CPU irq's.  This isn't an essential change, but it eliminates the
mask/unmask overhead of handle_level_irq().
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
Tested-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

The essential problem we're currently having is that dino (and gsc) is a
cascaded CPU interrupt.  Under the old __do_IRQ() handler, our CPU
interrupts basically did an ack followed by an end.  In the new scheme,
we replaced them with level handlers which do a mask, an ack and then an
unmask (but no end).  Instead, with the renaming of end to eoi, we
actually want to call the percpu flow handlers, because they actually
have all the characteristics we want.

This patch does the conversion and gets my C360 booting again.
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Signed-off-by: NKyle McMartin <kyle@redhat.com>

Shift the ->end call (cpu eoi) from __do_IRQ into our
unmask handler. Also nuke some redundant code.
Signed-off-by: NKyle McMartin <kyle@redhat.com>

Only major change is renaming functions to match the conventions
expected by the generic irq code.
Signed-off-by: NKyle McMartin <kyle@redhat.com>

Use proper accessors and handlers for generic irq cleanups. We just
call back into __do_IRQ through desc->handler now, and remove the
explicit calls.
Signed-off-by: NKyle McMartin <kyle@redhat.com>

The typename member of struct irq_chip was kept for migration purposes
and is obsolete since more than 2 years. Fix up the leftovers.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons.  After more than two years it's
time to remove them finally.

This patch cleans up one of the remaining users.  When all such patches
hit mainline we can remove the defines and typedefs finally.

Impact: cleanup

Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Fix miscompilation in arch/parisc/kernel/irq.c:
123: warning: passing arg 1 of `cpumask_setall' from incompatible pointer type
141: warning: passing arg 1 of `cpumask_copy' from incompatible pointer type
300: warning: passing arg 1 of `cpumask_copy' from incompatible pointer type
357: warning: passing arg 2 of `cpumask_copy' from incompatible pointer type
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

according to Ingo, change set_affinity() in irq_chip should return int,
because that way we can handle failure cases in a much cleaner way, in
the genirq layer.

v2: fix two typos

[ Impact: extend API ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-arch@vger.kernel.org
LKML-Reference: <49F654E9.4070809@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup, futureproof

In fact, all cpumask ops will only be valid (in general) for bit
numbers < nr_cpu_ids.  So use that instead of NR_CPUS in various
places.

This is always safe: no cpu number can be >= nr_cpu_ids, and
nr_cpu_ids is initialized to NR_CPUS at boot.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMike Travis <travis@sgi.com>
Acked-by: NIngo Molnar <mingo@elte.hu>

cpumask arg to the affinity function is now const, sort
that out through the irq_desc implementations.
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

cpumask api needs to take a pointer to irq_desc[cpu].affinity
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Impact: cleanup, update to new cpumask API

Irq_desc.affinity and irq_desc.pending_mask are now cpumask_var_t's
so access to them should be using the new cpumask API.
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Impact: cleanup, update to new cpumask API

Irq_desc.affinity and irq_desc.pending_mask are now cpumask_var_t's
so access to them should be using the new cpumask API.
Signed-off-by: NMike Travis <travis@sgi.com>

Impact: build fix

Ingo Molnar wrote:

> tip/arch/blackfin/kernel/irqchip.c: In function 'show_interrupts':
> tip/arch/blackfin/kernel/irqchip.c:85: error: 'struct kernel_stat' has no member named 'irqs'
> make[2]: *** [arch/blackfin/kernel/irqchip.o] Error 1
> make[2]: *** Waiting for unfinished jobs....
>

So could move kstat_irqs array to irq_desc struct.

(s390, m68k, sparc) are not touched yet, because they don't support genirq
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

parisc: Replace most arrays sized by NR_CPUS with percpu variables.
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

trivial fixes:
- use KERN_WARNING for printk()
- use BUG_ON() instead of "if (xx) BUG();"
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

--
To unsubscribe from this list: send the line "unsubscribe linux-parisc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Impact: change existing irq_chip API

Not much point with gentle transition here: the struct irq_chip's
setaffinity method signature needs to change.

Fortunately, not widely used code, but hits a few architectures.

Note: In irq_select_affinity() I save a temporary in by mangling
irq_desc[irq].affinity directly.  Ingo, does this break anything?

(Folded in fix from KOSAKI Motohiro)
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMike Travis <travis@sgi.com>
Reviewed-by: NGrant Grundler <grundler@parisc-linux.org>
Acked-by: NIngo Molnar <mingo@redhat.com>
Cc: ralf@linux-mips.org
Cc: grundler@parisc-linux.org
Cc: jeremy@xensource.com
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

The timer interrupt had accidentally been marked IRQ_DISABLED since
IRQ_PER_CPU had been OR-ed in, instead of set. This had been working
by accident for quite a while.

Commit c642b839 changed the behaviour of
IRQ_PER_CPU interrupts, which previously weren't checked for IRQ_DISABLED.
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Kudos to Thibaut Varene for spotting the (mis)use of appropriately named
global_ack_eiem. This took a long time to figure out and both insight
from myself, Kyle McMartin, and James Bottomley were required to narrow
down which bit of code could have this race condition.

The symptom was interrupts stopped getting delivered while some workload
was generating IO interrupts on two different CPUs. One of the interrupt
sources would get masked off and stay unmasked. Problem was global_ack_eiem
was accessed with read/modified/write sequence and not protected by
a spinlock.

PA-RISC doesn't need a global ack flag though. External Interrupts
are _always_ delivered to a single CPU (except for "global broadcast
interrupt" which AFAIK currently is not used.) So we don't have to worry
about any given IRQ vector getting delivered to more than one CPU.

Tested on a500 and rp34xx boxen. rsync to/from gsyprf11 (a500)
would lock up the box since NIC (tg3) interrupt and SCSI (sym2)
were on "opposite" CPUs (2 CPU system). Put them on the same CPU
or apply this patch and 10GB of data would rsync completely.

Please apply the following critical patch.

thanks,
grant
Signed-off-by: NGrant Grundler <grundler@parisc-linux.org>
Acked-by: NThibaut VARENE <T-Bone@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Add IRQF_IRQPOLL to the timer interrupt on parisc.
Signed-off-by: NBernhard Walle <bwalle@suse.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Grant Grundler <grundler@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Actually set the irq_regs pointer.
Signed-off-by: NMatthew Wilcox <matthew@wil.cx>

Signed-off-by: NMatthew Wilcox <matthew@wil.cx>

Our prior mode of operation didn't allow nested interrupts
because it makes the interrupt code much simpler.  However,
nested interrupts are better for latency.

This code uses the EIEM register to simulate level interrupts
and thus achieve nesting.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Clean up enough to get things compiling again in the interim.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Use the new IRQF_ constants and remove the SA_INTERRUPT define
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>