Tests with aligned and misaligned memory access of different sizes via
pointer returned by bpf_rdonly_cast().
Suggested-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
---
.../bpf/progs/mem_rdonly_untrusted.c | 41 +++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c
index 00604755e698..b0486af36f55 100644
--- a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c
+++ b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c
@@ -133,4 +133,45 @@ int mixed_mem_type(void *ctx)
return *p;
}
+__attribute__((__aligned__(8)))
+u8 global[] = {
+ 0x11, 0x22, 0x33, 0x44,
+ 0x55, 0x66, 0x77, 0x88,
+ 0x99
+};
+
+__always_inline
+static u64 combine(void *p)
+{
+ u64 acc;
+
+ acc = 0;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+ acc |= (*(u64 *)p >> 56) << 24;
+ acc |= (*(u32 *)p >> 24) << 16;
+ acc |= (*(u16 *)p >> 8) << 8;
+ acc |= *(u8 *)p;
+#else
+ acc |= (*(u64 *)p & 0xff) << 24;
+ acc |= (*(u32 *)p & 0xff) << 16;
+ acc |= (*(u16 *)p & 0xff) << 8;
+ acc |= *(u8 *)p;
+#endif
+ return acc;
+}
+
+SEC("socket")
+__retval(0x88442211)
+int diff_size_access(void *ctx)
+{
+ return combine(bpf_rdonly_cast(&global, 0));
+}
+
+SEC("socket")
+__retval(0x99553322)
+int misaligned_access(void *ctx)
+{
+ return combine(bpf_rdonly_cast(&global, 0) + 1);
+}
+
char _license[] SEC("license") = "GPL";
--
2.47.1
