On 2/14/24 13:41, Charlie Jenkins wrote:
The test cases for ip_fast_csum and csum_ipv6_magic were failing on a
variety of architectures that are big endian or do not support
misalgined accesses. Both of these test cases are changed to support big
and little endian architectures.
The test for ip_fast_csum is changed to align the data along (14 +
NET_IP_ALIGN) bytes which is the alignment of an IP header. The test for
csum_ipv6_magic aligns the data using a struct. An extra padding field
is added to the struct to ensure that the size of the struct is the same
on all architectures (44 bytes).
The test for csum_ipv6_magic somewhat arbitrarily aligned saddr and
daddr. This would fail on parisc64 due to the following code snippet in
arch/parisc/include/asm/checksum.h:
add %4, %0, %0\n"
ldd,ma 8(%1), %6\n"
ldd,ma 8(%2), %7\n"
add,dc %5, %0, %0\n"
The second add is expecting carry flags from the first add. Normally,
a double word load (ldd) does not modify the carry flags. However,
because saddr and daddr may be misaligned, ldd triggers a misalignment
trap that gets handled in arch/parisc/kernel/unaligned.c. This causes
many additional instructions to be executed between the two adds. This
can be easily solved by adding the carry into %0 before executing the
ldd.
However, that is not necessary since ipv6 headers should always be
aligned on a 16-byte boundary on parisc since NET_IP_ALIGN is set to 2
and the ethernet header size is 14.
Architectures that set NET_IP_ALIGN to 0 must support misaligned saddr
and daddr, but that is not tested here.
Fixes: 6f4c45cbcb00 ("kunit: Add tests for csum_ipv6_magic and ip_fast_csum")
Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
Reviewed-and-Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Guenter
