xics supports only one ipi per cpu, and expects software to use some
queue to know why the interrupt was sent. In Linux, we use a an array
of bitmaps indexed by cpu to identify the message. Currently the bits
are set in smp.c and decoded in xics.c, with the data structure in a
header file. Consolidate the code in xics.c similar to mpic and other
interrupt controllers.
Also, while making the the array static, the message word doesn't need
to be volatile as set_bit and test_clear_bit take care of it for us, and
put it under ifdef smp.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The code in xics.c to setup the i8259 cascaded irq handler is not really
xics specific, so move it into setup.c - we will clean this up further in
a subsequent patch.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This splits off the kexec path bits of the xics_teardown_cpu() routine
into its own xics_kexec_teardown_cpu() routine. With the previous
combined routine the CPPR for a cpu that is being removed may have its
CPPR reset in the plpar_eoi() call (which explicitly sets the CPPR to
a non-zero value). Splitting of the kexec bits of the code prevents
this from happening in the cpu remove path.
Once again, this does not cause the cpu remove from the kernel to
fail, but it does cause cpu dlpar operations to not be able to return
the cpu to the hypervisor.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The per-processor interrupt request register and current processor
priority register are only accessed on the current cpu. In fact the
hypervisor doesn't even let us choose which cpu's registers to access.
The only function to use cpu twice is xics_migrate_irqs_away, not a fast
path. But we can cache the result of get_hard_processor_id() instead of
calling get_hard_smp_processor_id(cpu) in a loop across the call to rtas.
Years ago the irq code passed smp_processor_id into get_irq, I thought
we might initialize the CPPR third party at boot as an extra measure of
saftey, and it made the code symmetric with the qirr (queued interrupt
for software generated interrupts), but now it is just extra and
sometimes unneeded work to pass it down.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.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: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
This adds the new irq remapper core and removes the old one. Because
there are some fundamental conflicts with the old code, like the value
of NO_IRQ which I'm now setting to 0 (as per discussions with Linus),
etc..., this commit also changes the relevant platform and driver code
over to use the new remapper (so as not to cause difficulties later
in bisecting).
This patch removes the old pre-parsing of the open firmware interrupt
tree along with all the bogus assumptions it made to try to renumber
interrupts according to the platform. This is all to be handled by the
new code now.
For the pSeries XICS interrupt controller, a single remapper host is
created for the whole machine regardless of how many interrupt
presentation and source controllers are found, and it's set to match
any device node that isn't a 8259. That works fine on pSeries and
avoids having to deal with some of the complexities of split source
controllers vs. presentation controllers in the pSeries device trees.
The powerpc i8259 PIC driver now always requests the legacy interrupt
range. It also has the feature of being able to match any device node
(including NULL) if passed no device node as an input. That will help
porting over platforms with broken device-trees like Pegasos who don't
have a proper interrupt tree.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adapts the generic powerpc interrupt handling code, and all of
the platforms except for the embedded 6xx machines, to use the new
genirq framework.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch moves the XICS interrupt controller code into the
platforms/pseries directory, since it only appears on pSeries
machines. If it ever appears on some other machine we can move it to
sysdev, although xics.c itself will need a bunch of changes in that
case to remove pSeries specific assumptions.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Milton Miller
Michael Ellerman
Nathan Fontenot
David Howells
Benjamin Herrenschmidt
David Gibson