xref: /rk3399_ARM-atf/docs/design/cpu-specific-build-macros.rst (revision 8a6a9560b5dcccfb68064c0c8c9b4b47981c6ac7)
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
259For Cortex-A77, the following errata build flags are defined :
260
261-  ``ERRATA_A77_1508412``: This applies errata 1508412 workaround to Cortex-A77
262   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
263
264-  ``ERRATA_A77_1925769``: This applies errata 1925769 workaround to Cortex-A77
265   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
266
267-  ``ERRATA_A77_1946167``: This applies errata 1946167 workaround to Cortex-A77
268   CPU. This needs to be enabled only for revision <= r1p1 of the CPU.
269
270-  ``ERRATA_A77_1791578``: This applies errata 1791578 workaround to Cortex-A77
271   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
272
273-  ``ERRATA_A77_2356587``: This applies errata 2356587 workaround to Cortex-A77
274   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
275
276 -  ``ERRATA_A77_1800714``: This applies errata 1800714 workaround to Cortex-A77
277    CPU. This needs to be enabled for revisions <= r1p1 of the CPU.
278
279For Cortex-A78, the following errata build flags are defined :
280
281-  ``ERRATA_A78_1688305``: This applies errata 1688305 workaround to Cortex-A78
282   CPU. This needs to be enabled only for revision r0p0 - r1p0 of the CPU.
283
284-  ``ERRATA_A78_1941498``: This applies errata 1941498 workaround to Cortex-A78
285   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
286
287-  ``ERRATA_A78_1951500``: This applies errata 1951500 workaround to Cortex-A78
288   CPU. This needs to be enabled for revisions r1p0 and r1p1, r0p0 has the same
289   issue but there is no workaround for that revision.
290
291-  ``ERRATA_A78_1821534``: This applies errata 1821534 workaround to Cortex-A78
292   CPU. This needs to be enabled for revisions r0p0 and r1p0.
293
294-  ``ERRATA_A78_1952683``: This applies errata 1952683 workaround to Cortex-A78
295   CPU. This needs to be enabled for revision r0p0, it is fixed in r1p0.
296
297-  ``ERRATA_A78_2132060``: This applies errata 2132060 workaround to Cortex-A78
298   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2. It
299   is still open.
300
301-  ``ERRATA_A78_2242635``: This applies errata 2242635 workaround to Cortex-A78
302   CPU. This needs to be enabled for revisions r1p0, r1p1, and r1p2. The issue
303   is present in r0p0 but there is no workaround. It is still open.
304
305-  ``ERRATA_A78_2376745``: This applies errata 2376745 workaround to Cortex-A78
306   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
307   it is still open.
308
309-  ``ERRATA_A78_2395406``: This applies errata 2395406 workaround to Cortex-A78
310   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
311   it is still open.
312
313For Cortex-A78 AE, the following errata build flags are defined :
314
315- ``ERRATA_A78_AE_1941500`` : This applies errata 1941500 workaround to
316   Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1.
317   This erratum is still open.
318
319- ``ERRATA_A78_AE_1951502`` : This applies errata 1951502 workaround to
320  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
321  erratum is still open.
322
323- ``ERRATA_A78_AE_2376748`` : This applies errata 2376748 workaround to
324  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
325  erratum is still open.
326
327- ``ERRATA_A78_AE_2395408`` : This applies errata 2395408 workaround to
328  Cortex-A78 AE CPU. This needs to be enabled for revisions r0p0 and r0p1. This
329  erratum is still open.
330
331For Cortex-A78C, the following errata build flags are defined :
332
333- ``ERRATA_A78C_2132064`` : This applies errata 2132064 workaround to
334  Cortex-A78C CPU. This needs to be enabled for revisions r0p1, r0p2 and
335  it is still open.
336
337- ``ERRATA_A78C_2242638`` : This applies errata 2242638 workaround to
338  Cortex-A78C CPU. This needs to be enabled for revisions r0p1, r0p2 and
339  it is still open.
340
341- ``ERRATA_A78C_2376749`` : This applies errata 2376749 workaround to
342  Cortex-A78C CPU. This needs to be enabled for revisions r0p1 and r0p2. This
343  erratum is still open.
344
345- ``ERRATA_A78C_2395411`` : This applies errata 2395411 workaround to
346  Cortex-A78C CPU. This needs to be enabled for revisions r0p1 and r0p2. This
347  erratum is still open.
348
349For Cortex-X1 CPU, the following errata build flags are defined:
350
351- ``ERRATA_X1_1821534`` : This applies errata 1821534 workaround to Cortex-X1
352   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
353
354- ``ERRATA_X1_1688305`` : This applies errata 1688305 workaround to Cortex-X1
355   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
356
357- ``ERRATA_X1_1827429`` : This applies errata 1827429 workaround to Cortex-X1
358   CPU. This needs to be enabled only for revision <= r1p0 of the CPU.
359
360For Neoverse N1, the following errata build flags are defined :
361
362-  ``ERRATA_N1_1073348``: This applies errata 1073348 workaround to Neoverse-N1
363   CPU. This needs to be enabled only for revision r0p0 and r1p0 of the CPU.
364
365-  ``ERRATA_N1_1130799``: This applies errata 1130799 workaround to Neoverse-N1
366   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
367
368-  ``ERRATA_N1_1165347``: This applies errata 1165347 workaround to Neoverse-N1
369   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
370
371-  ``ERRATA_N1_1207823``: This applies errata 1207823 workaround to Neoverse-N1
372   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
373
374-  ``ERRATA_N1_1220197``: This applies errata 1220197 workaround to Neoverse-N1
375   CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
376
377-  ``ERRATA_N1_1257314``: This applies errata 1257314 workaround to Neoverse-N1
378   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
379
380-  ``ERRATA_N1_1262606``: This applies errata 1262606 workaround to Neoverse-N1
381   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
382
383-  ``ERRATA_N1_1262888``: This applies errata 1262888 workaround to Neoverse-N1
384   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
385
386-  ``ERRATA_N1_1275112``: This applies errata 1275112 workaround to Neoverse-N1
387   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
388
389-  ``ERRATA_N1_1315703``: This applies errata 1315703 workaround to Neoverse-N1
390   CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
391
392-  ``ERRATA_N1_1542419``: This applies errata 1542419 workaround to Neoverse-N1
393   CPU. This needs to be enabled only for revisions r3p0 - r4p0 of the CPU.
394
395-  ``ERRATA_N1_1868343``: This applies errata 1868343 workaround to Neoverse-N1
396   CPU. This needs to be enabled only for revision <= r4p0 of the CPU.
397
398-  ``ERRATA_N1_1946160``: This applies errata 1946160 workaround to Neoverse-N1
399   CPU. This needs to be enabled for revisions r3p0, r3p1, r4p0, and r4p1, for
400   revisions r0p0, r1p0, and r2p0 there is no workaround.
401
402For Neoverse V1, the following errata build flags are defined :
403
404-  ``ERRATA_V1_1618635``: This applies errata 1618635 workaround to Neoverse-V1
405   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
406   r1p0.
407
408-  ``ERRATA_V1_1774420``: This applies errata 1774420 workaround to Neoverse-V1
409   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
410   in r1p1.
411
412-  ``ERRATA_V1_1791573``: This applies errata 1791573 workaround to Neoverse-V1
413   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
414   in r1p1.
415
416-  ``ERRATA_V1_1852267``: This applies errata 1852267 workaround to Neoverse-V1
417   CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
418   in r1p1.
419
420-  ``ERRATA_V1_1925756``: This applies errata 1925756 workaround to Neoverse-V1
421   CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
422
423-  ``ERRATA_V1_1940577``: This applies errata 1940577 workaround to Neoverse-V1
424   CPU. This needs to be enabled only for revision r1p0 and r1p1 of the
425   CPU.
426
427-  ``ERRATA_V1_1966096``: This applies errata 1966096 workaround to Neoverse-V1
428   CPU. This needs to be enabled for revisions r1p0 and r1p1 of the CPU, the
429   issue is present in r0p0 as well but there is no workaround for that
430   revision.  It is still open.
431
432-  ``ERRATA_V1_2139242``: This applies errata 2139242 workaround to Neoverse-V1
433   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the
434   CPU.  It is still open.
435
436-  ``ERRATA_V1_2108267``: This applies errata 2108267 workaround to Neoverse-V1
437   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
438   It is still open.
439
440-  ``ERRATA_V1_2216392``: This applies errata 2216392 workaround to Neoverse-V1
441   CPU. This needs to be enabled for revisions r1p0 and r1p1 of the CPU, the
442   issue is present in r0p0 as well but there is no workaround for that
443   revision.  It is still open.
444
445-  ``ERRATA_V1_2294912``: This applies errata 2294912 workaround to Neoverse-V1
446   CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU.
447
448-  ``ERRATA_V1_2372203``: This applies errata 2372203 workaround to Neoverse-V1
449   CPU. This needs to be enabled for revisions r0p0, r1p0 and r1p1 of the CPU.
450   It is still open.
451
452For Cortex-A710, the following errata build flags are defined :
453
454-  ``ERRATA_A710_1987031``: This applies errata 1987031 workaround to
455   Cortex-A710 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
456   r2p0 of the CPU. It is still open.
457
458-  ``ERRATA_A710_2081180``: This applies errata 2081180 workaround to
459   Cortex-A710 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
460   r2p0 of the CPU. It is still open.
461
462-  ``ERRATA_A710_2055002``: This applies errata 2055002 workaround to
463   Cortex-A710 CPU. This needs to be enabled for revisions r1p0, r2p0 of the CPU
464   and is still open.
465
466-  ``ERRATA_A710_2017096``: This applies errata 2017096 workaround to
467   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
468   of the CPU and is still open.
469
470-  ``ERRATA_A710_2083908``: This applies errata 2083908 workaround to
471   Cortex-A710 CPU. This needs to be enabled for revision r2p0 of the CPU and
472   is still open.
473
474-  ``ERRATA_A710_2058056``: This applies errata 2058056 workaround to
475   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
476   of the CPU and is still open.
477
478-  ``ERRATA_A710_2267065``: This applies errata 2267065 workaround to
479   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
480   of the CPU and is fixed in r2p1.
481
482-  ``ERRATA_A710_2136059``: This applies errata 2136059 workaround to
483   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
484   of the CPU and is fixed in r2p1.
485
486-  ``ERRATA_A710_2147715``: This applies errata 2147715 workaround to
487   Cortex-A710 CPU. This needs to be enabled for revision r2p0 of the CPU
488   and is fixed in r2p1.
489
490-  ``ERRATA_A710_2216384``: This applies errata 2216384 workaround to
491   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
492   of the CPU and is fixed in r2p1.
493
494-  ``ERRATA_A710_2282622``: This applies errata 2282622 workaround to
495   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
496   of the CPU and is fixed in r2p1.
497
498-  ``ERRATA_A710_2008768``: This applies errata 2008768 workaround to
499   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
500   of the CPU and is fixed in r2p1.
501
502-  ``ERRATA_A710_2371105``: This applies errata 2371105 workaround to
503   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
504   of the CPU and is fixed in r2p1.
505
506For Neoverse N2, the following errata build flags are defined :
507
508-  ``ERRATA_N2_2002655``: This applies errata 2002655 workaround to Neoverse-N2
509   CPU. This needs to be enabled for revision r0p0 of the CPU, it is still open.
510
511-  ``ERRATA_N2_2067956``: This applies errata 2067956 workaround to Neoverse-N2
512   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
513
514-  ``ERRATA_N2_2025414``: This applies errata 2025414 workaround to Neoverse-N2
515   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
516
517-  ``ERRATA_N2_2189731``: This applies errata 2189731 workaround to Neoverse-N2
518   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
519
520-  ``ERRATA_N2_2138956``: This applies errata 2138956 workaround to Neoverse-N2
521   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
522
523-  ``ERRATA_N2_2138953``: This applies errata 2138953 workaround to Neoverse-N2
524   CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
525
526-  ``ERRATA_N2_2242415``: This applies errata 2242415 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_2138958``: This applies errata 2138958 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_2242400``: This applies errata 2242400 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_2280757``: This applies errata 2280757 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_2376738``: This applies errata 2376738 workaround to Neoverse-N2
539   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
540   r0p1.
541
542-  ``ERRATA_N2_2388450``: This applies errata 2388450 workaround to Neoverse-N2
543   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
544   r0p1.
545
546For Cortex-X2, the following errata build flags are defined :
547
548-  ``ERRATA_X2_2002765``: This applies errata 2002765 workaround to Cortex-X2
549   CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
550   it is still open.
551
552-  ``ERRATA_X2_2058056``: This applies errata 2058056 workaround to Cortex-X2
553   CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
554   it is still open.
555
556-  ``ERRATA_X2_2083908``: This applies errata 2083908 workaround to Cortex-X2
557   CPU. This needs to be enabled for revision r2p0 of the CPU, it is still open.
558
559-  ``ERRATA_X2_2017096``: This applies errata 2017096 workaround to
560   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
561   r2p0 of the CPU, it is fixed in r2p1.
562
563-  ``ERRATA_X2_2081180``: This applies errata 2081180 workaround to
564   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
565   r2p0 of the CPU, it is fixed in r2p1.
566
567-  ``ERRATA_X2_2216384``: This applies errata 2216384 workaround to
568   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
569   r2p0 of the CPU, it is fixed in r2p1.
570
571-  ``ERRATA_X2_2147715``: This applies errata 2147715 workaround to
572   Cortex-X2 CPU. This needs to be enabled only for revision r2p0 of the CPU,
573   it is fixed in r2p1.
574
575-  ``ERRATA_X2_2371105``: This applies errata 2371105 workaround to
576   Cortex-X2 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
577   of the CPU and is fixed in r2p1.
578
579For Cortex-A510, the following errata build flags are defined :
580
581-  ``ERRATA_A510_1922240``: This applies errata 1922240 workaround to
582   Cortex-A510 CPU. This needs to be enabled only for revision r0p0, it is
583   fixed in r0p1.
584
585-  ``ERRATA_A510_2288014``: This applies errata 2288014 workaround to
586   Cortex-A510 CPU. This needs to be enabled only for revisions r0p0, r0p1,
587   r0p2, r0p3 and r1p0, it is fixed in r1p1.
588
589-  ``ERRATA_A510_2042739``: This applies errata 2042739 workaround to
590   Cortex-A510 CPU. This needs to be enabled only for revisions r0p0, r0p1 and
591   r0p2, it is fixed in r0p3.
592
593-  ``ERRATA_A510_2041909``: This applies errata 2041909 workaround to
594   Cortex-A510 CPU. This needs to be enabled only for revision r0p2 and is fixed
595   in r0p3. The issue is also present in r0p0 and r0p1 but there is no
596   workaround for those revisions.
597
598-  ``ERRATA_A510_2250311``: This applies errata 2250311 workaround to
599   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
600   r0p3 and r1p0, it is fixed in r1p1. This workaround disables MPMM even if
601   ENABLE_MPMM=1.
602
603-  ``ERRATA_A510_2218950``: This applies errata 2218950 workaround to
604   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
605   r0p3 and r1p0, it is fixed in r1p1.
606
607-  ``ERRATA_A510_2172148``: This applies errata 2172148 workaround to
608   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
609   r0p3 and r1p0, it is fixed in r1p1.
610
611- ``ERRATA_A510_2347730``: This applies errata 2347730 workaround to
612   Cortex-A510 CPU. This needs to be enabled for revisions r0p0, r0p1, r0p2,
613   r0p3, r1p0 and r1p1. It is fixed in r1p2.
614
615-  ``ERRATA_A510_2371937``: This applies errata 2371937 workaround to
616   Cortex-A510 CPU. This needs to applied for revisions r0p0, r0p1, r0p2,
617   r0p3, r1p0, r1p1, and is fixed in r1p2.
618
619DSU Errata Workarounds
620----------------------
621
622Similar to CPU errata, TF-A also implements workarounds for DSU (DynamIQ
623Shared Unit) errata. The DSU errata details can be found in the respective Arm
624documentation:
625
626- `Arm DSU Software Developers Errata Notice`_.
627
628Each erratum is identified by an ``ID``, as defined in the DSU errata notice
629document. Thus, the build flags which enable/disable the errata workarounds
630have the format ``ERRATA_DSU_<ID>``. The implementation and application logic
631of DSU errata workarounds are similar to `CPU errata workarounds`_.
632
633For DSU errata, the following build flags are defined:
634
635-  ``ERRATA_DSU_798953``: This applies errata 798953 workaround for the
636   affected DSU configurations. This errata applies only for those DSUs that
637   revision is r0p0 (on r0p1 it is fixed). However, please note that this
638   workaround results in increased DSU power consumption on idle.
639
640-  ``ERRATA_DSU_936184``: This applies errata 936184 workaround for the
641   affected DSU configurations. This errata applies only for those DSUs that
642   contain the ACP interface **and** the DSU revision is older than r2p0 (on
643   r2p0 it is fixed). However, please note that this workaround results in
644   increased DSU power consumption on idle.
645
646-  ``ERRATA_DSU_2313941``: This applies errata 2313941 workaround for the
647   affected DSU configurations. This errata applies for those DSUs with
648   revisions r0p0, r1p0, r2p0, r2p1, r3p0, r3p1 and is still open. However,
649   please note that this workaround results in increased DSU power consumption
650   on idle.
651
652CPU Specific optimizations
653--------------------------
654
655This section describes some of the optimizations allowed by the CPU micro
656architecture that can be enabled by the platform as desired.
657
658-  ``SKIP_A57_L1_FLUSH_PWR_DWN``: This flag enables an optimization in the
659   Cortex-A57 cluster power down sequence by not flushing the Level 1 data
660   cache. The L1 data cache and the L2 unified cache are inclusive. A flush
661   of the L2 by set/way flushes any dirty lines from the L1 as well. This
662   is a known safe deviation from the Cortex-A57 TRM defined power down
663   sequence. Each Cortex-A57 based platform must make its own decision on
664   whether to use the optimization.
665
666-  ``A53_DISABLE_NON_TEMPORAL_HINT``: This flag disables the cache non-temporal
667   hint. The LDNP/STNP instructions as implemented on Cortex-A53 do not behave
668   in a way most programmers expect, and will most probably result in a
669   significant speed degradation to any code that employs them. The Armv8-A
670   architecture (see Arm DDI 0487A.h, section D3.4.3) allows cores to ignore
671   the non-temporal hint and treat LDNP/STNP as LDP/STP instead. Enabling this
672   flag enforces this behaviour. This needs to be enabled only for revisions
673   <= r0p3 of the CPU and is enabled by default.
674
675-  ``A57_DISABLE_NON_TEMPORAL_HINT``: This flag has the same behaviour as
676   ``A53_DISABLE_NON_TEMPORAL_HINT`` but for Cortex-A57. This needs to be
677   enabled only for revisions <= r1p2 of the CPU and is enabled by default,
678   as recommended in section "4.7 Non-Temporal Loads/Stores" of the
679   `Cortex-A57 Software Optimization Guide`_.
680
681- ''A57_ENABLE_NON_CACHEABLE_LOAD_FWD'': This flag enables non-cacheable
682   streaming enhancement feature for Cortex-A57 CPUs. Platforms can set
683   this bit only if their memory system meets the requirement that cache
684   line fill requests from the Cortex-A57 processor are atomic. Each
685   Cortex-A57 based platform must make its own decision on whether to use
686   the optimization. This flag is disabled by default.
687
688-  ``NEOVERSE_Nx_EXTERNAL_LLC``: This flag indicates that an external last
689   level cache(LLC) is present in the system, and that the DataSource field
690   on the master CHI interface indicates when data is returned from the LLC.
691   This is used to control how the LL_CACHE* PMU events count.
692   Default value is 0 (Disabled).
693
694GIC Errata Workarounds
695----------------------
696-  ``GIC600_ERRATA_WA_2384374``: This flag applies part 2 of errata 2384374
697   workaround for the affected GIC600 and GIC600-AE implementations. It applies
698   to implementations of GIC600 and GIC600-AE with revisions less than or equal
699   to r1p6 and r0p2 respectively. If the platform sets GICV3_SUPPORT_GIC600,
700   then this flag is enabled; otherwise, it is 0 (Disabled).
701
702--------------
703
704*Copyright (c) 2014-2022, Arm Limited and Contributors. All rights reserved.*
705
706.. _CVE-2017-5715: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5715
707.. _CVE-2018-3639: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3639
708.. _CVE-2022-23960: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-23960
709.. _Cortex-A53 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm048406/index.html
710.. _Cortex-A57 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm049219/index.html
711.. _Cortex-A72 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm012079/index.html
712.. _Cortex-A57 Software Optimization Guide: http://infocenter.arm.com/help/topic/com.arm.doc.uan0015b/Cortex_A57_Software_Optimization_Guide_external.pdf
713.. _Arm DSU Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm138168/index.html
714