1/*
2 * Copyright (c) 2013-2015 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Stephan Diestelhorst
38 */
39
40/**
41 * @file
42 * Implementation of a snoop filter.
43 */
44
45#include "base/misc.hh"
46#include "base/trace.hh"
47#include "debug/SnoopFilter.hh"
48#include "mem/snoop_filter.hh"
49#include "sim/system.hh"
50
51void
52SnoopFilter::eraseIfNullEntry(SnoopFilterCache::iterator& sf_it)
53{
54 SnoopItem& sf_item = sf_it->second;
55 if (!(sf_item.requested | sf_item.holder)) {
56 cachedLocations.erase(sf_it);
57 DPRINTF(SnoopFilter, "%s: Removed SF entry.\n",
58 __func__);
59 }
60}
61
62std::pair<SnoopFilter::SnoopList, Cycles>
63SnoopFilter::lookupRequest(const Packet* cpkt, const SlavePort& slave_port)
64{
65 DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
66 __func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
67
68 // Ultimately we should check if the packet came from an
69 // allocating source, not just if the port is snooping
70 bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
71 Addr line_addr = cpkt->getBlockAddr(linesize);
72 SnoopMask req_port = portToMask(slave_port);
73 reqLookupResult = cachedLocations.find(line_addr);
74 bool is_hit = (reqLookupResult != cachedLocations.end());
75
76 // If the snoop filter has no entry, and we should not allocate,
77 // do not create a new snoop filter entry, simply return a NULL
78 // portlist.
79 if (!is_hit && !allocate)
80 return snoopDown(lookupLatency);
81
82 // If no hit in snoop filter create a new element and update iterator
83 if (!is_hit)
84 reqLookupResult = cachedLocations.emplace(line_addr, SnoopItem()).first;
85 SnoopItem& sf_item = reqLookupResult->second;
86 SnoopMask interested = sf_item.holder | sf_item.requested;
87
88 // Store unmodified value of snoop filter item in temp storage in
89 // case we need to revert because of a send retry in
90 // updateRequest.
91 retryItem = sf_item;
92
93 totRequests++;
94 if (is_hit) {
95 // Single bit set -> value is a power of two
96 if (isPow2(interested))
97 hitSingleRequests++;
98 else
99 hitMultiRequests++;
100 }
101
102 DPRINTF(SnoopFilter, "%s: SF value %x.%x\n",
103 __func__, sf_item.requested, sf_item.holder);
104
105 // If we are not allocating, we are done
106 if (!allocate)
107 return snoopSelected(maskToPortList(interested & ~req_port),
108 lookupLatency);
109
110 if (cpkt->needsResponse()) {
111 if (!cpkt->cacheResponding()) {
112 // Max one request per address per port
113 panic_if(sf_item.requested & req_port, "double request :( " \
114 "SF value %x.%x\n", sf_item.requested, sf_item.holder);
115
116 // Mark in-flight requests to distinguish later on
117 sf_item.requested |= req_port;
118 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
119 __func__, sf_item.requested, sf_item.holder);
120 } else {
121 // NOTE: The memInhibit might have been asserted by a cache closer
122 // to the CPU, already -> the response will not be seen by this
123 // filter -> we do not need to keep the in-flight request, but make
124 // sure that we know that that cluster has a copy
125 panic_if(!(sf_item.holder & req_port), "Need to hold the value!");
126 DPRINTF(SnoopFilter,
127 "%s: not marking request. SF value %x.%x\n",
128 __func__, sf_item.requested, sf_item.holder);
129 }
130 } else { // if (!cpkt->needsResponse())
131 assert(cpkt->isEviction());
132 // make sure that the sender actually had the line
133 panic_if(!(sf_item.holder & req_port), "requester %x is not a " \
134 "holder :( SF value %x.%x\n", req_port,
135 sf_item.requested, sf_item.holder);
136 // CleanEvicts and Writebacks -> the sender and all caches above
137 // it may not have the line anymore.
138 if (!cpkt->isBlockCached()) {
139 sf_item.holder &= ~req_port;
140 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
141 __func__, sf_item.requested, sf_item.holder);
142 }
143 }
144
145 return snoopSelected(maskToPortList(interested & ~req_port), lookupLatency);
146}
147
148void
149SnoopFilter::finishRequest(bool will_retry, const Packet* cpkt)
150{
151 if (reqLookupResult != cachedLocations.end()) {
152 // since we rely on the caller, do a basic check to ensure
153 // that finishRequest is being called following lookupRequest
154 assert(reqLookupResult->first == cpkt->getBlockAddr(linesize));
155 if (will_retry) {
156 // Undo any changes made in lookupRequest to the snoop filter
157 // entry if the request will come again. retryItem holds
158 // the previous value of the snoopfilter entry.
159 reqLookupResult->second = retryItem;
160
161 DPRINTF(SnoopFilter, "%s: restored SF value %x.%x\n",
162 __func__, retryItem.requested, retryItem.holder);
163 }
164
165 eraseIfNullEntry(reqLookupResult);
166 }
167}
168
169std::pair<SnoopFilter::SnoopList, Cycles>
170SnoopFilter::lookupSnoop(const Packet* cpkt)
171{
172 DPRINTF(SnoopFilter, "%s: packet addr 0x%x cmd %s\n",
173 __func__, cpkt->getAddr(), cpkt->cmdString());
174
175 assert(cpkt->isRequest());
176
177 Addr line_addr = cpkt->getBlockAddr(linesize);
178 auto sf_it = cachedLocations.find(line_addr);
179 bool is_hit = (sf_it != cachedLocations.end());
180
181 panic_if(!is_hit && (cachedLocations.size() >= maxEntryCount),
182 "snoop filter exceeded capacity of %d cache blocks\n",
183 maxEntryCount);
184
185 // If the snoop filter has no entry, simply return a NULL
186 // portlist, there is no point creating an entry only to remove it
187 // later
188 if (!is_hit)
189 return snoopDown(lookupLatency);
190
191 SnoopItem& sf_item = sf_it->second;
192
193 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
194 __func__, sf_item.requested, sf_item.holder);
195
196 SnoopMask interested = (sf_item.holder | sf_item.requested);
197
198 totSnoops++;
199 // Single bit set -> value is a power of two
200 if (isPow2(interested))
201 hitSingleSnoops++;
202 else
203 hitMultiSnoops++;
204
205 // ReadEx and Writes require both invalidation and exlusivity, while reads
206 // require neither. Writebacks on the other hand require exclusivity but
207 // not the invalidation. Previously Writebacks did not generate upward
208 // snoops so this was never an aissue. Now that Writebacks generate snoops
209 // we need to special case for Writebacks.
210 assert(cpkt->isWriteback() || cpkt->req->isUncacheable() ||
211 (cpkt->isInvalidate() == cpkt->needsWritable()));
212 if (cpkt->isInvalidate() && !sf_item.requested) {
213 // Early clear of the holder, if no other request is currently going on
214 // @todo: This should possibly be updated even though we do not filter
215 // upward snoops
216 sf_item.holder = 0;
217 }
218
219 eraseIfNullEntry(sf_it);
220 DPRINTF(SnoopFilter, "%s: new SF value %x.%x interest: %x \n",
221 __func__, sf_item.requested, sf_item.holder, interested);
222
223 return snoopSelected(maskToPortList(interested), lookupLatency);
224}
225
226void
227SnoopFilter::updateSnoopResponse(const Packet* cpkt,
228 const SlavePort& rsp_port,
229 const SlavePort& req_port)
230{
231 DPRINTF(SnoopFilter, "%s: packet rsp %s req %s addr 0x%x cmd %s\n",
232 __func__, rsp_port.name(), req_port.name(), cpkt->getAddr(),
233 cpkt->cmdString());
234
235 assert(cpkt->isResponse());
236 assert(cpkt->cacheResponding());
237
238 // Ultimately we should check if the packet came from an
239 // allocating source, not just if the port is snooping
240 bool allocate = !cpkt->req->isUncacheable() && req_port.isSnooping();
241 if (!allocate)
242 return;
243
244 Addr line_addr = cpkt->getBlockAddr(linesize);
245 SnoopMask rsp_mask = portToMask(rsp_port);
246 SnoopMask req_mask = portToMask(req_port);
247 SnoopItem& sf_item = cachedLocations[line_addr];
248
249 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
250 __func__, sf_item.requested, sf_item.holder);
251
252 // The source should have the line
253 panic_if(!(sf_item.holder & rsp_mask), "SF value %x.%x does not have "\
254 "the line\n", sf_item.requested, sf_item.holder);
255
256 // The destination should have had a request in
257 panic_if(!(sf_item.requested & req_mask), "SF value %x.%x missing "\
258 "the original request\n", sf_item.requested, sf_item.holder);
259
| 1/*
2 * Copyright (c) 2013-2015 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Stephan Diestelhorst
38 */
39
40/**
41 * @file
42 * Implementation of a snoop filter.
43 */
44
45#include "base/misc.hh"
46#include "base/trace.hh"
47#include "debug/SnoopFilter.hh"
48#include "mem/snoop_filter.hh"
49#include "sim/system.hh"
50
51void
52SnoopFilter::eraseIfNullEntry(SnoopFilterCache::iterator& sf_it)
53{
54 SnoopItem& sf_item = sf_it->second;
55 if (!(sf_item.requested | sf_item.holder)) {
56 cachedLocations.erase(sf_it);
57 DPRINTF(SnoopFilter, "%s: Removed SF entry.\n",
58 __func__);
59 }
60}
61
62std::pair<SnoopFilter::SnoopList, Cycles>
63SnoopFilter::lookupRequest(const Packet* cpkt, const SlavePort& slave_port)
64{
65 DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
66 __func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
67
68 // Ultimately we should check if the packet came from an
69 // allocating source, not just if the port is snooping
70 bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
71 Addr line_addr = cpkt->getBlockAddr(linesize);
72 SnoopMask req_port = portToMask(slave_port);
73 reqLookupResult = cachedLocations.find(line_addr);
74 bool is_hit = (reqLookupResult != cachedLocations.end());
75
76 // If the snoop filter has no entry, and we should not allocate,
77 // do not create a new snoop filter entry, simply return a NULL
78 // portlist.
79 if (!is_hit && !allocate)
80 return snoopDown(lookupLatency);
81
82 // If no hit in snoop filter create a new element and update iterator
83 if (!is_hit)
84 reqLookupResult = cachedLocations.emplace(line_addr, SnoopItem()).first;
85 SnoopItem& sf_item = reqLookupResult->second;
86 SnoopMask interested = sf_item.holder | sf_item.requested;
87
88 // Store unmodified value of snoop filter item in temp storage in
89 // case we need to revert because of a send retry in
90 // updateRequest.
91 retryItem = sf_item;
92
93 totRequests++;
94 if (is_hit) {
95 // Single bit set -> value is a power of two
96 if (isPow2(interested))
97 hitSingleRequests++;
98 else
99 hitMultiRequests++;
100 }
101
102 DPRINTF(SnoopFilter, "%s: SF value %x.%x\n",
103 __func__, sf_item.requested, sf_item.holder);
104
105 // If we are not allocating, we are done
106 if (!allocate)
107 return snoopSelected(maskToPortList(interested & ~req_port),
108 lookupLatency);
109
110 if (cpkt->needsResponse()) {
111 if (!cpkt->cacheResponding()) {
112 // Max one request per address per port
113 panic_if(sf_item.requested & req_port, "double request :( " \
114 "SF value %x.%x\n", sf_item.requested, sf_item.holder);
115
116 // Mark in-flight requests to distinguish later on
117 sf_item.requested |= req_port;
118 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
119 __func__, sf_item.requested, sf_item.holder);
120 } else {
121 // NOTE: The memInhibit might have been asserted by a cache closer
122 // to the CPU, already -> the response will not be seen by this
123 // filter -> we do not need to keep the in-flight request, but make
124 // sure that we know that that cluster has a copy
125 panic_if(!(sf_item.holder & req_port), "Need to hold the value!");
126 DPRINTF(SnoopFilter,
127 "%s: not marking request. SF value %x.%x\n",
128 __func__, sf_item.requested, sf_item.holder);
129 }
130 } else { // if (!cpkt->needsResponse())
131 assert(cpkt->isEviction());
132 // make sure that the sender actually had the line
133 panic_if(!(sf_item.holder & req_port), "requester %x is not a " \
134 "holder :( SF value %x.%x\n", req_port,
135 sf_item.requested, sf_item.holder);
136 // CleanEvicts and Writebacks -> the sender and all caches above
137 // it may not have the line anymore.
138 if (!cpkt->isBlockCached()) {
139 sf_item.holder &= ~req_port;
140 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
141 __func__, sf_item.requested, sf_item.holder);
142 }
143 }
144
145 return snoopSelected(maskToPortList(interested & ~req_port), lookupLatency);
146}
147
148void
149SnoopFilter::finishRequest(bool will_retry, const Packet* cpkt)
150{
151 if (reqLookupResult != cachedLocations.end()) {
152 // since we rely on the caller, do a basic check to ensure
153 // that finishRequest is being called following lookupRequest
154 assert(reqLookupResult->first == cpkt->getBlockAddr(linesize));
155 if (will_retry) {
156 // Undo any changes made in lookupRequest to the snoop filter
157 // entry if the request will come again. retryItem holds
158 // the previous value of the snoopfilter entry.
159 reqLookupResult->second = retryItem;
160
161 DPRINTF(SnoopFilter, "%s: restored SF value %x.%x\n",
162 __func__, retryItem.requested, retryItem.holder);
163 }
164
165 eraseIfNullEntry(reqLookupResult);
166 }
167}
168
169std::pair<SnoopFilter::SnoopList, Cycles>
170SnoopFilter::lookupSnoop(const Packet* cpkt)
171{
172 DPRINTF(SnoopFilter, "%s: packet addr 0x%x cmd %s\n",
173 __func__, cpkt->getAddr(), cpkt->cmdString());
174
175 assert(cpkt->isRequest());
176
177 Addr line_addr = cpkt->getBlockAddr(linesize);
178 auto sf_it = cachedLocations.find(line_addr);
179 bool is_hit = (sf_it != cachedLocations.end());
180
181 panic_if(!is_hit && (cachedLocations.size() >= maxEntryCount),
182 "snoop filter exceeded capacity of %d cache blocks\n",
183 maxEntryCount);
184
185 // If the snoop filter has no entry, simply return a NULL
186 // portlist, there is no point creating an entry only to remove it
187 // later
188 if (!is_hit)
189 return snoopDown(lookupLatency);
190
191 SnoopItem& sf_item = sf_it->second;
192
193 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
194 __func__, sf_item.requested, sf_item.holder);
195
196 SnoopMask interested = (sf_item.holder | sf_item.requested);
197
198 totSnoops++;
199 // Single bit set -> value is a power of two
200 if (isPow2(interested))
201 hitSingleSnoops++;
202 else
203 hitMultiSnoops++;
204
205 // ReadEx and Writes require both invalidation and exlusivity, while reads
206 // require neither. Writebacks on the other hand require exclusivity but
207 // not the invalidation. Previously Writebacks did not generate upward
208 // snoops so this was never an aissue. Now that Writebacks generate snoops
209 // we need to special case for Writebacks.
210 assert(cpkt->isWriteback() || cpkt->req->isUncacheable() ||
211 (cpkt->isInvalidate() == cpkt->needsWritable()));
212 if (cpkt->isInvalidate() && !sf_item.requested) {
213 // Early clear of the holder, if no other request is currently going on
214 // @todo: This should possibly be updated even though we do not filter
215 // upward snoops
216 sf_item.holder = 0;
217 }
218
219 eraseIfNullEntry(sf_it);
220 DPRINTF(SnoopFilter, "%s: new SF value %x.%x interest: %x \n",
221 __func__, sf_item.requested, sf_item.holder, interested);
222
223 return snoopSelected(maskToPortList(interested), lookupLatency);
224}
225
226void
227SnoopFilter::updateSnoopResponse(const Packet* cpkt,
228 const SlavePort& rsp_port,
229 const SlavePort& req_port)
230{
231 DPRINTF(SnoopFilter, "%s: packet rsp %s req %s addr 0x%x cmd %s\n",
232 __func__, rsp_port.name(), req_port.name(), cpkt->getAddr(),
233 cpkt->cmdString());
234
235 assert(cpkt->isResponse());
236 assert(cpkt->cacheResponding());
237
238 // Ultimately we should check if the packet came from an
239 // allocating source, not just if the port is snooping
240 bool allocate = !cpkt->req->isUncacheable() && req_port.isSnooping();
241 if (!allocate)
242 return;
243
244 Addr line_addr = cpkt->getBlockAddr(linesize);
245 SnoopMask rsp_mask = portToMask(rsp_port);
246 SnoopMask req_mask = portToMask(req_port);
247 SnoopItem& sf_item = cachedLocations[line_addr];
248
249 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
250 __func__, sf_item.requested, sf_item.holder);
251
252 // The source should have the line
253 panic_if(!(sf_item.holder & rsp_mask), "SF value %x.%x does not have "\
254 "the line\n", sf_item.requested, sf_item.holder);
255
256 // The destination should have had a request in
257 panic_if(!(sf_item.requested & req_mask), "SF value %x.%x missing "\
258 "the original request\n", sf_item.requested, sf_item.holder);
259
|
313 sf_item.holder = 0;
314 }
315 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
316 __func__, sf_item.requested, sf_item.holder);
317 eraseIfNullEntry(sf_it);
318
319}
320
321void
322SnoopFilter::updateResponse(const Packet* cpkt, const SlavePort& slave_port)
323{
324 DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
325 __func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
326
327 assert(cpkt->isResponse());
328
329 // Ultimately we should check if the packet came from an
330 // allocating source, not just if the port is snooping
331 bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
332 if (!allocate)
333 return;
334
335 Addr line_addr = cpkt->getBlockAddr(linesize);
336 SnoopMask slave_mask = portToMask(slave_port);
337 SnoopItem& sf_item = cachedLocations[line_addr];
338
339 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
340 __func__, sf_item.requested, sf_item.holder);
341
342 // Make sure we have seen the actual request, too
343 panic_if(!(sf_item.requested & slave_mask), "SF value %x.%x missing "\
344 "request bit\n", sf_item.requested, sf_item.holder);
345
| 306 sf_item.holder = 0;
307 }
308 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
309 __func__, sf_item.requested, sf_item.holder);
310 eraseIfNullEntry(sf_it);
311
312}
313
314void
315SnoopFilter::updateResponse(const Packet* cpkt, const SlavePort& slave_port)
316{
317 DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
318 __func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
319
320 assert(cpkt->isResponse());
321
322 // Ultimately we should check if the packet came from an
323 // allocating source, not just if the port is snooping
324 bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
325 if (!allocate)
326 return;
327
328 Addr line_addr = cpkt->getBlockAddr(linesize);
329 SnoopMask slave_mask = portToMask(slave_port);
330 SnoopItem& sf_item = cachedLocations[line_addr];
331
332 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
333 __func__, sf_item.requested, sf_item.holder);
334
335 // Make sure we have seen the actual request, too
336 panic_if(!(sf_item.requested & slave_mask), "SF value %x.%x missing "\
337 "request bit\n", sf_item.requested, sf_item.holder);
338
|