Re: [Fault-injection-developer] RFC: KIRQ

[Rusty L. <ru...@li...>]

> Hi, folks
> I revised the KIRQ according to Rusty's comment.
> 
> # This is a BitKeeper generated patch for the following project:
> # Project Name: Linux kernel tree
> # This patch format is intended for GNU patch command version 2.5 or higher.
> # This patch includes the following deltas:
> #            ChangeSet 1.901   -> 1.902  
> #    arch/i386/Kconfig 1.14    -> 1.16   
> # arch/i386/kernel/Makefile 1.31    -> 1.32   
> #                (new)         -> 1.4     arch/i386/kernel/kirq.c
> #                (new)         -> 1.3     include/asm-i386/kirq.h
> #
> # The following is the BitKeeper ChangeSet Log
> # --------------------------------------------
> # 02/12/20 st...@ma... 1.892.1.3
> # Refine config file.
> # --------------------------------------------
> # 02/12/20 st...@ma... 1.902
> # Merge manticore.sh.intel.com:/home/stanley/linux-2.5
> # into manticore.sh.intel.com:/home/stanley/work/2.5-kirq
> # --------------------------------------------
> #
> diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig
> --- a/arch/i386/Kconfig Fri Dec 20 14:24:01 2002
> +++ b/arch/i386/Kconfig Fri Dec 20 14:24:01 2002
> @@ -1544,6 +1544,14 @@
>     best used in conjunction with the NMI watchdog so that spinlock
>     deadlocks are also debuggable.
>  
> +config KIRQ
> + bool "Kernel Irq interceptor for X86(experimental)"
> + depends on DEBUG_KERNEL && EXPERIMENTAL
> + help
> +   This option enable an IRQ interceptor. You can get the control
> +   before any specified ISR is executing and decide whether it
> +   should be executing through "register_kirq/unregister_kirq".
> +
>  config DEBUG_HIGHMEM
>   bool "Highmem debugging"
>   depends on DEBUG_KERNEL && HIGHMEM
> diff -Nru a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
> --- a/arch/i386/kernel/Makefile Fri Dec 20 14:24:01 2002
> +++ b/arch/i386/kernel/Makefile Fri Dec 20 14:24:01 2002
> @@ -4,7 +4,7 @@
>  
>  EXTRA_TARGETS := head.o init_task.o
>  
> -export-objs     := mca.o i386_ksyms.o time.o
> +export-objs     := mca.o i386_ksyms.o time.o kirq.o
>  
>  obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \
>   ptrace.o i8259.o ioport.o ldt.o setup.o time.o sys_i386.o \
> @@ -29,6 +29,7 @@
>  obj-$(CONFIG_PROFILING) += profile.o
>  obj-$(CONFIG_EDD)             += edd.o
>  obj-$(CONFIG_MODULES) += module.o
> +obj-$(CONFIG_KIRQ) += kirq.o
>  obj-y += sysenter.o
>  
>  EXTRA_AFLAGS   := -traditional
> diff -Nru a/arch/i386/kernel/kirq.c b/arch/i386/kernel/kirq.c
> --- /dev/null Wed Dec 31 16:00:00 1969
> +++ b/arch/i386/kernel/kirq.c Fri Dec 20 14:24:01 2002
> @@ -0,0 +1,103 @@
> +/* Support for kernel irq interceptor.
> +   (C) 2002 Stanley Wang <sta...@in...>.
> +*/
> +
> +#include <linux/config.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/spinlock.h>
> +#include <linux/mm.h>
> +#include <linux/slab.h>
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>
> +#include <asm/kirq.h>
> +
> +void kirq_handler(int irq, void *dev_id, struct pt_regs *regs)
> +{
> + int i;
> + struct kirq *p = kirq_list + irq;
> + if (p->handler != NULL){
> + i = (*(p->handler))(p, irq, dev_id, regs);
> + if ( i == 0 )
> + (*(p->isr))(irq, dev_id, regs);
> + }else{
> + printk(KERN_ERR "Miss KIRQ handler!\n");

This might be a little too cryptic for a system admin
to figure out what is happening from the system log file.

How about:
printk(KERN_ERR "%s: Dropping unexpected interrupt #%i\n", 
__FUNCTION__, irq); 

> + }
> + return;
> +}
> +
> +int register_kirq(int irq, char *devname, kirq_handler_t handler)
> +{
> + struct irqaction *action;
> + irq_desc_t *desc = irq_desc + irq;
> + struct kirq *p = kirq_list + irq;
> + unsigned long flags;
> + 
> + if (handler == NULL) {
> + printk(KERN_ERR "Register KIRQ failed: Missing handler!\n");
> + }
> +
> + if (p->handler) {
> + printk(KERN_ERR "Register KIRQ failed: KIRQ already
> exist!\n");
> + }

Did you mean to return an error on the conditions above?

> + 
> + spin_lock_irqsave(&desc->lock,flags);
> + 
> + action = desc->action;
> + while (action) {
> + if (strcmp(action->name,devname)) {
> + action = action->next;
> + }else{
> + break;
> + }
> + }
> +
> + if (!action) {
> + spin_unlock_irqrestore(&desc->lock,flags);
> + return -1; 
> + }
> +
> + p->isr = action->handler;
> + p->handler = handler;
> + p->dev_id = action->dev_id;
> + 
> + action->handler = kirq_handler;
> + 
> + spin_unlock_irqrestore(&desc->lock,flags);
> +
> + return 0;
> +}
> +
> +int unregister_kirq(int irq)
> +{
> + struct irqaction *action;
> + irq_desc_t *desc = irq_desc + irq;
> + struct kirq *p = kirq_list + irq;
> + unsigned long flags;
> + 
> + spin_lock_irqsave(&desc->lock,flags);
> + 
> + action = desc->action;
> + while ( action && action->dev_id != p->dev_id) {
> + action = action->next;
> + }
> +
> + if (!action) {
> + printk(KERN_ERR "Unregister KIRQ failed!\n");
> + spin_unlock_irqrestore(&desc->lock,flags);
> + return -1;
> + }
> +
> + action->handler = p->isr;
> + 
> + p->isr = NULL;
> + p->handler = NULL;
> + p->dev_id = NULL;
> + 
> + spin_unlock_irqrestore(&desc->lock,flags);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(register_kirq);
> +EXPORT_SYMBOL_GPL(unregister_kirq);
> +
> diff -Nru a/include/asm-i386/kirq.h b/include/asm-i386/kirq.h
> --- /dev/null Wed Dec 31 16:00:00 1969
> +++ b/include/asm-i386/kirq.h Fri Dec 20 14:24:01 2002
> @@ -0,0 +1,28 @@
> +#ifndef _ASM_KIRQ_H
> +#define _ASM_KIRQ_H
> +
> +#include <linux/errno.h>
> +
> +/* Define return value for kirq handler. */
> +#define KIRQ_CONTINUE 0
> +#define KIRQ_SKIP 1
> +
> +struct kirq;
> +typedef int (*kirq_handler_t)(struct kirq *, int, void *, struct pt_regs
> *);
> +struct kirq {
> + void *dev_id;
> + void (*isr)(int, void *, struct pt_regs *);
> + kirq_handler_t handler;
> +};
> +
> +struct kirq kirq_list[NR_IRQS] =
> + { [0 ... NR_IRQS-1] = { NULL, NULL, NULL}};
> +
> +#ifdef CONFIG_KIRQ
> +extern int register_kirq(int irq, char *devname, kirq_handler_t handler);
> +extern int unregister_kirq(int irq);
> +#else
> +int register_kirq(int irq, char *devname, kirq_handler_t handler) { return
> -ENOSYS; }
> +int unregister_kirq(int irq) {}
> +#endif /*CONFIG_KIRQ*/
> +#endif /*_ASM_KIRQ_H*/
> 
> Your Sincerely,
> Stanley Wang 
> 
> SW Engineer, Intel Corporation.
> Intel China Software Lab. 
> Tel: 021-52574545 ext. 1171 
> iNet: 8-752-1171 
>  
> Opinions expressed are those of the author and do not represent Intel
> Corporation
> 
> 
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