On 12/03/26 11:52 pm, Yonghong Song wrote:
On 3/12/26 1:01 AM, Hari Bathini wrote:
On powerpc, immediate load instructions are sign extended. In case
of unsigned types, arguments should be explicitly zero-extended by
the caller. For kfunc call, this needs to be handled in the JIT code.
In bpf_kfunc_call_test4(), that tests for sign-extension of signed
argument types in kfunc calls, add some additional failure checks.
And add bpf_kfunc_call_test5() to test zero-extension of unsigned
argument types in kfunc calls.
Signed-off-by: Hari Bathini <[email protected]>
LGTM with a nit below.
Acked-by: Yonghong Song <[email protected]>
Thanks for the review, Yonghong.
---
Changes in v2:
- Added asm version of the selftest for consistent testing across
different BPF ISA versions.
- Added comments clearly stating the intent of the test cases.
- Updated sign-extension selftest to have additional failure checks.
.../selftests/bpf/prog_tests/kfunc_call.c | 2 +
.../selftests/bpf/progs/kfunc_call_test.c | 98 +++++++++++++++++++
.../selftests/bpf/test_kmods/bpf_testmod.c | 54 +++++++++-
.../bpf/test_kmods/bpf_testmod_kfunc.h | 1 +
4 files changed, 154 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/
tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index f79c8e53cb3e..62f3fb79f5d1 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -74,6 +74,8 @@ static struct kfunc_test_params kfunc_tests[] = {
TC_TEST(kfunc_call_test1, 12),
TC_TEST(kfunc_call_test2, 3),
TC_TEST(kfunc_call_test4, -1234),
+ TC_TEST(kfunc_call_test5, 0),
+ TC_TEST(kfunc_call_test5_asm, 0),
TC_TEST(kfunc_call_test_ref_btf_id, 0),
TC_TEST(kfunc_call_test_get_mem, 42),
SYSCALL_TEST(kfunc_syscall_test, 0),
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/
tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 8b86113a0126..5edc51564f71 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -2,8 +2,106 @@
/* Copyright (c) 2021 Facebook */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
#include "../test_kmods/bpf_testmod_kfunc.h"
+SEC("tc")
+int kfunc_call_test5(struct __sk_buff *skb)
+{
+ struct bpf_sock *sk = skb->sk;
+ int ret;
+ u32 val32;
+ u16 val16;
+ u8 val8;
+
+ if (!sk)
+ return -1;
+
+ sk = bpf_sk_fullsock(sk);
+ if (!sk)
+ return -1;
+
+ /*
+ * Test with constant values to verify zero-extension.
+ * ISA-dependent BPF asm:
+ * With ALU32: w1 = 0xFF; w2 = 0xFFFF; w3 = 0xFFFFffff
+ * Without ALU32: r1 = 0xFF; r2 = 0xFFFF; r3 = 0xFFFFffff
+ * Both zero-extend to 64-bit before the kfunc call.
+ */
+ ret = bpf_kfunc_call_test5(0xFF, 0xFFFF, 0xFFFFffffULL);
Can we just use 0xFFFFffff instead of 0xFFFFffffULL?
Alexei, can you confirm if I need to respin with this change?
- Hari
