Commit 0f9a623dd6c9b5b4dd00c232f29525bfc7a8ecf2
Committed by
Ingo Molnar
Ingo Molnar
1 parent
46e91d00b1
Exists in
master
and in
4 other branches
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>
Showing 3 changed files with 26 additions and 5 deletions Side-by-side Diff
arch/x86/mm/kmmio.c
| ... | ... | @@ -311,7 +311,12 @@ |
| 311 | 311 | struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx); |
| 312 | 312 | |
| 313 | 313 | if (!ctx->active) { |
| 314 | - pr_debug("kmmio: spurious debug trap on CPU %d.\n", | |
| 314 | + /* | |
| 315 | + * debug traps without an active context are due to either | |
| 316 | + * something external causing them (f.e. using a debugger while | |
| 317 | + * mmio tracing enabled), or erroneous behaviour | |
| 318 | + */ | |
| 319 | + pr_warning("kmmio: unexpected debug trap on CPU %d.\n", | |
| 315 | 320 | smp_processor_id()); |
| 316 | 321 | goto out; |
| 317 | 322 | } |
| ... | ... | @@ -529,8 +534,8 @@ |
| 529 | 534 | } |
| 530 | 535 | EXPORT_SYMBOL(unregister_kmmio_probe); |
| 531 | 536 | |
| 532 | -static int kmmio_die_notifier(struct notifier_block *nb, unsigned long val, | |
| 533 | - void *args) | |
| 537 | +static int | |
| 538 | +kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args) | |
| 534 | 539 | { |
| 535 | 540 | struct die_args *arg = args; |
| 536 | 541 | |
| 537 | 542 | |
| 538 | 543 | |
| 539 | 544 | |
| ... | ... | @@ -545,12 +550,24 @@ |
| 545 | 550 | .notifier_call = kmmio_die_notifier |
| 546 | 551 | }; |
| 547 | 552 | |
| 548 | -static int __init init_kmmio(void) | |
| 553 | +int kmmio_init(void) | |
| 549 | 554 | { |
| 550 | 555 | int i; |
| 556 | + | |
| 551 | 557 | for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) |
| 552 | 558 | INIT_LIST_HEAD(&kmmio_page_table[i]); |
| 559 | + | |
| 553 | 560 | return register_die_notifier(&nb_die); |
| 554 | 561 | } |
| 555 | -fs_initcall(init_kmmio); /* should be before device_initcall() */ | |
| 562 | + | |
| 563 | +void kmmio_cleanup(void) | |
| 564 | +{ | |
| 565 | + int i; | |
| 566 | + | |
| 567 | + unregister_die_notifier(&nb_die); | |
| 568 | + for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) { | |
| 569 | + WARN_ONCE(!list_empty(&kmmio_page_table[i]), | |
| 570 | + KERN_ERR "kmmio_page_table not empty at cleanup, any further tracing will leak memory.\n"); | |
| 571 | + } | |
| 572 | +} |
arch/x86/mm/mmio-mod.c
| ... | ... | @@ -451,6 +451,7 @@ |
| 451 | 451 | |
| 452 | 452 | if (nommiotrace) |
| 453 | 453 | pr_info(NAME "MMIO tracing disabled.\n"); |
| 454 | + kmmio_init(); | |
| 454 | 455 | enter_uniprocessor(); |
| 455 | 456 | spin_lock_irq(&trace_lock); |
| 456 | 457 | atomic_inc(&mmiotrace_enabled); |
| ... | ... | @@ -473,6 +474,7 @@ |
| 473 | 474 | |
| 474 | 475 | clear_trace_list(); /* guarantees: no more kmmio callbacks */ |
| 475 | 476 | leave_uniprocessor(); |
| 477 | + kmmio_cleanup(); | |
| 476 | 478 | pr_info(NAME "disabled.\n"); |
| 477 | 479 | out: |
| 478 | 480 | mutex_unlock(&mmiotrace_mutex); |
include/linux/mmiotrace.h
| ... | ... | @@ -30,6 +30,8 @@ |
| 30 | 30 | |
| 31 | 31 | extern int register_kmmio_probe(struct kmmio_probe *p); |
| 32 | 32 | extern void unregister_kmmio_probe(struct kmmio_probe *p); |
| 33 | +extern int kmmio_init(void); | |
| 34 | +extern void kmmio_cleanup(void); | |
| 33 | 35 | |
| 34 | 36 | #ifdef CONFIG_MMIOTRACE |
| 35 | 37 | /* kmmio is active by some kmmio_probes? */ |