[Fault-injection-developer] RFC: IRQ interceptor infrastructure

[Wang, S. <sta...@in...>]

Hi folks,
There is the IRQ interceptor infrastructure: KIRQ



# 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	1.892   -> 1.894  
#	   arch/i386/Kconfig	1.14    -> 1.15   
#	arch/i386/kernel/Makefile	1.31    -> 1.32   
#	               (new)	        -> 1.3     arch/i386/kernel/kirq.c
#	               (new)	        -> 1.2     include/asm-i386/kirq.h
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/12/18	st...@st...	1.893
# Add KIRQ Support
# --------------------------------------------
# 02/12/18	st...@ma...	1.894
# Fix stupid bug.
# --------------------------------------------
#
diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig
--- a/arch/i386/Kconfig	Wed Dec 18 20:54:04 2002
+++ b/arch/i386/Kconfig	Wed Dec 18 20:54:04 2002
@@ -1544,6 +1544,12 @@
 	  best used in conjunction with the NMI watchdog so that spinlock
 	  deadlocks are also debuggable.
 
+config KIRQ
+	bool "Kernel Irq interceptor"
+	depends on DEBUG_KERNEL
+	help
+	  This option enable an IRQ interceptor.
+
 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	Wed Dec 18 20:54:04 2002
+++ b/arch/i386/kernel/Makefile	Wed Dec 18 20:54:04 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	Wed Dec 18 20:54:04 2002
@@ -0,0 +1,99 @@
+#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");
+	}
+	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");
+	}
+	
+	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	Wed Dec 18 20:54:04 2002
@@ -0,0 +1,24 @@
+#ifndef _ASM_KIRQ_H
+#define _ASM_KIRQ_H
+
+#include <linux/errno.h>
+
+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