20060303

1 files changed, 161 insertions, 0 deletions

diff --git a/os/port/portbreak.c b/os/port/portbreak.c
new file mode 100644
index 00000000..d64f40f6
--- /dev/null
+++ b/os/port/portbreak.c
@@ -0,0 +1,161 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "portfns.h"
+#include "ureg.h"
+#include "../port/error.h"
+
+//
+// These bits used to be in port/devdbg but were removed in
+// order to allow for using hardware debug features on certain
+// architectures
+//
+
+extern void breakset(Bkpt *b);
+extern void breakrestore(Bkpt *b);
+extern Bkpt* breakclear(int id);
+extern void breaknotify(Bkpt *b, Proc *p);
+extern int breakmatch(BkptCond *cond, Ureg *ur, Proc *p);
+
+void	skipfree(Bkpt *b);
+Bkpt*newskip(ulong addr, Bkpt *skipb, Proc *skipp);
+Bkpt *skipalloc;
+extern Bkpt	*breakpoints;
+typedef struct SkipArg SkipArg;
+struct SkipArg
+{
+	Bkpt *b;
+	Proc *p;
+};
+
+void
+skiphandler(Bkpt *b)
+{
+	SkipArg *a = b->aux;
+	Bkpt *l;
+
+	if(breakclear(b->id) == nil)
+		panic("skiphandler: breakclear() failed");
+	breakrestore(a->b);
+	l = a->b->link;
+	while(l != nil) {
+		breakrestore(l);
+		l = l->link;
+	}
+	skipfree(b);
+	a->p->dbgstop = 0;		// Whoo!
+	if(a->p->state == Stopped)
+		ready(a->p);
+}
+
+Bkpt*
+newskip(ulong addr, Bkpt *skipb, Proc *skipp)
+{
+	Bkpt *b;
+	SkipArg *a;
+
+	b = skipalloc;
+	if(b == nil)
+		panic("newskip(): no free skips\n");
+	skipalloc = b->next;
+
+	b->addr = addr;
+	b->conditions->val = addr;
+	b->link = nil;
+	a = b->aux;
+	a->b = skipb;
+	a->p = skipp;
+
+	return b;
+}
+
+void
+skipfree(Bkpt *b)
+{
+	b->next = skipalloc;
+	skipalloc = b;
+}
+
+//
+// Called from the exception handler when a breakpoint instruction has been
+// hit.  This cannot not be called unless at least one breakpoint with this
+// address is in the list of breakpoints.  (All breakpoint notifications must
+// previously have been set via setbreak())
+//
+//	foreach breakpoint in list
+//		if breakpoint matches conditions
+//			notify the break handler
+//	if no breakpoints matched the conditions
+//		pick a random breakpoint set to this address
+//
+//		set a breakpoint at the next instruction to be executed,
+//		and pass the current breakpoint to the "skiphandler"
+//
+//		clear the current breakpoint
+//
+//		Tell the scheduler to stop scheduling, so the caller is
+//		guaranteed to execute the instruction, followed by the
+//		added breakpoint.
+//
+//
+int
+breakhit(Ureg *ur, Proc *p)
+{
+	Bkpt *b;
+	int nmatched;
+	Bkpt *skip;
+
+	nmatched = 0;
+	for(b = breakpoints; b != nil; b = b->next) {
+		if(breakmatch(b->conditions, ur, p)) {
+			breaknotify(b, p);
+			++nmatched;
+		}
+	}
+
+	if(nmatched)
+		return BrkSched;
+
+	skip = nil;
+	for(b = breakpoints; b != nil;  b = b->next) {
+		if(b->addr == ur->pc) {
+			if(breakclear(b->id) == nil)
+				panic("breakhit: breakclear() failed");
+
+			if(skip == nil)
+				skip = newskip(machnextaddr(ur), b, p);
+			else {
+				b->link = skip->link;
+				skip->link = b;
+			}
+		}
+	}
+	if(skip == nil)
+		return BrkSched;
+	breakset(skip);
+	return BrkNoSched;
+}
+
+void
+portbreakinit(void)
+{
+	Bkpt *b;
+	int i;
+
+	skipalloc = mallocz(conf.nproc*(sizeof(Bkpt)+sizeof(BkptCond)+sizeof(SkipArg)), 1);
+	if(skipalloc == nil)
+		error(Enomem);
+
+	b = skipalloc;
+	for(i=0; i < conf.nproc-1; i++) {
+		b->id = -(i+1);
+		b->conditions = (BkptCond*)((uchar*)b + sizeof(Bkpt));
+		b->conditions->op = 'b';
+		b->handler = skiphandler;
+		b->aux = (SkipArg*)((uchar*)b+sizeof(Bkpt)+sizeof(BkptCond));
+		b->next = (Bkpt*)((uchar*)b+sizeof(Bkpt)+sizeof(BkptCond)+sizeof(SkipArg));
+		b = b->next;
+	}
+	b->next = nil;
+}