On 7/28/21 10:04 AM, Johan Almbladh wrote:
On a 32-bit architecture, the context pointer should occupy the low
half of R0, and the other half should be zero.
I think this is probably true. The word choice "should" indicates
this doesn't need to be the case if people choose a different
implementation, right?
Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
---
lib/test_bpf.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 55914b6236aa..314af6eaeb92 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -2084,6 +2084,22 @@ static struct bpf_test tests[] = {
#undef NUMER
#undef DENOM
},
+#ifdef CONFIG_32BIT
+ {
+ "INT: 32-bit context pointer word order and zero-extension",
+ .u.insns_int = {
+ BPF_ALU32_IMM(BPF_MOV, R0, 0),
+ BPF_JMP32_IMM(BPF_JEQ, R1, 0, 3),
+ BPF_ALU64_IMM(BPF_RSH, R1, 32),
+ BPF_JMP32_IMM(BPF_JNE, R1, 0, 1),
+ BPF_ALU32_IMM(BPF_MOV, R0, 1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } }
+ },
+#endif
{
"check: missing ret",
.u.insns = {
