[PATCH bpf-next v2 2/2] bpftool: Probe for bounded loop support

[Paul Chaignon <paul@xxxxxxxxxxxxx>]

This patch probes for bounded loop support and displays the results as
part of the miscellaneous section, as shown below.

  $ bpftool feature probe | grep loops
  Bounded loop support is available
  $ bpftool feature probe macro | grep LOOPS
  #define HAVE_BOUNDED_LOOPS
  $ bpftool feature probe -j | jq .misc
  {
    "have_large_insn_limit": true,
    "have_bounded_loops": true
  }

Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Signed-off-by: Paul Chaignon <paul@xxxxxxxxxxxxx>
---
Changes in v2:
  - Resending to fix a format error.

 tools/bpf/bpftool/feature.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 5397077d0d9e..7aee920162e5 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -654,6 +654,18 @@ probe_large_insn_limit(const char *define_prefix, __u32 ifindex)
 			   res, define_prefix);
 }
 
+static void
+probe_bounded_loops(const char *define_prefix, __u32 ifindex)
+{
+	bool res;
+
+	res = bpf_probe_bounded_loops(ifindex);
+	print_bool_feature("have_bounded_loops",
+			   "Bounded loop support",
+			   "BOUNDED_LOOPS",
+			   res, define_prefix);
+}
+
 static void
 section_system_config(enum probe_component target, const char *define_prefix)
 {
@@ -768,6 +780,7 @@ static void section_misc(const char *define_prefix, __u32 ifindex)
 			    "/*** eBPF misc features ***/",
 			    define_prefix);
 	probe_large_insn_limit(define_prefix, ifindex);
+	probe_bounded_loops(define_prefix, ifindex);
 	print_end_section();
 }
 
-- 
2.25.1