android_kernel_motorola_sm6225/include/asm-frv
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
..
a.out.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
atomic.h [PATCH] frv: NULL noise removal in frv xchg() 2006-06-23 07:42:55 -07:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
ax88796.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
bitops.h [PATCH] FRV: Optimise ffs() 2006-09-26 08:48:54 -07:00
bug.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
bugs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
busctl-regs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
byteorder.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
cacheflush.h [PATCH] FRV: Miscellaneous fixes 2006-02-14 16:09:35 -08:00
checksum.h [PATCH] frv: misc __user annotations 2006-06-23 07:42:54 -07:00
cpu-irqs.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
cpumask.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cputime.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
current.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
delay.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
div64.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dm9000.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dma-mapping.h [PATCH] frv: miscellaneous changes 2006-01-08 20:13:38 -08:00
dma.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
elf.h [PATCH] FDPIC: Add coredump capability for the ELF-FDPIC binfmt 2006-07-10 13:24:22 -07:00
emergency-restart.h [PATCH] Add emergency_restart() 2005-07-26 14:35:41 -07:00
errno.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fcntl.h [PATCH] Clean up struct flock64 definitions 2005-09-07 16:57:38 -07:00
fpu.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
futex.h [PATCH] lightweight robust futexes updates 2006-03-27 08:44:49 -08:00
gdb-stub.h [PATCH] FRV: Introduce asm-offsets for FRV arch 2006-07-10 13:24:22 -07:00
gpio-regs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hardirq.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
highmem.h [PATCH] frv: misc sparse annotations 2006-06-23 07:42:55 -07:00
hw_irq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ide.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
init.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
io.h [PATCH] frv: Add missing qualifier to memcpy_fromio() prototype 2006-06-23 07:42:55 -07:00
ioctl.h [PATCH] Generic ioctl.h 2006-01-10 08:01:34 -08:00
ioctls.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipcbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
irc-regs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
irq.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
irq_regs.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
Kbuild Add empty Kbuild files for 'make headers_install' in remaining arches. 2006-06-18 12:58:53 +01:00
kmap_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
linkage.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
local.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
math-emu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mb-regs.h [PATCH] frv: basic __iomem annotations 2006-06-23 07:42:54 -07:00
mb86943a.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mb93091-fpga-irqs.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
mb93093-fpga-irqs.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
mb93493-irqs.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
mb93493-regs.h [PATCH] FRV: Use the generic IRQ stuff 2006-09-26 08:48:53 -07:00
mc146818rtc.h [PATCH] frv: miscellaneous changes 2006-01-08 20:13:38 -08:00
mem-layout.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mman.h [PATCH] add asm-generic/mman.h 2006-02-15 15:32:22 -08:00
mmu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmu_context.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
module.h [PATCH] frv: add module support stubs 2006-01-08 20:13:37 -08:00
msgbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mutex.h [PATCH] mutex subsystem, add default include/asm-*/mutex.h files 2006-01-09 15:59:19 -08:00
namei.h fix file specification in comments 2006-10-03 23:01:26 +02:00
page.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
param.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
percpu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgalloc.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
pgtable.h [PATCH] paravirt: remove set pte atomic 2006-10-01 00:39:34 -07:00
poll.h [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications 2006-03-25 08:22:56 -08:00
posix_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
processor.h [PATCH] Make cpu_relax() imply barrier() on all arches 2006-07-12 12:56:45 -07:00
ptrace.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
registers.h [PATCH] FRV: Introduce asm-offsets for FRV arch 2006-07-10 13:24:22 -07:00
resource.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
scatterlist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sections.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
segment.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
semaphore.h [PATCH] FRV: Make the FRV arch work again 2005-11-28 14:42:23 -08:00
sembuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
serial-regs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
serial.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
setup.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
shmbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
shmparam.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sigcontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
siginfo.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.h [PATCH] irq-flags: FRV: Use the new IRQF_ constants 2006-07-02 13:58:46 -07:00
smp.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
socket.h [AF_UNIX]: Datagram getpeersec 2006-06-29 16:58:06 -07:00
sockios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spinlock.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spr-regs.h [PATCH] FRV: Use virtual interrupt disablement 2006-02-14 16:09:35 -08:00
stat.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
statfs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
string.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
suspend.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
system.h [PATCH] remove set_wmb - arch removal 2006-07-14 21:56:14 -07:00
termbits.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
termios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
thread_info.h [PATCH] FRV: Introduce asm-offsets for FRV arch 2006-07-10 13:24:22 -07:00
timer-regs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
timex.h [PATCH] ntp: cleanup defines and comments 2006-10-01 00:39:27 -07:00
tlb.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlbflush.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
topology.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
types.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
uaccess.h [PATCH] frv: __user infrastructure 2006-06-23 07:42:54 -07:00
ucontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unaligned.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
unistd.h [PATCH] remove remaining errno and __KERNEL_SYSCALLS__ references 2006-10-02 07:57:23 -07:00
user.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vga.h [PATCH] frv: miscellaneous changes 2006-01-08 20:13:38 -08:00
virtconvert.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
xor.h [PATCH] frv: miscellaneous changes 2006-01-08 20:13:38 -08:00