This renaming is present from Linux v5.6 upwards, and was introduced by
commit:
1c5eb4481e01 ("tracing: Rename trace_buffer to array_buffer")
Rename the internal references from trace_buffer to array_buffer. Backwards
compatibility with older kernels is provided by checking whether struct
trace_array has an array_buffer field - should that not be the case, the
old naming scheme is used instead.
Signed-off-by: Valentin Schneider <valentin.schnei...@arm.com>
---
extensions/trace.c | 53 ++++++++++++++++++++++++++++++----------------
1 file changed, 35 insertions(+), 18 deletions(-)
diff --git a/extensions/trace.c b/extensions/trace.c
index c26b6c7..b4bbb98 100644
--- a/extensions/trace.c
+++ b/extensions/trace.c
@@ -31,9 +31,9 @@ static int per_cpu_buffer_sizes;
*/
static int encapsulated_current_trace;
/*
- * trace_buffer is supported
+ * array_buffer (trace_buffer pre v5.8) is supported
*/
-static int trace_buffer_available;
+static int array_buffer_available;
/*
* max_buffer is supported
*/
@@ -51,9 +51,9 @@ static int buffer_page_real_end_available;
#define koffset(struct, member) struct##_##member##_offset
static int koffset(trace_array, current_trace);
-static int koffset(trace_array, trace_buffer);
+static int koffset(trace_array, array_buffer);
static int koffset(trace_array, max_buffer);
-static int koffset(trace_buffer, buffer);
+static int koffset(array_buffer, buffer);
static int koffset(trace_array, buffer);
static int koffset(tracer, name);
@@ -117,7 +117,7 @@ static ulong max_tr_trace;
struct trace_instance {
char name[NAME_MAX + 1];
- ulong trace_buffer;
+ ulong array_buffer;
ulong max_buffer;
ulong ring_buffer;
unsigned pages;
@@ -174,8 +174,7 @@ static int write_and_check(int fd, void *data, size_t size)
static int init_offsets(void)
{
-#define init_offset(struct, member) do { \
- koffset(struct, member) = MEMBER_OFFSET(#struct, #member);\
+#define check_offset(struct, member) do { \
if (koffset(struct, member) < 0) { \
fprintf(fp, "failed to init the offset, struct:"\
#struct ", member:" #member); \
@@ -184,12 +183,29 @@ static int init_offsets(void)
} \
} while (0)
+#define init_offset(struct, member) do { \
+ koffset(struct, member) = MEMBER_OFFSET(#struct, #member); \
+ check_offset(struct, member); \
+ } while (0)
+
+#define init_offset_alternative(struct, member, alt_struct, alt_member) do {
\
+ koffset(struct, member) = MEMBER_OFFSET(#alt_struct,
#alt_member); \
+ check_offset(struct, member); \
+ } while (0)
+
if (encapsulated_current_trace)
init_offset(trace_array, current_trace);
- if (trace_buffer_available) {
- init_offset(trace_array, trace_buffer);
- init_offset(trace_buffer, buffer);
+ if (array_buffer_available) {
+ if (MEMBER_EXISTS("trace_array", "array_buffer")) {
+ init_offset(trace_array, array_buffer);
+ init_offset(array_buffer, buffer);
+ } else {
+ init_offset_alternative(trace_array, array_buffer,
+ trace_array, trace_buffer);
+ init_offset_alternative(array_buffer, buffer,
+ trace_buffer, buffer);
+ }
if (max_buffer_available)
init_offset(trace_array, max_buffer);
@@ -486,17 +502,17 @@ out_fail:
static int ftrace_init_trace(struct trace_instance *ti, ulong instance_addr)
{
- if (trace_buffer_available) {
- ti->trace_buffer = instance_addr +
- koffset(trace_array, trace_buffer);
- read_value(ti->ring_buffer, ti->trace_buffer,
- trace_buffer, buffer);
+ if (array_buffer_available) {
+ ti->array_buffer = instance_addr +
+ koffset(trace_array, array_buffer);
+ read_value(ti->ring_buffer, ti->array_buffer,
+ array_buffer, buffer);
if (max_buffer_available) {
ti->max_buffer = instance_addr +
koffset(trace_array, max_buffer);
read_value(ti->max_tr_ring_buffer, ti->max_buffer,
- trace_buffer, buffer);
+ array_buffer, buffer);
}
} else {
read_value(ti->ring_buffer, instance_addr, trace_array, buffer);
@@ -683,8 +699,9 @@ static int ftrace_init(void)
current_trace = sym_current_trace->value;
}
- if (MEMBER_EXISTS("trace_array", "trace_buffer")) {
- trace_buffer_available = 1;
+ if (MEMBER_EXISTS("trace_array", "array_buffer") ||
+ MEMBER_EXISTS("trace_array", "trace_buffer")) {
+ array_buffer_available = 1;
if (MEMBER_EXISTS("trace_array", "max_buffer"))
max_buffer_available = 1;
--
2.27.0
--
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