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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)
73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
/* $Id: netjet.h,v 2.8.2.2 2004/01/12 22:52:28 keil Exp $
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*
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* NETjet common header file
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*
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* Author Karsten Keil
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* Copyright by Karsten Keil <keil@isdn4linux.de>
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* by Matt Henderson,
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* Traverse Technologies P/L www.traverse.com.au
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*
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* This software may be used and distributed according to the terms
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* of the GNU General Public License, incorporated herein by reference.
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*
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*/
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extern const char *CardType[];
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#define byteout(addr,val) outb(val,addr)
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#define bytein(addr) inb(addr)
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#define NETJET_CTRL 0x00
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#define NETJET_DMACTRL 0x01
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#define NETJET_AUXCTRL 0x02
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#define NETJET_AUXDATA 0x03
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#define NETJET_IRQMASK0 0x04
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#define NETJET_IRQMASK1 0x05
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#define NETJET_IRQSTAT0 0x06
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#define NETJET_IRQSTAT1 0x07
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#define NETJET_DMA_READ_START 0x08
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#define NETJET_DMA_READ_IRQ 0x0c
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#define NETJET_DMA_READ_END 0x10
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#define NETJET_DMA_READ_ADR 0x14
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#define NETJET_DMA_WRITE_START 0x18
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#define NETJET_DMA_WRITE_IRQ 0x1c
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#define NETJET_DMA_WRITE_END 0x20
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#define NETJET_DMA_WRITE_ADR 0x24
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#define NETJET_PULSE_CNT 0x28
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#define NETJET_ISAC_OFF 0xc0
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#define NETJET_ISACIRQ 0x10
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#define NETJET_IRQM0_READ 0x0c
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#define NETJET_IRQM0_READ_1 0x04
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#define NETJET_IRQM0_READ_2 0x08
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#define NETJET_IRQM0_WRITE 0x03
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#define NETJET_IRQM0_WRITE_1 0x01
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#define NETJET_IRQM0_WRITE_2 0x02
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#define NETJET_DMA_TXSIZE 512
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#define NETJET_DMA_RXSIZE 128
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#define HDLC_ZERO_SEARCH 0
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#define HDLC_FLAG_SEARCH 1
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#define HDLC_FLAG_FOUND 2
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#define HDLC_FRAME_FOUND 3
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#define HDLC_NULL 4
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#define HDLC_PART 5
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#define HDLC_FULL 6
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#define HDLC_FLAG_VALUE 0x7e
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u_char NETjet_ReadIC(struct IsdnCardState *cs, u_char offset);
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void NETjet_WriteIC(struct IsdnCardState *cs, u_char offset, u_char value);
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void NETjet_ReadICfifo(struct IsdnCardState *cs, u_char *data, int size);
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void NETjet_WriteICfifo(struct IsdnCardState *cs, u_char *data, int size);
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void read_tiger(struct IsdnCardState *cs);
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void write_tiger(struct IsdnCardState *cs);
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void netjet_fill_dma(struct BCState *bcs);
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void netjet_interrupt(int intno, void *dev_id);
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void inittiger(struct IsdnCardState *cs);
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void release_io_netjet(struct IsdnCardState *cs);
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