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[soc.git] / src / soc / decoder / isa / radixmmu.py
1 # SPDX-License-Identifier: LGPLv3+
2 # Copyright (C) 2020, 2021 Luke Kenneth Casson Leighton <lkcl@lkcl.net>
3 # Copyright (C) 2021 Tobias Platen
4 # Funded by NLnet http://nlnet.nl
5 """core of the python-based POWER9 simulator
6
7 this is part of a cycle-accurate POWER9 simulator. its primary purpose is
8 not speed, it is for both learning and educational purposes, as well as
9 a method of verifying the HDL.
10
11 related bugs:
12
13 * https://bugs.libre-soc.org/show_bug.cgi?id=604
14 """
15
16 from nmigen.back.pysim import Settle
17 from copy import copy
18 from soc.decoder.selectable_int import (FieldSelectableInt, SelectableInt,
19 selectconcat)
20 from soc.decoder.helpers import exts, gtu, ltu, undefined
21 from soc.decoder.isa.mem import Mem
22
23 import math
24 import sys
25
26 # very quick, TODO move to SelectableInt utils later
27 def genmask(shift, size):
28 res = SelectableInt(0, size)
29 for i in range(size):
30 if i < shift:
31 res[size-1-i] = SelectableInt(1, 1)
32 return res
33
34 """
35 Get Root Page
36
37 //Accessing 2nd double word of partition table (pate1)
38 //Ref: Power ISA Manual v3.0B, Book-III, section 5.7.6.1
39 // PTCR Layout
40 // ====================================================
41 // -----------------------------------------------
42 // | /// | PATB | /// | PATS |
43 // -----------------------------------------------
44 // 0 4 51 52 58 59 63
45 // PATB[4:51] holds the base address of the Partition Table,
46 // right shifted by 12 bits.
47 // This is because the address of the Partition base is
48 // 4k aligned. Hence, the lower 12bits, which are always
49 // 0 are ommitted from the PTCR.
50 //
51 // Thus, The Partition Table Base is obtained by (PATB << 12)
52 //
53 // PATS represents the partition table size right-shifted by 12 bits.
54 // The minimal size of the partition table is 4k.
55 // Thus partition table size = (1 << PATS + 12).
56 //
57 // Partition Table
58 // ====================================================
59 // 0 PATE0 63 PATE1 127
60 // |----------------------|----------------------|
61 // | | |
62 // |----------------------|----------------------|
63 // | | |
64 // |----------------------|----------------------|
65 // | | | <-- effLPID
66 // |----------------------|----------------------|
67 // .
68 // .
69 // .
70 // |----------------------|----------------------|
71 // | | |
72 // |----------------------|----------------------|
73 //
74 // The effective LPID forms the index into the Partition Table.
75 //
76 // Each entry in the partition table contains 2 double words, PATE0, PATE1,
77 // corresponding to that partition.
78 //
79 // In case of Radix, The structure of PATE0 and PATE1 is as follows.
80 //
81 // PATE0 Layout
82 // -----------------------------------------------
83 // |1|RTS1|/| RPDB | RTS2 | RPDS |
84 // -----------------------------------------------
85 // 0 1 2 3 4 55 56 58 59 63
86 //
87 // HR[0] : For Radix Page table, first bit should be 1.
88 // RTS1[1:2] : Gives one fragment of the Radix treesize
89 // RTS2[56:58] : Gives the second fragment of the Radix Tree size.
90 // RTS = (RTS1 << 3 + RTS2) + 31.
91 //
92 // RPDB[4:55] = Root Page Directory Base.
93 // RPDS = Logarithm of Root Page Directory Size right shifted by 3.
94 // Thus, Root page directory size = 1 << (RPDS + 3).
95 // Note: RPDS >= 5.
96 //
97 // PATE1 Layout
98 // -----------------------------------------------
99 // |///| PRTB | // | PRTS |
100 // -----------------------------------------------
101 // 0 3 4 51 52 58 59 63
102 //
103 // PRTB[4:51] = Process Table Base. This is aligned to size.
104 // PRTS[59: 63] = Process Table Size right shifted by 12.
105 // Minimal size of the process table is 4k.
106 // Process Table Size = (1 << PRTS + 12).
107 // Note: PRTS <= 24.
108 //
109 // Computing the size aligned Process Table Base:
110 // table_base = (PRTB & ~((1 << PRTS) - 1)) << 12
111 // Thus, the lower 12+PRTS bits of table_base will
112 // be zero.
113
114
115 //Ref: Power ISA Manual v3.0B, Book-III, section 5.7.6.2
116 //
117 // Process Table
118 // ==========================
119 // 0 PRTE0 63 PRTE1 127
120 // |----------------------|----------------------|
121 // | | |
122 // |----------------------|----------------------|
123 // | | |
124 // |----------------------|----------------------|
125 // | | | <-- effPID
126 // |----------------------|----------------------|
127 // .
128 // .
129 // .
130 // |----------------------|----------------------|
131 // | | |
132 // |----------------------|----------------------|
133 //
134 // The effective Process id (PID) forms the index into the Process Table.
135 //
136 // Each entry in the partition table contains 2 double words, PRTE0, PRTE1,
137 // corresponding to that process
138 //
139 // In case of Radix, The structure of PRTE0 and PRTE1 is as follows.
140 //
141 // PRTE0 Layout
142 // -----------------------------------------------
143 // |/|RTS1|/| RPDB | RTS2 | RPDS |
144 // -----------------------------------------------
145 // 0 1 2 3 4 55 56 58 59 63
146 //
147 // RTS1[1:2] : Gives one fragment of the Radix treesize
148 // RTS2[56:58] : Gives the second fragment of the Radix Tree size.
149 // RTS = (RTS1 << 3 + RTS2) << 31,
150 // since minimal Radix Tree size is 4G.
151 //
152 // RPDB = Root Page Directory Base.
153 // RPDS = Root Page Directory Size right shifted by 3.
154 // Thus, Root page directory size = RPDS << 3.
155 // Note: RPDS >= 5.
156 //
157 // PRTE1 Layout
158 // -----------------------------------------------
159 // | /// |
160 // -----------------------------------------------
161 // 0 63
162 // All bits are reserved.
163
164
165 """
166
167 # see qemu/target/ppc/mmu-radix64.c for reference
168 class RADIX:
169 def __init__(self, mem, caller):
170 self.mem = mem
171 self.caller = caller
172 #TODO move to lookup
173 self.dsisr = self.caller.spr["DSISR"]
174 self.dar = self.caller.spr["DAR"]
175 self.pidr = self.caller.spr["PIDR"]
176 self.prtbl = self.caller.spr["PRTBL"]
177
178 # cached page table stuff
179 self.pgtbl0 = 0
180 self.pt0_valid = False
181 self.pgtbl3 = 0
182 self.pt3_valid = False
183
184 def __call__(self, addr, sz):
185 val = self.ld(addr.value, sz, swap=False)
186 print("RADIX memread", addr, sz, val)
187 return SelectableInt(val, sz*8)
188
189 def ld(self, address, width=8, swap=True, check_in_mem=False):
190 print("RADIX: ld from addr 0x%x width %d" % (address, width))
191
192 addr = SelectableInt(address, 64)
193 (shift, mbits, pgbase) = self._decode_prte(addr)
194 #shift = SelectableInt(0, 32)
195
196 pte = self._walk_tree(address,shift)
197 # use pte to caclculate phys address
198 return self.mem.ld(address, width, swap, check_in_mem)
199
200 # XXX set SPRs on error
201
202 # TODO implement
203 def st(self, addr, v, width=8, swap=True):
204 print("RADIX: st to addr 0x%x width %d data %x" % (addr, width, v))
205
206 shift = SelectableInt(0, 32)
207 pte = self._walk_tree(addr,shift)
208
209 # use pte to caclculate phys address (addr)
210 return self.mem.st(addr, v, width, swap)
211
212 # XXX set SPRs on error
213
214 def memassign(self, addr, sz, val):
215 print("memassign", addr, sz, val)
216 self.st(addr.value, val.value, sz, swap=False)
217
218 def _next_level(self):
219 return True
220 ## DSISR_R_BADCONFIG
221 ## read_entry
222 ## DSISR_NOPTE
223 ## Prepare for next iteration
224
225 def _walk_tree(self, addr, shift):
226 """walk tree
227
228 // vaddr 64 Bit
229 // vaddr |-----------------------------------------------------|
230 // | Unused | Used |
231 // |-----------|-----------------------------------------|
232 // | 0000000 | usefulBits = X bits (typically 52) |
233 // |-----------|-----------------------------------------|
234 // | |<--Cursize---->| |
235 // | | Index | |
236 // | | into Page | |
237 // | | Directory | |
238 // |-----------------------------------------------------|
239 // | |
240 // V |
241 // PDE |---------------------------| |
242 // |V|L|//| NLB |///|NLS| |
243 // |---------------------------| |
244 // PDE = Page Directory Entry |
245 // [0] = V = Valid Bit |
246 // [1] = L = Leaf bit. If 0, then |
247 // [4:55] = NLB = Next Level Base |
248 // right shifted by 8 |
249 // [59:63] = NLS = Next Level Size |
250 // | NLS >= 5 |
251 // | V
252 // | |--------------------------|
253 // | | usfulBits = X-Cursize |
254 // | |--------------------------|
255 // |---------------------><--NLS-->| |
256 // | Index | |
257 // | into | |
258 // | PDE | |
259 // |--------------------------|
260 // |
261 // If the next PDE obtained by |
262 // (NLB << 8 + 8 * index) is a |
263 // nonleaf, then repeat the above. |
264 // |
265 // If the next PDE is a leaf, |
266 // then Leaf PDE structure is as |
267 // follows |
268 // |
269 // |
270 // Leaf PDE |
271 // |------------------------------| |----------------|
272 // |V|L|sw|//|RPN|sw|R|C|/|ATT|EAA| | usefulBits |
273 // |------------------------------| |----------------|
274 // [0] = V = Valid Bit |
275 // [1] = L = Leaf Bit = 1 if leaf |
276 // PDE |
277 // [2] = Sw = Sw bit 0. |
278 // [7:51] = RPN = Real Page Number, V
279 // real_page = RPN << 12 -------------> Logical OR
280 // [52:54] = Sw Bits 1:3 |
281 // [55] = R = Reference |
282 // [56] = C = Change V
283 // [58:59] = Att = Physical Address
284 // 0b00 = Normal Memory
285 // 0b01 = SAO
286 // 0b10 = Non Idenmpotent
287 // 0b11 = Tolerant I/O
288 // [60:63] = Encoded Access
289 // Authority
290 //
291 """
292 # get sprs
293 print("_walk_tree")
294 pidr = self.caller.spr["PIDR"]
295 prtbl = self.caller.spr["PRTBL"]
296 print(pidr)
297 print(prtbl)
298 #prtable_addr = self._get_prtable_addr(shift, prtbl, addr, pidr)
299 #print("prtable_addr",prtable_addr)
300
301 # TODO read root entry from process table first
302
303 # walk tree starts on prtbl
304 while True:
305 ret = self._next_level()
306 if ret: return ret
307
308 def _decode_prte(self, data):
309 """PRTE0 Layout
310 -----------------------------------------------
311 |/|RTS1|/| RPDB | RTS2 | RPDS |
312 -----------------------------------------------
313 0 1 2 3 4 55 56 58 59 63
314 """
315 # note that SelectableInt does big-endian! so the indices
316 # below *directly* match the spec, unlike microwatt which
317 # has to turn them around (to LE)
318 zero = SelectableInt(0, 1)
319 rts = selectconcat(zero,
320 data[56:59], # RTS2
321 data[1:3], # RTS1
322 )
323 masksize = data[59:64] # RPDS
324 mbits = selectconcat(zero, masksize)
325 pgbase = selectconcat(data[8:56], # part of RPDB
326 SelectableInt(0, 16),)
327
328 return (rts, mbits, pgbase)
329
330 def _segment_check(self, addr, mbits, shift):
331 """checks segment valid
332 mbits := '0' & r.mask_size;
333 v.shift := r.shift + (31 - 12) - mbits;
334 nonzero := or(r.addr(61 downto 31) and not finalmask(30 downto 0));
335 if r.addr(63) /= r.addr(62) or nonzero = '1' then
336 v.state := RADIX_FINISH;
337 v.segerror := '1';
338 elsif mbits < 5 or mbits > 16 or mbits > (r.shift + (31 - 12)) then
339 v.state := RADIX_FINISH;
340 v.badtree := '1';
341 else
342 v.state := RADIX_LOOKUP;
343 """
344 # note that SelectableInt does big-endian! so the indices
345 # below *directly* match the spec, unlike microwatt which
346 # has to turn them around (to LE)
347 mask = genmask(shift, 44)
348 nonzero = addr[1:32] & mask[13:44] # mask 31 LSBs (BE numbered 13:44)
349 print ("RADIX _segment_check nonzero", bin(nonzero.value))
350 print ("RADIX _segment_check addr[0-1]", addr[0].value, addr[1].value)
351 if addr[0] != addr[1] or nonzero == 1:
352 return "segerror"
353 limit = shift + (31 - 12)
354 if mbits < 5 or mbits > 16 or mbits > limit:
355 return "badtree"
356 new_shift = shift + (31 - 12) - mbits
357 return new_shift
358
359 def _check_perms(self, data, priv, iside, store):
360 """check page permissions
361 // Leaf PDE |
362 // |------------------------------| |----------------|
363 // |V|L|sw|//|RPN|sw|R|C|/|ATT|EAA| | usefulBits |
364 // |------------------------------| |----------------|
365 // [0] = V = Valid Bit |
366 // [1] = L = Leaf Bit = 1 if leaf |
367 // PDE |
368 // [2] = Sw = Sw bit 0. |
369 // [7:51] = RPN = Real Page Number, V
370 // real_page = RPN << 12 -------------> Logical OR
371 // [52:54] = Sw Bits 1:3 |
372 // [55] = R = Reference |
373 // [56] = C = Change V
374 // [58:59] = Att = Physical Address
375 // 0b00 = Normal Memory
376 // 0b01 = SAO
377 // 0b10 = Non Idenmpotent
378 // 0b11 = Tolerant I/O
379 // [60:63] = Encoded Access
380 // Authority
381 //
382 -- test leaf bit
383 -- check permissions and RC bits
384 perm_ok := '0';
385 if r.priv = '1' or data(3) = '0' then
386 if r.iside = '0' then
387 perm_ok := data(1) or (data(2) and not r.store);
388 else
389 -- no IAMR, so no KUEP support for now
390 -- deny execute permission if cache inhibited
391 perm_ok := data(0) and not data(5);
392 end if;
393 end if;
394 rc_ok := data(8) and (data(7) or not r.store);
395 if perm_ok = '1' and rc_ok = '1' then
396 v.state := RADIX_LOAD_TLB;
397 else
398 v.state := RADIX_FINISH;
399 v.perm_err := not perm_ok;
400 -- permission error takes precedence over RC error
401 v.rc_error := perm_ok;
402 end if;
403 """
404 # check permissions and RC bits
405 perm_ok = 0
406 if priv == 1 or data[60] == 0:
407 if iside == 0:
408 perm_ok = data[62] | (data[61] & (store == 0))
409 # no IAMR, so no KUEP support for now
410 # deny execute permission if cache inhibited
411 perm_ok = data[63] & ~data[58]
412 rc_ok = data[55] & (data[56] | (store == 0))
413 if perm_ok == 1 and rc_ok == 1:
414 return True
415 return "perm_err" if perm_ok == 0 else "rc_err"
416
417 def _get_prtable_addr(self, shift, prtbl, addr, pid):
418 """
419 if r.addr(63) = '1' then
420 effpid := x"00000000";
421 else
422 effpid := r.pid;
423 end if;
424 x"00" & r.prtbl(55 downto 36) &
425 ((r.prtbl(35 downto 12) and not finalmask(23 downto 0)) or
426 (effpid(31 downto 8) and finalmask(23 downto 0))) &
427 effpid(7 downto 0) & "0000";
428 """
429 finalmask = genmask(shift, 44)
430 finalmask24 = finalmask[20:44]
431 if addr[0].value == 1:
432 effpid = SelectableInt(0, 32)
433 else:
434 effpid = self.pid[32:64] # TODO, check on this
435 zero16 = SelectableInt(0, 16)
436 zero4 = SelectableInt(0, 4)
437 res = selectconcat(zero16,
438 prtbl[8:28], #
439 (prtbl[28:52] & ~finalmask24) | #
440 (effpid[0:24] & finalmask24), #
441 effpid[24:32],
442 zero4
443 )
444 return res
445
446 def _get_pgtable_addr(self, mask_size, pgbase, addrsh):
447 """
448 x"00" & r.pgbase(55 downto 19) &
449 ((r.pgbase(18 downto 3) and not mask) or (addrsh and mask)) &
450 "000";
451 """
452 mask16 = genmask(mask_size+5, 16)
453 zero8 = SelectableInt(0, 8)
454 zero3 = SelectableInt(0, 3)
455 res = selectconcat(zero8,
456 pgbase[8:45], #
457 (prtbl[45:61] & ~mask16) | #
458 (addrsh & mask16), #
459 zero3
460 )
461 return res
462
463 def _get_pte(self, shift, addr, pde):
464 """
465 x"00" &
466 ((r.pde(55 downto 12) and not finalmask) or
467 (r.addr(55 downto 12) and finalmask))
468 & r.pde(11 downto 0);
469 """
470 finalmask = genmask(shift, 44)
471 zero8 = SelectableInt(0, 8)
472 res = selectconcat(zero8,
473 (pde[8:52] & ~finalmask) | #
474 (addr[8:52] & finalmask), #
475 pde[52:64],
476 )
477 return res
478
479
480 # very quick test of maskgen function (TODO, move to util later)
481 if __name__ == '__main__':
482 # set up dummy minimal ISACaller
483 spr = {'DSISR': SelectableInt(0, 64),
484 'DAR': SelectableInt(0, 64),
485 'PIDR': SelectableInt(0, 64),
486 'PRTBL': SelectableInt(0, 64)
487 }
488 class ISACaller: pass
489 caller = ISACaller()
490 caller.spr = spr
491
492 shift = SelectableInt(5, 6)
493 mask = genmask(shift, 43)
494 print (" mask", bin(mask.value))
495
496 mem = Mem(row_bytes=8)
497 mem = RADIX(mem, caller)
498 # -----------------------------------------------
499 # |/|RTS1|/| RPDB | RTS2 | RPDS |
500 # -----------------------------------------------
501 # |0|1 2|3|4 55|56 58|59 63|
502 data = SelectableInt(0, 64)
503 data[1:3] = 0b01
504 data[56:59] = 0b11
505 data[59:64] = 0b01101 # mask
506 data[55] = 1
507 (rts, mbits, pgbase) = mem._decode_prte(data)
508 print (" rts", bin(rts.value), rts.bits)
509 print (" mbits", bin(mbits.value), mbits.bits)
510 print (" pgbase", hex(pgbase.value), pgbase.bits)
511 addr = SelectableInt(0x1000, 64)
512 check = mem._segment_check(addr, mbits, shift)
513 print (" segment check", check)