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authorStuart Bennett <stuart@freedesktop.org>2009-04-28 19:17:51 (GMT)
committerIngo Molnar <mingo@elte.hu>2009-04-29 09:33:34 (GMT)
commit0f9a623dd6c9b5b4dd00c232f29525bfc7a8ecf2 (patch)
treed442cd6e03cb458b231374697ed7bb04caafabc2
parent46e91d00b1165b14b484aa33800e1bba0794ae1a (diff)
downloadlinux-0f9a623dd6c9b5b4dd00c232f29525bfc7a8ecf2.tar.xz
tracing: x86, mmiotrace: only register for die notifier when tracer active
Follow up to afcfe024aebd74b0984a41af9a34e009cf5badaf in Linus' tree ("x86: mmiotrace: quieten spurious warning message") Signed-off-by: Stuart Bennett <stuart@freedesktop.org> Acked-by: Pekka Paalanen <pq@iki.fi> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1240946271-7083-5-git-send-email-stuart@freedesktop.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/mm/kmmio.c27
-rw-r--r--arch/x86/mm/mmio-mod.c2
-rw-r--r--include/linux/mmiotrace.h2
3 files changed, 26 insertions, 5 deletions
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index a769d1a..256ce64 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -311,7 +311,12 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);
if (!ctx->active) {
- pr_debug("kmmio: spurious debug trap on CPU %d.\n",
+ /*
+ * debug traps without an active context are due to either
+ * something external causing them (f.e. using a debugger while
+ * mmio tracing enabled), or erroneous behaviour
+ */
+ pr_warning("kmmio: unexpected debug trap on CPU %d.\n",
smp_processor_id());
goto out;
}
@@ -529,8 +534,8 @@ void unregister_kmmio_probe(struct kmmio_probe *p)
}
EXPORT_SYMBOL(unregister_kmmio_probe);
-static int kmmio_die_notifier(struct notifier_block *nb, unsigned long val,
- void *args)
+static int
+kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
{
struct die_args *arg = args;
@@ -545,11 +550,23 @@ static struct notifier_block nb_die = {
.notifier_call = kmmio_die_notifier
};
-static int __init init_kmmio(void)
+int kmmio_init(void)
{
int i;
+
for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++)
INIT_LIST_HEAD(&kmmio_page_table[i]);
+
return register_die_notifier(&nb_die);
}
-fs_initcall(init_kmmio); /* should be before device_initcall() */
+
+void kmmio_cleanup(void)
+{
+ int i;
+
+ unregister_die_notifier(&nb_die);
+ for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) {
+ WARN_ONCE(!list_empty(&kmmio_page_table[i]),
+ KERN_ERR "kmmio_page_table not empty at cleanup, any further tracing will leak memory.\n");
+ }
+}
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index c9342ed..132772a 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -451,6 +451,7 @@ void enable_mmiotrace(void)
if (nommiotrace)
pr_info(NAME "MMIO tracing disabled.\n");
+ kmmio_init();
enter_uniprocessor();
spin_lock_irq(&trace_lock);
atomic_inc(&mmiotrace_enabled);
@@ -473,6 +474,7 @@ void disable_mmiotrace(void)
clear_trace_list(); /* guarantees: no more kmmio callbacks */
leave_uniprocessor();
+ kmmio_cleanup();
pr_info(NAME "disabled.\n");
out:
mutex_unlock(&mmiotrace_mutex);
diff --git a/include/linux/mmiotrace.h b/include/linux/mmiotrace.h
index 3d1b7bd..97491f7 100644
--- a/include/linux/mmiotrace.h
+++ b/include/linux/mmiotrace.h
@@ -30,6 +30,8 @@ extern unsigned int kmmio_count;
extern int register_kmmio_probe(struct kmmio_probe *p);
extern void unregister_kmmio_probe(struct kmmio_probe *p);
+extern int kmmio_init(void);
+extern void kmmio_cleanup(void);
#ifdef CONFIG_MMIOTRACE
/* kmmio is active by some kmmio_probes? */