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sfc: falcon: use padding to fix alignment in loopback test

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Add two bytes of padding to the start of struct ef4_loopback_payload,
 which are not sent on the wire.  This ensures the 'ip' member is
 4-byte aligned, preventing the following W=1 warning:
net/ethernet/sfc/falcon/selftest.c:43:15: error: field ip within 'struct ef4_loopback_payload' is less aligned than 'struct iphdr' and is usually due to 'struct ef4_loopback_payload' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
        struct iphdr ip;

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Edward Cree 2023-06-23 19:38:06 +01:00 committed by David S. Miller
parent 30c24dd87f
commit 1186c6b31e
1 changed files with 28 additions and 19 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

47
drivers/net/ethernet/sfc/falcon/selftest.c
View file

@ -39,12 +39,16 @@
* Falcon only performs RSS on TCP/UDP packets. * Falcon only performs RSS on TCP/UDP packets.
*/ */
struct ef4_loopback_payload { struct ef4_loopback_payload {
char pad[2]; /* Ensures ip is 4-byte aligned */
struct ethhdr header; struct ethhdr header;
struct iphdr ip; struct iphdr ip;
struct udphdr udp; struct udphdr udp;
__be16 iteration; __be16 iteration;
char msg[64]; char msg[64];
} __packed; } __packed __aligned(4);
#define EF4_LOOPBACK_PAYLOAD_LEN (sizeof(struct ef4_loopback_payload) - \
offsetof(struct ef4_loopback_payload, \
header))
/* Loopback test source MAC address */ /* Loopback test source MAC address */
static const u8 payload_source[ETH_ALEN] __aligned(2) = { static const u8 payload_source[ETH_ALEN] __aligned(2) = {
@ -284,7 +288,7 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
const char *buf_ptr, int pkt_len) const char *buf_ptr, int pkt_len)
{ {
struct ef4_loopback_state *state = efx->loopback_selftest; struct ef4_loopback_state *state = efx->loopback_selftest;
struct ef4_loopback_payload *received; struct ef4_loopback_payload received;
struct ef4_loopback_payload *payload; struct ef4_loopback_payload *payload;
BUG_ON(!buf_ptr); BUG_ON(!buf_ptr);
@ -295,13 +299,14 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
payload = &state->payload; payload = &state->payload;
received = (struct ef4_loopback_payload *) buf_ptr; memcpy(&received.header, buf_ptr,
received->ip.saddr = payload->ip.saddr; min_t(int, pkt_len, EF4_LOOPBACK_PAYLOAD_LEN));
received.ip.saddr = payload->ip.saddr;
if (state->offload_csum) if (state->offload_csum)
received->ip.check = payload->ip.check; received.ip.check = payload->ip.check;
/* Check that header exists */ /* Check that header exists */
if (pkt_len < sizeof(received->header)) { if (pkt_len < sizeof(received.header)) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw runt RX packet (length %d) in %s loopback " "saw runt RX packet (length %d) in %s loopback "
"test\n", pkt_len, LOOPBACK_MODE(efx)); "test\n", pkt_len, LOOPBACK_MODE(efx));
@ -309,7 +314,7 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
} }
/* Check that the ethernet header exists */ /* Check that the ethernet header exists */
if (memcmp(&received->header, &payload->header, ETH_HLEN) != 0) { if (memcmp(&received.header, &payload->header, ETH_HLEN) != 0) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw non-loopback RX packet in %s loopback test\n", "saw non-loopback RX packet in %s loopback test\n",
LOOPBACK_MODE(efx)); LOOPBACK_MODE(efx));
@ -317,16 +322,16 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
} }
/* Check packet length */ /* Check packet length */
if (pkt_len != sizeof(*payload)) { if (pkt_len != EF4_LOOPBACK_PAYLOAD_LEN) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw incorrect RX packet length %d (wanted %d) in " "saw incorrect RX packet length %d (wanted %d) in "
"%s loopback test\n", pkt_len, (int)sizeof(*payload), "%s loopback test\n", pkt_len,
LOOPBACK_MODE(efx)); (int)EF4_LOOPBACK_PAYLOAD_LEN, LOOPBACK_MODE(efx));
goto err; goto err;
} }
/* Check that IP header matches */ /* Check that IP header matches */
if (memcmp(&received->ip, &payload->ip, sizeof(payload->ip)) != 0) { if (memcmp(&received.ip, &payload->ip, sizeof(payload->ip)) != 0) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw corrupted IP header in %s loopback test\n", "saw corrupted IP header in %s loopback test\n",
LOOPBACK_MODE(efx)); LOOPBACK_MODE(efx));
@ -334,7 +339,7 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
} }
/* Check that msg and padding matches */ /* Check that msg and padding matches */
if (memcmp(&received->msg, &payload->msg, sizeof(received->msg)) != 0) { if (memcmp(&received.msg, &payload->msg, sizeof(received.msg)) != 0) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw corrupted RX packet in %s loopback test\n", "saw corrupted RX packet in %s loopback test\n",
LOOPBACK_MODE(efx)); LOOPBACK_MODE(efx));
@ -342,10 +347,10 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
} }
/* Check that iteration matches */ /* Check that iteration matches */
if (received->iteration != payload->iteration) { if (received.iteration != payload->iteration) {
netif_err(efx, drv, efx->net_dev, netif_err(efx, drv, efx->net_dev,
"saw RX packet from iteration %d (wanted %d) in " "saw RX packet from iteration %d (wanted %d) in "
"%s loopback test\n", ntohs(received->iteration), "%s loopback test\n", ntohs(received.iteration),
ntohs(payload->iteration), LOOPBACK_MODE(efx)); ntohs(payload->iteration), LOOPBACK_MODE(efx));
goto err; goto err;
} }
@ -365,7 +370,8 @@ void ef4_loopback_rx_packet(struct ef4_nic *efx,
buf_ptr, pkt_len, 0); buf_ptr, pkt_len, 0);
netif_err(efx, drv, efx->net_dev, "expected packet:\n"); netif_err(efx, drv, efx->net_dev, "expected packet:\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 0x10, 1, print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 0x10, 1,
&state->payload, sizeof(state->payload), 0); &state->payload.header, EF4_LOOPBACK_PAYLOAD_LEN,
0);
} }
#endif #endif
atomic_inc(&state->rx_bad); atomic_inc(&state->rx_bad);
@ -387,14 +393,15 @@ static void ef4_iterate_state(struct ef4_nic *efx)
payload->ip.daddr = htonl(INADDR_LOOPBACK); payload->ip.daddr = htonl(INADDR_LOOPBACK);
payload->ip.ihl = 5; payload->ip.ihl = 5;
payload->ip.check = (__force __sum16) htons(0xdead); payload->ip.check = (__force __sum16) htons(0xdead);
payload->ip.tot_len = htons(sizeof(*payload) - sizeof(struct ethhdr)); payload->ip.tot_len = htons(sizeof(*payload) -
offsetof(struct ef4_loopback_payload, ip));
payload->ip.version = IPVERSION; payload->ip.version = IPVERSION;
payload->ip.protocol = IPPROTO_UDP; payload->ip.protocol = IPPROTO_UDP;
/* Initialise udp header */ /* Initialise udp header */
payload->udp.source = 0; payload->udp.source = 0;
payload->udp.len = htons(sizeof(*payload) - sizeof(struct ethhdr) - payload->udp.len = htons(sizeof(*payload) -
sizeof(struct iphdr)); offsetof(struct ef4_loopback_payload, udp));
payload->udp.check = 0; /* checksum ignored */ payload->udp.check = 0; /* checksum ignored */
/* Fill out payload */ /* Fill out payload */
@ -420,7 +427,7 @@ static int ef4_begin_loopback(struct ef4_tx_queue *tx_queue)
for (i = 0; i < state->packet_count; i++) { for (i = 0; i < state->packet_count; i++) {
/* Allocate an skb, holding an extra reference for /* Allocate an skb, holding an extra reference for
* transmit completion counting */ * transmit completion counting */
skb = alloc_skb(sizeof(state->payload), GFP_KERNEL); skb = alloc_skb(EF4_LOOPBACK_PAYLOAD_LEN, GFP_KERNEL);
if (!skb) if (!skb)
return -ENOMEM; return -ENOMEM;
state->skbs[i] = skb; state->skbs[i] = skb;
@ -431,6 +438,8 @@ static int ef4_begin_loopback(struct ef4_tx_queue *tx_queue)
payload = skb_put(skb, sizeof(state->payload)); payload = skb_put(skb, sizeof(state->payload));
memcpy(payload, &state->payload, sizeof(state->payload)); memcpy(payload, &state->payload, sizeof(state->payload));
payload->ip.saddr = htonl(INADDR_LOOPBACK | (i << 2)); payload->ip.saddr = htonl(INADDR_LOOPBACK | (i << 2));
/* Strip off the leading padding */
skb_pull(skb, offsetof(struct ef4_loopback_payload, header));
/* Ensure everything we've written is visible to the /* Ensure everything we've written is visible to the
* interrupt handler. */ * interrupt handler. */