Now that we have address information, use BTF declaration tag
of form
[105031] DECL_TAG 'address=0xffffffff81777410' type_id=105030 component_idx=-1
...which points at the function in question.
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
btf_encoder.c | 34 +++++++++++++++++++++++++---------
btf_encoder.h | 4 ++--
dwarves.h | 1 +
pahole.c | 12 ++++++++++--
4 files changed, 38 insertions(+), 13 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index edf72e6..3bd0fe0 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -99,7 +99,7 @@ struct btf_encoder {
static LIST_HEAD(encoders);
static pthread_mutex_t encoders__lock = PTHREAD_MUTEX_INITIALIZER;
-static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder);
+static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder, struct conf_load *conf_load);
/* mutex only needed for add/delete, as this can happen in multiple encoding
* threads. Traversal of the list is currently confined to thread collection.
@@ -710,7 +710,7 @@ static int32_t btf_encoder__add_var_secinfo(struct btf_encoder *encoder, uint32_
return gobuffer__add(&encoder->percpu_secinfo, &si, sizeof(si));
}
-int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other)
+int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other, struct conf_load *conf_load)
{
struct gobuffer *var_secinfo_buf = &other->percpu_secinfo;
size_t sz = gobuffer__size(var_secinfo_buf);
@@ -723,7 +723,7 @@ int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder
if (encoder == other)
return 0;
- btf_encoder__add_saved_funcs(other);
+ btf_encoder__add_saved_funcs(other, conf_load);
for (i = 0; i < nr_var_secinfo; i++) {
vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + i;
@@ -881,7 +881,7 @@ static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct functi
return 0;
}
-static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct function *fn)
+static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct function *fn, struct conf_load *conf_load)
{
int btf_fnproto_id, btf_fn_id, tag_type_id;
struct llvm_annotation *annot;
@@ -903,10 +903,26 @@ static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct functio
return -1;
}
}
+ if (conf_load->btf_gen_func_addr) {
+ if (fn->low_pc) {
+ char addr_tag[64];
+
+ snprintf(addr_tag, sizeof(addr_tag), "address=0x%lx", fn->low_pc);
+ tag_type_id = btf_encoder__add_decl_tag(encoder, addr_tag, btf_fn_id, -1);
+ if (tag_type_id < 0) {
+ fprintf(stderr, "error: failed to encode tag '%s' to func %s\n",
+ addr_tag, name);
+ return -1;
+ }
+ } else {
+ if (encoder->verbose)
+ printf("no addr info for func '%s'\n", name);
+ }
+ }
return 0;
}
-static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
+static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder, struct conf_load *conf_load)
{
int i;
@@ -956,7 +972,7 @@ static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
}
} else {
encoder->type_id_off = func->state.type_id_off;
- btf_encoder__add_func(encoder, fn);
+ btf_encoder__add_func(encoder, fn, conf_load);
}
fn->proto.processed = 1;
}
@@ -1356,12 +1372,12 @@ out:
return err;
}
-int btf_encoder__encode(struct btf_encoder *encoder)
+int btf_encoder__encode(struct btf_encoder *encoder, struct conf_load *conf_load)
{
int err;
/* for single-threaded case, saved funcs are added here */
- btf_encoder__add_saved_funcs(encoder);
+ btf_encoder__add_saved_funcs(encoder, conf_load);
if (gobuffer__size(&encoder->percpu_secinfo) != 0)
btf_encoder__add_datasec(encoder, PERCPU_SECTION);
@@ -1871,7 +1887,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
if (save)
err = btf_encoder__save_func(encoder, fn, func);
else
- err = btf_encoder__add_func(encoder, fn);
+ err = btf_encoder__add_func(encoder, fn, conf_load);
if (err)
goto out;
}
diff --git a/btf_encoder.h b/btf_encoder.h
index 34516bb..b5440cd 100644
--- a/btf_encoder.h
+++ b/btf_encoder.h
@@ -19,12 +19,12 @@ struct list_head;
struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filename, struct btf *base_btf, bool skip_encoding_vars, bool force, bool gen_floats, bool verbose);
void btf_encoder__delete(struct btf_encoder *encoder);
-int btf_encoder__encode(struct btf_encoder *encoder);
+int btf_encoder__encode(struct btf_encoder *encoder, struct conf_load *conf_load);
int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct conf_load *conf_load);
struct btf *btf_encoder__btf(struct btf_encoder *encoder);
-int btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other);
+int btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other, struct conf_load *conf_load);
#endif /* _BTF_ENCODER_H_ */
diff --git a/dwarves.h b/dwarves.h
index 9cf13dd..8486cfc 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -68,6 +68,7 @@ struct conf_load {
bool skip_encoding_btf_enum64;
bool btf_gen_optimized;
bool skip_encoding_btf_inconsistent_proto;
+ bool btf_gen_func_addr;
uint8_t hashtable_bits;
uint8_t max_hashtable_bits;
uint16_t kabi_prefix_len;
diff --git a/pahole.c b/pahole.c
index 6fc4ed6..b799ea6 100644
--- a/pahole.c
+++ b/pahole.c
@@ -1232,6 +1232,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
#define ARGP_skip_emitting_atomic_typedefs 338
#define ARGP_btf_gen_optimized 339
#define ARGP_skip_encoding_btf_inconsistent_proto 340
+#define ARGP_btf_gen_func_addr 341
static const struct argp_option pahole__options[] = {
{
@@ -1654,6 +1655,11 @@ static const struct argp_option pahole__options[] = {
.key = ARGP_skip_encoding_btf_inconsistent_proto,
.doc = "Skip functions that have multiple inconsistent function prototypes sharing the same name, or that use unexpected registers for parameter values."
},
+ {
+ .name = "btf_gen_func_addr",
+ .key = ARGP_btf_gen_func_addr,
+ .doc = "Encode function addresses as a BTF declaration tag pointing at the function; this allows easier matching of BTF function descriptions to kernel function addresses."
+ },
{
.name = NULL,
}
@@ -1829,6 +1835,8 @@ static error_t pahole__options_parser(int key, char *arg,
conf_load.btf_gen_optimized = true; break;
case ARGP_skip_encoding_btf_inconsistent_proto:
conf_load.skip_encoding_btf_inconsistent_proto = true; break;
+ case ARGP_btf_gen_func_addr:
+ conf_load.btf_gen_func_addr = true; break;
default:
return ARGP_ERR_UNKNOWN;
}
@@ -3009,7 +3017,7 @@ static int pahole_threads_collect(struct conf_load *conf, int nr_threads, void *
*/
if (!threads[i]->btf)
continue;
- err = btf_encoder__add_encoder(btf_encoder, threads[i]->encoder);
+ err = btf_encoder__add_encoder(btf_encoder, threads[i]->encoder, conf);
if (err < 0)
goto out;
}
@@ -3567,7 +3575,7 @@ try_sole_arg_as_class_names:
header = NULL;
if (btf_encode && btf_encoder) { // maybe all CUs were filtered out and thus we don't have an encoder?
- err = btf_encoder__encode(btf_encoder);
+ err = btf_encoder__encode(btf_encoder, &conf_load);
if (err) {
fputs("Failed to encode BTF\n", stderr);
goto out_cus_delete;
--
2.31.1
