[PATCH bpf v3] selftests/bpf: fix "alu with different scalars 1" on s390

[PATCH bpf v3] selftests/bpf: fix "alu with different scalars 1" on s390

[Ilya Leoshkevich]

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.

Change the test to load the whole int in order to make it
endianness-independent.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---

v1->v2:
- use __BYTE_ORDER instead of __BYTE_ORDER__.
v2->v3:
- load the whole int instead of byte.

 tools/testing/selftests/bpf/verifier/value_ptr_arith.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
index c3de1a2c9dc5..a53d99cebd9f 100644
--- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
+++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
@@ -183,7 +183,7 @@
 	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
 	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
 	BPF_EXIT_INSN(),
-	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+	BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
 	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3),
 	BPF_MOV64_IMM(BPF_REG_2, 0),
 	BPF_MOV64_IMM(BPF_REG_3, 0x100000),
-- 
2.21.0

Re: [PATCH bpf v3] selftests/bpf: fix "alu with different scalars 1" on s390

[Alexei Starovoitov]

On Tue, Jul 16, 2019 at 12:53:53PM +0200, Ilya Leoshkevich 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.
> 
> Change the test to load the whole int in order to make it
> endianness-independent.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>

Applied, Thanks