On Thu, Jul 4, 2019 at 1:53 AM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote: > > BPF_LDX_MEM is used to load the least significant byte of the retrieved > test_val.index, however, on big-endian machines it ends up retrieving > the most significant byte. > > Use the correct least significant byte offset on big-endian machines. > > Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> > --- > > v1->v2: > - use __BYTE_ORDER instead of __BYTE_ORDER__. > > tools/testing/selftests/bpf/verifier/value_ptr_arith.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c > index c3de1a2c9dc5..e5940c4e8b8f 100644 > --- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c > +++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c > @@ -183,7 +183,11 @@ > BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), > BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), > BPF_EXIT_INSN(), > +#if __BYTE_ORDER == __LITTLE_ENDIAN > BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0), > +#else > + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, sizeof(int) - 1), > +#endif I think tests should be arch and endian independent where possible. In this case test_val.index is 4 byte and 4 byte load should work just as well.
