perf_snapshot_branch_stack is set up in an architecture-agnostic way, so there is no reason for BPF subsystem to keep track of which architectures do support LBR or not. E.g., it looks like ARM64 might soon get support for BRBE ([0]), which (with proper integration) should be possible to utilize using this BPF helper. perf_snapshot_branch_stack static call will point to __static_call_return0() by default, which just returns zero, which will lead to -ENOENT, as expected. So no need to guard anything here. [0] https://lore.kernel.org/linux-arm-kernel/20240125094119.2542332-1-anshuman.khandual@xxxxxxx/ Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> --- kernel/trace/bpf_trace.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 434e3ece6688..6d000332b17b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1182,9 +1182,6 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = { BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) { -#ifndef CONFIG_X86 - return -ENOENT; -#else static const u32 br_entry_size = sizeof(struct perf_branch_entry); u32 entry_cnt = size / br_entry_size; @@ -1197,7 +1194,6 @@ BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) return -ENOENT; return entry_cnt * br_entry_size; -#endif } static const struct bpf_func_proto bpf_get_branch_snapshot_proto = { -- 2.43.0
