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kernel-aes67/drivers/misc/ibmasm/ibmasm.h
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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/*
* IBM ASM Service Processor Device Driver
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2004
*
* Author: Max Asböck <amax@us.ibm.com>
*
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/input.h>
/* Driver identification */
#define DRIVER_NAME "ibmasm"
#define DRIVER_VERSION "1.0"
#define DRIVER_AUTHOR "Max Asbock <masbock@us.ibm.com>, Vernon Mauery <vernux@us.ibm.com>"
#define DRIVER_DESC "IBM ASM Service Processor Driver"
#define err(msg) printk(KERN_ERR "%s: " msg "\n", DRIVER_NAME)
#define info(msg) printk(KERN_INFO "%s: " msg "\n", DRIVER_NAME)
extern int ibmasm_debug;
#define dbg(STR, ARGS...) \
do { \
if (ibmasm_debug) \
printk(KERN_DEBUG STR , ##ARGS); \
} while (0)
static inline char *get_timestamp(char *buf)
{
struct timeval now;
do_gettimeofday(&now);
sprintf(buf, "%lu.%lu", now.tv_sec, now.tv_usec);
return buf;
}
#define IBMASM_CMD_PENDING 0
#define IBMASM_CMD_COMPLETE 1
#define IBMASM_CMD_FAILED 2
#define IBMASM_CMD_TIMEOUT_NORMAL 45
#define IBMASM_CMD_TIMEOUT_EXTRA 240
#define IBMASM_CMD_MAX_BUFFER_SIZE 0x8000
#define REVERSE_HEARTBEAT_TIMEOUT 120
#define HEARTBEAT_BUFFER_SIZE 0x400
#ifdef IA64
#define IBMASM_DRIVER_VPD "Lin64 6.08 "
#else
#define IBMASM_DRIVER_VPD "Lin32 6.08 "
#endif
#define SYSTEM_STATE_OS_UP 5
#define SYSTEM_STATE_OS_DOWN 4
#define IBMASM_NAME_SIZE 16
#define IBMASM_NUM_EVENTS 10
#define IBMASM_EVENT_MAX_SIZE 2048u
struct command {
struct list_head queue_node;
wait_queue_head_t wait;
unsigned char *buffer;
size_t buffer_size;
int status;
struct kobject kobj;
spinlock_t *lock;
};
#define to_command(c) container_of(c, struct command, kobj)
static inline void command_put(struct command *cmd)
{
unsigned long flags;
spinlock_t *lock = cmd->lock;
spin_lock_irqsave(lock, flags);
kobject_put(&cmd->kobj);
spin_unlock_irqrestore(lock, flags);
}
static inline void command_get(struct command *cmd)
{
kobject_get(&cmd->kobj);
}
struct ibmasm_event {
unsigned int serial_number;
unsigned int data_size;
unsigned char data[IBMASM_EVENT_MAX_SIZE];
};
struct event_buffer {
struct ibmasm_event events[IBMASM_NUM_EVENTS];
unsigned int next_serial_number;
unsigned int next_index;
struct list_head readers;
};
struct event_reader {
int cancelled;
unsigned int next_serial_number;
wait_queue_head_t wait;
struct list_head node;
unsigned int data_size;
unsigned char data[IBMASM_EVENT_MAX_SIZE];
};
struct reverse_heartbeat {
wait_queue_head_t wait;
unsigned int stopped;
};
struct ibmasm_remote {
struct input_dev *keybd_dev;
struct input_dev *mouse_dev;
};
struct service_processor {
struct list_head node;
spinlock_t lock;
void __iomem *base_address;
unsigned int irq;
struct command *current_command;
struct command *heartbeat;
struct list_head command_queue;
struct event_buffer *event_buffer;
char dirname[IBMASM_NAME_SIZE];
char devname[IBMASM_NAME_SIZE];
unsigned int number;
struct ibmasm_remote remote;
int serial_line;
struct device *dev;
};
/* command processing */
extern struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size);
extern void ibmasm_exec_command(struct service_processor *sp, struct command *cmd);
extern void ibmasm_wait_for_response(struct command *cmd, int timeout);
extern void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size);
/* event processing */
extern int ibmasm_event_buffer_init(struct service_processor *sp);
extern void ibmasm_event_buffer_exit(struct service_processor *sp);
extern void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size);
extern void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader);
extern void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader);
extern int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader);
extern void ibmasm_cancel_next_event(struct event_reader *reader);
/* heartbeat - from SP to OS */
extern void ibmasm_register_panic_notifier(void);
extern void ibmasm_unregister_panic_notifier(void);
extern int ibmasm_heartbeat_init(struct service_processor *sp);
extern void ibmasm_heartbeat_exit(struct service_processor *sp);
extern void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size);
/* reverse heartbeat - from OS to SP */
extern void ibmasm_init_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb);
extern int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb);
extern void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb);
/* dot commands */
extern void ibmasm_receive_message(struct service_processor *sp, void *data, int data_size);
extern int ibmasm_send_driver_vpd(struct service_processor *sp);
extern int ibmasm_send_os_state(struct service_processor *sp, int os_state);
/* low level message processing */
extern int ibmasm_send_i2o_message(struct service_processor *sp);
extern irqreturn_t ibmasm_interrupt_handler(int irq, void * dev_id);
/* remote console */
extern void ibmasm_handle_mouse_interrupt(struct service_processor *sp);
extern int ibmasm_init_remote_input_dev(struct service_processor *sp);
extern void ibmasm_free_remote_input_dev(struct service_processor *sp);
/* file system */
extern int ibmasmfs_register(void);
extern void ibmasmfs_unregister(void);
extern void ibmasmfs_add_sp(struct service_processor *sp);
/* uart */
#ifdef CONFIG_SERIAL_8250
extern void ibmasm_register_uart(struct service_processor *sp);
extern void ibmasm_unregister_uart(struct service_processor *sp);
#else
#define ibmasm_register_uart(sp) do { } while(0)
#define ibmasm_unregister_uart(sp) do { } while(0)
#endif
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