1 /*
2 * Based on linux/arch/arm/mm/nommu.c
3 *
4 * ARM PMSAv7 supporting functions.
5 */
6
7 #include <linux/bitops.h>
8 #include <linux/memblock.h>
9 #include <linux/string.h>
10
11 #include <asm/cacheflush.h>
12 #include <asm/cp15.h>
13 #include <asm/cputype.h>
14 #include <asm/mpu.h>
15 #include <asm/sections.h>
16
17 #include "mm.h"
18
19 struct region {
20 phys_addr_t base;
21 phys_addr_t size;
22 unsigned long subreg;
23 };
24
25 static struct region __initdata mem[MPU_MAX_REGIONS];
26 #ifdef CONFIG_XIP_KERNEL
27 static struct region __initdata xip[MPU_MAX_REGIONS];
28 #endif
29
30 static unsigned int __initdata mpu_min_region_order;
31 static unsigned int __initdata mpu_max_regions;
32
33 static int __init __mpu_min_region_order(void);
34 static int __init __mpu_max_regions(void);
35
36 #ifndef CONFIG_CPU_V7M
37
38 #define DRBAR __ACCESS_CP15(c6, 0, c1, 0)
39 #define IRBAR __ACCESS_CP15(c6, 0, c1, 1)
40 #define DRSR __ACCESS_CP15(c6, 0, c1, 2)
41 #define IRSR __ACCESS_CP15(c6, 0, c1, 3)
42 #define DRACR __ACCESS_CP15(c6, 0, c1, 4)
43 #define IRACR __ACCESS_CP15(c6, 0, c1, 5)
44 #define RNGNR __ACCESS_CP15(c6, 0, c2, 0)
45
46 /* Region number */
rgnr_write(u32 v)47 static inline void rgnr_write(u32 v)
48 {
49 write_sysreg(v, RNGNR);
50 }
51
52 /* Data-side / unified region attributes */
53
54 /* Region access control register */
dracr_write(u32 v)55 static inline void dracr_write(u32 v)
56 {
57 write_sysreg(v, DRACR);
58 }
59
60 /* Region size register */
drsr_write(u32 v)61 static inline void drsr_write(u32 v)
62 {
63 write_sysreg(v, DRSR);
64 }
65
66 /* Region base address register */
drbar_write(u32 v)67 static inline void drbar_write(u32 v)
68 {
69 write_sysreg(v, DRBAR);
70 }
71
drbar_read(void)72 static inline u32 drbar_read(void)
73 {
74 return read_sysreg(DRBAR);
75 }
76 /* Optional instruction-side region attributes */
77
78 /* I-side Region access control register */
iracr_write(u32 v)79 static inline void iracr_write(u32 v)
80 {
81 write_sysreg(v, IRACR);
82 }
83
84 /* I-side Region size register */
irsr_write(u32 v)85 static inline void irsr_write(u32 v)
86 {
87 write_sysreg(v, IRSR);
88 }
89
90 /* I-side Region base address register */
irbar_write(u32 v)91 static inline void irbar_write(u32 v)
92 {
93 write_sysreg(v, IRBAR);
94 }
95
irbar_read(void)96 static inline u32 irbar_read(void)
97 {
98 return read_sysreg(IRBAR);
99 }
100
101 #else
102
rgnr_write(u32 v)103 static inline void rgnr_write(u32 v)
104 {
105 writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RNR);
106 }
107
108 /* Data-side / unified region attributes */
109
110 /* Region access control register */
dracr_write(u32 v)111 static inline void dracr_write(u32 v)
112 {
113 u32 rsr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(15, 0);
114
115 writel_relaxed((v << 16) | rsr, BASEADDR_V7M_SCB + PMSAv7_RASR);
116 }
117
118 /* Region size register */
drsr_write(u32 v)119 static inline void drsr_write(u32 v)
120 {
121 u32 racr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(31, 16);
122
123 writel_relaxed(v | racr, BASEADDR_V7M_SCB + PMSAv7_RASR);
124 }
125
126 /* Region base address register */
drbar_write(u32 v)127 static inline void drbar_write(u32 v)
128 {
129 writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RBAR);
130 }
131
drbar_read(void)132 static inline u32 drbar_read(void)
133 {
134 return readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RBAR);
135 }
136
137 /* ARMv7-M only supports a unified MPU, so I-side operations are nop */
138
iracr_write(u32 v)139 static inline void iracr_write(u32 v) {}
irsr_write(u32 v)140 static inline void irsr_write(u32 v) {}
irbar_write(u32 v)141 static inline void irbar_write(u32 v) {}
irbar_read(void)142 static inline unsigned long irbar_read(void) {return 0;}
143
144 #endif
145
try_split_region(phys_addr_t base,phys_addr_t size,struct region * region)146 static bool __init try_split_region(phys_addr_t base, phys_addr_t size, struct region *region)
147 {
148 unsigned long subreg, bslots, sslots;
149 phys_addr_t abase = base & ~(size - 1);
150 phys_addr_t asize = base + size - abase;
151 phys_addr_t p2size = 1 << __fls(asize);
152 phys_addr_t bdiff, sdiff;
153
154 if (p2size != asize)
155 p2size *= 2;
156
157 bdiff = base - abase;
158 sdiff = p2size - asize;
159 subreg = p2size / PMSAv7_NR_SUBREGS;
160
161 if ((bdiff % subreg) || (sdiff % subreg))
162 return false;
163
164 bslots = bdiff / subreg;
165 sslots = sdiff / subreg;
166
167 if (bslots || sslots) {
168 int i;
169
170 if (subreg < PMSAv7_MIN_SUBREG_SIZE)
171 return false;
172
173 if (bslots + sslots > PMSAv7_NR_SUBREGS)
174 return false;
175
176 for (i = 0; i < bslots; i++)
177 _set_bit(i, ®ion->subreg);
178
179 for (i = 1; i <= sslots; i++)
180 _set_bit(PMSAv7_NR_SUBREGS - i, ®ion->subreg);
181 }
182
183 region->base = abase;
184 region->size = p2size;
185
186 return true;
187 }
188
allocate_region(phys_addr_t base,phys_addr_t size,unsigned int limit,struct region * regions)189 static int __init allocate_region(phys_addr_t base, phys_addr_t size,
190 unsigned int limit, struct region *regions)
191 {
192 int count = 0;
193 phys_addr_t diff = size;
194 int attempts = MPU_MAX_REGIONS;
195
196 while (diff) {
197 /* Try cover region as is (maybe with help of subregions) */
198 if (try_split_region(base, size, ®ions[count])) {
199 count++;
200 base += size;
201 diff -= size;
202 size = diff;
203 } else {
204 /*
205 * Maximum aligned region might overflow phys_addr_t
206 * if "base" is 0. Hence we keep everything below 4G
207 * until we take the smaller of the aligned region
208 * size ("asize") and rounded region size ("p2size"),
209 * one of which is guaranteed to be smaller than the
210 * maximum physical address.
211 */
212 phys_addr_t asize = (base - 1) ^ base;
213 phys_addr_t p2size = (1 << __fls(diff)) - 1;
214
215 size = asize < p2size ? asize + 1 : p2size + 1;
216 }
217
218 if (count > limit)
219 break;
220
221 if (!attempts)
222 break;
223
224 attempts--;
225 }
226
227 return count;
228 }
229
230 /* MPU initialisation functions */
pmsav7_adjust_lowmem_bounds(void)231 void __init pmsav7_adjust_lowmem_bounds(void)
232 {
233 phys_addr_t specified_mem_size = 0, total_mem_size = 0;
234 struct memblock_region *reg;
235 bool first = true;
236 phys_addr_t mem_start;
237 phys_addr_t mem_end;
238 unsigned int mem_max_regions;
239 int num, i;
240
241 /* Free-up PMSAv7_PROBE_REGION */
242 mpu_min_region_order = __mpu_min_region_order();
243
244 /* How many regions are supported */
245 mpu_max_regions = __mpu_max_regions();
246
247 mem_max_regions = min((unsigned int)MPU_MAX_REGIONS, mpu_max_regions);
248
249 /* We need to keep one slot for background region */
250 mem_max_regions--;
251
252 #ifndef CONFIG_CPU_V7M
253 /* ... and one for vectors */
254 mem_max_regions--;
255 #endif
256
257 #ifdef CONFIG_XIP_KERNEL
258 /* plus some regions to cover XIP ROM */
259 num = allocate_region(CONFIG_XIP_PHYS_ADDR, __pa(_exiprom) - CONFIG_XIP_PHYS_ADDR,
260 mem_max_regions, xip);
261
262 mem_max_regions -= num;
263 #endif
264
265 for_each_memblock(memory, reg) {
266 if (first) {
267 phys_addr_t phys_offset = PHYS_OFFSET;
268
269 /*
270 * Initially only use memory continuous from
271 * PHYS_OFFSET */
272 if (reg->base != phys_offset)
273 panic("First memory bank must be contiguous from PHYS_OFFSET");
274
275 mem_start = reg->base;
276 mem_end = reg->base + reg->size;
277 specified_mem_size = reg->size;
278 first = false;
279 } else {
280 /*
281 * memblock auto merges contiguous blocks, remove
282 * all blocks afterwards in one go (we can't remove
283 * blocks separately while iterating)
284 */
285 pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
286 &mem_end, ®->base);
287 memblock_remove(reg->base, 0 - reg->base);
288 break;
289 }
290 }
291
292 memset(mem, 0, sizeof(mem));
293 num = allocate_region(mem_start, specified_mem_size, mem_max_regions, mem);
294
295 for (i = 0; i < num; i++) {
296 unsigned long subreg = mem[i].size / PMSAv7_NR_SUBREGS;
297
298 total_mem_size += mem[i].size - subreg * hweight_long(mem[i].subreg);
299
300 pr_debug("MPU: base %pa size %pa disable subregions: %*pbl\n",
301 &mem[i].base, &mem[i].size, PMSAv7_NR_SUBREGS, &mem[i].subreg);
302 }
303
304 if (total_mem_size != specified_mem_size) {
305 pr_warn("Truncating memory from %pa to %pa (MPU region constraints)",
306 &specified_mem_size, &total_mem_size);
307 memblock_remove(mem_start + total_mem_size,
308 specified_mem_size - total_mem_size);
309 }
310 }
311
__mpu_max_regions(void)312 static int __init __mpu_max_regions(void)
313 {
314 /*
315 * We don't support a different number of I/D side regions so if we
316 * have separate instruction and data memory maps then return
317 * whichever side has a smaller number of supported regions.
318 */
319 u32 dregions, iregions, mpuir;
320
321 mpuir = read_cpuid_mputype();
322
323 dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;
324
325 /* Check for separate d-side and i-side memory maps */
326 if (mpuir & MPUIR_nU)
327 iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION;
328
329 /* Use the smallest of the two maxima */
330 return min(dregions, iregions);
331 }
332
mpu_iside_independent(void)333 static int __init mpu_iside_independent(void)
334 {
335 /* MPUIR.nU specifies whether there is *not* a unified memory map */
336 return read_cpuid_mputype() & MPUIR_nU;
337 }
338
__mpu_min_region_order(void)339 static int __init __mpu_min_region_order(void)
340 {
341 u32 drbar_result, irbar_result;
342
343 /* We've kept a region free for this probing */
344 rgnr_write(PMSAv7_PROBE_REGION);
345 isb();
346 /*
347 * As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum
348 * region order
349 */
350 drbar_write(0xFFFFFFFC);
351 drbar_result = irbar_result = drbar_read();
352 drbar_write(0x0);
353 /* If the MPU is non-unified, we use the larger of the two minima*/
354 if (mpu_iside_independent()) {
355 irbar_write(0xFFFFFFFC);
356 irbar_result = irbar_read();
357 irbar_write(0x0);
358 }
359 isb(); /* Ensure that MPU region operations have completed */
360 /* Return whichever result is larger */
361
362 return __ffs(max(drbar_result, irbar_result));
363 }
364
mpu_setup_region(unsigned int number,phys_addr_t start,unsigned int size_order,unsigned int properties,unsigned int subregions,bool need_flush)365 static int __init mpu_setup_region(unsigned int number, phys_addr_t start,
366 unsigned int size_order, unsigned int properties,
367 unsigned int subregions, bool need_flush)
368 {
369 u32 size_data;
370
371 /* We kept a region free for probing resolution of MPU regions*/
372 if (number > mpu_max_regions
373 || number >= MPU_MAX_REGIONS)
374 return -ENOENT;
375
376 if (size_order > 32)
377 return -ENOMEM;
378
379 if (size_order < mpu_min_region_order)
380 return -ENOMEM;
381
382 /* Writing N to bits 5:1 (RSR_SZ) specifies region size 2^N+1 */
383 size_data = ((size_order - 1) << PMSAv7_RSR_SZ) | 1 << PMSAv7_RSR_EN;
384 size_data |= subregions << PMSAv7_RSR_SD;
385
386 if (need_flush)
387 flush_cache_all();
388
389 dsb(); /* Ensure all previous data accesses occur with old mappings */
390 rgnr_write(number);
391 isb();
392 drbar_write(start);
393 dracr_write(properties);
394 isb(); /* Propagate properties before enabling region */
395 drsr_write(size_data);
396
397 /* Check for independent I-side registers */
398 if (mpu_iside_independent()) {
399 irbar_write(start);
400 iracr_write(properties);
401 isb();
402 irsr_write(size_data);
403 }
404 isb();
405
406 /* Store region info (we treat i/d side the same, so only store d) */
407 mpu_rgn_info.rgns[number].dracr = properties;
408 mpu_rgn_info.rgns[number].drbar = start;
409 mpu_rgn_info.rgns[number].drsr = size_data;
410
411 mpu_rgn_info.used++;
412
413 return 0;
414 }
415
416 /*
417 * Set up default MPU regions, doing nothing if there is no MPU
418 */
pmsav7_setup(void)419 void __init pmsav7_setup(void)
420 {
421 int i, region = 0, err = 0;
422
423 /* Setup MPU (order is important) */
424
425 /* Background */
426 err |= mpu_setup_region(region++, 0, 32,
427 PMSAv7_ACR_XN | PMSAv7_RGN_STRONGLY_ORDERED | PMSAv7_AP_PL1RW_PL0RW,
428 0, false);
429
430 #ifdef CONFIG_XIP_KERNEL
431 /* ROM */
432 for (i = 0; i < ARRAY_SIZE(xip); i++) {
433 /*
434 * In case we overwrite RAM region we set earlier in
435 * head-nommu.S (which is cachable) all subsequent
436 * data access till we setup RAM bellow would be done
437 * with BG region (which is uncachable), thus we need
438 * to clean and invalidate cache.
439 */
440 bool need_flush = region == PMSAv7_RAM_REGION;
441
442 if (!xip[i].size)
443 continue;
444
445 err |= mpu_setup_region(region++, xip[i].base, ilog2(xip[i].size),
446 PMSAv7_AP_PL1RO_PL0NA | PMSAv7_RGN_NORMAL,
447 xip[i].subreg, need_flush);
448 }
449 #endif
450
451 /* RAM */
452 for (i = 0; i < ARRAY_SIZE(mem); i++) {
453 if (!mem[i].size)
454 continue;
455
456 err |= mpu_setup_region(region++, mem[i].base, ilog2(mem[i].size),
457 PMSAv7_AP_PL1RW_PL0RW | PMSAv7_RGN_NORMAL,
458 mem[i].subreg, false);
459 }
460
461 /* Vectors */
462 #ifndef CONFIG_CPU_V7M
463 err |= mpu_setup_region(region++, vectors_base, ilog2(2 * PAGE_SIZE),
464 PMSAv7_AP_PL1RW_PL0NA | PMSAv7_RGN_NORMAL,
465 0, false);
466 #endif
467 if (err) {
468 panic("MPU region initialization failure! %d", err);
469 } else {
470 pr_info("Using ARMv7 PMSA Compliant MPU. "
471 "Region independence: %s, Used %d of %d regions\n",
472 mpu_iside_independent() ? "Yes" : "No",
473 mpu_rgn_info.used, mpu_max_regions);
474 }
475 }
476