Commit Graph

12 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
Luiz Fernando N. Capitulino 5482687b8b USB: ldusb: Use usb_endpoint_* functions.
Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-27 11:58:54 -07:00
Luiz Fernando N. Capitulino 066202dd48 USB: Make file operations structs in drivers/usb const.
Making structs const prevents accidental bugs and with the proper debug
options they're protected against corruption.

Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-27 11:58:52 -07:00
Jörn Engel 6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Arjan van de Ven 4186ecf8ad [PATCH] USB: convert a bunch of USB semaphores to mutexes
the patch below converts a bunch of semaphores-used-as-mutex in the USB
code to mutexes

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-20 14:49:55 -08:00
Oliver Neukum 1144cf7af2 [PATCH] USB: kzalloc in ldusb
another one for kzalloc

Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-20 14:49:53 -08:00
Michael Hund ba3e66e94b [PATCH] USB: add new device ids to ldusb
Signed-off-by: Michael Hund <mhund@ld-didactic.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-02-13 21:33:39 -08:00
Greg Kroah-Hartman 595b14cbcc [PATCH] USB: remove some left over devfs droppings hanging around in the usb drivers
As there is no more usb devfs support, these bits would just confuse
people.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-31 17:23:41 -08:00
Greg Kroah-Hartman 75318d2d7c [PATCH] USB: remove .owner field from struct usb_driver
It is no longer needed, so let's remove it, saving a bit of memory.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 13:48:34 -08:00
Alexey Dobriyan dd7d50081f [PATCH] USB ldusb: fmt warnings fixes for 64-bit platforms
Fix

drivers/usb/misc/ldusb.c: In function `ld_usb_read':
drivers/usb/misc/ldusb.c:467: warning: int format, different type arg (arg 4)
drivers/usb/misc/ldusb.c: In function `ld_usb_write':
drivers/usb/misc/ldusb.c:531: warning: int format, different type arg (arg 4)
drivers/usb/misc/ldusb.c:532: warning: int format, different type arg (arg 5)
drivers/usb/misc/ldusb.c:532: warning: int format, different type arg (arg 6)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-08 16:28:27 -07:00
Michael Hund a6db592e16 [PATCH] USB: ldusb fixes
below you will find the forgotten kmalloc check (sorry).

Signed-off-by: Michael Hund <mhund@ld-didactic.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-29 13:12:53 -07:00
Michael Hund 2824bd250f [PATCH] USB: add ldusb driver
The following driver provides complete interrupt-in and interrupt-out
reports (raw data) to a user program. Until now it uses the
HIDIOCGDEVINFO ioctl call, because I don't know better :-(. Perhaps, it
will be ok for you - and I will be happy, if you assign 8 minor numbers.

I have tested it in several environments and it works very well for me.
However, it has a problem with two or more devices at the same hub, if
the two or more devices need 1 ms interrupt-in transfers. Unfortunately
more than one interrupt-in transfer every ms isn't possible (ehci
driver?). This is why the min_interrupt_in_interval and
min_interrupt_out_interval are increased to 2 ms (see the corresponding
module parameters). This way, I can use two devices simultaneously at
the same hub.

Signed-off-by: Michael Hund <mhund@ld-didactic.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-12 11:52:57 -07:00