3 files changed, 97 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
index 7ff5fa93d056..a33874b081b6 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -27,6 +27,7 @@
 #include "bpf_iter_test_kern5.skel.h"
 #include "bpf_iter_test_kern6.skel.h"
 #include "bpf_iter_bpf_link.skel.h"
+#include "bpf_iter_ksym.skel.h"
 
 static int duration;
 
@@ -1120,6 +1121,19 @@ static void test_link_iter(void)
 	bpf_iter_bpf_link__destroy(skel);
 }
 
+static void test_ksym_iter(void)
+{
+	struct bpf_iter_ksym *skel;
+
+	skel = bpf_iter_ksym__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "bpf_iter_ksym__open_and_load"))
+		return;
+
+	do_dummy_read(skel->progs.dump_ksym);
+
+	bpf_iter_ksym__destroy(skel);
+}
+
 #define CMP_BUFFER_SIZE 1024
 static char task_vma_output[CMP_BUFFER_SIZE];
 static char proc_maps_output[CMP_BUFFER_SIZE];
@@ -1267,4 +1281,6 @@ void test_bpf_iter(void)
 		test_buf_neg_offset();
 	if (test__start_subtest("link-iter"))
 		test_link_iter();
+	if (test__start_subtest("ksym"))
+		test_ksym_iter();
 }
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h
index 97ec8bc76ae6..e9846606690d 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter.h
+++ b/tools/testing/selftests/bpf/progs/bpf_iter.h
@@ -22,6 +22,7 @@
 #define BTF_F_NONAME BTF_F_NONAME___not_used
 #define BTF_F_PTR_RAW BTF_F_PTR_RAW___not_used
 #define BTF_F_ZERO BTF_F_ZERO___not_used
+#define bpf_iter__ksym bpf_iter__ksym___not_used
 #include "vmlinux.h"
 #undef bpf_iter_meta
 #undef bpf_iter__bpf_map
@@ -44,6 +45,7 @@
 #undef BTF_F_NONAME
 #undef BTF_F_PTR_RAW
 #undef BTF_F_ZERO
+#undef bpf_iter__ksym
 
 struct bpf_iter_meta {
 	struct seq_file *seq;
@@ -151,3 +153,8 @@ enum {
 	BTF_F_PTR_RAW	=	(1ULL << 2),
 	BTF_F_ZERO	=	(1ULL << 3),
 };
+
+struct bpf_iter__ksym {
+	struct bpf_iter_meta *meta;
+	struct kallsym_iter *ksym;
+};
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c b/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
new file mode 100644
index 000000000000..285c008cbf9c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022, Oracle and/or its affiliates. */
+#include "bpf_iter.h"
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+unsigned long last_sym_value = 0;
+
+static inline char tolower(char c)
+{
+	if (c >= 'A' && c <= 'Z')
+		c += ('a' - 'A');
+	return c;
+}
+
+static inline char toupper(char c)
+{
+	if (c >= 'a' && c <= 'z')
+		c -= ('a' - 'A');
+	return c;
+}
+
+/* Dump symbols with max size; the latter is calculated by caching symbol N value
+ * and when iterating on symbol N+1, we can print max size of symbol N via
+ * address of N+1 - address of N.
+ */
+SEC("iter/ksym")
+int dump_ksym(struct bpf_iter__ksym *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	struct kallsym_iter *iter = ctx->ksym;
+	__u32 seq_num = ctx->meta->seq_num;
+	unsigned long value;
+	char type;
+	int ret;
+
+	if (!iter)
+		return 0;
+
+	if (seq_num == 0) {
+		BPF_SEQ_PRINTF(seq, "ADDR TYPE NAME MODULE_NAME KIND MAX_SIZE\n");
+		return 0;
+	}
+	if (last_sym_value)
+		BPF_SEQ_PRINTF(seq, "0x%x\n", iter->value - last_sym_value);
+	else
+		BPF_SEQ_PRINTF(seq, "\n");
+
+	value = iter->show_value ? iter->value : 0;
+
+	last_sym_value = value;
+
+	type = iter->type;
+
+	if (iter->module_name[0]) {
+		type = iter->exported ? toupper(type) : tolower(type);
+		BPF_SEQ_PRINTF(seq, "0x%llx %c %s [ %s ] ",
+			       value, type, iter->name, iter->module_name);
+	} else {
+		BPF_SEQ_PRINTF(seq, "0x%llx %c %s ", value, type, iter->name);
+	}
+	if (!iter->pos_arch_end || iter->pos_arch_end > iter->pos)
+		BPF_SEQ_PRINTF(seq, "CORE ");
+	else if (!iter->pos_mod_end || iter->pos_mod_end > iter->pos)
+		BPF_SEQ_PRINTF(seq, "MOD ");
+	else if (!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > iter->pos)
+		BPF_SEQ_PRINTF(seq, "FTRACE_MOD ");
+	else if (!iter->pos_bpf_end || iter->pos_bpf_end > iter->pos)
+		BPF_SEQ_PRINTF(seq, "BPF ");
+	else
+		BPF_SEQ_PRINTF(seq, "KPROBE ");
+	return 0;
+}