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Date:      Tue, 20 Jul 2004 05:34:04 GMT
From:      David Xu <davidxu@FreeBSD.org>
To:        Perforce Change Reviews <perforce@freebsd.org>
Subject:   PERFORCE change 57760 for review
Message-ID:  <200407200534.i6K5Y4iw080588@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=57760

Change 57760 by davidxu@davidxu_celeron on 2004/07/20 05:33:14

	Introduce a debug flag TDMF_NOUPCALL, this bit is used to inhibit
	kernel from scheduling upcall. When a thread hits a breakpoint or
	gets a step trap, we don't unbind the thread, let debug resume only
	the thread and single step it to pass breakpoint.

Affected files ...

.. //depot/projects/davidxu_ksedbg/src/sys/kern/kern_kse.c#10 edit
.. //depot/projects/davidxu_ksedbg/src/sys/sys/kse.h#6 edit

Differences ...

==== //depot/projects/davidxu_ksedbg/src/sys/kern/kern_kse.c#10 (text+ko) ====

@@ -150,26 +150,31 @@
 		error = set_mcontext(td, &tmbx.tm_context.uc_mcontext);
 	if (!error) {
 		suword32(&uap->tmbx->tm_lwp, td->td_tid);
-		if (uap->flags & KSE_SWITCHIN_SETTMBX) {
-			td->td_mailbox = uap->tmbx;
-			mtx_lock_spin(&sched_lock);
-			td->td_flags |= TDF_CAN_UNBIND;
-			mtx_unlock_spin(&sched_lock);
-		}
+
 		if (td->td_proc->p_flag & P_TRACED) {
 			if (tmbx.tm_dflags & TMDF_SSTEP)
 				ptrace_single_step(td);
 			else
 				ptrace_clear_single_step(td);
-			if (tmbx.tm_dflags & TMDF_DONOTRUNUSER) {
+
+			if (tmbx.tm_dflags & TMDF_NOUPCALL) {
+				td->td_mailbox = NULL;
+				goto out;
+			} else if (tmbx.tm_dflags & TMDF_DONOTRUNUSER) {
 				mtx_lock_spin(&sched_lock);
-				/* fuword can block, check again */
-				if (td->td_upcall)
-					ku->ku_flags |= KUF_DOUPCALL;
+				ku->ku_flags |= KUF_DOUPCALL;
 				mtx_unlock_spin(&sched_lock);
 			}
 		}
+
+		if (uap->flags & KSE_SWITCHIN_SETTMBX) {
+			td->td_mailbox = uap->tmbx;
+			mtx_lock_spin(&sched_lock);
+			td->td_flags |= TDF_CAN_UNBIND;
+			mtx_unlock_spin(&sched_lock);
+		}
 	}
+out:
 	return ((error == 0) ? EJUSTRETURN : error);
 }
 
@@ -946,6 +951,7 @@
 	cpu_set_upcall(td2, td);
 	/* Let the new thread become owner of the upcall */
 	ku->ku_owner   = td2;
+	ku->ku_mflags  = 0;
 	td2->td_upcall = ku;
 	td2->td_flags  = 0;
 	td2->td_pflags = TDP_SA|TDP_UPCALLING;
@@ -1079,20 +1085,21 @@
 		if (flags & TMF_NOUPCALL) {
 			td->td_mailbox = NULL;
 		} else {
-			td->td_mailbox = tmbx;
-			mtx_lock_spin(&sched_lock);
-			td->td_flags |= TDF_CAN_UNBIND;
-			mtx_unlock_spin(&sched_lock);
 			if (__predict_false(p->p_flag & P_TRACED)) {
 				flags = fuword32(&tmbx->tm_dflags);
-				if (flags & TMDF_DONOTRUNUSER) {
+				if (flags & TMDF_NOUPCALL) {
+					td->td_mailbox = NULL;
+					return;
+				} else if (flags & TMDF_DONOTRUNUSER) {
 					mtx_lock_spin(&sched_lock);
-					/* fuword can block, check again */
-					if (td->td_upcall)
-						ku->ku_flags |= KUF_DOUPCALL;
+					ku->ku_flags |= KUF_DOUPCALL;
 					mtx_unlock_spin(&sched_lock);
 				}
 			}
+			td->td_mailbox = tmbx;
+			mtx_lock_spin(&sched_lock);
+			td->td_flags |= TDF_CAN_UNBIND;
+			mtx_unlock_spin(&sched_lock);
 		}
 	}
 }

==== //depot/projects/davidxu_ksedbg/src/sys/sys/kse.h#6 (text+ko) ====

@@ -102,6 +102,7 @@
 /* These flags are kept in tm_dlfags */
 #define TMDF_SSTEP		0x01
 #define TMDF_DONOTRUNUSER	0x02
+#define TMDF_NOUPCALL		0x04
 
 /* Flags for kse_switchin */
 #define KSE_SWITCHIN_SETTMBX	0x01

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