[PATCH perf-tools-next v2 2/4] perf trace: Auto-assign kernel symbol beautifier to function pointer fields

Tracepoint fields that convey kernel function pointers, such as "function",
"fn", "work", "action", and "callsite" are currently formatted as generic
hexadecimal pointers by default.

Enhance syscall_arg_fmt__init_array() to automatically detect these
fields by name and type signature (e.g., typedefs ending with "_func_t"
or "_fn", or C function pointer types containing "(*)") and assign
SCA_KSYM as their default beautifier.

Additionally, register common function pointer field names within the
sorted syscall_arg_fmts__by_name lookup table. This ensures tracepoint
arguments such as workqueue:workqueue_execute_start.function are
symbolised automatically without requiring explicit per-event
configuration. For example:

    ❯ sudo tools/perf/perf trace --event workqueue:workqueue_execute_end --max-events 2 --show-cpu
         0.000 [000] kworker/u32:15/236682 workqueue:workqueue_execute_end(work: 0xffffffffab2f1420, function: toggle_allocation_gate)
         0.132 [000] kworker/u32:15/236682 workqueue:workqueue_execute_end(work: 0xffff8ac2c1adc010, function: flush_to_ldisc)

Signed-off-by: Aaron Tomlin <[email protected]>
---
 tools/perf/builtin-trace.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 003048946503..85abae09d328 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2198,6 +2198,15 @@ syscall_arg_fmt__init_array(struct syscall_arg_fmt *arg, struct tep_format_field
 		    ((len >= 4 && strcmp(field->name + len - 4, "name") == 0) ||
 		     strstr(field->name, "path") != NULL)) {
 			arg->scnprintf = SCA_FILENAME;
+		} else if ((field->type && (strstr(field->type, "(*)") != NULL ||
+					    strstr(field->type, "_func_t") != NULL ||
+					    strstr(field->type, "_fn") != NULL)) ||
+			   (((field->flags & TEP_FIELD_IS_POINTER) || field->size == sizeof(u64)) &&
+			    (strcmp(field->name, "fn") == 0 ||
+			     strcmp(field->name, "function") == 0 ||
+			     strcmp(field->name, "callsite") == 0 ||
+			     strcmp(field->name, "call_site") == 0))) {
+			arg->scnprintf = SCA_KSYM;
 		} else if ((field->flags & TEP_FIELD_IS_POINTER) || strstr(field->name, "addr") ||
 			   field_has_hex_fmt(field, len))
 			arg->scnprintf = SCA_PTR;
-- 
2.55.0