Fix KTR_CPUMASK in order to accept a string representing a cpuset_t.

This introduce all the underlying support for making this possible (via
the function cpusetobj_strscan() and keeps ktr_cpumask exported.  sparc64
implements its own assembly primitives for tracing events and needs to
properly check it.  Anyway the sparc64 logic is not implemented yet due
to lack of knowledge (by me) and time (by marius), but it is just a
matter of using ktr_cpumask when possible.

Tested and fixed by:	pluknet
Reviewed by:		marius

1 files changed, 51 insertions, 10 deletions

diff --git a/sys/kern/kern_ktr.c b/sys/kern/kern_ktr.c
index 2e5e06f..eff3d5b 100644
--- a/sys/kern/kern_ktr.c
+++ b/sys/kern/kern_ktr.c
@@ -40,8 +40,10 @@ __FBSDID("$FreeBSD$");
 #include "opt_alq.h"
 
 #include <sys/param.h>
+#include <sys/queue.h>
 #include <sys/alq.h>
 #include <sys/cons.h>
+#include <sys/cpuset.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/libkern.h>
@@ -68,10 +70,6 @@ __FBSDID("$FreeBSD$");
 #define	KTR_MASK	(0)
 #endif
 
-#ifndef KTR_CPUMASK
-#define	KTR_CPUMASK	(~0)
-#endif
-
 #ifndef KTR_TIME
 #define	KTR_TIME	get_cyclecount()
 #endif
@@ -84,11 +82,6 @@ FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
 
 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
 
-int	ktr_cpumask = KTR_CPUMASK;
-TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
-SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW,
-    &ktr_cpumask, 0, "Bitmask of CPUs on which KTR logging is enabled");
-
 int	ktr_mask = KTR_MASK;
 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
 SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW,
@@ -106,6 +99,54 @@ int	ktr_version = KTR_VERSION;
 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
     &ktr_version, 0, "Version of the KTR interface");
 
+cpuset_t ktr_cpumask;
+static char ktr_cpumask_str[CPUSETBUFSIZ];
+TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
+
+static void
+ktr_cpumask_initializer(void *dummy __unused)
+{
+
+	CPU_FILL(&ktr_cpumask);
+#ifdef KTR_CPUMASK
+	if (cpusetobj_strscan(&ktr_cpumask, KTR_CPUMASK) == -1)
+		CPU_FILL(&ktr_cpumask);
+#endif
+
+	/*
+	 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
+	 * already set, if necessary.
+	 */
+	if (ktr_cpumask_str[0] != '\0' &&
+	    cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
+		CPU_FILL(&ktr_cpumask);
+}
+SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
+    ktr_cpumask_initializer, NULL);
+
+static int
+sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
+{
+	char lktr_cpumask_str[CPUSETBUFSIZ];
+	cpuset_t imask;
+	int error;
+
+	cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
+	error = sysctl_handle_string(oidp, lktr_cpumask_str,
+	    sizeof(lktr_cpumask_str), req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+	if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
+		return (EINVAL);
+	CPU_COPY(&imask, &ktr_cpumask);
+
+	return (error);
+}
+SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
+    CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
+    sysctl_debug_ktr_cpumask, "S",
+    "Bitmask of CPUs on which KTR logging is enabled");
+
 volatile int	ktr_idx = 0;
 struct	ktr_entry ktr_buf[KTR_ENTRIES];
 
@@ -213,7 +254,7 @@ ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
 	if ((ktr_mask & mask) == 0)
 		return;
 	cpu = KTR_CPU;
-	if (((1 << cpu) & ktr_cpumask) == 0)
+	if (!CPU_ISSET(cpu, &ktr_cpumask))
 		return;
 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
 	td = curthread;