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linux-2.6/drivers/net/ibm_emac/ibm_emac_debug.c
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

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/*
* drivers/net/ibm_emac/ibm_emac_debug.c
*
* Driver for PowerPC 4xx on-chip ethernet controller, debug print routines.
*
* Copyright (c) 2004, 2005 Zultys Technologies
* Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/sysrq.h>
#include <asm/io.h>
#include "ibm_emac_core.h"
static void emac_desc_dump(int idx, struct ocp_enet_private *p)
{
int i;
printk("** EMAC%d TX BDs **\n"
" tx_cnt = %d tx_slot = %d ack_slot = %d\n",
idx, p->tx_cnt, p->tx_slot, p->ack_slot);
for (i = 0; i < NUM_TX_BUFF / 2; ++i)
printk
("bd[%2d] 0x%08x %c 0x%04x %4u - bd[%2d] 0x%08x %c 0x%04x %4u\n",
i, p->tx_desc[i].data_ptr, p->tx_skb[i] ? 'V' : ' ',
p->tx_desc[i].ctrl, p->tx_desc[i].data_len,
NUM_TX_BUFF / 2 + i,
p->tx_desc[NUM_TX_BUFF / 2 + i].data_ptr,
p->tx_skb[NUM_TX_BUFF / 2 + i] ? 'V' : ' ',
p->tx_desc[NUM_TX_BUFF / 2 + i].ctrl,
p->tx_desc[NUM_TX_BUFF / 2 + i].data_len);
printk("** EMAC%d RX BDs **\n"
" rx_slot = %d rx_stopped = %d rx_skb_size = %d rx_sync_size = %d\n"
" rx_sg_skb = 0x%p\n",
idx, p->rx_slot, p->commac.rx_stopped, p->rx_skb_size,
p->rx_sync_size, p->rx_sg_skb);
for (i = 0; i < NUM_RX_BUFF / 2; ++i)
printk
("bd[%2d] 0x%08x %c 0x%04x %4u - bd[%2d] 0x%08x %c 0x%04x %4u\n",
i, p->rx_desc[i].data_ptr, p->rx_skb[i] ? 'V' : ' ',
p->rx_desc[i].ctrl, p->rx_desc[i].data_len,
NUM_RX_BUFF / 2 + i,
p->rx_desc[NUM_RX_BUFF / 2 + i].data_ptr,
p->rx_skb[NUM_RX_BUFF / 2 + i] ? 'V' : ' ',
p->rx_desc[NUM_RX_BUFF / 2 + i].ctrl,
p->rx_desc[NUM_RX_BUFF / 2 + i].data_len);
}
static void emac_mac_dump(int idx, struct ocp_enet_private *dev)
{
struct emac_regs __iomem *p = dev->emacp;
printk("** EMAC%d registers **\n"
"MR0 = 0x%08x MR1 = 0x%08x TMR0 = 0x%08x TMR1 = 0x%08x\n"
"RMR = 0x%08x ISR = 0x%08x ISER = 0x%08x\n"
"IAR = %04x%08x VTPID = 0x%04x VTCI = 0x%04x\n"
"IAHT: 0x%04x 0x%04x 0x%04x 0x%04x "
"GAHT: 0x%04x 0x%04x 0x%04x 0x%04x\n"
"LSA = %04x%08x IPGVR = 0x%04x\n"
"STACR = 0x%08x TRTR = 0x%08x RWMR = 0x%08x\n"
"OCTX = 0x%08x OCRX = 0x%08x IPCR = 0x%08x\n",
idx, in_be32(&p->mr0), in_be32(&p->mr1),
in_be32(&p->tmr0), in_be32(&p->tmr1),
in_be32(&p->rmr), in_be32(&p->isr), in_be32(&p->iser),
in_be32(&p->iahr), in_be32(&p->ialr), in_be32(&p->vtpid),
in_be32(&p->vtci),
in_be32(&p->iaht1), in_be32(&p->iaht2), in_be32(&p->iaht3),
in_be32(&p->iaht4),
in_be32(&p->gaht1), in_be32(&p->gaht2), in_be32(&p->gaht3),
in_be32(&p->gaht4),
in_be32(&p->lsah), in_be32(&p->lsal), in_be32(&p->ipgvr),
in_be32(&p->stacr), in_be32(&p->trtr), in_be32(&p->rwmr),
in_be32(&p->octx), in_be32(&p->ocrx), in_be32(&p->ipcr)
);
emac_desc_dump(idx, dev);
}
static void emac_mal_dump(struct ibm_ocp_mal *mal)
{
struct ocp_func_mal_data *maldata = mal->def->additions;
int i;
printk("** MAL%d Registers **\n"
"CFG = 0x%08x ESR = 0x%08x IER = 0x%08x\n"
"TX|CASR = 0x%08x CARR = 0x%08x EOBISR = 0x%08x DEIR = 0x%08x\n"
"RX|CASR = 0x%08x CARR = 0x%08x EOBISR = 0x%08x DEIR = 0x%08x\n",
mal->def->index,
get_mal_dcrn(mal, MAL_CFG), get_mal_dcrn(mal, MAL_ESR),
get_mal_dcrn(mal, MAL_IER),
get_mal_dcrn(mal, MAL_TXCASR), get_mal_dcrn(mal, MAL_TXCARR),
get_mal_dcrn(mal, MAL_TXEOBISR), get_mal_dcrn(mal, MAL_TXDEIR),
get_mal_dcrn(mal, MAL_RXCASR), get_mal_dcrn(mal, MAL_RXCARR),
get_mal_dcrn(mal, MAL_RXEOBISR), get_mal_dcrn(mal, MAL_RXDEIR)
);
printk("TX|");
for (i = 0; i < maldata->num_tx_chans; ++i) {
if (i && !(i % 4))
printk("\n ");
printk("CTP%d = 0x%08x ", i, get_mal_dcrn(mal, MAL_TXCTPR(i)));
}
printk("\nRX|");
for (i = 0; i < maldata->num_rx_chans; ++i) {
if (i && !(i % 4))
printk("\n ");
printk("CTP%d = 0x%08x ", i, get_mal_dcrn(mal, MAL_RXCTPR(i)));
}
printk("\n ");
for (i = 0; i < maldata->num_rx_chans; ++i) {
u32 r = get_mal_dcrn(mal, MAL_RCBS(i));
if (i && !(i % 3))
printk("\n ");
printk("RCBS%d = 0x%08x (%d) ", i, r, r * 16);
}
printk("\n");
}
static struct ocp_enet_private *__emacs[4];
static struct ibm_ocp_mal *__mals[1];
void emac_dbg_register(int idx, struct ocp_enet_private *dev)
{
unsigned long flags;
if (idx >= sizeof(__emacs) / sizeof(__emacs[0])) {
printk(KERN_WARNING
"invalid index %d when registering EMAC for debugging\n",
idx);
return;
}
local_irq_save(flags);
__emacs[idx] = dev;
local_irq_restore(flags);
}
void mal_dbg_register(int idx, struct ibm_ocp_mal *mal)
{
unsigned long flags;
if (idx >= sizeof(__mals) / sizeof(__mals[0])) {
printk(KERN_WARNING
"invalid index %d when registering MAL for debugging\n",
idx);
return;
}
local_irq_save(flags);
__mals[idx] = mal;
local_irq_restore(flags);
}
void emac_dbg_dump_all(void)
{
unsigned int i;
unsigned long flags;
local_irq_save(flags);
for (i = 0; i < sizeof(__mals) / sizeof(__mals[0]); ++i)
if (__mals[i])
emac_mal_dump(__mals[i]);
for (i = 0; i < sizeof(__emacs) / sizeof(__emacs[0]); ++i)
if (__emacs[i])
emac_mac_dump(i, __emacs[i]);
local_irq_restore(flags);
}
#if defined(CONFIG_MAGIC_SYSRQ)
static void emac_sysrq_handler(int key, struct tty_struct *tty)
{
emac_dbg_dump_all();
}
static struct sysrq_key_op emac_sysrq_op = {
.handler = emac_sysrq_handler,
.help_msg = "emaC",
.action_msg = "Show EMAC(s) status",
};
int __init emac_init_debug(void)
{
return register_sysrq_key('c', &emac_sysrq_op);
}
void __exit emac_fini_debug(void)
{
unregister_sysrq_key('c', &emac_sysrq_op);
}
#else
int __init emac_init_debug(void)
{
return 0;
}
void __exit emac_fini_debug(void)
{
}
#endif /* CONFIG_MAGIC_SYSRQ */
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