linux/include/asm-i386
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
..
mach-bigsmp [PATCH] x86: convert bigsmp to use flat physical mode 2006-01-06 08:33:37 -08:00
mach-default IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
mach-es7000 [PATCH] i386: Allow to use GENERICARCH for UP kernels 2006-09-26 10:52:26 +02:00
mach-generic [PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs 2005-09-05 00:06:10 -07:00
mach-numaq [PATCH] Do not enforce unique IO_APIC_ID check for xAPIC systems (i386) 2005-06-23 09:45:09 -07:00
mach-summit [PATCH] i383 numa: fix numaq/summit apicid conflict 2006-10-03 18:46:10 -07:00
mach-visws IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
mach-voyager IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 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 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
acpi.h [PATCH] i386: Replace i386 open-coded cmdline parsing with 2006-09-26 10:52:32 +02:00
agp.h [PATCH] i386: inline asm cleanup 2005-09-05 00:06:11 -07:00
alternative-asm.i Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
alternative.h [PATCH] i386: 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
arch_hooks.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
atomic.h i386: improve and correct inline asm memory constraints 2006-07-08 15:24:18 -07:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
bitops.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
boot.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -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 [PATCH] namespaces: utsname: use init_utsname when appropriate 2006-10-02 07:57:21 -07:00
byteorder.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
cache.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
cacheflush.h [PATCH] x86/x86_64: mark rodata section read only: x86 parts 2006-01-06 08:33:36 -08:00
checksum.h [NET]: Fix ipl=>ihl typo in ip_fast_csum 2005-08-29 16:02:48 -07:00
cpu.h [PATCH] Register sysfs file for hotplugged new node 2006-06-27 17:32:36 -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 [PATCH] mark several functions __always_inline 2006-01-14 18:27:15 -08:00
debugreg.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
delay.h [PATCH] Time: i386 Conversion - part 3: Enable Generic Timekeeping 2006-06-26 09:58:21 -07:00
desc.h [PATCH] i386: Fix pack_descriptor() 2006-09-26 10:52:40 +02:00
div64.h [PATCH] include/asm-i386/: "extern inline" -> "static inline" 2005-09-10 10:06:34 -07:00
dma-mapping.h [PATCH] Use valid_dma_direction() in include/asm-i386/dma-mapping.h 2006-09-29 09:18:10 -07:00
dma.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
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] x86: Remove incorrect comment about ACPI e820 entries 2006-09-26 10:52:38 +02:00
edac.h [PATCH] EDAC: core EDAC support code 2006-01-18 19:20:31 -08:00
elf.h [PATCH] namespaces: utsname: switch to using uts namespaces 2006-10-02 07:57:21 -07:00
emergency-restart.h [PATCH] i386: Implement machine_emergency_reboot 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 flock64 definitions 2005-09-07 16:57:38 -07:00
fixmap.h [PATCH] x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor 2006-09-26 08:48:55 -07:00
floppy.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
frame.i Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
futex.h i386: improve and correct inline asm memory constraints 2006-07-08 15:24:18 -07:00
genapic.h [PATCH] i386: Allow to use GENERICARCH for UP kernels 2006-09-26 10:52:26 +02:00
hardirq.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
highmem.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
hpet.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
hw_irq.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
hypertransport.h [PATCH] Initial generic hypertransport interrupt support 2006-10-04 07:55:29 -07:00
i387.h [PATCH] i386: fix broken FP exception handling 2006-04-29 14:13:16 -07:00
i8253.h [PATCH] x86: i8253/i8259A lock cleanup 2005-06-30 08:45:10 -07:00
i8259.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
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: i386 irq: Remove the msi assumption that irq == vector 2006-10-04 07:55:28 -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
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
irq_regs.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
irq.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
irqflags.h [PATCH] lockdep: irqtrace cleanup of include/asm-i386/irqflags.h 2006-07-03 15:27:03 -07:00
ist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -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] Notify page fault call chain for i386 2006-06-26 09:58:22 -07:00
kexec.h [PATCH] i386: Avoid overwriting the current pgd (V4, i386) 2006-09-26 10:52:38 +02:00
kmap_types.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
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] i386: fix prevent_tail_call 2005-05-26 16:16:16 -07:00
local.h i386: improve and correct inline asm memory constraints 2006-07-08 15:24:18 -07:00
math_emu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mc146818rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mca_dma.h [PATCH] kernel-doc for kernel/dma.c 2006-10-03 08:03:41 -07:00
mca.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mce.h [PATCH] Don't trigger full rebuild via CONFIG_X86_MCE 2006-06-23 07:42:56 -07:00
mman.h [PATCH] add asm-generic/mman.h 2006-02-15 15:32:22 -08:00
mmu_context.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
mmu.h [PATCH] vdso: randomize the i386 vDSO by moving it into a vma 2006-06-27 17:32:38 -07:00
mmx.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmzone.h [PATCH] convert i386 NUMA KVA space to bootmem 2006-09-26 08:48:45 -07:00
module.h [PATCH] Base support for AMD Geode GX/LX processors 2006-01-06 08:33:38 -08:00
mpspec_def.h [PATCH] mpspec: remove unneeded packed attribute 2006-01-06 08:33:39 -08:00
mpspec.h [PATCH] mptspec: remove duplicate #include 2006-04-11 06:18:34 -07:00
msgbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
msidef.h [PATCH] genirq: i386 irq: Move msi message composition into io_apic.c 2006-10-04 07:55:28 -07:00
msr.h [PATCH] x86: more asm cleanups 2005-09-05 00:06:12 -07:00
mtrr.h [PATCH] Don't trigger full rebuild via CONFIG_MTRR 2006-06-23 07:42:56 -07:00
mutex.h [PATCH] i386: Remove lock section support in mutex.h 2006-09-26 10:52:31 +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
numa.h [PATCH] x86-64: Use ACPI PXM to parse PCI<->node assignments 2005-09-12 10:49:57 -07:00
numaq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
page.h [PATCH] vdso: randomize the i386 vDSO by moving it into a vma 2006-06-27 17:32:38 -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 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-2level-defs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgtable-2level.h [PATCH] paravirt: optimize ptep establish for pae 2006-10-01 00:39:34 -07:00
pgtable-3level-defs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgtable-3level.h [PATCH] paravirt: remove set pte atomic 2006-10-01 00:39:34 -07:00
pgtable.h [PATCH] paravirt: update pte hook 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 i386: improve and correct inline asm memory constraints 2006-07-08 15:24:18 -07:00
processor.h [PATCH] x86: roll all the cpuid asm into one __cpuid call 2006-09-26 08:48:55 -07:00
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] i386: Clean up spin/rwlocks 2006-09-26 10:52:32 +02:00
rwsem.h [PATCH] i386: Remove lock section support in rwsem.h 2006-09-26 10:52:31 +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] i386: Allow a kernel not to be in ring 0 2006-09-26 10:52:39 +02:00
semaphore.h [PATCH] i386: Use early clobbers for semaphores now 2006-09-27 14:39:51 -07:00
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 [PATCH] headers_check: don't expose PFN stuff to userspace in <asm-i386/setup.h> 2006-09-13 07:32:16 -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] headers_check: move inclusion of <linux/linkage.h> in <asm-i386/signal.h> 2006-09-13 07:32:15 -07:00
smp.h [PATCH] stack overflow safe kdump: safe_smp_processor_id() 2006-10-01 00:39:30 -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] sparsemem memory model for i386 2005-06-23 09:45:05 -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
srat.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
stacktrace.h [PATCH] i386: Do stacktracer conversion too 2006-09-26 10:52:34 +02:00
stat.h [PATCH] 2TB files: st_blocks is invalid when calling stat64 2006-03-26 08:57:00 -08:00
statfs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
string.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
suspend.h [PATCH] i386: Use loaddebug macro consistently 2005-04-16 15:24:46 -07:00
sync_bitops.h [PATCH] x86: implement always-locked bit ops, for memory shared with an SMP hypervisor 2006-09-26 08:48:55 -07:00
system.h [PATCH] x86: implement always-locked bit ops, for memory shared with an SMP hypervisor 2006-09-26 08:48:55 -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
therm_throt.h [PATCH] x86: Add a cumulative thermal throttle event counter. 2006-09-26 10:52:42 +02:00
thread_info.h [PATCH] i386: use thread_info flags for debug regs and IO bitmaps 2006-07-09 18:47:12 -07:00
timer.h [PATCH] Time: i386 Conversion - part 3: Enable Generic Timekeeping 2006-06-26 09:58:21 -07:00
timex.h [PATCH] Time: i386 Conversion - part 2: Rework TSC Support 2006-06-26 09:58:21 -07:00
tlb.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlbflush.h [PATCH] i386: Minor fixes & cleanup 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
tsc.h [PATCH] x86: remove config.h includes from asm-i386 & asm-x86_64 2006-09-26 10:52:36 +02:00
types.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
uaccess.h [PATCH] Make copy_from_user_inatomic NOT zero the tail on i386 2006-06-25 10:01:09 -07:00
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] remove remaining errno and __KERNEL_SYSCALLS__ references 2006-10-02 07:57:23 -07:00
unwind.h [PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder 2006-09-26 10:52:41 +02:00
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
vic.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vm86.h [PATCH] Make vm86 support optional 2006-01-08 20:14:11 -08:00
voyager.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
xor.h [PATCH] i386: inline asm cleanup 2005-09-05 00:06:11 -07:00