• David Howells's avatar
    IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
    David Howells authored
    
    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: default avatarDavid Howells <dhowells@redhat.com>
    (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
    7d12e780
8390.h 8.73 KB
/* Generic NS8390 register definitions. */
/* This file is part of Donald Becker's 8390 drivers, and is distributed
   under the same license. Auto-loading of 8390.o only in v2.2 - Paul G.
   Some of these names and comments originated from the Crynwr
   packet drivers, which are distributed under the GPL. */

#ifndef _8390_h
#define _8390_h

#include <linux/if_ether.h>
#include <linux/ioport.h>
#include <linux/skbuff.h>

#define TX_PAGES 12	/* Two Tx slots */

#define ETHER_ADDR_LEN 6

/* The 8390 specific per-packet-header format. */
struct e8390_pkt_hdr {
  unsigned char status; /* status */
  unsigned char next;   /* pointer to next packet. */
  unsigned short count; /* header + packet length in bytes */
};

#ifdef notdef
extern int ei_debug;
#else
#define ei_debug 1
#endif

#ifdef CONFIG_NET_POLL_CONTROLLER
extern void ei_poll(struct net_device *dev);
#endif

extern void NS8390_init(struct net_device *dev, int startp);
extern int ei_open(struct net_device *dev);
extern int ei_close(struct net_device *dev);
extern irqreturn_t ei_interrupt(int irq, void *dev_id);
extern struct net_device *__alloc_ei_netdev(int size);
static inline struct net_device *alloc_ei_netdev(void)
{
	return __alloc_ei_netdev(0);
}

/* You have one of these per-board */
struct ei_device {
	const char *name;
	void (*reset_8390)(struct net_device *);
	void (*get_8390_hdr)(struct net_device *, struct e8390_pkt_hdr *, int);
	void (*block_output)(struct net_device *, int, const unsigned char *, int);
	void (*block_input)(struct net_device *, int, struct sk_buff *, int);
	unsigned long rmem_start;
	unsigned long rmem_end;
	void __iomem *mem;
	unsigned char mcfilter[8];
	unsigned open:1;
	unsigned word16:1;  		/* We have the 16-bit (vs 8-bit) version of the card. */
	unsigned bigendian:1;		/* 16-bit big endian mode. Do NOT */
					/* set this on random 8390 clones! */
	unsigned txing:1;		/* Transmit Active */
	unsigned irqlock:1;		/* 8390's intrs disabled when '1'. */
	unsigned dmaing:1;		/* Remote DMA Active */
	unsigned char tx_start_page, rx_start_page, stop_page;
	unsigned char current_page;	/* Read pointer in buffer  */
	unsigned char interface_num;	/* Net port (AUI, 10bT.) to use. */
	unsigned char txqueue;		/* Tx Packet buffer queue length. */
	short tx1, tx2;			/* Packet lengths for ping-pong tx. */
	short lasttx;			/* Alpha version consistency check. */
	unsigned char reg0;		/* Register '0' in a WD8013 */
	unsigned char reg5;		/* Register '5' in a WD8013 */
	unsigned char saved_irq;	/* Original dev->irq value. */
	struct net_device_stats stat;	/* The new statistics table. */
	u32 *reg_offset;		/* Register mapping table */
	spinlock_t page_lock;		/* Page register locks */
	unsigned long priv;		/* Private field to store bus IDs etc. */
};

/* The maximum number of 8390 interrupt service routines called per IRQ. */
#define MAX_SERVICE 12

/* The maximum time waited (in jiffies) before assuming a Tx failed. (20ms) */
#define TX_TIMEOUT (20*HZ/100)

#define ei_status (*(struct ei_device *)netdev_priv(dev))

/* Some generic ethernet register configurations. */
#define E8390_TX_IRQ_MASK	0xa	/* For register EN0_ISR */
#define E8390_RX_IRQ_MASK	0x5
#define E8390_RXCONFIG		0x4	/* EN0_RXCR: broadcasts, no multicast,errors */
#define E8390_RXOFF		0x20	/* EN0_RXCR: Accept no packets */
#define E8390_TXCONFIG		0x00	/* EN0_TXCR: Normal transmit mode */
#define E8390_TXOFF		0x02	/* EN0_TXCR: Transmitter off */

/*  Register accessed at EN_CMD, the 8390 base addr.  */
#define E8390_STOP	0x01	/* Stop and reset the chip */
#define E8390_START	0x02	/* Start the chip, clear reset */
#define E8390_TRANS	0x04	/* Transmit a frame */
#define E8390_RREAD	0x08	/* Remote read */
#define E8390_RWRITE	0x10	/* Remote write  */
#define E8390_NODMA	0x20	/* Remote DMA */
#define E8390_PAGE0	0x00	/* Select page chip registers */
#define E8390_PAGE1	0x40	/* using the two high-order bits */
#define E8390_PAGE2	0x80	/* Page 3 is invalid. */

/*
 *	Only generate indirect loads given a machine that needs them.
 *      - removed AMIGA_PCMCIA from this list, handled as ISA io now
 */

#if defined(CONFIG_MAC) ||  \
    defined(CONFIG_ZORRO8390) || defined(CONFIG_ZORRO8390_MODULE) || \
    defined(CONFIG_HYDRA) || defined(CONFIG_HYDRA_MODULE)
#define EI_SHIFT(x)	(ei_local->reg_offset[x])
#undef inb
#undef inb_p
#undef outb
#undef outb_p

#define inb(port)   in_8(port)
#define outb(val,port)  out_8(port,val)
#define inb_p(port)   in_8(port)
#define outb_p(val,port)  out_8(port,val)

#elif defined(CONFIG_ARM_ETHERH) || defined(CONFIG_ARM_ETHERH_MODULE)
#define EI_SHIFT(x)	(ei_local->reg_offset[x])
#undef inb
#undef inb_p
#undef outb
#undef outb_p

#define inb(_p)		readb(_p)
#define outb(_v,_p)	writeb(_v,_p)
#define inb_p(_p)	inb(_p)
#define outb_p(_v,_p)	outb(_v,_p)

#elif defined(CONFIG_NE_H8300) || defined(CONFIG_NE_H8300_MODULE)
#define EI_SHIFT(x)	(ei_local->reg_offset[x])
#else
#define EI_SHIFT(x)	(x)
#endif

#define E8390_CMD	EI_SHIFT(0x00)  /* The command register (for all pages) */
/* Page 0 register offsets. */
#define EN0_CLDALO	EI_SHIFT(0x01)	/* Low byte of current local dma addr  RD */
#define EN0_STARTPG	EI_SHIFT(0x01)	/* Starting page of ring bfr WR */
#define EN0_CLDAHI	EI_SHIFT(0x02)	/* High byte of current local dma addr  RD */
#define EN0_STOPPG	EI_SHIFT(0x02)	/* Ending page +1 of ring bfr WR */
#define EN0_BOUNDARY	EI_SHIFT(0x03)	/* Boundary page of ring bfr RD WR */
#define EN0_TSR		EI_SHIFT(0x04)	/* Transmit status reg RD */
#define EN0_TPSR	EI_SHIFT(0x04)	/* Transmit starting page WR */
#define EN0_NCR		EI_SHIFT(0x05)	/* Number of collision reg RD */
#define EN0_TCNTLO	EI_SHIFT(0x05)	/* Low  byte of tx byte count WR */
#define EN0_FIFO	EI_SHIFT(0x06)	/* FIFO RD */
#define EN0_TCNTHI	EI_SHIFT(0x06)	/* High byte of tx byte count WR */
#define EN0_ISR		EI_SHIFT(0x07)	/* Interrupt status reg RD WR */
#define EN0_CRDALO	EI_SHIFT(0x08)	/* low byte of current remote dma address RD */
#define EN0_RSARLO	EI_SHIFT(0x08)	/* Remote start address reg 0 */
#define EN0_CRDAHI	EI_SHIFT(0x09)	/* high byte, current remote dma address RD */
#define EN0_RSARHI	EI_SHIFT(0x09)	/* Remote start address reg 1 */
#define EN0_RCNTLO	EI_SHIFT(0x0a)	/* Remote byte count reg WR */
#define EN0_RCNTHI	EI_SHIFT(0x0b)	/* Remote byte count reg WR */
#define EN0_RSR		EI_SHIFT(0x0c)	/* rx status reg RD */
#define EN0_RXCR	EI_SHIFT(0x0c)	/* RX configuration reg WR */
#define EN0_TXCR	EI_SHIFT(0x0d)	/* TX configuration reg WR */
#define EN0_COUNTER0	EI_SHIFT(0x0d)	/* Rcv alignment error counter RD */
#define EN0_DCFG	EI_SHIFT(0x0e)	/* Data configuration reg WR */
#define EN0_COUNTER1	EI_SHIFT(0x0e)	/* Rcv CRC error counter RD */
#define EN0_IMR		EI_SHIFT(0x0f)	/* Interrupt mask reg WR */
#define EN0_COUNTER2	EI_SHIFT(0x0f)	/* Rcv missed frame error counter RD */

/* Bits in EN0_ISR - Interrupt status register */
#define ENISR_RX	0x01	/* Receiver, no error */
#define ENISR_TX	0x02	/* Transmitter, no error */
#define ENISR_RX_ERR	0x04	/* Receiver, with error */
#define ENISR_TX_ERR	0x08	/* Transmitter, with error */
#define ENISR_OVER	0x10	/* Receiver overwrote the ring */
#define ENISR_COUNTERS	0x20	/* Counters need emptying */
#define ENISR_RDC	0x40	/* remote dma complete */
#define ENISR_RESET	0x80	/* Reset completed */
#define ENISR_ALL	0x3f	/* Interrupts we will enable */

/* Bits in EN0_DCFG - Data config register */
#define ENDCFG_WTS	0x01	/* word transfer mode selection */
#define ENDCFG_BOS	0x02	/* byte order selection */

/* Page 1 register offsets. */
#define EN1_PHYS   EI_SHIFT(0x01)	/* This board's physical enet addr RD WR */
#define EN1_PHYS_SHIFT(i)  EI_SHIFT(i+1) /* Get and set mac address */
#define EN1_CURPAG EI_SHIFT(0x07)	/* Current memory page RD WR */
#define EN1_MULT   EI_SHIFT(0x08)	/* Multicast filter mask array (8 bytes) RD WR */
#define EN1_MULT_SHIFT(i)  EI_SHIFT(8+i) /* Get and set multicast filter */

/* Bits in received packet status byte and EN0_RSR*/
#define ENRSR_RXOK	0x01	/* Received a good packet */
#define ENRSR_CRC	0x02	/* CRC error */
#define ENRSR_FAE	0x04	/* frame alignment error */
#define ENRSR_FO	0x08	/* FIFO overrun */
#define ENRSR_MPA	0x10	/* missed pkt */
#define ENRSR_PHY	0x20	/* physical/multicast address */
#define ENRSR_DIS	0x40	/* receiver disable. set in monitor mode */
#define ENRSR_DEF	0x80	/* deferring */

/* Transmitted packet status, EN0_TSR. */
#define ENTSR_PTX 0x01	/* Packet transmitted without error */
#define ENTSR_ND  0x02	/* The transmit wasn't deferred. */
#define ENTSR_COL 0x04	/* The transmit collided at least once. */
#define ENTSR_ABT 0x08  /* The transmit collided 16 times, and was deferred. */
#define ENTSR_CRS 0x10	/* The carrier sense was lost. */
#define ENTSR_FU  0x20  /* A "FIFO underrun" occurred during transmit. */
#define ENTSR_CDH 0x40	/* The collision detect "heartbeat" signal was lost. */
#define ENTSR_OWC 0x80  /* There was an out-of-window collision. */

#endif /* _8390_h */