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
James Bottomley
0f13fc09db [SCSI] 53c700: fix breakage caused by the autosense update
A bit of a brown paper bag issue.  The previous patch to remove the soon
to be ripped out fields that were used in autosense actually broke the
driver.  This patch fixes it and has been tested (honestly).

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-06-29 13:15:15 -04:00
Eric Sesterhenn
125e18745f [PATCH] More BUG_ON conversion
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: "Salyzyn, Mark" <mark_salyzyn@adaptec.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:43:08 -07:00
James Bottomley
67d59dfdeb [SCSI] 53c700: remove reliance on deprecated cmnd fields
This one's quite tricky.  The 53c700 uses the now deprecated fields of
the command structure for saving the prior command when it does
autosense.  To fix this, we have to add extra fields to the LUN to
accommodate a copy of the real command.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-06-19 19:34:01 -05:00
James Bottomley
8f23d47558 [SCSI] 53c700: update endian processing macros
This update now allows this driver to be used on big endian bus
machines that aren't parisc.  To do that, the driver must set a
CONFIG_53C700_BE_BUS in Kconfig to compile the right macro versions.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-12-16 09:51:01 -08:00
Jeff Garzik
017560fca4 [SCSI] use sfoo_printk() in drivers
Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-10-28 21:04:15 -05:00
56fece2008 [PATCH] finally fix 53c700 to use the generic iomem infrastructure
This driver has had it's own different infrastructure for doing this for
ages, but it's time it used the common one.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-04-16 20:09:43 -05:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00