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Subject[PATCHv2] perf tools: Convert legacy map definition to BTF-defined
Date
The libbpf is switching off support for legacy map definitions [1],
which will break the perf llvm tests.

Moving the base source map definition to BTF-defined, so we need
to use -g compile option for to add debug/BTF info.

[1] https://lore.kernel.org/bpf/20220627211527.2245459-1-andrii@kernel.org/
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/tests/bpf-script-example.c | 35 ++++++++++++++++++---------
tools/perf/util/llvm-utils.c | 2 +-
2 files changed, 24 insertions(+), 13 deletions(-)

v2 changes:
- added comments to macros [Ian]
- removed struct bpf_map_def, it's no longer needed

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index ab4b98b3165d..7981c69ed1b4 100644
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -17,20 +17,31 @@ static void *(*bpf_map_lookup_elem)(void *map, void *key) =
static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
(void *) BPF_FUNC_map_update_elem;

-struct bpf_map_def {
- unsigned int type;
- unsigned int key_size;
- unsigned int value_size;
- unsigned int max_entries;
-};
+/*
+ * Following macros are taken from tools/lib/bpf/bpf_helpers.h,
+ * and are used to create BTF defined maps. It is easier to take
+ * 2 simple macros, than being able to include above header in
+ * runtime.
+ *
+ * __uint - defines integer attribute of BTF map definition,
+ * Such attributes are represented using a pointer to an array,
+ * in which dimensionality of array encodes specified integer
+ * value.
+ *
+ * __type - defines pointer variable with typeof(val) type for
+ * attributes like key or value, which will be defined by the
+ * size of the type.
+ */
+#define __uint(name, val) int (*name)[val]
+#define __type(name, val) typeof(val) *name

#define SEC(NAME) __attribute__((section(NAME), used))
-struct bpf_map_def SEC("maps") flip_table = {
- .type = BPF_MAP_TYPE_ARRAY,
- .key_size = sizeof(int),
- .value_size = sizeof(int),
- .max_entries = 1,
-};
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, int);
+ __type(value, int);
+} flip_table SEC(".maps");

SEC("func=do_epoll_wait")
int bpf_func__SyS_epoll_pwait(void *ctx)
diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c
index 96c8ef60f4f8..2dc797007419 100644
--- a/tools/perf/util/llvm-utils.c
+++ b/tools/perf/util/llvm-utils.c
@@ -25,7 +25,7 @@
"$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
"-Wno-unused-value -Wno-pointer-sign " \
"-working-directory $WORKING_DIR " \
- "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
+ "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -g -O2 -o - $LLVM_OPTIONS_PIPE"

struct llvm_param llvm_param = {
.clang_path = "clang",
--
2.35.3
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