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)
removes the unneeded local variable rc
replace pci_module_init() with pci_register_driver()
two coding style issues on switch
Signed-off-by: Henrik Kretzschmar <henne@nachtwindheim.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
drivers/net/tulip/uli526x.c: In function `__check_mode':
drivers/net/tulip/uli526x.c:1693: warning: return from incompatible pointer type
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Replace the MODULE_PARM usage in uli526x.c with module_param.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
added missing include of dma-mapping.h, removed bogus ptrace.h (what the
hell was it doing there, in the first place?)
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
We want to extract our LAN card driver from tulip core driver and
make a new file uli526x.c at tulip folder, because we have added
some ethtool interface support and non-eprom support in our driver
and may be other change in the futher.
If our controllers support are still contained in the tulip core
driver, I think it'll increase the complexity of maintenance, you
know, tulip core driver include several files and support so many
other controllers. Furthermore, I tested the newest kernel 2.6.12
and I found the tulip driver can not work on our lan controller, and
I no time to debug it, so I aspired want to make a single uli526x.c
file just for our controllers. Could you help us remove the ULi
m5261/m5263 lan controller support from tulip core driver and add
the new single uli526x.c file for us?
Signed-off-by: Peer Chen <Peer.Chen@uli.com.tw>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
