linux-stable-rt/include/linux
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
..
amba
byteorder
dvb
hdlc
isdn
lockd [PATCH] Convert lockd to use the newer mutex instead of the older semaphore 2006-10-04 07:55:19 -07:00
mmc
mtd fix file specification in comments 2006-10-03 23:01:26 +02:00
netfilter
netfilter_arp
netfilter_bridge [NETFILTER]: ebt_mark: add or/and/xor action support to mark target 2006-10-04 00:30:57 -07:00
netfilter_ipv4
netfilter_ipv6
nfsd [PATCH] Fix linux/nfsd/const.h for make headers_check 2006-10-04 07:55:24 -07:00
raid [PATCH] md: remove MAX_MD_DEVS which is an arbitrary limit 2006-10-03 08:04:18 -07:00
spi
sunrpc [PATCH] knfsd: register all RPC programs with portmapper by default 2006-10-04 07:55:19 -07:00
tc_act
tc_ematch
usb IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
8250_pci.h
Kbuild [MIPS] Remove remaining reference to ite_gpio.h from Kbuild 2006-10-04 18:06:15 +01:00
a.out.h
ac97_codec.h [PATCH] The scheduled removal of some OSS drivers 2006-10-04 07:55:32 -07:00
acct.h
acpi.h
adb.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
adfs_fs.h
adfs_fs_i.h
adfs_fs_sb.h
aer.h
affs_hardblocks.h
agp_backend.h
agpgart.h
aio.h
aio_abi.h fix file specification in comments 2006-10-03 23:01:26 +02:00
amifd.h
amifdreg.h
amigaffs.h
apm_bios.h
arcdevice.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
arcfb.h
ata.h
atalk.h
atm.h
atm_eni.h
atm_he.h
atm_idt77105.h
atm_nicstar.h
atm_suni.h
atm_tcp.h
atm_zatm.h
atmapi.h
atmarp.h
atmbr2684.h
atmclip.h
atmdev.h
atmioc.h
atmlec.h
atmmpc.h
atmppp.h
atmsap.h
atmsvc.h
attribute_container.h
audit.h [PATCH] message types updated 2006-10-04 08:31:24 -04:00
auto_fs.h
auto_fs4.h
auxvec.h
awe_voice.h fix file specification in comments 2006-10-03 23:01:26 +02:00
ax25.h
b1lli.h
b1pcmcia.h
backing-dev.h
backlight.h
baycom.h
bcd.h
bfs_fs.h
binfmts.h
bio.h [PATCH] Document bi_sector and sector_t 2006-10-04 19:32:09 +02:00
bit_spinlock.h
bitmap.h
bitops.h
blkdev.h [PATCH] helper function for retrieving scsi_cmd given host based block layer tag 2006-10-04 19:32:09 +02:00
blkpg.h
blktrace_api.h
blockgroup_lock.h
bootmem.h
bpqether.h
buffer_head.h
cache.h
calc64.h
capability.h
capi.h
cciss_ioctl.h
cd1400.h
cdev.h
cdk.h
cdrom.h
chio.h
circ_buf.h
clk.h
clocksource.h
cm4000_cs.h
cn_proc.h
cobalt-nvram.h
coda.h
coda_cache.h
coda_fs_i.h
coda_linux.h
coda_proc.h
coda_psdev.h
coff.h
com20020.h
compat.h
compat_ioctl.h [PATCH] md: allow SET_BITMAP_FILE to work on 64bit kernel with 32bit userspace 2006-10-03 08:04:19 -07:00
compiler-gcc.h
compiler-gcc3.h
compiler-gcc4.h
compiler-intel.h
compiler.h
completion.h
comstats.h
concap.h
config.h Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
configfs.h
connector.h
console.h
console_struct.h
consolemap.h
cpu.h
cpufreq.h
cpumask.h
cpuset.h
cramfs_fs.h
cramfs_fs_sb.h
crash_dump.h
crc-ccitt.h
crc16.h
crc32.h
crc32c.h
crypto.h
cryptohash.h
ctype.h
cuda.h
cyclades.h
cyclomx.h
cycx_cfm.h
cycx_drv.h
cycx_x25.h
dcache.h
dccp.h
dcookies.h
debug_locks.h [PATCH] Need forward decl of task_struct in linux/debug_locks.h 2006-10-04 06:45:23 -06:00
debugfs.h
delay.h
delayacct.h
device-mapper.h [PATCH] dm table: add target flush 2006-10-03 08:04:16 -07:00
device.h
devpts_fs.h
dio.h
dirent.h
divert.h
dlm.h
dlm_device.h
dm-ioctl.h [PATCH] dm table: add target flush 2006-10-03 08:04:16 -07:00
dm9000.h
dma-mapping.h
dmaengine.h
dmapool.h
dmi.h
dn.h
dnotify.h
dqblk_v1.h
dqblk_v2.h
dqblk_xfs.h
ds1286.h
ds1742rtc.h
ds17287rtc.h
dtlk.h
edd.h
efi.h
efs_dir.h
efs_fs.h
efs_fs_i.h
efs_fs_sb.h
efs_vh.h
eisa.h
elevator.h
elf-em.h
elf-fdpic.h
elf.h
elfcore.h
elfnote.h
err.h
errno.h
errqueue.h
etherdevice.h
ethtool.h
eventpoll.h
ext2_fs.h
ext2_fs_sb.h
ext3_fs.h
ext3_fs_i.h
ext3_fs_sb.h
ext3_jbd.h
fadvise.h
fb.h
fcdevice.h
fcntl.h
fd.h
fd1772.h
fddidevice.h
fdreg.h
fib_rules.h
file.h
filter.h
firmware.h
flat.h
font.h
fs.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6 2006-10-04 09:06:16 -07:00
fs_enet_pd.h
fs_struct.h
fs_uart_pd.h
fsl_devices.h [POWERPC] Add QUICC Engine (QE) infrastructure 2006-10-04 15:24:27 +10:00
fsnotify.h
ftape-header-segment.h
ftape-vendors.h
ftape.h
fuse.h
futex.h
gameport.h
gen_stats.h
genalloc.h
generic_acl.h
generic_serial.h
genetlink.h
genhd.h
getcpu.h
gfp.h
gfs2_ondisk.h
gigaset_dev.h
hardirq.h [PATCH] genirq: irq: generalize the check for HARDIRQ_BITS 2006-10-04 07:55:28 -07:00
harrier_defs.h fix file specification in comments 2006-10-03 23:01:26 +02:00
hash.h
hayesesp.h
hdlc.h
hdlcdrv.h
hdpu_features.h
hdreg.h
hdsmart.h
hiddev.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
highmem.h
highuid.h
hil.h
hil_mlc.h
hippidevice.h
hp_sdc.h
hpet.h
hrtimer.h
htirq.h [PATCH] htirq: tidy up the htirq code 2006-10-04 07:55:30 -07:00
hugetlb.h
hw_random.h
hwmon-sysfs.h
hwmon-vid.h
hwmon.h
hysdn_if.h
i2c-algo-bit.h
i2c-algo-ite.h
i2c-algo-pca.h
i2c-algo-pcf.h
i2c-algo-sgi.h
i2c-dev.h
i2c-id.h
i2c-isa.h
i2c-ocores.h
i2c-pxa.h
i2c.h
i2o-dev.h
i2o.h
i8k.h
ibmtr.h
icmp.h
icmpv6.h
ide.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
idr.h
if.h
if_addr.h
if_arcnet.h
if_arp.h
if_bonding.h
if_bridge.h
if_cablemodem.h
if_ec.h
if_eql.h
if_ether.h
if_fc.h
if_fddi.h
if_frad.h
if_hippi.h
if_infiniband.h
if_link.h
if_ltalk.h
if_packet.h
if_plip.h
if_ppp.h
if_pppox.h
if_shaper.h
if_slip.h
if_strip.h
if_tr.h
if_tun.h
if_tunnel.h
if_vlan.h
if_wanpipe.h
if_wanpipe_common.h
igmp.h
in.h [XFRM]: BEET mode 2006-10-04 00:31:09 -07:00
in6.h
in_route.h
inet.h
inet_diag.h
inetdevice.h
init.h
init_task.h
initrd.h
inotify.h
input.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
interrupt.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
io.h
ioc3.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
ioc4.h
ioctl.h
ioctl32.h
ioport.h
ioprio.h
ip.h [XFRM]: BEET mode 2006-10-04 00:31:09 -07:00
ip6_tunnel.h
ip_mp_alg.h
ipc.h [PATCH] ipc: headers_check fix 2006-10-04 07:55:12 -07:00
ipmi.h
ipmi_msgdefs.h
ipmi_smi.h
ipsec.h [XFRM]: BEET mode 2006-10-04 00:31:09 -07:00
ipv6.h
ipv6_route.h
ipx.h
irda.h
irq.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
irq_cpustat.h
irqflags.h
irqreturn.h
isa.h
isapnp.h
isdn.h
isdn_divertif.h
isdn_ppp.h
isdnif.h
isicom.h
iso_fs.h
istallion.h
ixjuser.h
jbd.h
jffs.h
jffs2.h
jhash.h
jiffies.h
journal-head.h
joystick.h
kallsyms.h
kbd_diacr.h
kbd_kern.h
kd.h
kdev_t.h
kernel.h [PATCH] pr_debug: check pr_debug() arguments 2006-10-03 08:04:20 -07:00
kernel_stat.h
kernelcapi.h
kexec.h
key-ui.h
key.h
keyboard.h
keyctl.h
kfifo.h
klist.h
kmalloc_sizes.h
kmod.h
kobj_map.h
kobject.h
kprobes.h
kref.h
kthread.h
ktime.h
lapb.h
latency.h
lcd.h
leds.h
libata.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
libps2.h
license.h
limits.h
linkage.h
linux_logo.h
list.h
llc.h
lm_interface.h
lock_dlm_plock.h
lockdep.h
loop.h
lp.h
m41t00.h
m48t86.h
magic.h
major.h
matroxfb.h
mbcache.h
mc6821.h
mc146818rtc.h
mca-legacy.h
mca.h
memory.h
memory_hotplug.h
mempolicy.h
mempool.h
meye.h
migrate.h
mii.h
minix_fs.h
miscdevice.h
mm.h
mm_inline.h
mm_types.h
mman.h
mmtimer.h
mmzone.h
mod_devicetable.h
module.h
moduleloader.h
moduleparam.h
mount.h
mpage.h
mqueue.h
mroute.h
msdos_fs.h
msg.h
msi.h [PATCH] msi: refactor and move the msi irq_chip into the arch code 2006-10-04 07:55:29 -07:00
mtio.h
mutex-debug.h
mutex.h
mv643xx.h
n_r3964.h
namei.h
namespace.h
nbd.h
ncp.h
ncp_fs.h
ncp_fs_i.h
ncp_fs_sb.h
ncp_mount.h
ncp_no.h
neighbour.h
net.h
netdevice.h
netfilter.h
netfilter_arp.h
netfilter_bridge.h
netfilter_decnet.h
netfilter_ipv4.h [NETFILTER]: add type parameter to ip_route_me_harder 2006-10-04 00:30:54 -07:00
netfilter_ipv6.h
netlink.h
netpoll.h
netrom.h
nfs.h
nfs2.h
nfs3.h
nfs4.h
nfs4_acl.h
nfs4_mount.h
nfs_fs.h
nfs_fs_i.h
nfs_fs_sb.h
nfs_idmap.h
nfs_mount.h
nfs_page.h
nfs_xdr.h
nfsacl.h
nfsd_idmap.h
nls.h
nmi.h
node.h
nodemask.h
notifier.h [PATCH] Add SRCU-based notifier chains 2006-10-04 07:55:30 -07:00
nsc_gpio.h
nsproxy.h
nubus.h
numa.h
nvram.h
oprofile.h
page-flags.h
pagemap.h
pagevec.h
param.h
parport.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
parport_pc.h
parser.h
patchkey.h
pci-acpi.h
pci.h [PATCH] htirq: tidy up the htirq code 2006-10-04 07:55:30 -07:00
pci_ids.h [MIPS] Remove IT8172-based platforms, ITE 8172G and Globespan IVR support. 2006-10-03 17:59:17 +01:00
pci_regs.h [PATCH] Add Hypertransport capability defines 2006-10-04 07:55:29 -07:00
pcieport_if.h
percpu.h
percpu_counter.h
personality.h
pfkeyv2.h
pfn.h
pg.h
phonedev.h
phy.h
pid.h
pipe_fs_i.h
pkt_cls.h
pkt_sched.h
pktcdvd.h
platform_device.h
plist.h
pm.h
pm_legacy.h
pmu.h
pnp.h
pnpbios.h
poison.h
poll.h
posix-timers.h
posix_acl.h
posix_acl_xattr.h
posix_types.h
ppdev.h fix file specification in comments 2006-10-03 23:01:26 +02:00
ppp-comp.h
ppp_channel.h
ppp_defs.h
prctl.h
preempt.h
prefetch.h
prio_tree.h
proc_fs.h
profile.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
ps2esdi.h
pspace.h
ptrace.h
qic117.h
qnx4_fs.h
qnxtypes.h
quota.h
quotaio_v1.h
quotaio_v2.h
quotaops.h
radeonfb.h
radix-tree.h
raid_class.h [SCSI] raid class: handle component-add errors 2006-10-04 13:27:26 -05:00
ramfs.h
random.h
raw.h
rbtree.h
rcupdate.h [PATCH] RCU: CREDITS and MAINTAINERS 2006-10-04 07:55:31 -07:00
reboot.h
reboot_fixups.h
reiserfs_acl.h
reiserfs_fs.h
reiserfs_fs_i.h
reiserfs_fs_sb.h
reiserfs_xattr.h
relay.h
resource.h
resume-trace.h
rio.h
rio_drv.h
rio_ids.h
rio_regs.h
rmap.h
romfs_fs.h
root_dev.h
rose.h
route.h
rslib.h
rtc-v3020.h
rtc.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
rtmutex.h
rtnetlink.h
rwsem-spinlock.h
rwsem.h
sc26198.h
scatterlist.h
scc.h
sched.h
screen_info.h
sctp.h
scx200.h [PATCH] scx200_hrt: fix precedence bug manifesting as 27x clock in 1 MHz mode 2006-10-04 07:55:14 -07:00
scx200_gpio.h
sdla.h
sdla_fr.h
seccomp.h
securebits.h
security.h
selection.h
selinux.h
selinux_netlink.h
sem.h
seq_file.h
seqlock.h
serial.h
serial167.h
serialP.h
serial_8250.h
serial_core.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
serial_ip3106.h
serial_reg.h
serio.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
shm.h
shmem_fs.h
signal.h
skbuff.h
slab.h [PATCH] slab: clean up leak tracking ifdefs a little bit 2006-10-04 07:55:13 -07:00
smb.h
smb_fs.h
smb_fs_i.h
smb_fs_sb.h
smb_mount.h
smbno.h
smp.h
smp_lock.h
snmp.h
socket.h
sockios.h
som.h
sonet.h
sonypi.h
sort.h
sound.h [PATCH] The scheduled removal of some OSS drivers 2006-10-04 07:55:32 -07:00
soundcard.h
spinlock.h
spinlock_api_smp.h
spinlock_api_up.h
spinlock_types.h
spinlock_types_up.h
spinlock_up.h
srcu.h [PATCH] SRCU: report out-of-memory errors 2006-10-04 07:55:30 -07:00
stacktrace.h
stallion.h
stat.h
statfs.h
stddef.h
stop_machine.h
string.h
stringify.h
superhyway.h
suspend.h
swap.h
swapops.h
synclink.h
sys.h
syscalls.h
sysctl.h
sysdev.h
sysfs.h
sysrq.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
sysv_fs.h
taskstats.h
taskstats_kern.h
tcp.h
telephony.h
termios.h
textsearch.h
textsearch_fsm.h
tfrc.h
thread_info.h
threads.h
ticable.h
tifm.h [PATCH] mmc: driver for TI FlashMedia card reader - source 2006-10-04 07:55:14 -07:00
time.h
timer.h
times.h
timex.h
tiocl.h
tipc.h
tipc_config.h
topology.h
toshiba.h
transport_class.h
trdevice.h
tsacct_kern.h
tty.h
tty_driver.h
tty_flip.h
tty_ldisc.h
types.h [PATCH] Document bi_sector and sector_t 2006-10-04 19:32:09 +02:00
uaccess.h
udf_fs.h
udf_fs_i.h
udf_fs_sb.h
udp.h
ufs_fs.h
ufs_fs_i.h
ufs_fs_sb.h
uinput.h
uio.h
ultrasound.h
umem.h
un.h
unistd.h
unwind.h
usb.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
usb_ch9.h
usb_gadget.h
usb_gadgetfs.h
usb_usual.h
usbdevice_fs.h
user.h
utime.h
uts.h
utsname.h [PATCH] ipc: headers_check fix 2006-10-04 07:55:12 -07:00
vermagic.h
vfs.h
via.h
video_decoder.h
video_encoder.h
videodev.h
videodev2.h V4L/DVB (4673): Mark the two newer ioctls as experimental 2006-10-03 15:14:16 -03:00
videotext.h
vmalloc.h
vmstat.h
vt.h
vt_buffer.h
vt_kern.h
wait.h
wanrouter.h
watchdog.h
wireless.h
workqueue.h
writeback.h fix file specification in comments 2006-10-03 23:01:26 +02:00
x25.h
xattr.h
xfrm.h [XFRM]: BEET mode 2006-10-04 00:31:09 -07:00
yam.h
zconf.h
zftape.h
zlib.h
zorro.h
zorro_ids.h
zutil.h