--- Gnu-Mach/kern/pc_sample.c	2020/09/02 04:45:16	1.1.1.2
+++ Gnu-Mach/kern/pc_sample.c	2020/09/02 04:52:00	1.1.1.4
@@ -43,18 +43,21 @@
 
 typedef sampled_pc_t sampled_pcs[MAX_PC_SAMPLES];
 
-int pc_sampling_enabled = 0;
-decl_simple_lock_data(, pc_sampling_lock)	/* lock for enabling */
-
 void take_pc_sample(
-    register thread_t t,
-    register sample_control_t *cp,
-    sampled_pc_flavor_t flavor)
+    const thread_t t,
+    sample_control_t *cp,
+    sampled_pc_flavor_t flavor,
+    boolean_t usermode,
+    vm_offset_t kern_pc)
 {
     vm_offset_t pc;
     struct sampled_pc *sample;
     
-    pc = interrupted_pc(t);
+    if (usermode)
+	pc = interrupted_pc(t);
+    else
+	pc = kern_pc;
+
     cp->seqno++;
     sample = &((sampled_pc_t *)cp->buffer)[cp->seqno % MAX_PC_SAMPLES];
     sample->id = (vm_offset_t)t;
@@ -192,6 +195,9 @@ get_sampled_pcs(
 		   (sampled_pc_array_t)cp->buffer,
 		   (seqidx2 + 1) * sizeof(sampled_pc_t));
 	}
+    } else if (nsamples < 0) {
+	/* Bogus SEQNO supplied.  */
+	nsamples = 0;
     } else {
 	/*  could either be zero because of overflow, or because
 	 *  we are being lied to.  In either case, return nothing.
@@ -244,8 +250,8 @@ task_get_sampled_pcs(
 
 kern_return_t
 thread_enable_pc_sampling(
-    thread_t thread,
-    int *tickp,
+    const thread_t thread,
+    const int *tickp,
     sampled_pc_flavor_t flavors)
 {
     return KERN_FAILURE;	/* not implemented */
@@ -253,8 +259,8 @@ thread_enable_pc_sampling(
 
 kern_return_t
 task_enable_pc_sampling(
-    task_t task,
-    int *tickp,
+    const task_t task,
+    const int *tickp,
     sampled_pc_flavor_t flavors)
 {
     return KERN_FAILURE;	/* not implemented */
@@ -262,36 +268,36 @@ task_enable_pc_sampling(
 
 kern_return_t
 thread_disable_pc_sampling(
-    thread_t thread,
-    int *samplecntp)
+    const thread_t thread,
+    const int *samplecntp)
 {
     return KERN_FAILURE;	/* not implemented */
 }
 
 kern_return_t
 task_disable_pc_sampling(
-    task_t task,
-    int *samplecntp)
+    const task_t task,
+    const int *samplecntp)
 {
     return KERN_FAILURE;	/* not implemented */
 }
 
 kern_return_t
 thread_get_sampled_pcs(
-	thread_t thread,
-	sampled_pc_seqno_t *seqnop,
-	sampled_pc_array_t sampled_pcs_out,
-	int *sampled_pcs_cntp)
+	const thread_t thread,
+	const sampled_pc_seqno_t *seqnop,
+	const sampled_pc_array_t sampled_pcs_out,
+	const int *sampled_pcs_cntp)
 {
     return KERN_FAILURE;	/* not implemented */
 }
 
 kern_return_t
 task_get_sampled_pcs(
-	task_t task,
-	sampled_pc_seqno_t *seqnop,
-	sampled_pc_array_t sampled_pcs_out,
-	int *sampled_pcs_cntp)
+	const task_t task,
+	const sampled_pc_seqno_t *seqnop,
+	const sampled_pc_array_t sampled_pcs_out,
+	const int *sampled_pcs_cntp)
 {
     return KERN_FAILURE;	/* not implemented */
 }