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)
The fs_no mean used to be fs_enet driver driven, hence it was an
enumeration across all the possible fs_enet "users" in the SoC. Now, with
QE on the pipeline, and to make DTS descriptions more clear, fs_no features
relevant SoC part number, with additional field to describe the SoC type.
Another reason for that is now not only fs_enet is going to utilize those
stuff. There might be UART, HLDC, and even USB, so to prevent confusion and
be ready for upcoming OF_device transfer, fs_enet and cpm_uart drivers were
updated in that concern, as well as the relevant DTS.
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Incorporating the new way of cpm2 immr access, introduced in the previous
patch, into CPM2 peripheral devices (fs_enet and cpm_uart). Both ppc and
powerpc approved working( real actions taken in powerpc only, ppc just
has a wrapper to keep init stuff consistent).
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
This patch should update the fs_enet infrastructure to utilize Phy Abstraction
Layer subsystem. Along with the above, there are apparent bugfixes, overhaul
and improvements.
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Due to the recent update of the platform code, some platform device
drivers fail to compile. This fix is for fs_enet, adding #include of a
new header, to which a number of platform stuff has been relocated.
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The following patches fixes a bug with erroneous calling of
dma_unmap_single. It never triggered because on normal ppc32
the calls is a NOP. Out of tree drivers need this fix however.
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
