7d12e780e0
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)
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
#ifndef _ASM_HW_IRQ_H
|
|
#define _ASM_HW_IRQ_H
|
|
|
|
/*
|
|
* linux/include/asm/hw_irq.h
|
|
*
|
|
* (C) 1992, 1993 Linus Torvalds, (C) 1997 Ingo Molnar
|
|
*
|
|
* moved some of the old arch/i386/kernel/irq.h to here. VY
|
|
*
|
|
* IRQ/IPI changes taken from work by Thomas Radke
|
|
* <tomsoft@informatik.tu-chemnitz.de>
|
|
*/
|
|
|
|
#include <linux/profile.h>
|
|
#include <asm/atomic.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/sections.h>
|
|
|
|
#define NMI_VECTOR 0x02
|
|
|
|
/*
|
|
* Various low-level irq details needed by irq.c, process.c,
|
|
* time.c, io_apic.c and smp.c
|
|
*
|
|
* Interrupt entry/exit code at both C and assembly level
|
|
*/
|
|
|
|
extern u8 irq_vector[NR_IRQ_VECTORS];
|
|
#define IO_APIC_VECTOR(irq) (irq_vector[irq])
|
|
|
|
extern void (*interrupt[NR_IRQS])(void);
|
|
|
|
#ifdef CONFIG_SMP
|
|
fastcall void reschedule_interrupt(void);
|
|
fastcall void invalidate_interrupt(void);
|
|
fastcall void call_function_interrupt(void);
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_LOCAL_APIC
|
|
fastcall void apic_timer_interrupt(void);
|
|
fastcall void error_interrupt(void);
|
|
fastcall void spurious_interrupt(void);
|
|
fastcall void thermal_interrupt(void);
|
|
#define platform_legacy_irq(irq) ((irq) < 16)
|
|
#endif
|
|
|
|
void disable_8259A_irq(unsigned int irq);
|
|
void enable_8259A_irq(unsigned int irq);
|
|
int i8259A_irq_pending(unsigned int irq);
|
|
void make_8259A_irq(unsigned int irq);
|
|
void init_8259A(int aeoi);
|
|
void FASTCALL(send_IPI_self(int vector));
|
|
void init_VISWS_APIC_irqs(void);
|
|
void setup_IO_APIC(void);
|
|
void disable_IO_APIC(void);
|
|
void print_IO_APIC(void);
|
|
int IO_APIC_get_PCI_irq_vector(int bus, int slot, int fn);
|
|
void send_IPI(int dest, int vector);
|
|
void setup_ioapic_dest(void);
|
|
|
|
extern unsigned long io_apic_irqs;
|
|
|
|
extern atomic_t irq_err_count;
|
|
extern atomic_t irq_mis_count;
|
|
|
|
#define IO_APIC_IRQ(x) (((x) >= 16) || ((1<<(x)) & io_apic_irqs))
|
|
|
|
#endif /* _ASM_HW_IRQ_H */
|