Add a blurb in the trace sample file to describe the macro used to add sizeof to value conversions.
Signed-off-by: Jeremy Linton <[email protected]> --- samples/trace_events/trace-events-sample.h | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 76a75ab..a7431d4 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -225,26 +225,36 @@ TRACE_DEFINE_ENUM(TRACE_SAMPLE_FOO); TRACE_DEFINE_ENUM(TRACE_SAMPLE_BAR); TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO); +/* + * The same problem as above applies to sizeof(), so there is also + * a macro to solve that problem. In the case show below foo_bar/format + * contains a string "__print_array(...,sizeof(phys_addr_t))" for which + * the sizeof() result varies depending on the kernel. Adding the following + * macro decodes the size before transferring it to userspace. + */ + +TRACE_DEFINE_SIZEOF(phys_addr_t); + TRACE_EVENT(foo_bar, - TP_PROTO(const char *foo, int bar, const int *lst, + TP_PROTO(const char *foo, int bar, const phys_addr_t *lst, const char *string, const struct cpumask *mask), TP_ARGS(foo, bar, lst, string, mask), TP_STRUCT__entry( - __array( char, foo, 10 ) - __field( int, bar ) - __dynamic_array(int, list, __length_of(lst)) - __string( str, string ) - __bitmask( cpus, num_possible_cpus() ) + __array( char, foo, 10 ) + __field( int, bar ) + __dynamic_array(phys_addr_t, list, __length_of(lst) ) + __string( str, string ) + __bitmask( cpus, num_possible_cpus() ) ), TP_fast_assign( strlcpy(__entry->foo, foo, 10); __entry->bar = bar; memcpy(__get_dynamic_array(list), lst, - __length_of(lst) * sizeof(int)); + __length_of(lst) * sizeof(phys_addr_t)); __assign_str(str, string); __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); ), @@ -291,8 +301,8 @@ TRACE_EVENT(foo_bar, * This prints out the array that is defined by __array in a nice format. */ __print_array(__get_dynamic_array(list), - __get_dynamic_array_len(list) / sizeof(int), - sizeof(int)), + __get_dynamic_array_len(list) / sizeof(phys_addr_t), + sizeof(phys_addr_t)), __get_str(str), __get_bitmask(cpus)) ); -- 2.9.4
