[PATCH bpf-next V2] bpf_helpers.h: define bpf_tail_call_static when building with GCC

[PATCH bpf-next V2] bpf_helpers.h: define bpf_tail_call_static when building with GCC

[Jose E. Marchesi]

[Changes from V1;
- Add minimum GCC version that supports bpf_tail_call_static.]

The definition of bpf_tail_call_static in tools/lib/bpf/bpf_helpers.h
is guarded by a preprocessor check to assure that clang is recent
enough to support it.  This patch updates the guard so the function is
compiled when using GCC 13 or later as well.

Tested in bpf-next master.
No regressions.

Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Yonghong Song <yhs@meta.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: david.faust@oracle.com
Cc: cupertino.miranda@oracle.com
---
 tools/lib/bpf/bpf_helpers.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index cd17f6d0791f..62e1c0cc4a59 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -137,7 +137,8 @@
 /*
  * Helper function to perform a tail call with a constant/immediate map slot.
  */
-#if __clang_major__ >= 8 && defined(__bpf__)
+#if (defined(__clang__) && __clang_major__ >= 8) || (!defined(__clang__) && __GNUC__ > 12)
+#if defined(__bpf__)
 static __always_inline void
 bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 {
@@ -165,6 +166,7 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 		     : "r0", "r1", "r2", "r3", "r4", "r5");
 }
 #endif
+#endif
 
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
-- 
2.30.2

Re: [PATCH bpf-next V2] bpf_helpers.h: define bpf_tail_call_static when building with GCC

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Fri, 26 Apr 2024 16:51:58 +0200 you wrote:
> [Changes from V1;
> - Add minimum GCC version that supports bpf_tail_call_static.]
> 
> The definition of bpf_tail_call_static in tools/lib/bpf/bpf_helpers.h
> is guarded by a preprocessor check to assure that clang is recent
> enough to support it.  This patch updates the guard so the function is
> compiled when using GCC 13 or later as well.
> 
> [...]

Here is the summary with links:
  - [bpf-next,V2] bpf_helpers.h: define bpf_tail_call_static when building with GCC
    https://git.kernel.org/bpf/bpf-next/c/6e25bcf06af0

You are awesome, thank you!
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