x86, ds: selftest each cpu

Perform debug store selftests on each cpu.

Cover both the normal and the _noirq variant of the debug store interface.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144559.394583000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 135 insertions, 47 deletions

diff --git a/arch/x86/kernel/ds_selftest.c b/arch/x86/kernel/ds_selftest.c
index cccc19a38f6d..599a96300628 100644
--- a/arch/x86/kernel/ds_selftest.c
+++ b/arch/x86/kernel/ds_selftest.c
@@ -11,13 +11,21 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/smp.h>
+#include <linux/cpu.h>
 
 #include <asm/ds.h>
 
 
-#define BUFFER_SIZE 1021 /* Intentionally chose an odd size. */
+#define BUFFER_SIZE     521 /* Intentionally chose an odd size. */
 
 
+struct ds_selftest_bts_conf {
+        struct bts_tracer *tracer;
+        int error;
+        int (*suspend)(struct bts_tracer *);
+        int (*resume)(struct bts_tracer *);
+};
+
 static int ds_selftest_bts_consistency(const struct bts_trace *trace)
 {
         int error = 0;
@@ -125,36 +133,32 @@ static int ds_selftest_bts_read(struct bts_tracer *tracer,
         return 0;
 }
 
-int ds_selftest_bts(void)
+static void ds_selftest_bts_cpu(void *arg)
 {
+        struct ds_selftest_bts_conf *conf = arg;
         const struct bts_trace *trace;
-        struct bts_tracer *tracer;
-        int error = 0;
         void *top;
-        unsigned char buffer[BUFFER_SIZE];
 
-        printk(KERN_INFO "[ds] bts selftest...");
-
-        tracer = ds_request_bts_cpu(smp_processor_id(), buffer, BUFFER_SIZE,
-                                    NULL, (size_t)-1, BTS_KERNEL);
-        if (IS_ERR(tracer)) {
-                error = PTR_ERR(tracer);
-                tracer = NULL;
+        if (IS_ERR(conf->tracer)) {
+                conf->error = PTR_ERR(conf->tracer);
+                conf->tracer = NULL;
 
                 printk(KERN_CONT
-                       "initialization failed (err: %d)...", error);
-                goto out;
+                       "initialization failed (err: %d)...", conf->error);
+                return;
         }
 
-        /* The return should already give us enough trace. */
-        ds_suspend_bts(tracer);
+        /* We should meanwhile have enough trace. */
+        conf->error = conf->suspend(conf->tracer);
+        if (conf->error < 0)
+                return;
 
         /* Let's see if we can access the trace. */
-        trace = ds_read_bts(tracer);
+        trace = ds_read_bts(conf->tracer);
 
-        error = ds_selftest_bts_consistency(trace);
-        if (error < 0)
-                goto out;
+        conf->error = ds_selftest_bts_consistency(trace);
+        if (conf->error < 0)
+                return;
 
         /* If everything went well, we should have a few trace entries. */
         if (trace->ds.top == trace->ds.begin) {
@@ -168,10 +172,11 @@ int ds_selftest_bts(void)
         }
 
         /* Let's try to read the trace we collected. */
-        error = ds_selftest_bts_read(tracer, trace,
+        conf->error =
+                ds_selftest_bts_read(conf->tracer, trace,
                                      trace->ds.begin, trace->ds.top);
-        if (error < 0)
-                goto out;
+        if (conf->error < 0)
+                return;
 
         /*
          * Let's read the trace again.
@@ -179,26 +184,31 @@ int ds_selftest_bts(void)
          */
         top = trace->ds.top;
 
-        trace = ds_read_bts(tracer);
-        error = ds_selftest_bts_consistency(trace);
-        if (error < 0)
-                goto out;
+        trace = ds_read_bts(conf->tracer);
+        conf->error = ds_selftest_bts_consistency(trace);
+        if (conf->error < 0)
+                return;
 
         if (top != trace->ds.top) {
                 printk(KERN_CONT "suspend not working...");
-                error = -1;
-                goto out;
+                conf->error = -1;
+                return;
         }
 
         /* Let's collect some more trace - see if resume is working. */
-        ds_resume_bts(tracer);
-        ds_suspend_bts(tracer);
+        conf->error = conf->resume(conf->tracer);
+        if (conf->error < 0)
+                return;
+
+        conf->error = conf->suspend(conf->tracer);
+        if (conf->error < 0)
+                return;
 
-        trace = ds_read_bts(tracer);
+        trace = ds_read_bts(conf->tracer);
 
-        error = ds_selftest_bts_consistency(trace);
-        if (error < 0)
-                goto out;
+        conf->error = ds_selftest_bts_consistency(trace);
+        if (conf->error < 0)
+                return;
 
         if (trace->ds.top == top) {
                 /*
@@ -210,35 +220,113 @@ int ds_selftest_bts(void)
                 printk(KERN_CONT
                        "no resume progress/overflow...");
 
-                error = ds_selftest_bts_read(tracer, trace,
+                conf->error =
+                        ds_selftest_bts_read(conf->tracer, trace,
                                              trace->ds.begin, trace->ds.end);
         } else if (trace->ds.top < top) {
                 /*
                  * We had a buffer overflow - the entire buffer should
                  * contain trace records.
                  */
-                error = ds_selftest_bts_read(tracer, trace,
+                conf->error =
+                        ds_selftest_bts_read(conf->tracer, trace,
                                              trace->ds.begin, trace->ds.end);
         } else {
                 /*
                  * It is quite likely that the buffer did not overflow.
                  * Let's just check the delta trace.
                  */
-                error = ds_selftest_bts_read(tracer, trace,
-                                             top, trace->ds.top);
+                conf->error =
+                        ds_selftest_bts_read(conf->tracer, trace, top,
+                                             trace->ds.top);
         }
-        if (error < 0)
-                goto out;
+        if (conf->error < 0)
+                return;
 
-        error = 0;
+        conf->error = 0;
+}
 
-        /* The final test: release the tracer while tracing is suspended. */
- out:
-        ds_release_bts(tracer);
+static int ds_suspend_bts_wrap(struct bts_tracer *tracer)
+{
+        ds_suspend_bts(tracer);
+        return 0;
+}
+
+static int ds_resume_bts_wrap(struct bts_tracer *tracer)
+{
+        ds_resume_bts(tracer);
+        return 0;
+}
 
-        printk(KERN_CONT "%s.\n", (error ? "failed" : "passed"));
+static void ds_release_bts_noirq_wrap(void *tracer)
+{
+        (void)ds_release_bts_noirq(tracer);
+}
 
-        return error;
+static int ds_selftest_bts_bad_release_noirq(int cpu,
+                                             struct bts_tracer *tracer)
+{
+        int error = -EPERM;
+
+        /* Try to release the tracer on the wrong cpu. */
+        get_cpu();
+        if (cpu != smp_processor_id()) {
+                error = ds_release_bts_noirq(tracer);
+                if (error != -EPERM)
+                        printk(KERN_CONT "release on wrong cpu...");
+        }
+        put_cpu();
+
+        return error ? 0 : -1;
+}
+
+int ds_selftest_bts(void)
+{
+        struct ds_selftest_bts_conf conf;
+        unsigned char buffer[BUFFER_SIZE];
+        int cpu;
+
+        printk(KERN_INFO "[ds] bts selftest...");
+        conf.error = 0;
+
+        get_online_cpus();
+        for_each_online_cpu(cpu) {
+                conf.suspend = ds_suspend_bts_wrap;
+                conf.resume = ds_resume_bts_wrap;
+                conf.tracer =
+                        ds_request_bts_cpu(cpu, buffer, BUFFER_SIZE,
+                                           NULL, (size_t)-1, BTS_KERNEL);
+                ds_selftest_bts_cpu(&conf);
+                ds_release_bts(conf.tracer);
+                if (conf.error < 0)
+                        goto out;
+
+                conf.suspend = ds_suspend_bts_noirq;
+                conf.resume = ds_resume_bts_noirq;
+                conf.tracer =
+                        ds_request_bts_cpu(cpu, buffer, BUFFER_SIZE,
+                                           NULL, (size_t)-1, BTS_KERNEL);
+                smp_call_function_single(cpu, ds_selftest_bts_cpu, &conf, 1);
+                if (conf.error >= 0) {
+                        conf.error =
+                                ds_selftest_bts_bad_release_noirq(cpu,
+                                                                  conf.tracer);
+                        /* We must not release the tracer twice. */
+                        if (conf.error < 0)
+                                conf.tracer = NULL;
+                }
+                smp_call_function_single(cpu, ds_release_bts_noirq_wrap,
+                                         conf.tracer, 1);
+                if (conf.error < 0)
+                        goto out;
+        }
+
+        conf.error = 0;
+ out:
+        put_online_cpus();
+        printk(KERN_CONT "%s.\n", (conf.error ? "failed" : "passed"));
+
+        return conf.error;
 }
 
 int ds_selftest_pebs(void)