diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2013-06-12 21:16:25 +0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2013-06-20 07:30:40 +0400 |
| commit | 1a891cf19cdfb645827969cc6aeaeebdefeb87b2 (patch) | |
| tree | 7f62a3cd802158e8c29a6fdac1a54f39ba47a454 | |
| parent | aaf6ac0f0871cb7fc0f28f3a00edf329bc7adc29 (diff) | |
| download | linux-1a891cf19cdfb645827969cc6aeaeebdefeb87b2.tar.xz | |
tracing: Add binary '&' filter for events
There are some cases when filtering on a set flag of a field of a tracepoint
is useful. But currently the only filtering commands for numbered fields
is ==, !=, <, <=, >, >=. This does not help when you just want to trace if
a specific flag is set. For example:
> # sudo trace-cmd record -e brcmfmac:brcmf_dbg -f 'level & 0x40000'
> disable all
> enable brcmfmac:brcmf_dbg
> path = /sys/kernel/debug/tracing/events/brcmfmac/brcmf_dbg/enable
> (level & 0x40000)
> ^
> parse_error: Invalid operator
>
When trying to trace brcmf_dbg when level has its 1 << 18 bit set, the
filter fails to perform.
By allowing a binary '&' operation, this gives the user the ability to
test a bit.
Note, a binary '|' is not added, as it doesn't make sense as fields must
be compared to constants (for now), and ORing a constant will always return
true.
Link: http://lkml.kernel.org/r/1371057385.9844.261.camel@gandalf.local.home
Suggested-by: Arend van Spriel <arend@broadcom.com>
Tested-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | Documentation/trace/events.txt | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 6 |
2 files changed, 7 insertions, 1 deletions
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt index bb24c2a0e870..41911240c65c 100644 --- a/Documentation/trace/events.txt +++ b/Documentation/trace/events.txt @@ -183,7 +183,7 @@ The relational-operators depend on the type of the field being tested: The operators available for numeric fields are: -==, !=, <, <=, >, >= +==, !=, <, <=, >, >=, & And for string fields they are: diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index e1b653f7e1ca..0d883dc057d6 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -44,6 +44,7 @@ enum filter_op_ids OP_LE, OP_GT, OP_GE, + OP_BAND, OP_NONE, OP_OPEN_PAREN, }; @@ -54,6 +55,7 @@ struct filter_op { int precedence; }; +/* Order must be the same as enum filter_op_ids above */ static struct filter_op filter_ops[] = { { OP_OR, "||", 1 }, { OP_AND, "&&", 2 }, @@ -64,6 +66,7 @@ static struct filter_op filter_ops[] = { { OP_LE, "<=", 5 }, { OP_GT, ">", 5 }, { OP_GE, ">=", 5 }, + { OP_BAND, "&", 6 }, { OP_NONE, "OP_NONE", 0 }, { OP_OPEN_PAREN, "(", 0 }, }; @@ -156,6 +159,9 @@ static int filter_pred_##type(struct filter_pred *pred, void *event) \ case OP_GE: \ match = (*addr >= val); \ break; \ + case OP_BAND: \ + match = (*addr & val); \ + break; \ default: \ break; \ } \ |