From bd7d30bd1d3856d8354b5acef947d68ad1faf886 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 19 Aug 2026 09:05:33 -0700 Subject: xsk: align TX metadata layout across ABIs Add explicit padding before launch_time so xsk_tx_metadata has the same layout on 32-bit and 64-bit systems. On several architectures (csky, i386, nios2, m65k, openrisc, sh), the old native 32-bit layout put launch_time at offset 12 and had a natural size of 20 bytes. Using sizeof(struct xsk_tx_metadata) as tx_metadata_len was already rejected because the length must be a multiple of eight, so the straightforward use of the interface was broken on those ABIs. Userspace could still register a padded length of 24 bytes, though; mixing the old and new layouts then silently reads launch_time from the wrong offset and misprograms packet launch times. This intentionally replaces that incompatible layout because the affected architectures are unlikely to have any notable users. (x86_64 and arm64 have the most users and are _not_ affected) Fixes: ca4419f15abd ("xsk: Add launch time hardware offload support to XDP Tx metadata") Reviewed-by: Simon Horman Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20260819160535.1472459-2-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- tools/include/uapi/linux/if_xdp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/include') diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h index 23a062781468..50d67df78911 100644 --- a/tools/include/uapi/linux/if_xdp.h +++ b/tools/include/uapi/linux/if_xdp.h @@ -149,6 +149,7 @@ struct xsk_tx_metadata { __u16 csum_start; /* Offset from csum_start where checksum should be stored. */ __u16 csum_offset; + __u32 reserved; /* XDP_TXMD_FLAGS_LAUNCH_TIME */ /* Launch time in nanosecond against the PTP HW Clock */ -- cgit