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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)		19 years ago
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Kconfig	[WATCHDOG] iTCO_wdt (Intel TCO Timer) driver	19 years ago
Makefile	[WATCHDOG] iTCO_wdt (Intel TCO Timer) driver	19 years ago
acquirewdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
advantechwdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
alim1535_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
alim7101_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
at91_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
booke_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
cpu5wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
ep93xx_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
eurotechwdt.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
i8xx_tco.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
i8xx_tco.h	…
i6300esb.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
iTCO_wdt.c	Remove all inclusions of <linux/config.h>	19 years ago
ib700wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
ibmasr.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
indydog.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
ixp4xx_wdt.c	fix file specification in comments	19 years ago
ixp2000_wdt.c	fix file specification in comments	19 years ago
machzwd.c	[WATCHDOG] improve machzwd detection	19 years ago
mixcomwd.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
mpc8xx_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
mpc83xx_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
mpcore_wdt.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
mv64x60_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
omap_wdt.c	Remove all inclusions of <linux/config.h>	19 years ago
omap_wdt.h	…
pcwd.c	Remove all inclusions of <linux/config.h>	19 years ago
pcwd_pci.c	Remove all inclusions of <linux/config.h>	19 years ago
pcwd_usb.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
pnx4008_wdt.c	Remove all inclusions of <linux/config.h>	19 years ago
s3c2410_wdt.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
sa1100_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
sbc60xxwdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
sbc8360.c	…
sbc_epx_c3.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
sc520_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
sc1200wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
scx200_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
shwdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
softdog.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
w83627hf_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
w83877f_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
w83977f_wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
wafer5823wdt.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
wd501p.h	…
wdrtas.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
wdt.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
wdt285.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
wdt977.c	[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()	19 years ago
wdt_pci.c	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago