kernel debugger support for ipipe (2.6.26)

Index: b/arch/x86/kernel/ipipe.c
===================================================================
@@ -697,8 +697,10 @@ static __ipipe_exptr __ipipe_std_extable
 #endif
 };
 
-#ifdef CONFIG_KGDB
+#if defined(CONFIG_KGDB) || defined(CONFIG_KGDB_MODULE)
 #include <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <asm/uaccess.h>
 
 static int __ipipe_xlate_signo[] = {
 

@@ -746,24 +748,34 @@ int __ipipe_handle_exception(struct pt_r
 		barrier();
 	}
 
-#ifdef CONFIG_KGDB
-	/* catch exception KGDB is interested in over non-root domains */
-	if (!ipipe_root_domain_p &&
-	    __ipipe_xlate_signo[vector] >= 0 &&
-	    !kgdb_handle_exception(vector, __ipipe_xlate_signo[vector], error_code, regs)) {
-		if (!flags)
-			__clear_bit(IPIPE_STALL_FLAG,
-				    &ipipe_root_cpudom_var(status));
-		return 1;
+#if defined(CONFIG_KGDB) || defined(CONFIG_KGDB_MODULE)
+	if (unlikely(__ipipe_kgdb_notify)) {
+		const struct exception_table_entry *fixup;
+		struct die_args args;
+
+		/* Fixup kgdb-own faults immediately. */
+		if (*__ipipe_kgdb_may_fault) {
+			fixup = search_exception_tables(regs->ip);
+			BUG_ON(!fixup);
+			regs->ip = fixup->fixup;
+			goto exit_stop;
+		}
+
+		/* Catch any exception over non-root domains that
+		 * kgdb might be interested in. */
+		if (!ipipe_root_domain_p && __ipipe_xlate_signo[vector] >= 0) {
+			args.regs = regs;
+			args.err = error_code;
+			args.trapnr = vector;
+			args.signr = __ipipe_xlate_signo[vector];
+			if (__ipipe_kgdb_notify(NULL, DIE_TRAP, &args) == NOTIFY_STOP)
+				goto exit_stop;
+		}
 	}
 #endif /* CONFIG_KGDB */
 
-	if (unlikely(ipipe_trap_notify(vector, regs))) {
-		if (!flags)
-			__clear_bit(IPIPE_STALL_FLAG,
-				    &ipipe_root_cpudom_var(status));
-		return 1;
-	}
+	if (unlikely(ipipe_trap_notify(vector, regs)))
+		goto exit_stop;
 
 	/* Detect unhandled faults over non-root domains. */
 

@@ -800,23 +812,31 @@ int __ipipe_handle_exception(struct pt_r
 	__fixup_if(regs);
 
 	return 0;
+
+exit_stop:
+	if (!flags)
+		__clear_bit(IPIPE_STALL_FLAG, &ipipe_root_cpudom_var(status));
+	return 1;
 }
 
 int __ipipe_divert_exception(struct pt_regs *regs, int vector)
 {
-#ifdef CONFIG_KGDB
-	/* catch int1 and int3 over non-root domains */
-#ifdef CONFIG_X86_32
-	if (!ipipe_root_domain_p && vector != ex_do_device_not_available) {
-#else
-	if (!ipipe_root_domain_p) {
-#endif
-		unsigned int condition = 0;
-
-		if (vector == 1)
-			get_debugreg(condition, 6);
-		if (!kgdb_handle_exception(vector, SIGTRAP, condition, regs))
-			return 1;
+#if defined(CONFIG_KGDB) || defined(CONFIG_KGDB_MODULE)
+	/* Catch debug and breakpoint exception over non-root domains. */
+	if (__ipipe_kgdb_notify && !ipipe_root_domain_p) {
+		struct die_args args = { .regs = regs, .signr = SIGTRAP };
+
+		if (vector == 1) {
+			get_debugreg(args.err, 6);
+			args.trapnr = 0;
+			if (__ipipe_kgdb_notify(NULL, DIE_DEBUG, &args) == NOTIFY_STOP)
+				return 1;
+		} else if (vector == 3) {
+			args.err = 0;
+			args.trapnr = 3;
+			if (__ipipe_kgdb_notify(NULL, DIE_INT3, &args) == NOTIFY_STOP)
+				return 1;
+		}
 	}
 #endif /* CONFIG_KGDB */
 

@@ -865,8 +885,16 @@ int __ipipe_handle_irq(struct pt_regs *r
 		irq = vector;
 		m_ack = 1;
 	}
-
 #endif /* !CONFIG_X86_32 */
+
+#if defined(CONFIG_KGDB) || defined(CONFIG_KGDB_MODULE)
+	if (unlikely(irq == __ipipe_kgdb_irq)) {
+		ipipe_root_domain->irqs[irq].acknowledge(irq);
+		__ipipe_kgdb_irq_handler(irq, NULL);
+		irq_desc[irq].ipipe_end(irq, &irq_desc[irq]);
+		goto finalize_nosync;
+	}
+#endif /* CONFIG_KGDB */
 	head = __ipipe_pipeline.next;
 	next_domain = list_entry(head, struct ipipe_domain, p_link);
 	if (likely(test_bit(IPIPE_WIRED_FLAG, &next_domain->irqs[irq].control))) {

Index: b/include/linux/ipipe.h
===================================================================
@@ -26,6 +26,7 @@
 #include <linux/cache.h>
 #include <linux/percpu.h>
 #include <linux/mutex.h>
+#include <linux/notifier.h>
 #include <linux/linkage.h>
 #include <linux/ipipe_base.h>
 #include <linux/ipipe_compat.h>

@@ -512,6 +513,18 @@ static inline void local_irq_restore_nos
 
 #define ipipe_root_domain_p		(ipipe_current_domain == ipipe_root_domain)
 
+extern int *__ipipe_kgdb_may_fault;
+extern int (*__ipipe_kgdb_notify)(struct notifier_block *, unsigned long, void *);
+
+extern int __ipipe_kgdb_irq;
+extern int (*__ipipe_kgdb_irq_handler)(int, void *);
+
+#define IPIPE_KGDB_IRQ_NONE	-1
+
+void ipipe_kgdb_set_fault_handler(int *kgdb_may_fault,
+	int (*handler)(struct notifier_block *, unsigned long, void *));
+void ipipe_kgdb_set_irq_handler(int irq, int (*handler)(int, void *));
+
 #else	/* !CONFIG_IPIPE */
 
 #define ipipe_init()			do { } while(0)

Index: b/kernel/ipipe/core.c
===================================================================
@@ -1586,6 +1586,41 @@ void ipipe_check_context(struct ipipe_do
 EXPORT_SYMBOL(ipipe_check_context);
 #endif /* CONFIG_IPIPE_DEBUG_CONTEXT */
 
+#if defined(CONFIG_KGDB) || defined(CONFIG_KGDB_MODULE)
+int *__ipipe_kgdb_may_fault = NULL;
+int (*__ipipe_kgdb_notify)(struct notifier_block *, unsigned long, void *);
+
+void ipipe_kgdb_set_fault_handler(int *kgdb_may_fault,
+	int (*handler)(struct notifier_block *, unsigned long, void *))
+{
+	unsigned long flags;
+
+	flags = ipipe_critical_enter(NULL);
+
+	__ipipe_kgdb_may_fault = kgdb_may_fault;
+	__ipipe_kgdb_notify = handler;
+
+	ipipe_critical_exit(flags);
+}
+EXPORT_SYMBOL_GPL(ipipe_kgdb_set_fault_handler);
+
+int __ipipe_kgdb_irq = IPIPE_KGDB_IRQ_NONE;
+irq_handler_t __ipipe_kgdb_irq_handler;
+
+void ipipe_kgdb_set_irq_handler(int irq, irq_handler_t handler)
+{
+	unsigned long flags;
+
+	flags = ipipe_critical_enter(NULL);
+
+	__ipipe_kgdb_irq = irq;
+	__ipipe_kgdb_irq_handler = handler;
+
+	ipipe_critical_exit(flags);
+}
+EXPORT_SYMBOL_GPL(ipipe_kgdb_set_irq_handler);
+#endif /* CONFIG_KGDB */
+
 EXPORT_SYMBOL(ipipe_virtualize_irq);
 EXPORT_SYMBOL(ipipe_control_irq);
 EXPORT_SYMBOL(ipipe_suspend_domain);

Index: b/drivers/serial/8250_kgdb.c
===================================================================
@@ -363,6 +363,9 @@ static int kgdb8250_late_init(void)
 			goto rollback;
 	}
 
+#ifdef CONFIG_IPIPE
+	ipipe_kgdb_set_irq_handler(kgdb8250_port.irq, kgdb8250_interrupt);
+#endif
 	if (request_irq(kgdb8250_port.irq, kgdb8250_interrupt, IRQF_SHARED,
 			"kgdb", &kgdb8250_port) == 0) {
 		/* Turn on RX interrupt only. */

@@ -402,6 +405,14 @@ static void kgdb8250_cleanup(void)
 	kgdb8250_iowrite(0, UART_IER);
 	(void) kgdb8250_ioread(UART_RX);
 
+#ifdef CONFIG_IPIPE
+	/* We cannot run module_get/put over I-pipe domains, so enforce the
+	 * deregistration protocol here. */
+	while (kgdb_connected)
+		kgdb_breakpoint();
+
+	ipipe_kgdb_set_irq_handler(IPIPE_KGDB_IRQ_NONE, NULL);
+#endif /* CONFIG_IPIPE */
 	if (kgdb8250_irq >= 0)
 		free_irq(kgdb8250_irq, &kgdb8250_port);
 

@@ -457,6 +468,7 @@ static int kgdb8250_set_config(const cha
 	return kgdb8250_late_init();
 }
 
+#ifndef CONFIG_IPIPE
 static void kgdb8250_pre_exception_handler(void)
 {
 	if (!kgdb_connected)

@@ -468,14 +480,17 @@ static void kgdb8250_post_exception_hand
 	if (!kgdb_connected)
 		module_put(THIS_MODULE);
 }
+#endif /* !CONFIG_IPIPE */
 
 static struct kgdb_io kgdb8250_io_ops = {
 	.name = "kgdb8250",
 	.read_char = kgdb8250_get_debug_char,
 	.write_char = kgdb8250_put_debug_char,
 	.init = kgdb8250_early_init,
+#ifndef CONFIG_IPIPE
 	.pre_exception = kgdb8250_pre_exception_handler,
 	.post_exception = kgdb8250_post_exception_handler,
+#endif /* !CONFIG_IPIPE */
 };
 
 module_init(kgdb8250_late_init);

218 lines not on this page · raw message

Index: b/arch/x86/kernel/kgdb.c
===================================================================
@@ -489,9 +489,9 @@ kgdb_notify(struct notifier_block *self,
 	unsigned long flags;
 	int ret;
 
-	local_irq_save(flags);
+	local_irq_save_hw(flags);
 	ret = __kgdb_notify(ptr, cmd);
-	local_irq_restore(flags);
+	local_irq_restore_hw(flags);
 
 	return ret;
 }

@@ -513,6 +513,10 @@ static struct notifier_block kgdb_notifi
  */
 int kgdb_arch_init(void)
 {
+#ifdef CONFIG_IPIPE
+	extern int kgdb_may_fault;
+	ipipe_kgdb_set_fault_handler(&kgdb_may_fault, kgdb_notify);
+#endif
 	return register_die_notifier(&kgdb_notifier);
 }
 

@@ -525,6 +529,9 @@ int kgdb_arch_init(void)
 void kgdb_arch_exit(void)
 {
 	unregister_die_notifier(&kgdb_notifier);
+#ifdef CONFIG_IPIPE
+	ipipe_kgdb_set_fault_handler(NULL, NULL);
+#endif
 }
 
 /**