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-rw-r--r--arch/x86/kernel/ds_selftest.c408
1 files changed, 408 insertions, 0 deletions
diff --git a/arch/x86/kernel/ds_selftest.c b/arch/x86/kernel/ds_selftest.c
new file mode 100644
index 00000000000..6bc7c199ab9
--- /dev/null
+++ b/arch/x86/kernel/ds_selftest.c
@@ -0,0 +1,408 @@
+/*
+ * Debug Store support - selftest
+ *
+ *
+ * Copyright (C) 2009 Intel Corporation.
+ * Markus Metzger <markus.t.metzger@intel.com>, 2009
+ */
+
+#include "ds_selftest.h"
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/smp.h>
+#include <linux/cpu.h>
+
+#include <asm/ds.h>
+
+
+#define BUFFER_SIZE 521 /* Intentionally chose an odd size. */
+#define SMALL_BUFFER_SIZE 24 /* A single bts entry. */
+
+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;
+
+ if (!trace) {
+ printk(KERN_CONT "failed to access trace...");
+ /* Bail out. Other tests are pointless. */
+ return -1;
+ }
+
+ if (!trace->read) {
+ printk(KERN_CONT "bts read not available...");
+ error = -1;
+ }
+
+ /* Do some sanity checks on the trace configuration. */
+ if (!trace->ds.n) {
+ printk(KERN_CONT "empty bts buffer...");
+ error = -1;
+ }
+ if (!trace->ds.size) {
+ printk(KERN_CONT "bad bts trace setup...");
+ error = -1;
+ }
+ if (trace->ds.end !=
+ (char *)trace->ds.begin + (trace->ds.n * trace->ds.size)) {
+ printk(KERN_CONT "bad bts buffer setup...");
+ error = -1;
+ }
+ /*
+ * We allow top in [begin; end], since its not clear when the
+ * overflow adjustment happens: after the increment or before the
+ * write.
+ */
+ if ((trace->ds.top < trace->ds.begin) ||
+ (trace->ds.end < trace->ds.top)) {
+ printk(KERN_CONT "bts top out of bounds...");
+ error = -1;
+ }
+
+ return error;
+}
+
+static int ds_selftest_bts_read(struct bts_tracer *tracer,
+ const struct bts_trace *trace,
+ const void *from, const void *to)
+{
+ const unsigned char *at;
+
+ /*
+ * Check a few things which do not belong to this test.
+ * They should be covered by other tests.
+ */
+ if (!trace)
+ return -1;
+
+ if (!trace->read)
+ return -1;
+
+ if (to < from)
+ return -1;
+
+ if (from < trace->ds.begin)
+ return -1;
+
+ if (trace->ds.end < to)
+ return -1;
+
+ if (!trace->ds.size)
+ return -1;
+
+ /* Now to the test itself. */
+ for (at = from; (void *)at < to; at += trace->ds.size) {
+ struct bts_struct bts;
+ unsigned long index;
+ int error;
+
+ if (((void *)at - trace->ds.begin) % trace->ds.size) {
+ printk(KERN_CONT
+ "read from non-integer index...");
+ return -1;
+ }
+ index = ((void *)at - trace->ds.begin) / trace->ds.size;
+
+ memset(&bts, 0, sizeof(bts));
+ error = trace->read(tracer, at, &bts);
+ if (error < 0) {
+ printk(KERN_CONT
+ "error reading bts trace at [%lu] (0x%p)...",
+ index, at);
+ return error;
+ }
+
+ switch (bts.qualifier) {
+ case BTS_BRANCH:
+ break;
+ default:
+ printk(KERN_CONT
+ "unexpected bts entry %llu at [%lu] (0x%p)...",
+ bts.qualifier, index, at);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static void ds_selftest_bts_cpu(void *arg)
+{
+ struct ds_selftest_bts_conf *conf = arg;
+ const struct bts_trace *trace;
+ void *top;
+
+ if (IS_ERR(conf->tracer)) {
+ conf->error = PTR_ERR(conf->tracer);
+ conf->tracer = NULL;
+
+ printk(KERN_CONT
+ "initialization failed (err: %d)...", conf->error);
+ return;
+ }
+
+ /* 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(conf->tracer);
+
+ 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) {
+ /*
+ * It is possible but highly unlikely that we got a
+ * buffer overflow and end up at exactly the same
+ * position we started from.
+ * Let's issue a warning, but continue.
+ */
+ printk(KERN_CONT "no trace/overflow...");
+ }
+
+ /* Let's try to read the trace we collected. */
+ conf->error =
+ ds_selftest_bts_read(conf->tracer, trace,
+ trace->ds.begin, trace->ds.top);
+ if (conf->error < 0)
+ return;
+
+ /*
+ * Let's read the trace again.
+ * Since we suspended tracing, we should get the same result.
+ */
+ top = trace->ds.top;
+
+ 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...");
+ conf->error = -1;
+ return;
+ }
+
+ /* Let's collect some more trace - see if resume is working. */
+ 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(conf->tracer);
+
+ conf->error = ds_selftest_bts_consistency(trace);
+ if (conf->error < 0)
+ return;
+
+ if (trace->ds.top == top) {
+ /*
+ * It is possible but highly unlikely that we got a
+ * buffer overflow and end up at exactly the same
+ * position we started from.
+ * Let's issue a warning and check the full trace.
+ */
+ printk(KERN_CONT
+ "no resume progress/overflow...");
+
+ 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.
+ */
+ 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.
+ */
+ conf->error =
+ ds_selftest_bts_read(conf->tracer, trace, top,
+ trace->ds.top);
+ }
+ if (conf->error < 0)
+ return;
+
+ conf->error = 0;
+}
+
+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;
+}
+
+static void ds_release_bts_noirq_wrap(void *tracer)
+{
+ (void)ds_release_bts_noirq(tracer);
+}
+
+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;
+}
+
+static int ds_selftest_bts_bad_request_cpu(int cpu, void *buffer)
+{
+ struct bts_tracer *tracer;
+ int error;
+
+ /* Try to request cpu tracing while task tracing is active. */
+ tracer = ds_request_bts_cpu(cpu, buffer, BUFFER_SIZE, NULL,
+ (size_t)-1, BTS_KERNEL);
+ error = PTR_ERR(tracer);
+ if (!IS_ERR(tracer)) {
+ ds_release_bts(tracer);
+ error = 0;
+ }
+
+ if (error != -EPERM)
+ printk(KERN_CONT "cpu/task tracing overlap...");
+
+ return error ? 0 : -1;
+}
+
+static int ds_selftest_bts_bad_request_task(void *buffer)
+{
+ struct bts_tracer *tracer;
+ int error;
+
+ /* Try to request cpu tracing while task tracing is active. */
+ tracer = ds_request_bts_task(current, buffer, BUFFER_SIZE, NULL,
+ (size_t)-1, BTS_KERNEL);
+ error = PTR_ERR(tracer);
+ if (!IS_ERR(tracer)) {
+ error = 0;
+ ds_release_bts(tracer);
+ }
+
+ if (error != -EPERM)
+ printk(KERN_CONT "task/cpu tracing overlap...");
+
+ return error ? 0 : -1;
+}
+
+int ds_selftest_bts(void)
+{
+ struct ds_selftest_bts_conf conf;
+ unsigned char buffer[BUFFER_SIZE], *small_buffer;
+ unsigned long irq;
+ int cpu;
+
+ printk(KERN_INFO "[ds] bts selftest...");
+ conf.error = 0;
+
+ small_buffer = (unsigned char *)ALIGN((unsigned long)buffer, 8) + 8;
+
+ 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);
+ if (conf.error >= 0)
+ conf.error = ds_selftest_bts_bad_request_task(buffer);
+ 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;
+ }
+ if (conf.error >= 0)
+ conf.error = ds_selftest_bts_bad_request_task(buffer);
+ smp_call_function_single(cpu, ds_release_bts_noirq_wrap,
+ conf.tracer, 1);
+ if (conf.error < 0)
+ goto out;
+ }
+
+ conf.suspend = ds_suspend_bts_wrap;
+ conf.resume = ds_resume_bts_wrap;
+ conf.tracer =
+ ds_request_bts_task(current, buffer, BUFFER_SIZE,
+ NULL, (size_t)-1, BTS_KERNEL);
+ ds_selftest_bts_cpu(&conf);
+ if (conf.error >= 0)
+ conf.error = ds_selftest_bts_bad_request_cpu(0, buffer);
+ 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_task(current, small_buffer, SMALL_BUFFER_SIZE,
+ NULL, (size_t)-1, BTS_KERNEL);
+ local_irq_save(irq);
+ ds_selftest_bts_cpu(&conf);
+ if (conf.error >= 0)
+ conf.error = ds_selftest_bts_bad_request_cpu(0, buffer);
+ ds_release_bts_noirq(conf.tracer);
+ local_irq_restore(irq);
+ 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)
+{
+ return 0;
+}
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