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However, function pointer arguments are currently not recognised during BTF pretty-printing and default to hexadecimal output. Introduce btf_is_func_ptr() to inspect BTF type hierarchies (i.e., traversing pointers, typedefs, and type modifiers) to determine whether a parameter resolves to a function prototype (BTF_KIND_FUNC_PROTO). Generalise BTF type caching via syscall_arg_fmt__cache_btf_type() to handle structs, unions, enums, and function pointers alike. When a field is identified as a kernel function pointer, trace__btf_scnprintf() routes its value to syscall_arg__scnprintf_ksym(), enabling automatic zero-config symbolisation of kernel function pointers whenever BTF is available. Signed-off-by: Aaron Tomlin --- tools/perf/builtin-trace.c | 39 ++++++++++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 825b16581581..94dc720a2b3a 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -974,21 +974,43 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size, #define SCA_GETRANDOM_FLAGS syscall_arg__scnprintf_getrandom_flags #ifdef HAVE_LIBBPF_SUPPORT -static void syscall_arg_fmt__cache_btf_enum(struct syscall_arg_fmt *arg_fmt, struct btf *btf, char *type) +static bool btf_is_func_ptr(const struct btf *btf, const struct btf_type *type) +{ + while (type) { + if (btf_is_ptr(type)) { + type = btf__type_by_id(btf, type->type); + return type && btf_is_func_proto(type); + } + if (btf_is_typedef(type) || btf_is_mod(type)) { + type = btf__type_by_id(btf, type->type); + } else { + break; + } + } + return false; +} + +static void syscall_arg_fmt__cache_btf_type(struct syscall_arg_fmt *arg_fmt, + struct btf *btf, char *type) { int id; - type = strstr(type, "enum "); if (type == NULL) return; - type += 5; // skip "enum " to get the enumeration name + if (strstarts(type, "enum ")) + type += 5; + else if (strstarts(type, "struct ")) + type += 7; + else if (strstarts(type, "union ")) + type += 6; id = btf__find_by_name(btf, type); if (id < 0) return; arg_fmt->type = btf__type_by_id(btf, id); + arg_fmt->type_id = id; } static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_arg *arg, u64 *val) @@ -1023,8 +1045,7 @@ static bool syscall_arg__strtoul_btf_type(char *bf, size_t size, struct syscall_ return false; if (arg->fmt->type == NULL) { - // See if this is an enum - syscall_arg_fmt__cache_btf_enum(arg->fmt, btf, type); + syscall_arg_fmt__cache_btf_type(arg->fmt, btf, type); } // Now let's see if we have a BTF type resolved @@ -1111,8 +1132,7 @@ static size_t trace__btf_scnprintf(struct trace *trace, struct syscall_arg *arg, return 0; if (arg_fmt->type == NULL) { - // Check if this is an enum and if we have the BTF type for it. - syscall_arg_fmt__cache_btf_enum(arg_fmt, trace->btf, type); + syscall_arg_fmt__cache_btf_type(arg_fmt, trace->btf, type); } // Did we manage to find a BTF type for the syscall/tracepoint argument? @@ -1123,6 +1143,8 @@ static size_t trace__btf_scnprintf(struct trace *trace, struct syscall_arg *arg, return btf_enum_scnprintf(arg_fmt->type, trace->btf, bf, size, val); else if (btf_is_struct(arg_fmt->type) || btf_is_union(arg_fmt->type)) return btf_struct_scnprintf(arg_fmt->type, trace->btf, bf, size, arg); + else if (btf_is_func_ptr(trace->btf, arg_fmt->type)) + return syscall_arg__scnprintf_ksym(bf, size, arg); return 0; } @@ -2566,7 +2588,8 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size, default_scnprintf = sc->arg_fmt[arg.idx].scnprintf; - if (trace->force_btf || default_scnprintf == NULL || default_scnprintf == SCA_PTR) { + if (trace->force_btf || default_scnprintf == NULL || + default_scnprintf == SCA_PTR || default_scnprintf == SCA_KSYM) { btf_printed = trace__btf_scnprintf(trace, &arg, bf + printed, size - printed, val, field->type); if (btf_printed) { -- 2.55.0