linux/include/asm-x86_64
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
..
8253pit.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
a.out.h [PATCH] x86_64: TASK_SIZE fixes for compatibility mode processes 2005-06-21 18:46:12 -07:00
acpi.h [PATCH] Remove some cruft in apic id checking during processor setup 2006-09-26 10:52:37 +02:00
agp.h [PATCH] AGP fix for Xen VMM 2005-06-07 12:35:43 -07:00
alternative-asm.i Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
alternative.h [PATCH] x86_64: Remove alternative_smp 2006-08-30 16:05:15 -07:00
apic.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
apicdef.h x86_64: Remove stale lapic definition from apicdef.h 2006-04-01 22:50:03 -05:00
atomic.h [PATCH] x86_64: x86_64 version of the smp alternative patch. 2006-06-26 10:48:14 -07:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
bitops.h [PATCH] optimize hweight64 for x86_64 2006-09-26 10:52:38 +02:00
boot.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
bootsetup.h [PATCH] Increase number of e820 entries hard limit from 32 to 128 2005-05-01 08:58:51 -07:00
bug.h [PATCH] x86-64: reduce x86-64 bug frame by 4 bytes 2005-09-12 10:50:58 -07:00
bugs.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
byteorder.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache.h fix file specification in comments 2006-10-03 23:01:26 +02:00
cacheflush.h [PATCH] x86/x86_64: mark rodata section read-only: x86-64 support 2006-01-06 08:33:36 -08:00
calgary.h [PATCH] x86: remove config.h includes from asm-i386 & asm-x86_64 2006-09-26 10:52:36 +02:00
calling.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
checksum.h [NET]: Fix ipl=>ihl typo in ip_fast_csum 2005-08-29 16:02:48 -07:00
compat.h [PATCH] amd64: task_pt_regs() 2006-01-12 09:08:51 -08:00
cpu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpufeature.h [PATCH] x86_64: i386/x86-64 Add nmi watchdog support for new Intel CPUs 2006-06-26 10:48:22 -07:00
cputime.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
current.h kbuild: alpha,x86_64 use generic asm-offsets.h support 2005-09-09 21:28:48 +02:00
debugreg.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
desc.h [PATCH] x86_64: Align and pad x86_64 GDT on page boundary 2006-01-11 19:04:53 -08:00
div64.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dma-mapping.h [PATCH] Move valid_dma_direction() from x86_64 to generic code 2006-09-29 09:18:10 -07:00
dma.h [PATCH] x86_64: Remove long obsolete CVS 2006-06-26 10:48:16 -07:00
dmi.h [PATCH] x86_64: Implement early DMI scanning 2006-03-25 09:10:55 -08:00
dwarf2.h [PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder 2006-09-26 10:52:41 +02:00
e820.h [PATCH] Have x86_64 use add_active_range() and free_area_init_nodes 2006-09-27 08:26:11 -07:00
edac.h [PATCH] EDAC: core EDAC support code 2006-01-18 19:20:31 -08:00
elf.h [PATCH] Fix 'make headers_check' on x86_64 2006-09-16 12:54:32 -07:00
emergency-restart.h [PATCH] x86_64: Implemenent machine_emergency_restart 2005-07-26 14:35:42 -07:00
errno.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fcntl.h [PATCH] Clean up struct flock definitions 2005-09-07 16:57:38 -07:00
fixmap.h [PATCH] Remove all ifdefs for local/io apic 2006-09-26 10:52:29 +02:00
floppy.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
fpu32.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
futex.h [PATCH] lightweight robust futexes updates 2006-03-27 08:44:49 -08:00
genapic.h [PATCH] remove int_delivery_dest 2006-09-26 10:52:31 +02:00
hardirq.h [PATCH] genirq: irq: generalize the check for HARDIRQ_BITS 2006-10-04 07:55:28 -07:00
hpet.h [PATCH] x86_64: Rename oem_force_hpet_timer to apic_is_clustered_box 2006-06-26 10:48:19 -07:00
hw_irq.h [PATCH] genirq: x86_64 irq: make vector_irq per cpu 2006-10-04 07:55:29 -07:00
hypertransport.h [PATCH] Initial generic hypertransport interrupt support 2006-10-04 07:55:29 -07:00
i387.h [PATCH] Add __must_check to copy_*_user 2006-09-26 10:52:39 +02:00
ia32_unistd.h [PATCH] x86_64: Remove most of ia32_unistd.h 2006-06-26 10:48:15 -07:00
ia32.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
ide.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
idle.h [PATCH] x86_64: Add idle notifiers 2006-01-11 19:04:55 -08:00
intel_arch_perfmon.h [PATCH] x86: i386/x86-64 Add nmi watchdog support for new Intel CPUs 2006-09-26 10:52:27 +02:00
io_apic.h [PATCH] genirq: x86_64 irq: Kill irq compression 2006-10-04 07:55:29 -07:00
io.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
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
ipcbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipi.h [PATCH] x86_64: Remove useless KDB vector 2006-01-11 19:05:00 -08:00
irq_regs.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
irq.h [PATCH] genirq: x86_64 irq: make vector_irq per cpu 2006-10-04 07:55:29 -07:00
irqflags.h [PATCH] lockdep: irqtrace cleanup of include/asm-x86_64/irqflags.h 2006-07-03 15:27:03 -07:00
k8.h [PATCH] x86_64: Clean and enhance up K8 northbridge access code 2006-06-26 10:48:15 -07:00
Kbuild [PATCH] Split i386 and x86_64 ptrace.h 2006-09-26 08:49:10 -07:00
kdebug.h [PATCH] lockdep: beautify x86_64 stacktraces 2006-07-03 15:27:02 -07:00
kexec.h [PATCH] Avoid overwriting the current pgd (V4, x86_64) 2006-09-26 10:52:38 +02:00
kmap_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kprobes.h [PATCH] IA64: kprobe invalidate icache of jump buffer 2006-07-31 13:28:38 -07:00
ldt.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
linkage.h [PATCH] Add proper alignment to ENTRY 2006-09-26 10:52:29 +02:00
local.h [PATCH] x86_64: Fix race in cpu_local_* on preemptible kernels 2006-06-26 10:48:21 -07:00
mach_apic.h [PATCH] remove int_delivery_dest 2006-09-26 10:52:31 +02:00
mc146818rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mce.h [PATCH] x86: Refactor thermal throttle processing 2006-09-26 10:52:42 +02:00
mman.h [PATCH] add asm-generic/mman.h 2006-02-15 15:32:22 -08:00
mmsegment.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
mmu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmzone.h [PATCH] Delete unused definitions of kvaddr_to_nid 2006-06-23 07:42:52 -07:00
module.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mpspec.h [PATCH] Replace mp bus array with bitmap for bus not pci 2006-09-26 10:52:30 +02:00
msgbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
msidef.h [PATCH] genirq: x86_64 irq: Move msi message composition into io_apic.c 2006-10-04 07:55:28 -07:00
msr.h [PATCH] Add macros for rdtscp 2006-09-26 10:52:28 +02:00
mtrr.h Move inclusion of <linux/compat.h> out of user scope in asm-x86_64/mtrr.h 2006-05-21 22:51:13 +01:00
mutex.h [PATCH] Don't use lock section for mutexes and semaphores 2006-09-26 10:52:32 +02:00
namei.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
nmi.h [PATCH] x86: Clean up x86 NMI sysctls 2006-09-30 01:47:55 +02:00
node.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
numa.h [PATCH] Unify pxm_to_node() and node_to_pxm() 2006-06-23 07:42:48 -07:00
page.h [PATCH] x86_64: Enlarge debug stack for nested kprobes 2006-07-28 19:28:00 -07:00
param.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
parport.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci-direct.h [PATCH] x86: Allow disabling early pci scans with pci=noearly or disallowing conf1 2006-09-26 10:52:41 +02:00
pci.h [PATCH] x86_64: Calgary IOMMU - Calgary specific bits 2006-06-26 10:48:19 -07:00
pda.h [PATCH] Fix idle notifiers 2006-09-26 10:52:40 +02:00
percpu.h Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6 2006-09-26 13:07:55 -07:00
pgalloc.h [PATCH] x86_64: actively synchronize vmalloc area when registering certain callbacks 2006-03-25 09:10:53 -08:00
pgtable.h Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6 2006-09-26 13:07:55 -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
prctl.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
processor.h [PATCH] x86_64: Save original IST values for checking stack addresses 2006-08-30 16:05:16 -07:00
proto.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
ptrace-abi.h [PATCH] Split i386 and x86_64 ptrace.h 2006-09-26 08:49:10 -07:00
ptrace.h [PATCH] Add regs_return_value() helper 2006-10-02 07:57:16 -07:00
resource.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rwlock.h [PATCH] Clean up spin/rwlocks 2006-09-26 10:52:32 +02:00
scatterlist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
seccomp.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 [PATCH] Add the vgetcpu vsyscall 2006-09-26 10:52:28 +02:00
semaphore.h [PATCH] Use early clobber in semaphores 2006-09-30 01:47:55 +02:00
sembuf.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
sigcontext32.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 [PATCH] consolidate SIGEV_PAD_SIZE 2005-05-01 08:59:08 -07:00
signal.h [PATCH] Add TIF_RESTORE_SIGMASK 2006-09-26 10:52:26 +02:00
smp.h Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6 2006-09-26 13:07:55 -07:00
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
sparsemem.h [PATCH] add x86-64 specific support for sparsemem 2005-06-23 09:45:07 -07:00
spinlock_types.h [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
spinlock.h [PATCH] Directed yield: cpu_relax variants for spinlocks and rw-locks 2006-10-01 00:39:21 -07:00
stacktrace.h [PATCH] Merge stacktrace and show_trace 2006-09-26 10:52:34 +02:00
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 [PATCH] x86_64: Use __always_inline for __inline_memcpy 2006-06-26 10:48:14 -07:00
suspend.h [PATCH] x86_64: eliminate set_debug() 2006-03-25 09:10:52 -08:00
swiotlb.h [PATCH] x86_64: Fix swiotlb=force 2006-07-29 20:59:55 -07:00
system.h [PATCH] Don't leak NT bit into next task 2006-09-26 10:52:41 +02:00
tce.h [PATCH] Calgary IOMMU: consolidate per bus data structures 2006-09-26 10:52:31 +02:00
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
therm_throt.h [PATCH] x86: Refactor thermal throttle processing 2006-09-26 10:52:42 +02:00
thread_info.h [PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw 2006-09-26 10:52:28 +02:00
timex.h [PATCH] x86_64: fix sync before RDTSC on Intel cpus 2006-04-11 06:38:57 -07:00
tlb.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlbflush.h [PATCH] Clean up and minor fixes to TLB flush 2006-09-26 10:52:29 +02:00
topology.h [PATCH] sched: introduce child field in sched_domain 2006-10-03 08:04:06 -07:00
types.h [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
uaccess.h [PATCH] Add proper sparse __user casts to __copy_to_user_inatomic 2006-09-30 01:47:55 +02:00
ucontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unaligned.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unistd.h [PATCH] rename the provided execve functions to kernel_execve 2006-10-02 07:57:23 -07:00
unwind.h [PATCH] Fix unwinder warning in traps.c 2006-09-26 10:52:42 +02:00
user32.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
user.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vga.h [PATCH] vgacon: make VGA_MAP_MEM take size, remove extra use 2006-06-22 15:05:58 -07:00
vsyscall32.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vsyscall.h [PATCH] kill wall_jiffies 2006-10-01 00:39:27 -07:00
xor.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00