diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/raw_tp_null.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/raw_tp_null.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/tools/testing/selftests/bpf/progs/raw_tp_null.c b/tools/testing/selftests/bpf/progs/raw_tp_null.c index 457f34c151e3..5927054b6dd9 100644 --- a/tools/testing/selftests/bpf/progs/raw_tp_null.c +++ b/tools/testing/selftests/bpf/progs/raw_tp_null.c @@ -3,6 +3,7 @@ #include <vmlinux.h> #include <bpf/bpf_tracing.h> +#include "bpf_misc.h" char _license[] SEC("license") = "GPL"; @@ -17,16 +18,14 @@ int BPF_PROG(test_raw_tp_null, struct sk_buff *skb) if (task->pid != tid) return 0; - i = i + skb->mark + 1; - /* The compiler may move the NULL check before this deref, which causes - * the load to fail as deref of scalar. Prevent that by using a barrier. + /* If dead code elimination kicks in, the increment +=2 will be + * removed. For raw_tp programs attaching to tracepoints in kernel + * modules, we mark input arguments as PTR_MAYBE_NULL, so branch + * prediction should never kick in. */ - barrier(); - /* If dead code elimination kicks in, the increment below will - * be removed. For raw_tp programs, we mark input arguments as - * PTR_MAYBE_NULL, so branch prediction should never kick in. - */ - if (!skb) - i += 2; + asm volatile ("%[i] += 1; if %[ctx] != 0 goto +1; %[i] += 2;" + : [i]"+r"(i) + : [ctx]"r"(skb) + : "memory"); return 0; } |