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
})
#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; \
l_break: break; \
l_continue:; \
})
+#endif
#ifndef bpf_nop_mov
#define bpf_nop_mov(var) \