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Linux/arch/x86/kernel/cpu/mtrr/cleanup.c

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  1 /*
  2  * MTRR (Memory Type Range Register) cleanup
  3  *
  4  *  Copyright (C) 2009 Yinghai Lu
  5  *
  6  * This library is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU Library General Public
  8  * License as published by the Free Software Foundation; either
  9  * version 2 of the License, or (at your option) any later version.
 10  *
 11  * This library is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 14  * Library General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU Library General Public
 17  * License along with this library; if not, write to the Free
 18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 19  */
 20 #include <linux/module.h>
 21 #include <linux/init.h>
 22 #include <linux/pci.h>
 23 #include <linux/smp.h>
 24 #include <linux/cpu.h>
 25 #include <linux/mutex.h>
 26 #include <linux/uaccess.h>
 27 #include <linux/kvm_para.h>
 28 #include <linux/range.h>
 29 
 30 #include <asm/processor.h>
 31 #include <asm/e820.h>
 32 #include <asm/mtrr.h>
 33 #include <asm/msr.h>
 34 
 35 #include "mtrr.h"
 36 
 37 struct var_mtrr_range_state {
 38         unsigned long   base_pfn;
 39         unsigned long   size_pfn;
 40         mtrr_type       type;
 41 };
 42 
 43 struct var_mtrr_state {
 44         unsigned long   range_startk;
 45         unsigned long   range_sizek;
 46         unsigned long   chunk_sizek;
 47         unsigned long   gran_sizek;
 48         unsigned int    reg;
 49 };
 50 
 51 /* Should be related to MTRR_VAR_RANGES nums */
 52 #define RANGE_NUM                               256
 53 
 54 static struct range __initdata          range[RANGE_NUM];
 55 static int __initdata                           nr_range;
 56 
 57 static struct var_mtrr_range_state __initdata   range_state[RANGE_NUM];
 58 
 59 static int __initdata debug_print;
 60 #define Dprintk(x...) do { if (debug_print) printk(KERN_DEBUG x); } while (0)
 61 
 62 #define BIOS_BUG_MSG KERN_WARNING \
 63         "WARNING: BIOS bug: VAR MTRR %d contains strange UC entry under 1M, check with your system vendor!\n"
 64 
 65 static int __init
 66 x86_get_mtrr_mem_range(struct range *range, int nr_range,
 67                        unsigned long extra_remove_base,
 68                        unsigned long extra_remove_size)
 69 {
 70         unsigned long base, size;
 71         mtrr_type type;
 72         int i;
 73 
 74         for (i = 0; i < num_var_ranges; i++) {
 75                 type = range_state[i].type;
 76                 if (type != MTRR_TYPE_WRBACK)
 77                         continue;
 78                 base = range_state[i].base_pfn;
 79                 size = range_state[i].size_pfn;
 80                 nr_range = add_range_with_merge(range, RANGE_NUM, nr_range,
 81                                                 base, base + size);
 82         }
 83         if (debug_print) {
 84                 printk(KERN_DEBUG "After WB checking\n");
 85                 for (i = 0; i < nr_range; i++)
 86                         printk(KERN_DEBUG "MTRR MAP PFN: %016llx - %016llx\n",
 87                                  range[i].start, range[i].end);
 88         }
 89 
 90         /* Take out UC ranges: */
 91         for (i = 0; i < num_var_ranges; i++) {
 92                 type = range_state[i].type;
 93                 if (type != MTRR_TYPE_UNCACHABLE &&
 94                     type != MTRR_TYPE_WRPROT)
 95                         continue;
 96                 size = range_state[i].size_pfn;
 97                 if (!size)
 98                         continue;
 99                 base = range_state[i].base_pfn;
100                 if (base < (1<<(20-PAGE_SHIFT)) && mtrr_state.have_fixed &&
101                     (mtrr_state.enabled & 1)) {
102                         /* Var MTRR contains UC entry below 1M? Skip it: */
103                         printk(BIOS_BUG_MSG, i);
104                         if (base + size <= (1<<(20-PAGE_SHIFT)))
105                                 continue;
106                         size -= (1<<(20-PAGE_SHIFT)) - base;
107                         base = 1<<(20-PAGE_SHIFT);
108                 }
109                 subtract_range(range, RANGE_NUM, base, base + size);
110         }
111         if (extra_remove_size)
112                 subtract_range(range, RANGE_NUM, extra_remove_base,
113                                  extra_remove_base + extra_remove_size);
114 
115         if  (debug_print) {
116                 printk(KERN_DEBUG "After UC checking\n");
117                 for (i = 0; i < RANGE_NUM; i++) {
118                         if (!range[i].end)
119                                 continue;
120                         printk(KERN_DEBUG "MTRR MAP PFN: %016llx - %016llx\n",
121                                  range[i].start, range[i].end);
122                 }
123         }
124 
125         /* sort the ranges */
126         nr_range = clean_sort_range(range, RANGE_NUM);
127         if  (debug_print) {
128                 printk(KERN_DEBUG "After sorting\n");
129                 for (i = 0; i < nr_range; i++)
130                         printk(KERN_DEBUG "MTRR MAP PFN: %016llx - %016llx\n",
131                                  range[i].start, range[i].end);
132         }
133 
134         return nr_range;
135 }
136 
137 #ifdef CONFIG_MTRR_SANITIZER
138 
139 static unsigned long __init sum_ranges(struct range *range, int nr_range)
140 {
141         unsigned long sum = 0;
142         int i;
143 
144         for (i = 0; i < nr_range; i++)
145                 sum += range[i].end - range[i].start;
146 
147         return sum;
148 }
149 
150 static int enable_mtrr_cleanup __initdata =
151         CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT;
152 
153 static int __init disable_mtrr_cleanup_setup(char *str)
154 {
155         enable_mtrr_cleanup = 0;
156         return 0;
157 }
158 early_param("disable_mtrr_cleanup", disable_mtrr_cleanup_setup);
159 
160 static int __init enable_mtrr_cleanup_setup(char *str)
161 {
162         enable_mtrr_cleanup = 1;
163         return 0;
164 }
165 early_param("enable_mtrr_cleanup", enable_mtrr_cleanup_setup);
166 
167 static int __init mtrr_cleanup_debug_setup(char *str)
168 {
169         debug_print = 1;
170         return 0;
171 }
172 early_param("mtrr_cleanup_debug", mtrr_cleanup_debug_setup);
173 
174 static void __init
175 set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
176              unsigned char type, unsigned int address_bits)
177 {
178         u32 base_lo, base_hi, mask_lo, mask_hi;
179         u64 base, mask;
180 
181         if (!sizek) {
182                 fill_mtrr_var_range(reg, 0, 0, 0, 0);
183                 return;
184         }
185 
186         mask = (1ULL << address_bits) - 1;
187         mask &= ~((((u64)sizek) << 10) - 1);
188 
189         base = ((u64)basek) << 10;
190 
191         base |= type;
192         mask |= 0x800;
193 
194         base_lo = base & ((1ULL<<32) - 1);
195         base_hi = base >> 32;
196 
197         mask_lo = mask & ((1ULL<<32) - 1);
198         mask_hi = mask >> 32;
199 
200         fill_mtrr_var_range(reg, base_lo, base_hi, mask_lo, mask_hi);
201 }
202 
203 static void __init
204 save_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
205               unsigned char type)
206 {
207         range_state[reg].base_pfn = basek >> (PAGE_SHIFT - 10);
208         range_state[reg].size_pfn = sizek >> (PAGE_SHIFT - 10);
209         range_state[reg].type = type;
210 }
211 
212 static void __init set_var_mtrr_all(unsigned int address_bits)
213 {
214         unsigned long basek, sizek;
215         unsigned char type;
216         unsigned int reg;
217 
218         for (reg = 0; reg < num_var_ranges; reg++) {
219                 basek = range_state[reg].base_pfn << (PAGE_SHIFT - 10);
220                 sizek = range_state[reg].size_pfn << (PAGE_SHIFT - 10);
221                 type = range_state[reg].type;
222 
223                 set_var_mtrr(reg, basek, sizek, type, address_bits);
224         }
225 }
226 
227 static unsigned long to_size_factor(unsigned long sizek, char *factorp)
228 {
229         unsigned long base = sizek;
230         char factor;
231 
232         if (base & ((1<<10) - 1)) {
233                 /* Not MB-aligned: */
234                 factor = 'K';
235         } else if (base & ((1<<20) - 1)) {
236                 factor = 'M';
237                 base >>= 10;
238         } else {
239                 factor = 'G';
240                 base >>= 20;
241         }
242 
243         *factorp = factor;
244 
245         return base;
246 }
247 
248 static unsigned int __init
249 range_to_mtrr(unsigned int reg, unsigned long range_startk,
250               unsigned long range_sizek, unsigned char type)
251 {
252         if (!range_sizek || (reg >= num_var_ranges))
253                 return reg;
254 
255         while (range_sizek) {
256                 unsigned long max_align, align;
257                 unsigned long sizek;
258 
259                 /* Compute the maximum size with which we can make a range: */
260                 if (range_startk)
261                         max_align = __ffs(range_startk);
262                 else
263                         max_align = BITS_PER_LONG - 1;
264 
265                 align = __fls(range_sizek);
266                 if (align > max_align)
267                         align = max_align;
268 
269                 sizek = 1UL << align;
270                 if (debug_print) {
271                         char start_factor = 'K', size_factor = 'K';
272                         unsigned long start_base, size_base;
273 
274                         start_base = to_size_factor(range_startk, &start_factor);
275                         size_base = to_size_factor(sizek, &size_factor);
276 
277                         Dprintk("Setting variable MTRR %d, "
278                                 "base: %ld%cB, range: %ld%cB, type %s\n",
279                                 reg, start_base, start_factor,
280                                 size_base, size_factor,
281                                 (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
282                                    ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other")
283                                 );
284                 }
285                 save_var_mtrr(reg++, range_startk, sizek, type);
286                 range_startk += sizek;
287                 range_sizek -= sizek;
288                 if (reg >= num_var_ranges)
289                         break;
290         }
291         return reg;
292 }
293 
294 static unsigned __init
295 range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
296                         unsigned long sizek)
297 {
298         unsigned long hole_basek, hole_sizek;
299         unsigned long second_basek, second_sizek;
300         unsigned long range0_basek, range0_sizek;
301         unsigned long range_basek, range_sizek;
302         unsigned long chunk_sizek;
303         unsigned long gran_sizek;
304 
305         hole_basek = 0;
306         hole_sizek = 0;
307         second_basek = 0;
308         second_sizek = 0;
309         chunk_sizek = state->chunk_sizek;
310         gran_sizek = state->gran_sizek;
311 
312         /* Align with gran size, prevent small block used up MTRRs: */
313         range_basek = ALIGN(state->range_startk, gran_sizek);
314         if ((range_basek > basek) && basek)
315                 return second_sizek;
316 
317         state->range_sizek -= (range_basek - state->range_startk);
318         range_sizek = ALIGN(state->range_sizek, gran_sizek);
319 
320         while (range_sizek > state->range_sizek) {
321                 range_sizek -= gran_sizek;
322                 if (!range_sizek)
323                         return 0;
324         }
325         state->range_sizek = range_sizek;
326 
327         /* Try to append some small hole: */
328         range0_basek = state->range_startk;
329         range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
330 
331         /* No increase: */
332         if (range0_sizek == state->range_sizek) {
333                 Dprintk("rangeX: %016lx - %016lx\n",
334                         range0_basek<<10,
335                         (range0_basek + state->range_sizek)<<10);
336                 state->reg = range_to_mtrr(state->reg, range0_basek,
337                                 state->range_sizek, MTRR_TYPE_WRBACK);
338                 return 0;
339         }
340 
341         /* Only cut back when it is not the last: */
342         if (sizek) {
343                 while (range0_basek + range0_sizek > (basek + sizek)) {
344                         if (range0_sizek >= chunk_sizek)
345                                 range0_sizek -= chunk_sizek;
346                         else
347                                 range0_sizek = 0;
348 
349                         if (!range0_sizek)
350                                 break;
351                 }
352         }
353 
354 second_try:
355         range_basek = range0_basek + range0_sizek;
356 
357         /* One hole in the middle: */
358         if (range_basek > basek && range_basek <= (basek + sizek))
359                 second_sizek = range_basek - basek;
360 
361         if (range0_sizek > state->range_sizek) {
362 
363                 /* One hole in middle or at the end: */
364                 hole_sizek = range0_sizek - state->range_sizek - second_sizek;
365 
366                 /* Hole size should be less than half of range0 size: */
367                 if (hole_sizek >= (range0_sizek >> 1) &&
368                     range0_sizek >= chunk_sizek) {
369                         range0_sizek -= chunk_sizek;
370                         second_sizek = 0;
371                         hole_sizek = 0;
372 
373                         goto second_try;
374                 }
375         }
376 
377         if (range0_sizek) {
378                 Dprintk("range0: %016lx - %016lx\n",
379                         range0_basek<<10,
380                         (range0_basek + range0_sizek)<<10);
381                 state->reg = range_to_mtrr(state->reg, range0_basek,
382                                 range0_sizek, MTRR_TYPE_WRBACK);
383         }
384 
385         if (range0_sizek < state->range_sizek) {
386                 /* Need to handle left over range: */
387                 range_sizek = state->range_sizek - range0_sizek;
388 
389                 Dprintk("range: %016lx - %016lx\n",
390                          range_basek<<10,
391                          (range_basek + range_sizek)<<10);
392 
393                 state->reg = range_to_mtrr(state->reg, range_basek,
394                                  range_sizek, MTRR_TYPE_WRBACK);
395         }
396 
397         if (hole_sizek) {
398                 hole_basek = range_basek - hole_sizek - second_sizek;
399                 Dprintk("hole: %016lx - %016lx\n",
400                          hole_basek<<10,
401                          (hole_basek + hole_sizek)<<10);
402                 state->reg = range_to_mtrr(state->reg, hole_basek,
403                                  hole_sizek, MTRR_TYPE_UNCACHABLE);
404         }
405 
406         return second_sizek;
407 }
408 
409 static void __init
410 set_var_mtrr_range(struct var_mtrr_state *state, unsigned long base_pfn,
411                    unsigned long size_pfn)
412 {
413         unsigned long basek, sizek;
414         unsigned long second_sizek = 0;
415 
416         if (state->reg >= num_var_ranges)
417                 return;
418 
419         basek = base_pfn << (PAGE_SHIFT - 10);
420         sizek = size_pfn << (PAGE_SHIFT - 10);
421 
422         /* See if I can merge with the last range: */
423         if ((basek <= 1024) ||
424             (state->range_startk + state->range_sizek == basek)) {
425                 unsigned long endk = basek + sizek;
426                 state->range_sizek = endk - state->range_startk;
427                 return;
428         }
429         /* Write the range mtrrs: */
430         if (state->range_sizek != 0)
431                 second_sizek = range_to_mtrr_with_hole(state, basek, sizek);
432 
433         /* Allocate an msr: */
434         state->range_startk = basek + second_sizek;
435         state->range_sizek  = sizek - second_sizek;
436 }
437 
438 /* Mininum size of mtrr block that can take hole: */
439 static u64 mtrr_chunk_size __initdata = (256ULL<<20);
440 
441 static int __init parse_mtrr_chunk_size_opt(char *p)
442 {
443         if (!p)
444                 return -EINVAL;
445         mtrr_chunk_size = memparse(p, &p);
446         return 0;
447 }
448 early_param("mtrr_chunk_size", parse_mtrr_chunk_size_opt);
449 
450 /* Granularity of mtrr of block: */
451 static u64 mtrr_gran_size __initdata;
452 
453 static int __init parse_mtrr_gran_size_opt(char *p)
454 {
455         if (!p)
456                 return -EINVAL;
457         mtrr_gran_size = memparse(p, &p);
458         return 0;
459 }
460 early_param("mtrr_gran_size", parse_mtrr_gran_size_opt);
461 
462 static unsigned long nr_mtrr_spare_reg __initdata =
463                                  CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT;
464 
465 static int __init parse_mtrr_spare_reg(char *arg)
466 {
467         if (arg)
468                 nr_mtrr_spare_reg = simple_strtoul(arg, NULL, 0);
469         return 0;
470 }
471 early_param("mtrr_spare_reg_nr", parse_mtrr_spare_reg);
472 
473 static int __init
474 x86_setup_var_mtrrs(struct range *range, int nr_range,
475                     u64 chunk_size, u64 gran_size)
476 {
477         struct var_mtrr_state var_state;
478         int num_reg;
479         int i;
480 
481         var_state.range_startk  = 0;
482         var_state.range_sizek   = 0;
483         var_state.reg           = 0;
484         var_state.chunk_sizek   = chunk_size >> 10;
485         var_state.gran_sizek    = gran_size >> 10;
486 
487         memset(range_state, 0, sizeof(range_state));
488 
489         /* Write the range: */
490         for (i = 0; i < nr_range; i++) {
491                 set_var_mtrr_range(&var_state, range[i].start,
492                                    range[i].end - range[i].start);
493         }
494 
495         /* Write the last range: */
496         if (var_state.range_sizek != 0)
497                 range_to_mtrr_with_hole(&var_state, 0, 0);
498 
499         num_reg = var_state.reg;
500         /* Clear out the extra MTRR's: */
501         while (var_state.reg < num_var_ranges) {
502                 save_var_mtrr(var_state.reg, 0, 0, 0);
503                 var_state.reg++;
504         }
505 
506         return num_reg;
507 }
508 
509 struct mtrr_cleanup_result {
510         unsigned long   gran_sizek;
511         unsigned long   chunk_sizek;
512         unsigned long   lose_cover_sizek;
513         unsigned int    num_reg;
514         int             bad;
515 };
516 
517 /*
518  * gran_size: 64K, 128K, 256K, 512K, 1M, 2M, ..., 2G
519  * chunk size: gran_size, ..., 2G
520  * so we need (1+16)*8
521  */
522 #define NUM_RESULT      136
523 #define PSHIFT          (PAGE_SHIFT - 10)
524 
525 static struct mtrr_cleanup_result __initdata result[NUM_RESULT];
526 static unsigned long __initdata min_loss_pfn[RANGE_NUM];
527 
528 static void __init print_out_mtrr_range_state(void)
529 {
530         char start_factor = 'K', size_factor = 'K';
531         unsigned long start_base, size_base;
532         mtrr_type type;
533         int i;
534 
535         for (i = 0; i < num_var_ranges; i++) {
536 
537                 size_base = range_state[i].size_pfn << (PAGE_SHIFT - 10);
538                 if (!size_base)
539                         continue;
540 
541                 size_base = to_size_factor(size_base, &size_factor),
542                 start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
543                 start_base = to_size_factor(start_base, &start_factor),
544                 type = range_state[i].type;
545 
546                 printk(KERN_DEBUG "reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
547                         i, start_base, start_factor,
548                         size_base, size_factor,
549                         (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
550                             ((type == MTRR_TYPE_WRPROT) ? "WP" :
551                              ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other"))
552                         );
553         }
554 }
555 
556 static int __init mtrr_need_cleanup(void)
557 {
558         int i;
559         mtrr_type type;
560         unsigned long size;
561         /* Extra one for all 0: */
562         int num[MTRR_NUM_TYPES + 1];
563 
564         /* Check entries number: */
565         memset(num, 0, sizeof(num));
566         for (i = 0; i < num_var_ranges; i++) {
567                 type = range_state[i].type;
568                 size = range_state[i].size_pfn;
569                 if (type >= MTRR_NUM_TYPES)
570                         continue;
571                 if (!size)
572                         type = MTRR_NUM_TYPES;
573                 num[type]++;
574         }
575 
576         /* Check if we got UC entries: */
577         if (!num[MTRR_TYPE_UNCACHABLE])
578                 return 0;
579 
580         /* Check if we only had WB and UC */
581         if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
582             num_var_ranges - num[MTRR_NUM_TYPES])
583                 return 0;
584 
585         return 1;
586 }
587 
588 static unsigned long __initdata range_sums;
589 
590 static void __init
591 mtrr_calc_range_state(u64 chunk_size, u64 gran_size,
592                       unsigned long x_remove_base,
593                       unsigned long x_remove_size, int i)
594 {
595         static struct range range_new[RANGE_NUM];
596         unsigned long range_sums_new;
597         static int nr_range_new;
598         int num_reg;
599 
600         /* Convert ranges to var ranges state: */
601         num_reg = x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
602 
603         /* We got new setting in range_state, check it: */
604         memset(range_new, 0, sizeof(range_new));
605         nr_range_new = x86_get_mtrr_mem_range(range_new, 0,
606                                 x_remove_base, x_remove_size);
607         range_sums_new = sum_ranges(range_new, nr_range_new);
608 
609         result[i].chunk_sizek = chunk_size >> 10;
610         result[i].gran_sizek = gran_size >> 10;
611         result[i].num_reg = num_reg;
612 
613         if (range_sums < range_sums_new) {
614                 result[i].lose_cover_sizek = (range_sums_new - range_sums) << PSHIFT;
615                 result[i].bad = 1;
616         } else {
617                 result[i].lose_cover_sizek = (range_sums - range_sums_new) << PSHIFT;
618         }
619 
620         /* Double check it: */
621         if (!result[i].bad && !result[i].lose_cover_sizek) {
622                 if (nr_range_new != nr_range || memcmp(range, range_new, sizeof(range)))
623                         result[i].bad = 1;
624         }
625 
626         if (!result[i].bad && (range_sums - range_sums_new < min_loss_pfn[num_reg]))
627                 min_loss_pfn[num_reg] = range_sums - range_sums_new;
628 }
629 
630 static void __init mtrr_print_out_one_result(int i)
631 {
632         unsigned long gran_base, chunk_base, lose_base;
633         char gran_factor, chunk_factor, lose_factor;
634 
635         gran_base = to_size_factor(result[i].gran_sizek, &gran_factor);
636         chunk_base = to_size_factor(result[i].chunk_sizek, &chunk_factor);
637         lose_base = to_size_factor(result[i].lose_cover_sizek, &lose_factor);
638 
639         pr_info("%sgran_size: %ld%c \tchunk_size: %ld%c \t",
640                 result[i].bad ? "*BAD*" : " ",
641                 gran_base, gran_factor, chunk_base, chunk_factor);
642         pr_cont("num_reg: %d  \tlose cover RAM: %s%ld%c\n",
643                 result[i].num_reg, result[i].bad ? "-" : "",
644                 lose_base, lose_factor);
645 }
646 
647 static int __init mtrr_search_optimal_index(void)
648 {
649         int num_reg_good;
650         int index_good;
651         int i;
652 
653         if (nr_mtrr_spare_reg >= num_var_ranges)
654                 nr_mtrr_spare_reg = num_var_ranges - 1;
655 
656         num_reg_good = -1;
657         for (i = num_var_ranges - nr_mtrr_spare_reg; i > 0; i--) {
658                 if (!min_loss_pfn[i])
659                         num_reg_good = i;
660         }
661 
662         index_good = -1;
663         if (num_reg_good != -1) {
664                 for (i = 0; i < NUM_RESULT; i++) {
665                         if (!result[i].bad &&
666                             result[i].num_reg == num_reg_good &&
667                             !result[i].lose_cover_sizek) {
668                                 index_good = i;
669                                 break;
670                         }
671                 }
672         }
673 
674         return index_good;
675 }
676 
677 int __init mtrr_cleanup(unsigned address_bits)
678 {
679         unsigned long x_remove_base, x_remove_size;
680         unsigned long base, size, def, dummy;
681         u64 chunk_size, gran_size;
682         mtrr_type type;
683         int index_good;
684         int i;
685 
686         if (!is_cpu(INTEL) || enable_mtrr_cleanup < 1)
687                 return 0;
688 
689         rdmsr(MSR_MTRRdefType, def, dummy);
690         def &= 0xff;
691         if (def != MTRR_TYPE_UNCACHABLE)
692                 return 0;
693 
694         /* Get it and store it aside: */
695         memset(range_state, 0, sizeof(range_state));
696         for (i = 0; i < num_var_ranges; i++) {
697                 mtrr_if->get(i, &base, &size, &type);
698                 range_state[i].base_pfn = base;
699                 range_state[i].size_pfn = size;
700                 range_state[i].type = type;
701         }
702 
703         /* Check if we need handle it and can handle it: */
704         if (!mtrr_need_cleanup())
705                 return 0;
706 
707         /* Print original var MTRRs at first, for debugging: */
708         printk(KERN_DEBUG "original variable MTRRs\n");
709         print_out_mtrr_range_state();
710 
711         memset(range, 0, sizeof(range));
712         x_remove_size = 0;
713         x_remove_base = 1 << (32 - PAGE_SHIFT);
714         if (mtrr_tom2)
715                 x_remove_size = (mtrr_tom2 >> PAGE_SHIFT) - x_remove_base;
716 
717         /*
718          * [0, 1M) should always be covered by var mtrr with WB
719          * and fixed mtrrs should take effect before var mtrr for it:
720          */
721         nr_range = add_range_with_merge(range, RANGE_NUM, 0, 0,
722                                         1ULL<<(20 - PAGE_SHIFT));
723         /* add from var mtrr at last */
724         nr_range = x86_get_mtrr_mem_range(range, nr_range,
725                                           x_remove_base, x_remove_size);
726 
727         range_sums = sum_ranges(range, nr_range);
728         printk(KERN_INFO "total RAM covered: %ldM\n",
729                range_sums >> (20 - PAGE_SHIFT));
730 
731         if (mtrr_chunk_size && mtrr_gran_size) {
732                 i = 0;
733                 mtrr_calc_range_state(mtrr_chunk_size, mtrr_gran_size,
734                                       x_remove_base, x_remove_size, i);
735 
736                 mtrr_print_out_one_result(i);
737 
738                 if (!result[i].bad) {
739                         set_var_mtrr_all(address_bits);
740                         printk(KERN_DEBUG "New variable MTRRs\n");
741                         print_out_mtrr_range_state();
742                         return 1;
743                 }
744                 printk(KERN_INFO "invalid mtrr_gran_size or mtrr_chunk_size, "
745                        "will find optimal one\n");
746         }
747 
748         i = 0;
749         memset(min_loss_pfn, 0xff, sizeof(min_loss_pfn));
750         memset(result, 0, sizeof(result));
751         for (gran_size = (1ULL<<16); gran_size < (1ULL<<32); gran_size <<= 1) {
752 
753                 for (chunk_size = gran_size; chunk_size < (1ULL<<32);
754                      chunk_size <<= 1) {
755 
756                         if (i >= NUM_RESULT)
757                                 continue;
758 
759                         mtrr_calc_range_state(chunk_size, gran_size,
760                                       x_remove_base, x_remove_size, i);
761                         if (debug_print) {
762                                 mtrr_print_out_one_result(i);
763                                 printk(KERN_INFO "\n");
764                         }
765 
766                         i++;
767                 }
768         }
769 
770         /* Try to find the optimal index: */
771         index_good = mtrr_search_optimal_index();
772 
773         if (index_good != -1) {
774                 printk(KERN_INFO "Found optimal setting for mtrr clean up\n");
775                 i = index_good;
776                 mtrr_print_out_one_result(i);
777 
778                 /* Convert ranges to var ranges state: */
779                 chunk_size = result[i].chunk_sizek;
780                 chunk_size <<= 10;
781                 gran_size = result[i].gran_sizek;
782                 gran_size <<= 10;
783                 x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
784                 set_var_mtrr_all(address_bits);
785                 printk(KERN_DEBUG "New variable MTRRs\n");
786                 print_out_mtrr_range_state();
787                 return 1;
788         } else {
789                 /* print out all */
790                 for (i = 0; i < NUM_RESULT; i++)
791                         mtrr_print_out_one_result(i);
792         }
793 
794         printk(KERN_INFO "mtrr_cleanup: can not find optimal value\n");
795         printk(KERN_INFO "please specify mtrr_gran_size/mtrr_chunk_size\n");
796 
797         return 0;
798 }
799 #else
800 int __init mtrr_cleanup(unsigned address_bits)
801 {
802         return 0;
803 }
804 #endif
805 
806 static int disable_mtrr_trim;
807 
808 static int __init disable_mtrr_trim_setup(char *str)
809 {
810         disable_mtrr_trim = 1;
811         return 0;
812 }
813 early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
814 
815 /*
816  * Newer AMD K8s and later CPUs have a special magic MSR way to force WB
817  * for memory >4GB. Check for that here.
818  * Note this won't check if the MTRRs < 4GB where the magic bit doesn't
819  * apply to are wrong, but so far we don't know of any such case in the wild.
820  */
821 #define Tom2Enabled             (1U << 21)
822 #define Tom2ForceMemTypeWB      (1U << 22)
823 
824 int __init amd_special_default_mtrr(void)
825 {
826         u32 l, h;
827 
828         if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
829                 return 0;
830         if (boot_cpu_data.x86 < 0xf)
831                 return 0;
832         /* In case some hypervisor doesn't pass SYSCFG through: */
833         if (rdmsr_safe(MSR_K8_SYSCFG, &l, &h) < 0)
834                 return 0;
835         /*
836          * Memory between 4GB and top of mem is forced WB by this magic bit.
837          * Reserved before K8RevF, but should be zero there.
838          */
839         if ((l & (Tom2Enabled | Tom2ForceMemTypeWB)) ==
840                  (Tom2Enabled | Tom2ForceMemTypeWB))
841                 return 1;
842         return 0;
843 }
844 
845 static u64 __init
846 real_trim_memory(unsigned long start_pfn, unsigned long limit_pfn)
847 {
848         u64 trim_start, trim_size;
849 
850         trim_start = start_pfn;
851         trim_start <<= PAGE_SHIFT;
852 
853         trim_size = limit_pfn;
854         trim_size <<= PAGE_SHIFT;
855         trim_size -= trim_start;
856 
857         return e820_update_range(trim_start, trim_size, E820_RAM, E820_RESERVED);
858 }
859 
860 /**
861  * mtrr_trim_uncached_memory - trim RAM not covered by MTRRs
862  * @end_pfn: ending page frame number
863  *
864  * Some buggy BIOSes don't setup the MTRRs properly for systems with certain
865  * memory configurations.  This routine checks that the highest MTRR matches
866  * the end of memory, to make sure the MTRRs having a write back type cover
867  * all of the memory the kernel is intending to use.  If not, it'll trim any
868  * memory off the end by adjusting end_pfn, removing it from the kernel's
869  * allocation pools, warning the user with an obnoxious message.
870  */
871 int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
872 {
873         unsigned long i, base, size, highest_pfn = 0, def, dummy;
874         mtrr_type type;
875         u64 total_trim_size;
876         /* extra one for all 0 */
877         int num[MTRR_NUM_TYPES + 1];
878 
879         /*
880          * Make sure we only trim uncachable memory on machines that
881          * support the Intel MTRR architecture:
882          */
883         if (!is_cpu(INTEL) || disable_mtrr_trim)
884                 return 0;
885 
886         rdmsr(MSR_MTRRdefType, def, dummy);
887         def &= 0xff;
888         if (def != MTRR_TYPE_UNCACHABLE)
889                 return 0;
890 
891         /* Get it and store it aside: */
892         memset(range_state, 0, sizeof(range_state));
893         for (i = 0; i < num_var_ranges; i++) {
894                 mtrr_if->get(i, &base, &size, &type);
895                 range_state[i].base_pfn = base;
896                 range_state[i].size_pfn = size;
897                 range_state[i].type = type;
898         }
899 
900         /* Find highest cached pfn: */
901         for (i = 0; i < num_var_ranges; i++) {
902                 type = range_state[i].type;
903                 if (type != MTRR_TYPE_WRBACK)
904                         continue;
905                 base = range_state[i].base_pfn;
906                 size = range_state[i].size_pfn;
907                 if (highest_pfn < base + size)
908                         highest_pfn = base + size;
909         }
910 
911         /* kvm/qemu doesn't have mtrr set right, don't trim them all: */
912         if (!highest_pfn) {
913                 printk(KERN_INFO "CPU MTRRs all blank - virtualized system.\n");
914                 return 0;
915         }
916 
917         /* Check entries number: */
918         memset(num, 0, sizeof(num));
919         for (i = 0; i < num_var_ranges; i++) {
920                 type = range_state[i].type;
921                 if (type >= MTRR_NUM_TYPES)
922                         continue;
923                 size = range_state[i].size_pfn;
924                 if (!size)
925                         type = MTRR_NUM_TYPES;
926                 num[type]++;
927         }
928 
929         /* No entry for WB? */
930         if (!num[MTRR_TYPE_WRBACK])
931                 return 0;
932 
933         /* Check if we only had WB and UC: */
934         if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
935                 num_var_ranges - num[MTRR_NUM_TYPES])
936                 return 0;
937 
938         memset(range, 0, sizeof(range));
939         nr_range = 0;
940         if (mtrr_tom2) {
941                 range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
942                 range[nr_range].end = mtrr_tom2 >> PAGE_SHIFT;
943                 if (highest_pfn < range[nr_range].end)
944                         highest_pfn = range[nr_range].end;
945                 nr_range++;
946         }
947         nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);
948 
949         /* Check the head: */
950         total_trim_size = 0;
951         if (range[0].start)
952                 total_trim_size += real_trim_memory(0, range[0].start);
953 
954         /* Check the holes: */
955         for (i = 0; i < nr_range - 1; i++) {
956                 if (range[i].end < range[i+1].start)
957                         total_trim_size += real_trim_memory(range[i].end,
958                                                             range[i+1].start);
959         }
960 
961         /* Check the top: */
962         i = nr_range - 1;
963         if (range[i].end < end_pfn)
964                 total_trim_size += real_trim_memory(range[i].end,
965                                                          end_pfn);
966 
967         if (total_trim_size) {
968                 pr_warning("WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing %lluMB of RAM.\n", total_trim_size >> 20);
969 
970                 if (!changed_by_mtrr_cleanup)
971                         WARN_ON(1);
972 
973                 pr_info("update e820 for mtrr\n");
974                 update_e820();
975 
976                 return 1;
977         }
978 
979         return 0;
980 }
981 

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