xref: /openbmc/linux/drivers/net/ethernet/sfc/rx.c (revision ae074e2b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /****************************************************************************
3  * Driver for Solarflare network controllers and boards
4  * Copyright 2005-2006 Fen Systems Ltd.
5  * Copyright 2005-2013 Solarflare Communications Inc.
6  */
7 
8 #include <linux/socket.h>
9 #include <linux/in.h>
10 #include <linux/slab.h>
11 #include <linux/ip.h>
12 #include <linux/ipv6.h>
13 #include <linux/tcp.h>
14 #include <linux/udp.h>
15 #include <linux/prefetch.h>
16 #include <linux/moduleparam.h>
17 #include <linux/iommu.h>
18 #include <net/ip.h>
19 #include <net/checksum.h>
20 #include <net/xdp.h>
21 #include <linux/bpf_trace.h>
22 #include "net_driver.h"
23 #include "efx.h"
24 #include "rx_common.h"
25 #include "filter.h"
26 #include "nic.h"
27 #include "selftest.h"
28 #include "workarounds.h"
29 
30 /* Preferred number of descriptors to fill at once */
31 #define EFX_RX_PREFERRED_BATCH 8U
32 
33 /* Maximum rx prefix used by any architecture. */
34 #define EFX_MAX_RX_PREFIX_SIZE 16
35 
36 /* Size of buffer allocated for skb header area. */
37 #define EFX_SKB_HEADERS  128u
38 
39 /* Each packet can consume up to ceil(max_frame_len / buffer_size) buffers */
40 #define EFX_RX_MAX_FRAGS DIV_ROUND_UP(EFX_MAX_FRAME_LEN(EFX_MAX_MTU), \
41 				      EFX_RX_USR_BUF_SIZE)
42 
efx_rx_packet__check_len(struct efx_rx_queue * rx_queue,struct efx_rx_buffer * rx_buf,int len)43 static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
44 				     struct efx_rx_buffer *rx_buf,
45 				     int len)
46 {
47 	struct efx_nic *efx = rx_queue->efx;
48 	unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
49 
50 	if (likely(len <= max_len))
51 		return;
52 
53 	/* The packet must be discarded, but this is only a fatal error
54 	 * if the caller indicated it was
55 	 */
56 	rx_buf->flags |= EFX_RX_PKT_DISCARD;
57 
58 	if (net_ratelimit())
59 		netif_err(efx, rx_err, efx->net_dev,
60 			  "RX queue %d overlength RX event (%#x > %#x)\n",
61 			  efx_rx_queue_index(rx_queue), len, max_len);
62 
63 	efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
64 }
65 
66 /* Allocate and construct an SKB around page fragments */
efx_rx_mk_skb(struct efx_channel * channel,struct efx_rx_buffer * rx_buf,unsigned int n_frags,u8 * eh,int hdr_len)67 static struct sk_buff *efx_rx_mk_skb(struct efx_channel *channel,
68 				     struct efx_rx_buffer *rx_buf,
69 				     unsigned int n_frags,
70 				     u8 *eh, int hdr_len)
71 {
72 	struct efx_nic *efx = channel->efx;
73 	struct sk_buff *skb;
74 
75 	/* Allocate an SKB to store the headers */
76 	skb = netdev_alloc_skb(efx->net_dev,
77 			       efx->rx_ip_align + efx->rx_prefix_size +
78 			       hdr_len);
79 	if (unlikely(skb == NULL)) {
80 		atomic_inc(&efx->n_rx_noskb_drops);
81 		return NULL;
82 	}
83 
84 	EFX_WARN_ON_ONCE_PARANOID(rx_buf->len < hdr_len);
85 
86 	memcpy(skb->data + efx->rx_ip_align, eh - efx->rx_prefix_size,
87 	       efx->rx_prefix_size + hdr_len);
88 	skb_reserve(skb, efx->rx_ip_align + efx->rx_prefix_size);
89 	__skb_put(skb, hdr_len);
90 
91 	/* Append the remaining page(s) onto the frag list */
92 	if (rx_buf->len > hdr_len) {
93 		rx_buf->page_offset += hdr_len;
94 		rx_buf->len -= hdr_len;
95 
96 		for (;;) {
97 			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
98 					rx_buf->page, rx_buf->page_offset,
99 					rx_buf->len, efx->rx_buffer_truesize);
100 			rx_buf->page = NULL;
101 
102 			if (skb_shinfo(skb)->nr_frags == n_frags)
103 				break;
104 
105 			rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
106 		}
107 	} else {
108 		__free_pages(rx_buf->page, efx->rx_buffer_order);
109 		rx_buf->page = NULL;
110 		n_frags = 0;
111 	}
112 
113 	/* Move past the ethernet header */
114 	skb->protocol = eth_type_trans(skb, efx->net_dev);
115 
116 	skb_mark_napi_id(skb, &channel->napi_str);
117 
118 	return skb;
119 }
120 
efx_rx_packet(struct efx_rx_queue * rx_queue,unsigned int index,unsigned int n_frags,unsigned int len,u16 flags)121 void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
122 		   unsigned int n_frags, unsigned int len, u16 flags)
123 {
124 	struct efx_nic *efx = rx_queue->efx;
125 	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
126 	struct efx_rx_buffer *rx_buf;
127 
128 	rx_queue->rx_packets++;
129 
130 	rx_buf = efx_rx_buffer(rx_queue, index);
131 	rx_buf->flags |= flags;
132 
133 	/* Validate the number of fragments and completed length */
134 	if (n_frags == 1) {
135 		if (!(flags & EFX_RX_PKT_PREFIX_LEN))
136 			efx_rx_packet__check_len(rx_queue, rx_buf, len);
137 	} else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
138 		   unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
139 		   unlikely(len > n_frags * efx->rx_dma_len) ||
140 		   unlikely(!efx->rx_scatter)) {
141 		/* If this isn't an explicit discard request, either
142 		 * the hardware or the driver is broken.
143 		 */
144 		WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
145 		rx_buf->flags |= EFX_RX_PKT_DISCARD;
146 	}
147 
148 	netif_vdbg(efx, rx_status, efx->net_dev,
149 		   "RX queue %d received ids %x-%x len %d %s%s\n",
150 		   efx_rx_queue_index(rx_queue), index,
151 		   (index + n_frags - 1) & rx_queue->ptr_mask, len,
152 		   (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
153 		   (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
154 
155 	/* Discard packet, if instructed to do so.  Process the
156 	 * previous receive first.
157 	 */
158 	if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
159 		efx_rx_flush_packet(channel);
160 		efx_discard_rx_packet(channel, rx_buf, n_frags);
161 		return;
162 	}
163 
164 	if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
165 		rx_buf->len = len;
166 
167 	/* Release and/or sync the DMA mapping - assumes all RX buffers
168 	 * consumed in-order per RX queue.
169 	 */
170 	efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
171 
172 	/* Prefetch nice and early so data will (hopefully) be in cache by
173 	 * the time we look at it.
174 	 */
175 	prefetch(efx_rx_buf_va(rx_buf));
176 
177 	rx_buf->page_offset += efx->rx_prefix_size;
178 	rx_buf->len -= efx->rx_prefix_size;
179 
180 	if (n_frags > 1) {
181 		/* Release/sync DMA mapping for additional fragments.
182 		 * Fix length for last fragment.
183 		 */
184 		unsigned int tail_frags = n_frags - 1;
185 
186 		for (;;) {
187 			rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
188 			if (--tail_frags == 0)
189 				break;
190 			efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
191 		}
192 		rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
193 		efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
194 	}
195 
196 	/* All fragments have been DMA-synced, so recycle pages. */
197 	rx_buf = efx_rx_buffer(rx_queue, index);
198 	efx_recycle_rx_pages(channel, rx_buf, n_frags);
199 
200 	/* Pipeline receives so that we give time for packet headers to be
201 	 * prefetched into cache.
202 	 */
203 	efx_rx_flush_packet(channel);
204 	channel->rx_pkt_n_frags = n_frags;
205 	channel->rx_pkt_index = index;
206 }
207 
efx_rx_deliver(struct efx_channel * channel,u8 * eh,struct efx_rx_buffer * rx_buf,unsigned int n_frags)208 static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
209 			   struct efx_rx_buffer *rx_buf,
210 			   unsigned int n_frags)
211 {
212 	struct sk_buff *skb;
213 	u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
214 
215 	skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
216 	if (unlikely(skb == NULL)) {
217 		struct efx_rx_queue *rx_queue;
218 
219 		rx_queue = efx_channel_get_rx_queue(channel);
220 		efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
221 		return;
222 	}
223 	skb_record_rx_queue(skb, channel->rx_queue.core_index);
224 
225 	/* Set the SKB flags */
226 	skb_checksum_none_assert(skb);
227 	if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
228 		skb->ip_summed = CHECKSUM_UNNECESSARY;
229 		skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
230 	}
231 
232 	efx_rx_skb_attach_timestamp(channel, skb);
233 
234 	if (channel->type->receive_skb)
235 		if (channel->type->receive_skb(channel, skb))
236 			return;
237 
238 	/* Pass the packet up */
239 	if (channel->rx_list != NULL)
240 		/* Add to list, will pass up later */
241 		list_add_tail(&skb->list, channel->rx_list);
242 	else
243 		/* No list, so pass it up now */
244 		netif_receive_skb(skb);
245 }
246 
247 /** efx_do_xdp: perform XDP processing on a received packet
248  *
249  * Returns true if packet should still be delivered.
250  */
efx_do_xdp(struct efx_nic * efx,struct efx_channel * channel,struct efx_rx_buffer * rx_buf,u8 ** ehp)251 static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
252 		       struct efx_rx_buffer *rx_buf, u8 **ehp)
253 {
254 	u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
255 	struct efx_rx_queue *rx_queue;
256 	struct bpf_prog *xdp_prog;
257 	struct xdp_frame *xdpf;
258 	struct xdp_buff xdp;
259 	u32 xdp_act;
260 	s16 offset;
261 	int err;
262 
263 	xdp_prog = rcu_dereference_bh(efx->xdp_prog);
264 	if (!xdp_prog)
265 		return true;
266 
267 	rx_queue = efx_channel_get_rx_queue(channel);
268 
269 	if (unlikely(channel->rx_pkt_n_frags > 1)) {
270 		/* We can't do XDP on fragmented packets - drop. */
271 		efx_free_rx_buffers(rx_queue, rx_buf,
272 				    channel->rx_pkt_n_frags);
273 		if (net_ratelimit())
274 			netif_err(efx, rx_err, efx->net_dev,
275 				  "XDP is not possible with multiple receive fragments (%d)\n",
276 				  channel->rx_pkt_n_frags);
277 		channel->n_rx_xdp_bad_drops++;
278 		return false;
279 	}
280 
281 	dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr,
282 				rx_buf->len, DMA_FROM_DEVICE);
283 
284 	/* Save the rx prefix. */
285 	EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
286 	memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
287 	       efx->rx_prefix_size);
288 
289 	xdp_init_buff(&xdp, efx->rx_page_buf_step, &rx_queue->xdp_rxq_info);
290 	/* No support yet for XDP metadata */
291 	xdp_prepare_buff(&xdp, *ehp - EFX_XDP_HEADROOM, EFX_XDP_HEADROOM,
292 			 rx_buf->len, false);
293 
294 	xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
295 
296 	offset = (u8 *)xdp.data - *ehp;
297 
298 	switch (xdp_act) {
299 	case XDP_PASS:
300 		/* Fix up rx prefix. */
301 		if (offset) {
302 			*ehp += offset;
303 			rx_buf->page_offset += offset;
304 			rx_buf->len -= offset;
305 			memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
306 			       efx->rx_prefix_size);
307 		}
308 		break;
309 
310 	case XDP_TX:
311 		/* Buffer ownership passes to tx on success. */
312 		xdpf = xdp_convert_buff_to_frame(&xdp);
313 		err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
314 		if (unlikely(err != 1)) {
315 			efx_free_rx_buffers(rx_queue, rx_buf, 1);
316 			if (net_ratelimit())
317 				netif_err(efx, rx_err, efx->net_dev,
318 					  "XDP TX failed (%d)\n", err);
319 			channel->n_rx_xdp_bad_drops++;
320 			trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
321 		} else {
322 			channel->n_rx_xdp_tx++;
323 		}
324 		break;
325 
326 	case XDP_REDIRECT:
327 		err = xdp_do_redirect(efx->net_dev, &xdp, xdp_prog);
328 		if (unlikely(err)) {
329 			efx_free_rx_buffers(rx_queue, rx_buf, 1);
330 			if (net_ratelimit())
331 				netif_err(efx, rx_err, efx->net_dev,
332 					  "XDP redirect failed (%d)\n", err);
333 			channel->n_rx_xdp_bad_drops++;
334 			trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
335 		} else {
336 			channel->n_rx_xdp_redirect++;
337 		}
338 		break;
339 
340 	default:
341 		bpf_warn_invalid_xdp_action(efx->net_dev, xdp_prog, xdp_act);
342 		efx_free_rx_buffers(rx_queue, rx_buf, 1);
343 		channel->n_rx_xdp_bad_drops++;
344 		trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
345 		break;
346 
347 	case XDP_ABORTED:
348 		trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
349 		fallthrough;
350 	case XDP_DROP:
351 		efx_free_rx_buffers(rx_queue, rx_buf, 1);
352 		channel->n_rx_xdp_drops++;
353 		break;
354 	}
355 
356 	return xdp_act == XDP_PASS;
357 }
358 
359 /* Handle a received packet.  Second half: Touches packet payload. */
__efx_rx_packet(struct efx_channel * channel)360 void __efx_rx_packet(struct efx_channel *channel)
361 {
362 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
363 	struct efx_nic *efx = channel->efx;
364 	struct efx_rx_buffer *rx_buf =
365 		efx_rx_buffer(rx_queue, channel->rx_pkt_index);
366 	u8 *eh = efx_rx_buf_va(rx_buf);
367 
368 	/* Read length from the prefix if necessary.  This already
369 	 * excludes the length of the prefix itself.
370 	 */
371 	if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN) {
372 		rx_buf->len = le16_to_cpup((__le16 *)
373 					   (eh + efx->rx_packet_len_offset));
374 		/* A known issue may prevent this being filled in;
375 		 * if that happens, just drop the packet.
376 		 * Must do that in the driver since passing a zero-length
377 		 * packet up to the stack may cause a crash.
378 		 */
379 		if (unlikely(!rx_buf->len)) {
380 			efx_free_rx_buffers(rx_queue, rx_buf,
381 					    channel->rx_pkt_n_frags);
382 			channel->n_rx_frm_trunc++;
383 			goto out;
384 		}
385 	}
386 
387 	/* If we're in loopback test, then pass the packet directly to the
388 	 * loopback layer, and free the rx_buf here
389 	 */
390 	if (unlikely(efx->loopback_selftest)) {
391 		efx_loopback_rx_packet(efx, eh, rx_buf->len);
392 		efx_free_rx_buffers(rx_queue, rx_buf,
393 				    channel->rx_pkt_n_frags);
394 		goto out;
395 	}
396 
397 	if (!efx_do_xdp(efx, channel, rx_buf, &eh))
398 		goto out;
399 
400 	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
401 		rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
402 
403 	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
404 		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh, 0);
405 	else
406 		efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
407 out:
408 	channel->rx_pkt_n_frags = 0;
409 }
410