Commit Graph

8 Commits

Author SHA1 Message Date
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
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)
2006-10-05 15:10:12 +01:00
Jeff Garzik 7282d491ec drivers/net: const-ify ethtool_ops declarations
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-09-13 14:30:00 -04:00
Jeff Garzik 846050dd49 Merge branch 'upstream-fixes' into upstream 2006-08-19 17:45:11 -04:00
Peter Korsgaard a4d0927248 [PATCH] smc911x: Re-release spinlock on spurious interrupt
The smc911x driver forgets to release the spinlock on spurious interrupts.
This little patch fixes it.

Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-08-19 17:44:29 -04:00
Dave Jones bcd6837387 [PATCH] remove unnecessary config.h includes from drivers/net/
config.h is automatically included by kbuild these days.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-08-14 14:00:43 -04:00
Thomas Gleixner 1fb9df5d30 [PATCH] irq-flags: drivers/net: Use the new IRQF_ constants
Signed-off-by: Thomas 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: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-02 13:58:51 -07:00
Jeff Garzik d5498bef6f [netdrvr smc911x] trim trailing whitespace 2006-04-20 17:39:14 -04:00
Dustin McIntire 0a0c72c911 [PATCH] RE: [PATCH 1/1] net driver: Add support for SMSC LAN911x line of ethernet chips
>
> The patch was badly wordwrapped.  Please fix and resend.
>

OK, I've fixed the wrapping and removed the CONFIG_ARM restriction.  I've also did my
best to modify the C style to conform to the comments.

I noticed that the patch is getting ignored by majordomo due to its size >100K.
Should it be broken up somehow to allow posting to the lists?

Signed-off-by: Dustin McIntire <dustin@sensoria.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-04-20 17:38:39 -04:00