Commit Graph

10 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
andrew.vasquez@qlogic.com
044cc6c8ec [SCSI] qla2xxx: Add ISP54xx support.
Chip is similar in form to our ISP24xx offering.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-03-12 09:38:03 -06:00
Andrew Vasquez
fa90c54f6d [SCSI] qla2xxx: Update license.
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-10-28 11:53:23 -05:00
Andrew Vasquez
ae91193cd5 [SCSI] qla2xxx: Update copyright banner.
Update copyright banner.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 11:12:12 -04:00
Andrew Vasquez
fa2a1ce53d [SCSI] qla2xxx: Code scrubbing.
Code scrubbing.

 - Remove trailing whitespace from driver files.
 - Remove unused #defines and inlines.
 - Standardize on C comments (// -> /* */)

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 11:03:15 -04:00
Andrew Vasquez
2b6c0cee90 [SCSI] qla2xxx: Add ISP24xx IOCB manipulation routines.
Add ISP24xx IOCB manipulation routines.

Add appropriate glue-code for ISP24xx support while
manipulting IOCB packets.  Add an ISP24xx specific
'start_scsi' routine due to command-type-7 layout
changes.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 11:00:07 -04:00
Andrew Vasquez
3d71644cf9 [SCSI] qla2xxx: Add ISP24xx definitions.
Add ISP24xx definitions.

Add requisite structure definitions and #define's for ISP24xx
support.  Also drop volatile modifiers from device_reg_* register
layouts as the members are never really accessed, only their
offsets within the layout are used during reads and writes.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 10:54:46 -04:00
Andrew Vasquez
abbd8870b9 [SCSI] qla2xxx: Factor-out ISP specific functions to method-based call tables.
Factor-out ISP specific functions to method-based call tables.

In anticipation of ISP24xx/ISP25xx support, factor-out ISP
specific functions into a method-based call table.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 10:47:30 -04:00
bdf796210e [PATCH] qla2xxx: remove lun discovery codes...
Remove internal lun discovery routines and support
structures.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-04-18 13:47:46 -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