[PATCH 5.13 187/300] selftests/bpf: Fix test_core_autosize on big-endian machines
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-09-13 14:09:21
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
From: Ilya Leoshkevich <iii@linux.ibm.com>
[ Upstream commit d164dd9a5c08c16a883b3de97d13948c7be7fa4d ]
The "probed" part of test_core_autosize copies an integer using
bpf_core_read() into an integer of a potentially different size.
On big-endian machines a destination offset is required for this to
produce a sensible result.
Fixes: 888d83b961f6 ("selftests/bpf: Validate libbpf's auto-sizing of LD/ST/STX instructions")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210812224814.187460-1-iii@linux.ibm.com (local)
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/bpf/progs/test_core_autosize.c | 20 ++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/test_core_autosize.c b/tools/testing/selftests/bpf/progs/test_core_autosize.c
index 44f5aa2e8956..9a7829c5e4a7 100644
--- a/tools/testing/selftests/bpf/progs/test_core_autosize.c
+++ b/tools/testing/selftests/bpf/progs/test_core_autosize.c@@ -125,6 +125,16 @@ int handle_downsize(void *ctx) return 0; } +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ +#define bpf_core_read_int bpf_core_read +#else +#define bpf_core_read_int(dst, sz, src) ({ \ + /* Prevent "subtraction from stack pointer prohibited" */ \ + volatile long __off = sizeof(*dst) - (sz); \ + bpf_core_read((char *)(dst) + __off, sz, src); \ +}) +#endif + SEC("raw_tp/sys_enter") int handle_probed(void *ctx) {
@@ -132,23 +142,23 @@ int handle_probed(void *ctx) __u64 tmp; tmp = 0; - bpf_core_read(&tmp, bpf_core_field_size(in->ptr), &in->ptr); + bpf_core_read_int(&tmp, bpf_core_field_size(in->ptr), &in->ptr); ptr_probed = tmp; tmp = 0; - bpf_core_read(&tmp, bpf_core_field_size(in->val1), &in->val1); + bpf_core_read_int(&tmp, bpf_core_field_size(in->val1), &in->val1); val1_probed = tmp; tmp = 0; - bpf_core_read(&tmp, bpf_core_field_size(in->val2), &in->val2); + bpf_core_read_int(&tmp, bpf_core_field_size(in->val2), &in->val2); val2_probed = tmp; tmp = 0; - bpf_core_read(&tmp, bpf_core_field_size(in->val3), &in->val3); + bpf_core_read_int(&tmp, bpf_core_field_size(in->val3), &in->val3); val3_probed = tmp; tmp = 0; - bpf_core_read(&tmp, bpf_core_field_size(in->val4), &in->val4); + bpf_core_read_int(&tmp, bpf_core_field_size(in->val4), &in->val4); val4_probed = tmp; return 0;
--
2.30.2