linux-toradex.git/arch/parisc/kernel/irq.c, branch v3.10.60

parisc: fix irq stack on UP and SMP

2013-05-24T21:29:01+00:00

The logic to detect if the irq stack was already in use with
raw_spin_trylock() is wrong, because it will generate a "trylock failure
on UP" error message with CONFIG_SMP=n and CONFIG_DEBUG_SPINLOCK=y.

arch_spin_trylock() can't be used either since in the CONFIG_SMP=n case
no atomic protection is given and we are reentrant here. A mutex didn't
worked either and brings more overhead by turning off interrupts.

So, let's use the fastest path for parisc which is the ldcw instruction.

Counting how often the irq stack was used is pretty useless, so just
drop this piece of code.

Signed-off-by: Helge Deller

parisc: show number of FPE and unaligned access handler calls in /proc/interrupts

2013-05-24T20:35:26+00:00

Show number of floating point assistant and unaligned access fixup
handler in /proc/interrupts file.

Signed-off-by: Helge Deller

parisc: implement irq stacks - part 2 (v2)

2013-05-11T19:10:15+00:00

This patch fixes few build issues which were introduced with the last
irq stack patch, e.g. the combination of stack overflow check and irq
stack.

Furthermore we now do proper locking and change the irq bh handler
to use the irq stack as well.

In /proc/interrupts one now can monitor how huge the irq stack has grown
and how often it was preferred over the kernel stack.

IRQ stacks are now enabled by default just to make sure that we not
overflow the kernel stack by accident.

Signed-off-by: Helge Deller

parisc: tlb flush counting fix for SMP and UP

2013-05-07T21:44:04+00:00

Fix up build error on UP and show correctly number of function call
(ipi) irqs.

Signed-off-by: Helge Deller

parisc: more irq statistics in /proc/interrupts

2013-05-07T20:39:22+00:00

Add framework and initial values for more fine grained statistics in
/proc/interrupts.

Signed-off-by: Helge Deller

parisc: implement irq stacks

2013-05-07T20:30:35+00:00

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 
Signed-off-by: Helge Deller

parisc: add kernel stack overflow check

2013-05-07T19:34:07+00:00

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: Helge Deller

parisc: remove IRQF_DISABLED

2013-02-20T21:50:26+00:00

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: Peter Zijlstra 
Acked-by: Ingo Molnar 
Signed-off-by: Helge Deller

parisc: don't claim cpu irqs more than once

2013-01-07T22:06:23+00:00

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: John David Anglin 
Cc: Kyle McMartin 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Signed-off-by: Helge Deller

parisc: Use irq_to_desc() in show_interrupts()

2011-03-29T12:48:08+00:00

Signed-off-by: Thomas Gleixner