Never mask interrupts immediately upon request.  Disabling interrupts in
high-performance codepaths is rare, and on the other hand this change could
recover lost edges (or even other types of lost interrupts) by conservatively
only masking interrupts after they happen.  (NOTE: with this change the
highlevel irq-disable code still soft-disables this IRQ line - and if such an
interrupt happens then the IRQ flow handler keeps the IRQ masked.)

Mark i8529A controllers as 'never loses an edge'.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We need to be able to get from an irq number to a struct msi_desc.
The msi_desc array in msi.c had several short comings the big one was
that it could not be used outside of msi.c.  Using irq_data in struct
irq_desc almost worked except on some architectures irq_data needs to
be used for something else.

So this patch adds a msi_desc pointer to irq_desc, adds the appropriate
wrappers and changes all of the msi code to use them.

The dynamic_irq_init/cleanup code was tweaked to ensure the new
field is left in a well defined state.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The sanity check for no_irq_chip in __set_irq_hander() is unconditional on
both install and uninstall of an handler.  This triggers false warnings and
replaces no_irq_chip by dummy_irq_chip in the uninstall case.

Check only, when a real handler is installed.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NSylvain Munaut <tnt@246tNt.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

__set_irq_handler: Kill a bogus space
Signed-off-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I got an oops when booting 2.6.19-rc5-mm1 on my ia64 machine.

Below is the log.

Oops 11012296146944 [1]
Modules linked in: binfmt_misc dm_mirror dm_multipath dm_mod thermal processor f
an container button sg eepro100 e100 mii

Pid: 0, CPU 0, comm:              swapper
psr : 0000121008022038 ifs : 800000000000040b ip  : [<a0000001000e1411>]    Not
tainted
ip is at __do_IRQ+0x371/0x3e0
unat: 0000000000000000 pfs : 000000000000040b rsc : 0000000000000003
rnat: 656960155aa56aa5 bsps: a00000010058b890 pr  : 656960155aa55a65
ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c0270033f
csd : 0000000000000000 ssd : 0000000000000000
b0  : a0000001000e1390 b6  : a0000001005beac0 b7  : e00000007f01aa00
f6  : 000000000000000000000 f7  : 0ffe69090000000000000
f8  : 1000a9090000000000000 f9  : 0ffff8000000000000000
f10 : 1000a908ffffff6f70000 f11 : 1003e0000000000000909
r1  : a000000100fbbff0 r2  : 0000000000010002 r3  : 0000000000010001
r8  : fffffffffffbffff r9  : a000000100bd8060 r10 : a000000100dd83b8
r11 : fffffffffffeffff r12 : a000000100bcbbb0 r13 : a000000100bc4000
r14 : 0000000000010000 r15 : 0000000000010000 r16 : a000000100c01aa8
r17 : a000000100d2c350 r18 : 0000000000000000 r19 : a000000100d2c300
r20 : a000000100c01a88 r21 : 0000000080010100 r22 : a000000100c01ac0
r23 : a0000001000108e0 r24 : e000000477980004 r25 : 0000000000000000
r26 : 0000000000000000 r27 : e00000000913400c r28 : e0000004799ee51c
r29 : e0000004778b87f0 r30 : a000000100d2c300 r31 : a00000010005c7e0

Call Trace:
 [<a000000100014600>] show_stack+0x40/0xa0
                                sp=a000000100bcb760 bsp=a000000100bc4f40
 [<a000000100014f00>] show_regs+0x840/0x880
                                sp=a000000100bcb930 bsp=a000000100bc4ee8
 [<a000000100037fb0>] die+0x250/0x320
                                sp=a000000100bcb930 bsp=a000000100bc4ea0
 [<a00000010005e5f0>] ia64_do_page_fault+0x8d0/0xa20
                                sp=a000000100bcb950 bsp=a000000100bc4e50
 [<a00000010000caa0>] ia64_leave_kernel+0x0/0x290
                                sp=a000000100bcb9e0 bsp=a000000100bc4e50
 [<a0000001000e1410>] __do_IRQ+0x370/0x3e0
                                sp=a000000100bcbbb0 bsp=a000000100bc4df0
 [<a000000100011f50>] ia64_handle_irq+0x170/0x220
                                sp=a000000100bcbbb0 bsp=a000000100bc4dc0
 [<a00000010000caa0>] ia64_leave_kernel+0x0/0x290
                                sp=a000000100bcbbb0 bsp=a000000100bc4dc0
 [<a000000100012390>] ia64_pal_call_static+0x90/0xc0
                                sp=a000000100bcbd80 bsp=a000000100bc4d78
 [<a000000100015630>] default_idle+0x90/0x160
                                sp=a000000100bcbd80 bsp=a000000100bc4d58
 [<a000000100014290>] cpu_idle+0x1f0/0x440
                                sp=a000000100bcbe20 bsp=a000000100bc4d18
 [<a000000100009980>] rest_init+0xc0/0xe0
                                sp=a000000100bcbe20 bsp=a000000100bc4d00
 [<a0000001009f8ea0>] start_kernel+0x6a0/0x6c0
                                sp=a000000100bcbe20 bsp=a000000100bc4ca0
 [<a0000001000089f0>] __end_ivt_text+0x6d0/0x6f0
                                sp=a000000100bcbe30 bsp=a000000100bc4c00
 <0>Kernel panic - not syncing: Aiee, killing interrupt handler!

The root cause is that some irq_chip variables, especially ia64_msi_chip,
initiate their memeber end to point to NULL. __do_IRQ doesn't check
if irq_chip->end is null and just calls it after processing the interrupt.

As irq_chip->end is called at many places, so I fix it by reinitiating
irq_chip->end to dummy_irq_chip.end, e.g., a noop function.
Signed-off-by: NZhang Yanmin <yanmin.zhang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Introduce desc->name and eliminate the handle_irq_name() hack.  Add
set_irq_chip_and_handler_name() to set the flow type and name at once.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

Typedef the IRQ flow handler function type.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 8e973fbdf5716b93a0a8c0365be33a31ca0fa351 commit)

Currently msi.c is doing sanity checks that make certain before an irq is
destroyed it has no more users.

By adding irq_has_action I can perform the test is a generic way, instead of
relying on a msi specific data structure.

By performing the core check in dynamic_irq_cleanup I ensure every user of
dynamic irqs has a test present and we don't free resources that are in use.

In msi.c this allows me to kill the attrib.state member of msi_desc and all of
the assciated code to maintain it.

To keep from freeing data structures when irq cleanup code is called to soon
changing dyanamic_irq_cleanup is insufficient because there are msi specific
data structures that are also not safe to free.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

With the msi support comes a new concept in irq handling, irqs that are
created dynamically at run time.

Currently the msi code allocates irqs backwards.  First it allocates a
platform dependent routing value for an interrupt the ``vector'' and then it
figures out from the vector which irq you are on.

This msi backwards allocator suffers from two basic problems.  The allocator
suffers because it is trying to do something that is architecture specific in
a generic way making it brittle, inflexible, and tied to tightly to the
architecture implementation.  The alloctor also suffers from it's very
backwards nature as it has tied things together that should have no
dependencies.

To solve the basic dynamic irq allocation problem two new architecture
specific functions are added: create_irq and destroy_irq.

create_irq takes no input and returns an unused irq number, that won't be
reused until it is returned to the free poll with destroy_irq.  The irq then
can be used for any purpose although the only initial consumer is the msi
code.

destroy_irq takes an irq number allocated with create_irq and returns it to
the free pool.

Making this functionality per architecture increases the simplicity of the irq
allocation code and increases it's flexibility.

dynamic_irq_init() and dynamic_irq_cleanup() are added to automate the
irq_desc initializtion that should happen for dynamic irqs.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NYoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NYoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

while porting the -rt tree to 2.6.18-rc7 i noticed the following
screaming-IRQ scenario on an SMP system:

 2274  0Dn.:1 0.001ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.010ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.020ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.029ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.039ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.048ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.058ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.068ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.077ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.087ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)
 2274  0Dn.:1 0.097ms: do_IRQ+0xc/0x103  <= (ret_from_intr+0x0/0xf)

as it turns out, the bug is caused by handle_level_irq(), which if it
races with another CPU already handling this IRQ, it _unmasks_ the IRQ
line on the way out. This is not how 2.6.17 works, and we introduced
this bug in one of the early genirq cleanups right before it went into
-mm. (the bug was not in the genirq patchset for a long time, and we
didnt notice the bug due to the lack of -rt rebase to the new genirq
code. -rt, and hardirq-preemption in particular opens up such races much
wider than anything else.)
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make the fasteoi handler mark disabled interrupts as pending if they
happen anyway. This allow implementation of a delayed disable scheme
with the fasteoi handler.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Patch from Thomas Gleixner

From: Thomas Gleixner <tglx@linutronix.de>

ARM has a couple of really dumb interrupt controllers.
Implement a generic one and fixup the ARM migration. ARM reused
the no_irq_chip for this purpose, but this does not work out
for platforms which are not converted to the new interrupt
type handling model.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Clean up the fastack concept by turning it into fasteoi and introducing the
->eoi() method for chips.

This also allows the cleanup of an i386 EOI quirk - now the quirk is
cleanly separated from the pure ACK implementation.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Note when a disable interrupt happened with the fasteoi handler as well so
that delayed disable can be implemented with fasteoi-type controllers.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Enable platforms to use the irq-chip and irq-flow abstractions: allow setting
of the chip, the type and provide highlevel handlers for common irq-flows.

[rostedt@goodmis.org: misroute-irq: Don't call desc->chip->end because of edge interrupts]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>