1Arm CPU Specific Build Macros
2=============================
3
4This document describes the various build options present in the CPU specific
5operations framework to enable errata workarounds and to enable optimizations
6for a specific CPU on a platform.
7
8Security Vulnerability Workarounds
9----------------------------------
10
11TF-A exports a series of build flags which control which security
12vulnerability workarounds should be applied at runtime.
13
14-  ``WORKAROUND_CVE_2017_5715``: Enables the security workaround for
15   `CVE-2017-5715`_. This flag can be set to 0 by the platform if none
16   of the PEs in the system need the workaround. Setting this flag to 0 provides
17   no performance benefit for non-affected platforms, it just helps to comply
18   with the recommendation in the spec regarding workaround discovery.
19   Defaults to 1.
20
21-  ``WORKAROUND_CVE_2018_3639``: Enables the security workaround for
22   `CVE-2018-3639`_. Defaults to 1. The TF-A project recommends to keep
23   the default value of 1 even on platforms that are unaffected by
24   CVE-2018-3639, in order to comply with the recommendation in the spec
25   regarding workaround discovery.
26
27-  ``DYNAMIC_WORKAROUND_CVE_2018_3639``: Enables dynamic mitigation for
28   `CVE-2018-3639`_. This build option should be set to 1 if the target
29   platform contains at least 1 CPU that requires dynamic mitigation.
30   Defaults to 0.
31
32-  ``WORKAROUND_CVE_2022_23960``: Enables mitigation for `CVE-2022-23960`_.
33   This build option should be set to 1 if the target platform contains at
34   least 1 CPU that requires this mitigation. Defaults to 1.
35
36.. _arm_cpu_macros_errata_workarounds:
37
38CPU Errata Workarounds
39----------------------
40
41TF-A exports a series of build flags which control the errata workarounds that
42are applied to each CPU by the reset handler. The errata details can be found
43in the CPU specific errata documents published by Arm:
44
45-  `Cortex-A53 MPCore Software Developers Errata Notice`_
46-  `Cortex-A57 MPCore Software Developers Errata Notice`_
47-  `Cortex-A72 MPCore Software Developers Errata Notice`_
48
49The errata workarounds are implemented for a particular revision or a set of
50processor revisions. This is checked by the reset handler at runtime. Each
51errata workaround is identified by its ``ID`` as specified in the processor's
52errata notice document. The format of the define used to enable/disable the
53errata workaround is ``ERRATA_<Processor name>_<ID>``, where the ``Processor name``
54is for example ``A57`` for the ``Cortex_A57`` CPU.
55
56Refer to :ref:`firmware_design_cpu_errata_reporting` for information on how to
57write errata workaround functions.
58
59All workarounds are disabled by default. The platform is responsible for
60enabling these workarounds according to its requirement by defining the
61errata workaround build flags in the platform specific makefile. In case
62these workarounds are enabled for the wrong CPU revision then the errata
63workaround is not applied. In the DEBUG build, this is indicated by
64printing a warning to the crash console.
65
66In the current implementation, a platform which has more than 1 variant
67with different revisions of a processor has no runtime mechanism available
68for it to specify which errata workarounds should be enabled or not.
69
70The value of the build flags is 0 by default, that is, disabled. A value of 1
71will enable it.
72
73For Cortex-A9, the following errata build flags are defined :
74
75-  ``ERRATA_A9_794073``: This applies errata 794073 workaround to Cortex-A9
76   CPU. This needs to be enabled for all revisions of the CPU.
77
78For Cortex-A15, the following errata build flags are defined :
79
80-  ``ERRATA_A15_816470``: This applies errata 816470 workaround to Cortex-A15
81   CPU. This needs to be enabled only for revision >= r3p0 of the CPU.
82
83-  ``ERRATA_A15_827671``: This applies errata 827671 workaround to Cortex-A15
84   CPU. This needs to be enabled only for revision >= r3p0 of the CPU.
85
86For Cortex-A17, the following errata build flags are defined :
87
88-  ``ERRATA_A17_852421``: This applies errata 852421 workaround to Cortex-A17
89   CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
90
91-  ``ERRATA_A17_852423``: This applies errata 852423 workaround to Cortex-A17
92   CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
93
94For Cortex-A35, the following errata build flags are defined :
95
96-  ``ERRATA_A35_855472``: This applies errata 855472 workaround to Cortex-A35
97   CPUs. This needs to be enabled only for revision r0p0 of Cortex-A35.
98
99For Cortex-A53, the following errata build flags are defined :
100
101-  ``ERRATA_A53_819472``: This applies errata 819472 workaround to all
102   CPUs. This needs to be enabled only for revision <= r0p1 of Cortex-A53.
103
104-  ``ERRATA_A53_824069``: This applies errata 824069 workaround to all
105   CPUs. This needs to be enabled only for revision <= r0p2 of Cortex-A53.
106
107-  ``ERRATA_A53_826319``: This applies errata 826319 workaround to Cortex-A53
108   CPU. This needs to be enabled only for revision <= r0p2 of the CPU.
109
110-  ``ERRATA_A53_827319``: This applies errata 827319 workaround to all
111   CPUs. This needs to be enabled only for revision <= r0p2 of Cortex-A53.
112
113-  ``ERRATA_A53_835769``: This applies erratum 835769 workaround at compile and
114   link time to Cortex-A53 CPU. This needs to be enabled for some variants of
115   revision <= r0p4. This workaround can lead the linker to create ``*.stub``
116   sections.
117
118-  ``ERRATA_A53_836870``: This applies errata 836870 workaround to Cortex-A53
119   CPU. This needs to be enabled only for revision <= r0p3 of the CPU. From
120   r0p4 and onwards, this errata is enabled by default in hardware.
121
122-  ``ERRATA_A53_843419``: This applies erratum 843419 workaround at link time
123   to Cortex-A53 CPU.  This needs to be enabled for some variants of revision
124   <= r0p4. This workaround can lead the linker to emit ``*.stub`` sections
125   which are 4kB aligned.
126
127-  ``ERRATA_A53_855873``: This applies errata 855873 workaround to Cortex-A53
128   CPUs. Though the erratum is present in every revision of the CPU,
129   this workaround is only applied to CPUs from r0p3 onwards, which feature
130   a chicken bit in CPUACTLR_EL1 to enable a hardware workaround.
131   Earlier revisions of the CPU have other errata which require the same
132   workaround in software, so they should be covered anyway.
133
134-  ``ERRATA_A53_1530924``: This applies errata 1530924 workaround to all
135   revisions of Cortex-A53 CPU.
136
137For Cortex-A55, the following errata build flags are defined :
138
139-  ``ERRATA_A55_768277``: This applies errata 768277 workaround to Cortex-A55
140   CPU. This needs to be enabled only for revision r0p0 of the CPU.
141
142-  ``ERRATA_A55_778703``: This applies errata 778703 workaround to Cortex-A55
143   CPU. This needs to be enabled only for revision r0p0 of the CPU.
144
145-  ``ERRATA_A55_798797``: This applies errata 798797 workaround to Cortex-A55
146   CPU. This needs to be enabled only for revision r0p0 of the CPU.
147
148-  ``ERRATA_A55_846532``: This applies errata 846532 workaround to Cortex-A55
149   CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
150
151-  ``ERRATA_A55_903758``: This applies errata 903758 workaround to Cortex-A55
152   CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
153
154-  ``ERRATA_A55_1221012``: This applies errata 1221012 workaround to Cortex-A55
155   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
156
157-  ``ERRATA_A55_1530923``: This applies errata 1530923 workaround to all
158   revisions of Cortex-A55 CPU.
159
160For Cortex-A57, the following errata build flags are defined :
161
162-  ``ERRATA_A57_806969``: This applies errata 806969 workaround to Cortex-A57
163   CPU. This needs to be enabled only for revision r0p0 of the CPU.
164
165-  ``ERRATA_A57_813419``: This applies errata 813419 workaround to Cortex-A57
166   CPU. This needs to be enabled only for revision r0p0 of the CPU.
167
168-  ``ERRATA_A57_813420``: This applies errata 813420 workaround to Cortex-A57
169   CPU. This needs to be enabled only for revision r0p0 of the CPU.
170
171-  ``ERRATA_A57_814670``: This applies errata 814670 workaround to Cortex-A57
172   CPU. This needs to be enabled only for revision r0p0 of the CPU.
173
174-  ``ERRATA_A57_817169``: This applies errata 817169 workaround to Cortex-A57
175   CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
176
177-  ``ERRATA_A57_826974``: This applies errata 826974 workaround to Cortex-A57
178   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
179
180-  ``ERRATA_A57_826977``: This applies errata 826977 workaround to Cortex-A57
181   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
182
183-  ``ERRATA_A57_828024``: This applies errata 828024 workaround to Cortex-A57
184   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
185
186-  ``ERRATA_A57_829520``: This applies errata 829520 workaround to Cortex-A57
187   CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
188
189-  ``ERRATA_A57_833471``: This applies errata 833471 workaround to Cortex-A57
190   CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
191
192-  ``ERRATA_A57_859972``: This applies errata 859972 workaround to Cortex-A57
193   CPU. This needs to be enabled only for revision <= r1p3 of the CPU.
194
195-  ``ERRATA_A57_1319537``: This applies errata 1319537 workaround to all
196   revisions of Cortex-A57 CPU.
197
198For Cortex-A72, the following errata build flags are defined :
199
200-  ``ERRATA_A72_859971``: This applies errata 859971 workaround to Cortex-A72
201   CPU. This needs to be enabled only for revision <= r0p3 of the CPU.
202
203-  ``ERRATA_A72_1319367``: This applies errata 1319367 workaround to all
204   revisions of Cortex-A72 CPU.
205
206For Cortex-A73, the following errata build flags are defined :
207
208-  ``ERRATA_A73_852427``: This applies errata 852427 workaround to Cortex-A73
209   CPU. This needs to be enabled only for revision r0p0 of the CPU.
210
211-  ``ERRATA_A73_855423``: This applies errata 855423 workaround to Cortex-A73
212   CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
213
214For Cortex-A75, the following errata build flags are defined :
215
216-  ``ERRATA_A75_764081``: This applies errata 764081 workaround to Cortex-A75
217   CPU. This needs to be enabled only for revision r0p0 of the CPU.
218
219-  ``ERRATA_A75_790748``: This applies errata 790748 workaround to Cortex-A75
220    CPU. This needs to be enabled only for revision r0p0 of the CPU.
221
222For Cortex-A76, the following errata build flags are defined :
223
224-  ``ERRATA_A76_1073348``: This applies errata 1073348 workaround to Cortex-A76
225   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
226
227-  ``ERRATA_A76_1130799``: This applies errata 1130799 workaround to Cortex-A76
228   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
229
230-  ``ERRATA_A76_1220197``: This applies errata 1220197 workaround to Cortex-A76
231   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
232
233-  ``ERRATA_A76_1257314``: This applies errata 1257314 workaround to Cortex-A76
234   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
235
236-  ``ERRATA_A76_1262606``: This applies errata 1262606 workaround to Cortex-A76
237   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
238
239-  ``ERRATA_A76_1262888``: This applies errata 1262888 workaround to Cortex-A76
240   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
241
242-  ``ERRATA_A76_1275112``: This applies errata 1275112 workaround to Cortex-A76
243   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
244
245-  ``ERRATA_A76_1791580``: This applies errata 1791580 workaround to Cortex-A76
246   CPU. This needs to be enabled only for revision <= r4p0 of the CPU.
247
248-  ``ERRATA_A76_1165522``: This applies errata 1165522 workaround to all
249   revisions of Cortex-A76 CPU. This errata is fixed in r3p0 but due to
250   limitation of errata framework this errata is applied to all revisions
251   of Cortex-A76 CPU.
252
253-  ``ERRATA_A76_1868343``: This applies errata 1868343 workaround to Cortex-A76
254   CPU. This needs to be enabled only for revision <= r4p0 of the CPU.
255
256-  ``ERRATA_A76_1946160``: This applies errata 1946160 workaround to Cortex-A76
257   CPU. This needs to be enabled only for revisions r3p0 - r4p1 of the CPU.
258
259-  ``ERRATA_A76_2743102``: This applies errata 2743102 workaround to Cortex-A76
260   CPU. This needs to be enabled for all revisions <= r4p1 of the CPU and is
261   still open.
262
263For Cortex-A77, the following errata build flags are defined :
264
265-  ``ERRATA_A77_1508412``: This applies errata 1508412 workaround to Cortex-A77
266   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
267
268-  ``ERRATA_A77_1925769``: This applies errata 1925769 workaround to Cortex-A77
269   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
270
271-  ``ERRATA_A77_1946167``: This applies errata 1946167 workaround to Cortex-A77
272   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
273
274-  ``ERRATA_A77_1791578``: This applies errata 1791578 workaround to Cortex-A77
275   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
276
277-  ``ERRATA_A77_2356587``: This applies errata 2356587 workaround to Cortex-A77
278   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
279
280 -  ``ERRATA_A77_1800714``: This applies errata 1800714 workaround to Cortex-A77
281    CPU. This needs to be enabled for revisions <= r1p1 of the CPU.
282
283 -  ``ERRATA_A77_2743100``: This applies errata 2743100 workaround to Cortex-A77
284    CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
285
286For Cortex-A78, the following errata build flags are defined :
287
288-  ``ERRATA_A78_1688305``: This applies errata 1688305 workaround to Cortex-A78
289   CPU. This needs to be enabled only for revision r0p0 - r1p0 of the CPU.
290
291-  ``ERRATA_A78_1941498``: This applies errata 1941498 workaround to Cortex-A78
292   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
293
294-  ``ERRATA_A78_1951500``: This applies errata 1951500 workaround to Cortex-A78
295   CPU. This needs to be enabled for revisions r1p0 and r1p1, r0p0 has the same
296   issue but there is no workaround for that revision.
297
298-  ``ERRATA_A78_1821534``: This applies errata 1821534 workaround to Cortex-A78
299   CPU. This needs to be enabled for revisions r0p0 and r1p0.
300
301-  ``ERRATA_A78_1952683``: This applies errata 1952683 workaround to Cortex-A78
302   CPU. This needs to be enabled for revision r0p0, it is fixed in r1p0.
303
304-  ``ERRATA_A78_2132060``: This applies errata 2132060 workaround to Cortex-A78
305   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2. It
306   is still open.
307
308-  ``ERRATA_A78_2242635``: This applies errata 2242635 workaround to Cortex-A78
309   CPU. This needs to be enabled for revisions r1p0, r1p1, and r1p2. The issue
310   is present in r0p0 but there is no workaround. It is still open.
311
312-  ``ERRATA_A78_2376745``: This applies errata 2376745 workaround to Cortex-A78
313   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
314   it is still open.
315
316-  ``ERRATA_A78_2395406``: This applies errata 2395406 workaround to Cortex-A78
317   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
318   it is still open.
319
320For Cortex-A78 AE, the following errata build flags are defined :
321
322- ``ERRATA_A78_AE_1941500`` : This applies errata 1941500 workaround to
323   Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1.
324   This erratum is still open.
325
326- ``ERRATA_A78_AE_1951502`` : This applies errata 1951502 workaround to
327  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
328  erratum is still open.
329
330- ``ERRATA_A78_AE_2376748`` : This applies errata 2376748 workaround to
331  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
332  erratum is still open.
333
334- ``ERRATA_A78_AE_2395408`` : This applies errata 2395408 workaround to
335  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
336  erratum is still open.
337
338For Cortex-A78C, the following errata build flags are defined :
339
340- ``ERRATA_A78C_2132064`` : This applies errata 2132064 workaround to
341  Cortex-A78C CPU. This needs to be enabled for revisions r0p1, r0p2 and
342  it is still open.
343
344- ``ERRATA_A78C_2242638`` : This applies errata 2242638 workaround to
345  Cortex-A78C CPU. This needs to be enabled for revisions r0p1, r0p2 and
346  it is still open.
347
348- ``ERRATA_A78C_2376749`` : This applies errata 2376749 workaround to
349  Cortex-A78C CPU. This needs to be enabled for revisions r0p1 and r0p2. This
350  erratum is still open.
351
352- ``ERRATA_A78C_2395411`` : This applies errata 2395411 workaround to
353  Cortex-A78C CPU. This needs to be enabled for revisions r0p1 and r0p2. This
354  erratum is still open.
355
356For Cortex-X1 CPU, the following errata build flags are defined:
357
358- ``ERRATA_X1_1821534`` : This applies errata 1821534 workaround to Cortex-X1
359   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
360
361- ``ERRATA_X1_1688305`` : This applies errata 1688305 workaround to Cortex-X1
362   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
363
364- ``ERRATA_X1_1827429`` : This applies errata 1827429 workaround to Cortex-X1
365   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
366
367For Neoverse N1, the following errata build flags are defined :
368
369-  ``ERRATA_N1_1073348``: This applies errata 1073348 workaround to Neoverse-N1
370   CPU. This needs to be enabled only for revision r0p0 and r1p0 of the CPU.
371
372-  ``ERRATA_N1_1130799``: This applies errata 1130799 workaround to Neoverse-N1
373   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
374
375-  ``ERRATA_N1_1165347``: This applies errata 1165347 workaround to Neoverse-N1
376   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
377
378-  ``ERRATA_N1_1207823``: This applies errata 1207823 workaround to Neoverse-N1
379   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
380
381-  ``ERRATA_N1_1220197``: This applies errata 1220197 workaround to Neoverse-N1
382   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
383
384-  ``ERRATA_N1_1257314``: This applies errata 1257314 workaround to Neoverse-N1
385   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
386
387-  ``ERRATA_N1_1262606``: This applies errata 1262606 workaround to Neoverse-N1
388   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
389
390-  ``ERRATA_N1_1262888``: This applies errata 1262888 workaround to Neoverse-N1
391   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
392
393-  ``ERRATA_N1_1275112``: This applies errata 1275112 workaround to Neoverse-N1
394   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
395
396-  ``ERRATA_N1_1315703``: This applies errata 1315703 workaround to Neoverse-N1
397   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
398
399-  ``ERRATA_N1_1542419``: This applies errata 1542419 workaround to Neoverse-N1
400   CPU. This needs to be enabled only for revisions r3p0 - r4p0 of the CPU.
401
402-  ``ERRATA_N1_1868343``: This applies errata 1868343 workaround to Neoverse-N1
403   CPU. This needs to be enabled only for revision <= r4p0 of the CPU.
404
405-  ``ERRATA_N1_1946160``: This applies errata 1946160 workaround to Neoverse-N1
406   CPU. This needs to be enabled for revisions r3p0, r3p1, r4p0, and r4p1, for
407   revisions r0p0, r1p0, and r2p0 there is no workaround.
408
409-  ``ERRATA_N1_2743102``: This applies errata 2743102 workaround to Neoverse-N1
410   CPU. This needs to be enabled for all revisions <= r4p1 of the CPU and is
411   still open.
412
413For Neoverse V1, the following errata build flags are defined :
414
415-  ``ERRATA_V1_1618635``: This applies errata 1618635 workaround to Neoverse-V1
416   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
417   r1p0.
418
419-  ``ERRATA_V1_1774420``: This applies errata 1774420 workaround to Neoverse-V1
420   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
421   in r1p1.
422
423-  ``ERRATA_V1_1791573``: This applies errata 1791573 workaround to Neoverse-V1
424   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
425   in r1p1.
426
427-  ``ERRATA_V1_1852267``: This applies errata 1852267 workaround to Neoverse-V1
428   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
429   in r1p1.
430
431-  ``ERRATA_V1_1925756``: This applies errata 1925756 workaround to Neoverse-V1
432   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
433
434-  ``ERRATA_V1_1940577``: This applies errata 1940577 workaround to Neoverse-V1
435   CPU. This needs to be enabled only for revision r1p0 and r1p1 of the
436   CPU.
437
438-  ``ERRATA_V1_1966096``: This applies errata 1966096 workaround to Neoverse-V1
439   CPU. This needs to be enabled for revisions r1p0 and r1p1 of the CPU, the
440   issue is present in r0p0 as well but there is no workaround for that
441   revision.  It is still open.
442
443-  ``ERRATA_V1_2139242``: This applies errata 2139242 workaround to Neoverse-V1
444   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the
445   CPU.  It is still open.
446
447-  ``ERRATA_V1_2108267``: This applies errata 2108267 workaround to Neoverse-V1
448   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
449   It is still open.
450
451-  ``ERRATA_V1_2216392``: This applies errata 2216392 workaround to Neoverse-V1
452   CPU. This needs to be enabled for revisions r1p0 and r1p1 of the CPU, the
453   issue is present in r0p0 as well but there is no workaround for that
454   revision.  It is still open.
455
456-  ``ERRATA_V1_2294912``: This applies errata 2294912 workaround to Neoverse-V1
457   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
458
459-  ``ERRATA_V1_2372203``: This applies errata 2372203 workaround to Neoverse-V1
460   CPU. This needs to be enabled for revisions r0p0, r1p0 and r1p1 of the CPU.
461   It is still open.
462
463For Cortex-A710, the following errata build flags are defined :
464
465-  ``ERRATA_A710_1987031``: This applies errata 1987031 workaround to
466   Cortex-A710 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
467   r2p0 of the CPU. It is still open.
468
469-  ``ERRATA_A710_2081180``: This applies errata 2081180 workaround to
470   Cortex-A710 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
471   r2p0 of the CPU. It is still open.
472
473-  ``ERRATA_A710_2055002``: This applies errata 2055002 workaround to
474   Cortex-A710 CPU. This needs to be enabled for revisions r1p0, r2p0 of the CPU
475   and is still open.
476
477-  ``ERRATA_A710_2017096``: This applies errata 2017096 workaround to
478   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
479   of the CPU and is still open.
480
481-  ``ERRATA_A710_2083908``: This applies errata 2083908 workaround to
482   Cortex-A710 CPU. This needs to be enabled for revision r2p0 of the CPU and
483   is still open.
484
485-  ``ERRATA_A710_2058056``: This applies errata 2058056 workaround to
486   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
487   of the CPU and is still open.
488
489-  ``ERRATA_A710_2267065``: This applies errata 2267065 workaround to
490   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
491   of the CPU and is fixed in r2p1.
492
493-  ``ERRATA_A710_2136059``: This applies errata 2136059 workaround to
494   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
495   of the CPU and is fixed in r2p1.
496
497-  ``ERRATA_A710_2147715``: This applies errata 2147715 workaround to
498   Cortex-A710 CPU. This needs to be enabled for revision r2p0 of the CPU
499   and is fixed in r2p1.
500
501-  ``ERRATA_A710_2216384``: This applies errata 2216384 workaround to
502   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
503   of the CPU and is fixed in r2p1.
504
505-  ``ERRATA_A710_2282622``: This applies errata 2282622 workaround to
506   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
507   of the CPU and is fixed in r2p1.
508
509- ``ERRATA_A710_2291219``: This applies errata 2291219 workaround to
510   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
511   of the CPU and is fixed in r2p1.
512
513-  ``ERRATA_A710_2008768``: This applies errata 2008768 workaround to
514   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
515   of the CPU and is fixed in r2p1.
516
517-  ``ERRATA_A710_2371105``: This applies errata 2371105 workaround to
518   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
519   of the CPU and is fixed in r2p1.
520
521For Neoverse N2, the following errata build flags are defined :
522
523-  ``ERRATA_N2_2002655``: This applies errata 2002655 workaround to Neoverse-N2
524   CPU. This needs to be enabled for revision r0p0 of the CPU, it is still open.
525
526-  ``ERRATA_N2_2067956``: This applies errata 2067956 workaround to Neoverse-N2
527   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
528
529-  ``ERRATA_N2_2025414``: This applies errata 2025414 workaround to Neoverse-N2
530   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
531
532-  ``ERRATA_N2_2189731``: This applies errata 2189731 workaround to Neoverse-N2
533   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
534
535-  ``ERRATA_N2_2138956``: This applies errata 2138956 workaround to Neoverse-N2
536   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
537
538-  ``ERRATA_N2_2138953``: This applies errata 2138953 workaround to Neoverse-N2
539   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
540
541-  ``ERRATA_N2_2242415``: This applies errata 2242415 workaround to Neoverse-N2
542   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
543
544-  ``ERRATA_N2_2138958``: This applies errata 2138958 workaround to Neoverse-N2
545   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
546
547-  ``ERRATA_N2_2242400``: This applies errata 2242400 workaround to Neoverse-N2
548   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
549
550-  ``ERRATA_N2_2280757``: This applies errata 2280757 workaround to Neoverse-N2
551   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
552
553-  ``ERRATA_N2_2326639``: This applies errata 2326639 workaround to Neoverse-N2
554   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
555   r0p1.
556
557-  ``ERRATA_N2_2376738``: This applies errata 2376738 workaround to Neoverse-N2
558   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
559   r0p1.
560
561-  ``ERRATA_N2_2388450``: This applies errata 2388450 workaround to Neoverse-N2
562   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
563   r0p1.
564
565For Cortex-X2, the following errata build flags are defined :
566
567-  ``ERRATA_X2_2002765``: This applies errata 2002765 workaround to Cortex-X2
568   CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
569   it is still open.
570
571-  ``ERRATA_X2_2058056``: This applies errata 2058056 workaround to Cortex-X2
572   CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
573   it is still open.
574
575-  ``ERRATA_X2_2083908``: This applies errata 2083908 workaround to Cortex-X2
576   CPU. This needs to be enabled for revision r2p0 of the CPU, it is still open.
577
578-  ``ERRATA_X2_2017096``: This applies errata 2017096 workaround to
579   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
580   r2p0 of the CPU, it is fixed in r2p1.
581
582-  ``ERRATA_X2_2081180``: This applies errata 2081180 workaround to
583   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
584   r2p0 of the CPU, it is fixed in r2p1.
585
586-  ``ERRATA_X2_2216384``: This applies errata 2216384 workaround to
587   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
588   r2p0 of the CPU, it is fixed in r2p1.
589
590-  ``ERRATA_X2_2147715``: This applies errata 2147715 workaround to
591   Cortex-X2 CPU. This needs to be enabled only for revision r2p0 of the CPU,
592   it is fixed in r2p1.
593
594-  ``ERRATA_X2_2371105``: This applies errata 2371105 workaround to
595   Cortex-X2 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
596   of the CPU and is fixed in r2p1.
597
598For Cortex-X3, the following errata build flags are defined :
599
600- ``ERRATA_X3_2313909``: This applies errata 2313909 workaround to
601  Cortex-X3 CPU. This needs to be enabled only for revisions r0p0 and r1p0
602  of the CPU, it is fixed in r1p1.
603
604For Cortex-A510, the following errata build flags are defined :
605
606-  ``ERRATA_A510_1922240``: This applies errata 1922240 workaround to
607   Cortex-A510 CPU. This needs to be enabled only for revision r0p0, it is
608   fixed in r0p1.
609
610-  ``ERRATA_A510_2288014``: This applies errata 2288014 workaround to
611   Cortex-A510 CPU. This needs to be enabled only for revisions r0p0, r0p1,
612   r0p2, r0p3 and r1p0, it is fixed in r1p1.
613
614-  ``ERRATA_A510_2042739``: This applies errata 2042739 workaround to
615   Cortex-A510 CPU. This needs to be enabled only for revisions r0p0, r0p1 and
616   r0p2, it is fixed in r0p3.
617
618-  ``ERRATA_A510_2041909``: This applies errata 2041909 workaround to
619   Cortex-A510 CPU. This needs to be enabled only for revision r0p2 and is fixed
620   in r0p3. The issue is also present in r0p0 and r0p1 but there is no
621   workaround for those revisions.
622
623-  ``ERRATA_A510_2250311``: This applies errata 2250311 workaround to
624   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
625   r0p3 and r1p0, it is fixed in r1p1. This workaround disables MPMM even if
626   ENABLE_MPMM=1.
627
628-  ``ERRATA_A510_2218950``: This applies errata 2218950 workaround to
629   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
630   r0p3 and r1p0, it is fixed in r1p1.
631
632-  ``ERRATA_A510_2172148``: This applies errata 2172148 workaround to
633   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
634   r0p3 and r1p0, it is fixed in r1p1.
635
636- ``ERRATA_A510_2347730``: This applies errata 2347730 workaround to
637   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
638   r0p3, r1p0 and r1p1. It is fixed in r1p2.
639
640-  ``ERRATA_A510_2371937``: This applies errata 2371937 workaround to
641   Cortex-A510 CPU. This needs to applied for revisions r0p0, r0p1, r0p2,
642   r0p3, r1p0, r1p1, and is fixed in r1p2.
643
644-  ``ERRATA_A510_2666669``: This applies errata 2666669 workaround to
645   Cortex-A510 CPU. This needs to applied for revisions r0p0, r0p1, r0p2,
646   r0p3, r1p0, r1p1. It is fixed in r1p2.
647
648DSU Errata Workarounds
649----------------------
650
651Similar to CPU errata, TF-A also implements workarounds for DSU (DynamIQ
652Shared Unit) errata. The DSU errata details can be found in the respective Arm
653documentation:
654
655- `Arm DSU Software Developers Errata Notice`_.
656
657Each erratum is identified by an ``ID``, as defined in the DSU errata notice
658document. Thus, the build flags which enable/disable the errata workarounds
659have the format ``ERRATA_DSU_<ID>``. The implementation and application logic
660of DSU errata workarounds are similar to `CPU errata workarounds`_.
661
662For DSU errata, the following build flags are defined:
663
664-  ``ERRATA_DSU_798953``: This applies errata 798953 workaround for the
665   affected DSU configurations. This errata applies only for those DSUs that
666   revision is r0p0 (on r0p1 it is fixed). However, please note that this
667   workaround results in increased DSU power consumption on idle.
668
669-  ``ERRATA_DSU_936184``: This applies errata 936184 workaround for the
670   affected DSU configurations. This errata applies only for those DSUs that
671   contain the ACP interface **and** the DSU revision is older than r2p0 (on
672   r2p0 it is fixed). However, please note that this workaround results in
673   increased DSU power consumption on idle.
674
675-  ``ERRATA_DSU_2313941``: This applies errata 2313941 workaround for the
676   affected DSU configurations. This errata applies for those DSUs with
677   revisions r0p0, r1p0, r2p0, r2p1, r3p0, r3p1 and is still open. However,
678   please note that this workaround results in increased DSU power consumption
679   on idle.
680
681CPU Specific optimizations
682--------------------------
683
684This section describes some of the optimizations allowed by the CPU micro
685architecture that can be enabled by the platform as desired.
686
687-  ``SKIP_A57_L1_FLUSH_PWR_DWN``: This flag enables an optimization in the
688   Cortex-A57 cluster power down sequence by not flushing the Level 1 data
689   cache. The L1 data cache and the L2 unified cache are inclusive. A flush
690   of the L2 by set/way flushes any dirty lines from the L1 as well. This
691   is a known safe deviation from the Cortex-A57 TRM defined power down
692   sequence. Each Cortex-A57 based platform must make its own decision on
693   whether to use the optimization.
694
695-  ``A53_DISABLE_NON_TEMPORAL_HINT``: This flag disables the cache non-temporal
696   hint. The LDNP/STNP instructions as implemented on Cortex-A53 do not behave
697   in a way most programmers expect, and will most probably result in a
698   significant speed degradation to any code that employs them. The Armv8-A
699   architecture (see Arm DDI 0487A.h, section D3.4.3) allows cores to ignore
700   the non-temporal hint and treat LDNP/STNP as LDP/STP instead. Enabling this
701   flag enforces this behaviour. This needs to be enabled only for revisions
702   <= r0p3 of the CPU and is enabled by default.
703
704-  ``A57_DISABLE_NON_TEMPORAL_HINT``: This flag has the same behaviour as
705   ``A53_DISABLE_NON_TEMPORAL_HINT`` but for Cortex-A57. This needs to be
706   enabled only for revisions <= r1p2 of the CPU and is enabled by default,
707   as recommended in section "4.7 Non-Temporal Loads/Stores" of the
708   `Cortex-A57 Software Optimization Guide`_.
709
710- ''A57_ENABLE_NON_CACHEABLE_LOAD_FWD'': This flag enables non-cacheable
711   streaming enhancement feature for Cortex-A57 CPUs. Platforms can set
712   this bit only if their memory system meets the requirement that cache
713   line fill requests from the Cortex-A57 processor are atomic. Each
714   Cortex-A57 based platform must make its own decision on whether to use
715   the optimization. This flag is disabled by default.
716
717-  ``NEOVERSE_Nx_EXTERNAL_LLC``: This flag indicates that an external last
718   level cache(LLC) is present in the system, and that the DataSource field
719   on the master CHI interface indicates when data is returned from the LLC.
720   This is used to control how the LL_CACHE* PMU events count.
721   Default value is 0 (Disabled).
722
723GIC Errata Workarounds
724----------------------
725-  ``GIC600_ERRATA_WA_2384374``: This flag applies part 2 of errata 2384374
726   workaround for the affected GIC600 and GIC600-AE implementations. It applies
727   to implementations of GIC600 and GIC600-AE with revisions less than or equal
728   to r1p6 and r0p2 respectively. If the platform sets GICV3_SUPPORT_GIC600,
729   then this flag is enabled; otherwise, it is 0 (Disabled).
730
731--------------
732
733*Copyright (c) 2014-2022, Arm Limited and Contributors. All rights reserved.*
734
735.. _CVE-2017-5715: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5715
736.. _CVE-2018-3639: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3639
737.. _CVE-2022-23960: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-23960
738.. _Cortex-A53 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm048406/index.html
739.. _Cortex-A57 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm049219/index.html
740.. _Cortex-A72 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm012079/index.html
741.. _Cortex-A57 Software Optimization Guide: http://infocenter.arm.com/help/topic/com.arm.doc.uan0015b/Cortex_A57_Software_Optimization_Guide_external.pdf
742.. _Arm DSU Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm138168/index.html
743