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tracing: x86, mmiotrace: only register for die notifier when tracer active

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Follow up to afcfe024ae 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>
This commit is contained in:
Stuart Bennett 2009-04-28 20:17:51 +01:00 committed by Ingo Molnar
parent 46e91d00b1
commit 0f9a623dd6
3 changed files with 26 additions and 5 deletions
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27
arch/x86/mm/kmmio.c
View File

@ -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");
}
}

2
arch/x86/mm/mmio-mod.c
View File

@ -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);

2
include/linux/mmiotrace.h
View File

@ -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? */