[linuxsh-dev] [PATCH] Backtrace Support

[Paul M. <le...@Ch...>]

Hello,

As I continue looking through some of my local pending changes, this was the
next one that popped up..

The current implementation of show_trace_task() is a bit on the .. uneventf=
ul
side of things. This patch removes the old dump_stack() in favor of a new
show_task() which happily either recieves a stack pointer, or reads it in in
the existing manner that dump_stack() did.

I haven't had the chance to do any extensive testing on this.. so any comme=
nts
on the patch would be appreciated.

Regards,

--=20
Paul Mundt <le...@ch...>

Index: ChangeLog
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RCS file: /cvsroot/linuxsh/linux/ChangeLog,v
retrieving revision 1.32
diff -u -r1.32 ChangeLog
--- ChangeLog	26 Feb 2002 09:15:15 -0000	1.32
+++ ChangeLog	28 Feb 2002 08:05:20 -0000
@@ -1,3 +1,10 @@
+2002-02-27  Paul Mundt  <le...@ch...>
+
+	* arch/sh/kernel/traps.c (dump_stack): Removed.
+	(show_task): Added.
+	(show_trace_task): Hand off actual stack pointer to show_task()
+	to do a real backtrace.
+
 2002-02-26  NIIBE Yutaka  <gn...@m1...>
=20
 	Updated to 2.5.3.
Index: arch/sh/kernel/traps.c
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RCS file: /cvsroot/linuxsh/linux/arch/sh/kernel/traps.c,v
retrieving revision 1.3.2.2
diff -u -r1.3.2.2 traps.c
--- arch/sh/kernel/traps.c	19 Jan 2002 23:55:14 -0000	1.3.2.2
+++ arch/sh/kernel/traps.c	25 Feb 2002 08:42:48 -0000
@@ -5,6 +5,7 @@
  *  SuperH version: Copyright (C) 1999 Niibe Yutaka
  *                  Copyright (C) 2000 Philipp Rumpf
  *                  Copyright (C) 2000 David Howells
+ *                  Copyright (C) 2002 Paul Mundt
  */
=20
 /*
@@ -560,29 +561,51 @@
 		     : "memory");
 }
=20
-void dump_stack(void)
+void show_task(unsigned long *sp)
 {
-	unsigned long *start;
-	unsigned long *end;
-	unsigned long *p;
-
-	asm("mov	r15, %0" : "=3Dr" (start));
-	asm("stc	r7_bank, %0" : "=3Dr" (end));
-	end +=3D 8192/4;
-
-	printk("%08lx:%08lx\n", (unsigned long)start, (unsigned long)end);
-	for (p=3Dstart; p < end; p++) {
-		extern long _text, _etext;
-		unsigned long v=3D*p;
-
-		if ((v >=3D (unsigned long )&_text)
-		    && (v <=3D (unsigned long )&_etext)) {
-			printk("%08lx\n", v);
+	unsigned long *stack, addr;
+	unsigned long module_start =3D VMALLOC_START;
+	unsigned long module_end =3D VMALLOC_END;
+	extern long _text, _etext;
+	int i =3D 1;
+
+	if (!sp) {
+		__asm__ __volatile__ (
+			"mov r15, %0\n\t"
+			"stc r7_bank, %1\n\t"
+			: "=3Dr" (module_start),
+			  "=3Dr" (module_end)
+		);
+	=09
+		sp =3D (unsigned long *)module_start;
+	}
+
+	stack =3D sp;
+
+	printk("\nCall trace: ");
+
+	while (((long)stack & (THREAD_SIZE - 1))) {
+		if (__get_user(addr, stack)) {
+			printk("Failing address 0x%lx\n", *stack);
+			break;
+		}
+		stack++;
+
+		if (((addr >=3D (unsigned long)&_text) &&
+		     (addr <=3D (unsigned long)&_etext)) ||
+		    ((addr >=3D module_start) && (addr <=3D module_end))) {
+			if (i && ((i % 8) =3D=3D 0))
+				printk("\n       ");
+
+			printk("[<%08lx>] ", addr);
+			i++;
 		}
 	}
+
+	printk("\n");
 }
=20
 void show_trace_task(struct task_struct *tsk)
 {
-	printk("Backtrace not yet implemented for SH.\n");
+	show_task((unsigned long *)tsk->thread.sp);
 }