[src/trunk]: src/sys/arch/i386/i386 fix backtrace of interrupt

[yamt <yamt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6021a38e535b
branches:  trunk
changeset: 764260:6021a38e535b
user:      yamt <yamt%NetBSD.org@localhost>
date:      Thu Apr 14 16:05:59 2011 +0000

description:
fix backtrace of interrupt

diffstat:

 sys/arch/i386/i386/db_machdep.c |  56 +++++++++++++++++++++++++---------------
 1 files changed, 35 insertions(+), 21 deletions(-)

diffs (102 lines):

diff -r c4a966dbbdb6 -r 6021a38e535b sys/arch/i386/i386/db_machdep.c
--- a/sys/arch/i386/i386/db_machdep.c   Thu Apr 14 16:04:12 2011 +0000
+++ b/sys/arch/i386/i386/db_machdep.c   Thu Apr 14 16:05:59 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_machdep.c,v 1.2 2011/04/11 04:22:31 mrg Exp $       */
+/*     $NetBSD: db_machdep.c,v 1.3 2011/04/14 16:05:59 yamt Exp $      */
 
 /* 
  * Mach Operating System
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_machdep.c,v 1.2 2011/04/11 04:22:31 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_machdep.c,v 1.3 2011/04/14 16:05:59 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -217,8 +217,7 @@
        static struct trapframe tf;
        static struct i386tss tss;
        struct i386_frame *fp;
-       struct intrframe *ifp;
-       int traptype, trapno, err, i;
+       int traptype;
        uintptr_t ptr;
 
        switch (is_trap) {
@@ -256,24 +255,23 @@
            case INTERRUPT:
            default:
                /* The only argument to trap() or syscall() is the trapframe. */
-               ptr = db_get_value((int)argp, 4, false);
-               db_read_bytes((db_addr_t)ptr, sizeof(tf), (char *)&tf);
                switch (is_trap) {
                case TRAP:
+                       ptr = db_get_value((int)argp, 4, false);
+                       db_read_bytes((db_addr_t)ptr, sizeof(tf), (char *)&tf);
                        (*pr)("--- trap (number %d) ---\n", tf.tf_trapno);
                        break;
                case SYSCALL:
+                       ptr = db_get_value((int)argp, 4, false);
+                       db_read_bytes((db_addr_t)ptr, sizeof(tf), (char *)&tf);
                        (*pr)("--- syscall (number %d) ---\n", tf.tf_eax);
                        break;
                case INTERRUPT:
                        (*pr)("--- interrupt ---\n");
                        /*
-                        * Get intrframe address as saved when switching
-                        * to interrupt stack, and convert to trapframe
-                        * (add 4).  See frame.h.
+                        * see the "XXX -1 here is a hack" comment below.
                         */
-                       ptr = db_get_value((int)(argp - 1) + 4, 4, false);
-                       db_read_bytes((db_addr_t)ptr, sizeof(tf), (char *)&tf);
+                       db_read_bytes((db_addr_t)argp, sizeof(tf), (char *)&tf);
                        break;
                }
                *ip = (db_addr_t)tf.tf_eip;
@@ -295,16 +293,32 @@
        if (db_frame_info(*nextframe, (db_addr_t)*ip, NULL, NULL, &traptype,
            NULL) != (db_sym_t)0
            && traptype == INTERRUPT) {
-               for (i = 0; i < 4; i++) {
-                       ifp = (struct intrframe *)(argp + i);
-                       err = db_get_value((int)&ifp->__if_err, 4, false);
-                       trapno = db_get_value((int)&ifp->__if_trapno, 4, false);
-                       if ((err == 0 || err == IREENT_MAGIC) && trapno == T_ASTFLT) {
-                               *nextframe = (long *)ifp - 1;
-                               break;
-                       }
-               }
-               if (i == 4) {
+               struct intrframe *ifp;
+               int trapno;
+               int err;
+
+               /*
+                * 2nd argument of interrupt handlers is a pointer to intrframe.
+                */
+               ifp = (struct intrframe *)
+                   db_get_value((db_addr_t)(argp + 1), sizeof(ifp), false);
+               /*
+                * check if it's a valid intrframe.
+                */
+               err = db_get_value((db_addr_t)&ifp->__if_err,
+                   sizeof(ifp->__if_err), false);
+               trapno = db_get_value((db_addr_t)&ifp->__if_trapno,
+                   sizeof(ifp->__if_trapno), false);
+               if ((err == 0 || err == IREENT_MAGIC) && trapno == T_ASTFLT) {
+                       /*
+                        * found seemingly valid intrframe.
+                        *
+                        * XXX -1 here is a hack.
+                        * for the next frame, we will be called with
+                        * argp = *nextframe + 2.  (long *)if - 1 + 2 = &tf.
+                        */
+                       *nextframe = (long *)ifp - 1;
+               } else {
                        (*pr)("DDB lost frame for ");
                        db_printsym(*ip, DB_STGY_ANY, pr);
                        (*pr)(", trying %p\n",argp);