Commit 965c6167 authored Apr 01, 2024 by Yonghong Song Committed by Daniel Borkmann Apr 02, 2024

selftests/bpf: Using llvm may_goto inline asm for cond_break macro

Currently, cond_break macro uses bytes to encode the may_goto insn.
Patch [1] in llvm implemented may_goto insn in BPF backend.
Replace byte-level encoding with llvm inline asm for better usability.
Using llvm may_goto insn is controlled by macro __BPF_FEATURE_MAY_GOTO.

  [1] https://github.com/llvm/llvm-project/commit/0e0bfacff71859d1f9212205f8f873d47029d3fb



Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240402025446.3215182-1-yonghong.song@linux.dev

parent 9dc182c5

tools/testing/selftests/bpf/bpf_experimental.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -326,6 +326,16 @@ l_true: \
		})
		#endif

		#ifdef __BPF_FEATURE_MAY_GOTO
		#define cond_break \
		({ __label__ l_break, l_continue; \
		asm volatile goto("may_goto %l[l_break]" \
		:::: l_break); \
		goto l_continue; \
		l_break: break; \
		l_continue:; \
		})
		#else
		#define cond_break \
		({ __label__ l_break, l_continue; \
		asm volatile goto("1:.byte 0xe5; \
		@@ -337,6 +347,7 @@ l_true: \
		l_break: break; \
		l_continue:; \
		})
		#endif

		#ifndef bpf_nop_mov
		#define bpf_nop_mov(var) \