1 /* MTRR (Memory Type Range Register) cleanup
3 Copyright (C) 2009 Yinghai Lu
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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/sort.h>
30 #include <asm/uaccess.h>
31 #include <asm/processor.h>
33 #include <asm/kvm_para.h>
36 /* should be related to MTRR_VAR_RANGES nums */
45 add_range(struct res_range *range, int nr_range, unsigned long start,
49 if (nr_range >= RANGE_NUM)
52 range[nr_range].start = start;
53 range[nr_range].end = end;
61 add_range_with_merge(struct res_range *range, int nr_range, unsigned long start,
66 /* try to merge it with old one */
67 for (i = 0; i < nr_range; i++) {
68 unsigned long final_start, final_end;
69 unsigned long common_start, common_end;
74 common_start = max(range[i].start, start);
75 common_end = min(range[i].end, end);
76 if (common_start > common_end + 1)
79 final_start = min(range[i].start, start);
80 final_end = max(range[i].end, end);
82 range[i].start = final_start;
83 range[i].end = final_end;
87 /* need to add that */
88 return add_range(range, nr_range, start, end);
92 subtract_range(struct res_range *range, unsigned long start, unsigned long end)
96 for (j = 0; j < RANGE_NUM; j++) {
100 if (start <= range[j].start && end >= range[j].end) {
106 if (start <= range[j].start && end < range[j].end &&
107 range[j].start < end + 1) {
108 range[j].start = end + 1;
113 if (start > range[j].start && end >= range[j].end &&
114 range[j].end > start - 1) {
115 range[j].end = start - 1;
119 if (start > range[j].start && end < range[j].end) {
120 /* find the new spare */
121 for (i = 0; i < RANGE_NUM; i++) {
122 if (range[i].end == 0)
126 range[i].end = range[j].end;
127 range[i].start = end + 1;
129 printk(KERN_ERR "run of slot in ranges\n");
131 range[j].end = start - 1;
137 static int __init cmp_range(const void *x1, const void *x2)
139 const struct res_range *r1 = x1;
140 const struct res_range *r2 = x2;
146 return start1 - start2;
149 struct var_mtrr_range_state {
150 unsigned long base_pfn;
151 unsigned long size_pfn;
155 static struct var_mtrr_range_state __initdata range_state[RANGE_NUM];
156 static int __initdata debug_print;
159 x86_get_mtrr_mem_range(struct res_range *range, int nr_range,
160 unsigned long extra_remove_base,
161 unsigned long extra_remove_size)
163 unsigned long i, base, size;
166 for (i = 0; i < num_var_ranges; i++) {
167 type = range_state[i].type;
168 if (type != MTRR_TYPE_WRBACK)
170 base = range_state[i].base_pfn;
171 size = range_state[i].size_pfn;
172 nr_range = add_range_with_merge(range, nr_range, base,
176 printk(KERN_DEBUG "After WB checking\n");
177 for (i = 0; i < nr_range; i++)
178 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
179 range[i].start, range[i].end + 1);
182 /* take out UC ranges */
183 for (i = 0; i < num_var_ranges; i++) {
184 type = range_state[i].type;
185 if (type != MTRR_TYPE_UNCACHABLE &&
186 type != MTRR_TYPE_WRPROT)
188 size = range_state[i].size_pfn;
191 base = range_state[i].base_pfn;
192 if (base < (1<<(20-PAGE_SHIFT)) && mtrr_state.have_fixed &&
193 (mtrr_state.enabled & 1)) {
194 /* Var MTRR contains UC entry below 1M? Skip it: */
195 printk(KERN_WARNING "WARNING: BIOS bug: VAR MTRR %d "
196 "contains strange UC entry under 1M, check "
197 "with your system vendor!\n", i);
198 if (base + size <= (1<<(20-PAGE_SHIFT)))
200 size -= (1<<(20-PAGE_SHIFT)) - base;
201 base = 1<<(20-PAGE_SHIFT);
203 subtract_range(range, base, base + size - 1);
205 if (extra_remove_size)
206 subtract_range(range, extra_remove_base,
207 extra_remove_base + extra_remove_size - 1);
209 /* get new range num */
211 for (i = 0; i < RANGE_NUM; i++) {
217 printk(KERN_DEBUG "After UC checking\n");
218 for (i = 0; i < nr_range; i++)
219 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
220 range[i].start, range[i].end + 1);
223 /* sort the ranges */
224 sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
226 printk(KERN_DEBUG "After sorting\n");
227 for (i = 0; i < nr_range; i++)
228 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
229 range[i].start, range[i].end + 1);
232 /* clear those is not used */
233 for (i = nr_range; i < RANGE_NUM; i++)
234 memset(&range[i], 0, sizeof(range[i]));
239 static struct res_range __initdata range[RANGE_NUM];
240 static int __initdata nr_range;
242 #ifdef CONFIG_MTRR_SANITIZER
244 static unsigned long __init sum_ranges(struct res_range *range, int nr_range)
250 for (i = 0; i < nr_range; i++)
251 sum += range[i].end + 1 - range[i].start;
256 static int enable_mtrr_cleanup __initdata =
257 CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT;
259 static int __init disable_mtrr_cleanup_setup(char *str)
261 enable_mtrr_cleanup = 0;
264 early_param("disable_mtrr_cleanup", disable_mtrr_cleanup_setup);
266 static int __init enable_mtrr_cleanup_setup(char *str)
268 enable_mtrr_cleanup = 1;
271 early_param("enable_mtrr_cleanup", enable_mtrr_cleanup_setup);
273 static int __init mtrr_cleanup_debug_setup(char *str)
278 early_param("mtrr_cleanup_debug", mtrr_cleanup_debug_setup);
280 struct var_mtrr_state {
281 unsigned long range_startk;
282 unsigned long range_sizek;
283 unsigned long chunk_sizek;
284 unsigned long gran_sizek;
289 set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
290 unsigned char type, unsigned int address_bits)
292 u32 base_lo, base_hi, mask_lo, mask_hi;
296 fill_mtrr_var_range(reg, 0, 0, 0, 0);
300 mask = (1ULL << address_bits) - 1;
301 mask &= ~((((u64)sizek) << 10) - 1);
303 base = ((u64)basek) << 10;
308 base_lo = base & ((1ULL<<32) - 1);
309 base_hi = base >> 32;
311 mask_lo = mask & ((1ULL<<32) - 1);
312 mask_hi = mask >> 32;
314 fill_mtrr_var_range(reg, base_lo, base_hi, mask_lo, mask_hi);
318 save_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
321 range_state[reg].base_pfn = basek >> (PAGE_SHIFT - 10);
322 range_state[reg].size_pfn = sizek >> (PAGE_SHIFT - 10);
323 range_state[reg].type = type;
327 set_var_mtrr_all(unsigned int address_bits)
329 unsigned long basek, sizek;
333 for (reg = 0; reg < num_var_ranges; reg++) {
334 basek = range_state[reg].base_pfn << (PAGE_SHIFT - 10);
335 sizek = range_state[reg].size_pfn << (PAGE_SHIFT - 10);
336 type = range_state[reg].type;
338 set_var_mtrr(reg, basek, sizek, type, address_bits);
342 static unsigned long to_size_factor(unsigned long sizek, char *factorp)
345 unsigned long base = sizek;
347 if (base & ((1<<10) - 1)) {
348 /* not MB alignment */
350 } else if (base & ((1<<20) - 1)) {
363 static unsigned int __init
364 range_to_mtrr(unsigned int reg, unsigned long range_startk,
365 unsigned long range_sizek, unsigned char type)
367 if (!range_sizek || (reg >= num_var_ranges))
370 while (range_sizek) {
371 unsigned long max_align, align;
374 /* Compute the maximum size I can make a range */
376 max_align = ffs(range_startk) - 1;
379 align = fls(range_sizek) - 1;
380 if (align > max_align)
385 char start_factor = 'K', size_factor = 'K';
386 unsigned long start_base, size_base;
388 start_base = to_size_factor(range_startk,
390 size_base = to_size_factor(sizek, &size_factor),
392 printk(KERN_DEBUG "Setting variable MTRR %d, "
393 "base: %ld%cB, range: %ld%cB, type %s\n",
394 reg, start_base, start_factor,
395 size_base, size_factor,
396 (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
397 ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other")
400 save_var_mtrr(reg++, range_startk, sizek, type);
401 range_startk += sizek;
402 range_sizek -= sizek;
403 if (reg >= num_var_ranges)
409 static unsigned __init
410 range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
413 unsigned long hole_basek, hole_sizek;
414 unsigned long second_basek, second_sizek;
415 unsigned long range0_basek, range0_sizek;
416 unsigned long range_basek, range_sizek;
417 unsigned long chunk_sizek;
418 unsigned long gran_sizek;
424 chunk_sizek = state->chunk_sizek;
425 gran_sizek = state->gran_sizek;
427 /* align with gran size, prevent small block used up MTRRs */
428 range_basek = ALIGN(state->range_startk, gran_sizek);
429 if ((range_basek > basek) && basek)
431 state->range_sizek -= (range_basek - state->range_startk);
432 range_sizek = ALIGN(state->range_sizek, gran_sizek);
434 while (range_sizek > state->range_sizek) {
435 range_sizek -= gran_sizek;
439 state->range_sizek = range_sizek;
441 /* try to append some small hole */
442 range0_basek = state->range_startk;
443 range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
446 if (range0_sizek == state->range_sizek) {
448 printk(KERN_DEBUG "rangeX: %016lx - %016lx\n",
450 (range0_basek + state->range_sizek)<<10);
451 state->reg = range_to_mtrr(state->reg, range0_basek,
452 state->range_sizek, MTRR_TYPE_WRBACK);
456 /* only cut back, when it is not the last */
458 while (range0_basek + range0_sizek > (basek + sizek)) {
459 if (range0_sizek >= chunk_sizek)
460 range0_sizek -= chunk_sizek;
470 range_basek = range0_basek + range0_sizek;
472 /* one hole in the middle */
473 if (range_basek > basek && range_basek <= (basek + sizek))
474 second_sizek = range_basek - basek;
476 if (range0_sizek > state->range_sizek) {
478 /* one hole in middle or at end */
479 hole_sizek = range0_sizek - state->range_sizek - second_sizek;
481 /* hole size should be less than half of range0 size */
482 if (hole_sizek >= (range0_sizek >> 1) &&
483 range0_sizek >= chunk_sizek) {
484 range0_sizek -= chunk_sizek;
494 printk(KERN_DEBUG "range0: %016lx - %016lx\n",
496 (range0_basek + range0_sizek)<<10);
497 state->reg = range_to_mtrr(state->reg, range0_basek,
498 range0_sizek, MTRR_TYPE_WRBACK);
501 if (range0_sizek < state->range_sizek) {
502 /* need to handle left over */
503 range_sizek = state->range_sizek - range0_sizek;
506 printk(KERN_DEBUG "range: %016lx - %016lx\n",
508 (range_basek + range_sizek)<<10);
509 state->reg = range_to_mtrr(state->reg, range_basek,
510 range_sizek, MTRR_TYPE_WRBACK);
514 hole_basek = range_basek - hole_sizek - second_sizek;
516 printk(KERN_DEBUG "hole: %016lx - %016lx\n",
518 (hole_basek + hole_sizek)<<10);
519 state->reg = range_to_mtrr(state->reg, hole_basek,
520 hole_sizek, MTRR_TYPE_UNCACHABLE);
527 set_var_mtrr_range(struct var_mtrr_state *state, unsigned long base_pfn,
528 unsigned long size_pfn)
530 unsigned long basek, sizek;
531 unsigned long second_sizek = 0;
533 if (state->reg >= num_var_ranges)
536 basek = base_pfn << (PAGE_SHIFT - 10);
537 sizek = size_pfn << (PAGE_SHIFT - 10);
539 /* See if I can merge with the last range */
540 if ((basek <= 1024) ||
541 (state->range_startk + state->range_sizek == basek)) {
542 unsigned long endk = basek + sizek;
543 state->range_sizek = endk - state->range_startk;
546 /* Write the range mtrrs */
547 if (state->range_sizek != 0)
548 second_sizek = range_to_mtrr_with_hole(state, basek, sizek);
550 /* Allocate an msr */
551 state->range_startk = basek + second_sizek;
552 state->range_sizek = sizek - second_sizek;
555 /* mininum size of mtrr block that can take hole */
556 static u64 mtrr_chunk_size __initdata = (256ULL<<20);
558 static int __init parse_mtrr_chunk_size_opt(char *p)
562 mtrr_chunk_size = memparse(p, &p);
565 early_param("mtrr_chunk_size", parse_mtrr_chunk_size_opt);
567 /* granity of mtrr of block */
568 static u64 mtrr_gran_size __initdata;
570 static int __init parse_mtrr_gran_size_opt(char *p)
574 mtrr_gran_size = memparse(p, &p);
577 early_param("mtrr_gran_size", parse_mtrr_gran_size_opt);
579 static int nr_mtrr_spare_reg __initdata =
580 CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT;
582 static int __init parse_mtrr_spare_reg(char *arg)
585 nr_mtrr_spare_reg = simple_strtoul(arg, NULL, 0);
589 early_param("mtrr_spare_reg_nr", parse_mtrr_spare_reg);
592 x86_setup_var_mtrrs(struct res_range *range, int nr_range,
593 u64 chunk_size, u64 gran_size)
595 struct var_mtrr_state var_state;
599 var_state.range_startk = 0;
600 var_state.range_sizek = 0;
602 var_state.chunk_sizek = chunk_size >> 10;
603 var_state.gran_sizek = gran_size >> 10;
605 memset(range_state, 0, sizeof(range_state));
607 /* Write the range etc */
608 for (i = 0; i < nr_range; i++)
609 set_var_mtrr_range(&var_state, range[i].start,
610 range[i].end - range[i].start + 1);
612 /* Write the last range */
613 if (var_state.range_sizek != 0)
614 range_to_mtrr_with_hole(&var_state, 0, 0);
616 num_reg = var_state.reg;
617 /* Clear out the extra MTRR's */
618 while (var_state.reg < num_var_ranges) {
619 save_var_mtrr(var_state.reg, 0, 0, 0);
626 struct mtrr_cleanup_result {
627 unsigned long gran_sizek;
628 unsigned long chunk_sizek;
629 unsigned long lose_cover_sizek;
630 unsigned int num_reg;
635 * gran_size: 64K, 128K, 256K, 512K, 1M, 2M, ..., 2G
636 * chunk size: gran_size, ..., 2G
637 * so we need (1+16)*8
639 #define NUM_RESULT 136
640 #define PSHIFT (PAGE_SHIFT - 10)
642 static struct mtrr_cleanup_result __initdata result[NUM_RESULT];
643 static unsigned long __initdata min_loss_pfn[RANGE_NUM];
645 static void __init print_out_mtrr_range_state(void)
648 char start_factor = 'K', size_factor = 'K';
649 unsigned long start_base, size_base;
652 for (i = 0; i < num_var_ranges; i++) {
654 size_base = range_state[i].size_pfn << (PAGE_SHIFT - 10);
658 size_base = to_size_factor(size_base, &size_factor),
659 start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
660 start_base = to_size_factor(start_base, &start_factor),
661 type = range_state[i].type;
663 printk(KERN_DEBUG "reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
664 i, start_base, start_factor,
665 size_base, size_factor,
666 (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
667 ((type == MTRR_TYPE_WRPROT) ? "WP" :
668 ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other"))
673 static int __init mtrr_need_cleanup(void)
678 /* extra one for all 0 */
679 int num[MTRR_NUM_TYPES + 1];
681 /* check entries number */
682 memset(num, 0, sizeof(num));
683 for (i = 0; i < num_var_ranges; i++) {
684 type = range_state[i].type;
685 size = range_state[i].size_pfn;
686 if (type >= MTRR_NUM_TYPES)
689 type = MTRR_NUM_TYPES;
690 if (type == MTRR_TYPE_WRPROT)
691 type = MTRR_TYPE_UNCACHABLE;
695 /* check if we got UC entries */
696 if (!num[MTRR_TYPE_UNCACHABLE])
699 /* check if we only had WB and UC */
700 if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
701 num_var_ranges - num[MTRR_NUM_TYPES])
707 static unsigned long __initdata range_sums;
708 static void __init mtrr_calc_range_state(u64 chunk_size, u64 gran_size,
709 unsigned long extra_remove_base,
710 unsigned long extra_remove_size,
714 static struct res_range range_new[RANGE_NUM];
715 static int nr_range_new;
716 unsigned long range_sums_new;
718 /* convert ranges to var ranges state */
719 num_reg = x86_setup_var_mtrrs(range, nr_range,
720 chunk_size, gran_size);
722 /* we got new setting in range_state, check it */
723 memset(range_new, 0, sizeof(range_new));
724 nr_range_new = x86_get_mtrr_mem_range(range_new, 0,
725 extra_remove_base, extra_remove_size);
726 range_sums_new = sum_ranges(range_new, nr_range_new);
728 result[i].chunk_sizek = chunk_size >> 10;
729 result[i].gran_sizek = gran_size >> 10;
730 result[i].num_reg = num_reg;
731 if (range_sums < range_sums_new) {
732 result[i].lose_cover_sizek =
733 (range_sums_new - range_sums) << PSHIFT;
736 result[i].lose_cover_sizek =
737 (range_sums - range_sums_new) << PSHIFT;
739 /* double check it */
740 if (!result[i].bad && !result[i].lose_cover_sizek) {
741 if (nr_range_new != nr_range ||
742 memcmp(range, range_new, sizeof(range)))
746 if (!result[i].bad && (range_sums - range_sums_new <
747 min_loss_pfn[num_reg])) {
748 min_loss_pfn[num_reg] =
749 range_sums - range_sums_new;
753 static void __init mtrr_print_out_one_result(int i)
755 char gran_factor, chunk_factor, lose_factor;
756 unsigned long gran_base, chunk_base, lose_base;
758 gran_base = to_size_factor(result[i].gran_sizek, &gran_factor),
759 chunk_base = to_size_factor(result[i].chunk_sizek, &chunk_factor),
760 lose_base = to_size_factor(result[i].lose_cover_sizek, &lose_factor),
761 printk(KERN_INFO "%sgran_size: %ld%c \tchunk_size: %ld%c \t",
762 result[i].bad ? "*BAD*" : " ",
763 gran_base, gran_factor, chunk_base, chunk_factor);
764 printk(KERN_CONT "num_reg: %d \tlose cover RAM: %s%ld%c\n",
765 result[i].num_reg, result[i].bad ? "-" : "",
766 lose_base, lose_factor);
769 static int __init mtrr_search_optimal_index(void)
775 if (nr_mtrr_spare_reg >= num_var_ranges)
776 nr_mtrr_spare_reg = num_var_ranges - 1;
778 for (i = num_var_ranges - nr_mtrr_spare_reg; i > 0; i--) {
779 if (!min_loss_pfn[i])
784 if (num_reg_good != -1) {
785 for (i = 0; i < NUM_RESULT; i++) {
786 if (!result[i].bad &&
787 result[i].num_reg == num_reg_good &&
788 !result[i].lose_cover_sizek) {
799 int __init mtrr_cleanup(unsigned address_bits)
801 unsigned long extra_remove_base, extra_remove_size;
802 unsigned long base, size, def, dummy;
804 u64 chunk_size, gran_size;
808 if (!is_cpu(INTEL) || enable_mtrr_cleanup < 1)
810 rdmsr(MTRRdefType_MSR, def, dummy);
812 if (def != MTRR_TYPE_UNCACHABLE)
815 /* get it and store it aside */
816 memset(range_state, 0, sizeof(range_state));
817 for (i = 0; i < num_var_ranges; i++) {
818 mtrr_if->get(i, &base, &size, &type);
819 range_state[i].base_pfn = base;
820 range_state[i].size_pfn = size;
821 range_state[i].type = type;
824 /* check if we need handle it and can handle it */
825 if (!mtrr_need_cleanup())
828 /* print original var MTRRs at first, for debugging: */
829 printk(KERN_DEBUG "original variable MTRRs\n");
830 print_out_mtrr_range_state();
832 memset(range, 0, sizeof(range));
833 extra_remove_size = 0;
834 extra_remove_base = 1 << (32 - PAGE_SHIFT);
837 (mtrr_tom2 >> PAGE_SHIFT) - extra_remove_base;
838 nr_range = x86_get_mtrr_mem_range(range, 0, extra_remove_base,
841 * [0, 1M) should always be coverred by var mtrr with WB
842 * and fixed mtrrs should take effective before var mtrr for it
844 nr_range = add_range_with_merge(range, nr_range, 0,
845 (1ULL<<(20 - PAGE_SHIFT)) - 1);
846 /* sort the ranges */
847 sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
849 range_sums = sum_ranges(range, nr_range);
850 printk(KERN_INFO "total RAM coverred: %ldM\n",
851 range_sums >> (20 - PAGE_SHIFT));
853 if (mtrr_chunk_size && mtrr_gran_size) {
855 mtrr_calc_range_state(mtrr_chunk_size, mtrr_gran_size,
856 extra_remove_base, extra_remove_size, i);
858 mtrr_print_out_one_result(i);
860 if (!result[i].bad) {
861 set_var_mtrr_all(address_bits);
862 printk(KERN_DEBUG "New variable MTRRs\n");
863 print_out_mtrr_range_state();
866 printk(KERN_INFO "invalid mtrr_gran_size or mtrr_chunk_size, "
867 "will find optimal one\n");
871 memset(min_loss_pfn, 0xff, sizeof(min_loss_pfn));
872 memset(result, 0, sizeof(result));
873 for (gran_size = (1ULL<<16); gran_size < (1ULL<<32); gran_size <<= 1) {
875 for (chunk_size = gran_size; chunk_size < (1ULL<<32);
881 mtrr_calc_range_state(chunk_size, gran_size,
882 extra_remove_base, extra_remove_size, i);
884 mtrr_print_out_one_result(i);
885 printk(KERN_INFO "\n");
892 /* try to find the optimal index */
893 index_good = mtrr_search_optimal_index();
895 if (index_good != -1) {
896 printk(KERN_INFO "Found optimal setting for mtrr clean up\n");
898 mtrr_print_out_one_result(i);
900 /* convert ranges to var ranges state */
901 chunk_size = result[i].chunk_sizek;
903 gran_size = result[i].gran_sizek;
905 x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
906 set_var_mtrr_all(address_bits);
907 printk(KERN_DEBUG "New variable MTRRs\n");
908 print_out_mtrr_range_state();
912 for (i = 0; i < NUM_RESULT; i++)
913 mtrr_print_out_one_result(i);
916 printk(KERN_INFO "mtrr_cleanup: can not find optimal value\n");
917 printk(KERN_INFO "please specify mtrr_gran_size/mtrr_chunk_size\n");
922 int __init mtrr_cleanup(unsigned address_bits)
928 static int disable_mtrr_trim;
930 static int __init disable_mtrr_trim_setup(char *str)
932 disable_mtrr_trim = 1;
935 early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
938 * Newer AMD K8s and later CPUs have a special magic MSR way to force WB
939 * for memory >4GB. Check for that here.
940 * Note this won't check if the MTRRs < 4GB where the magic bit doesn't
941 * apply to are wrong, but so far we don't know of any such case in the wild.
943 #define Tom2Enabled (1U << 21)
944 #define Tom2ForceMemTypeWB (1U << 22)
946 int __init amd_special_default_mtrr(void)
950 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
952 if (boot_cpu_data.x86 < 0xf || boot_cpu_data.x86 > 0x11)
954 /* In case some hypervisor doesn't pass SYSCFG through */
955 if (rdmsr_safe(MSR_K8_SYSCFG, &l, &h) < 0)
958 * Memory between 4GB and top of mem is forced WB by this magic bit.
959 * Reserved before K8RevF, but should be zero there.
961 if ((l & (Tom2Enabled | Tom2ForceMemTypeWB)) ==
962 (Tom2Enabled | Tom2ForceMemTypeWB))
967 static u64 __init real_trim_memory(unsigned long start_pfn,
968 unsigned long limit_pfn)
970 u64 trim_start, trim_size;
971 trim_start = start_pfn;
972 trim_start <<= PAGE_SHIFT;
973 trim_size = limit_pfn;
974 trim_size <<= PAGE_SHIFT;
975 trim_size -= trim_start;
977 return e820_update_range(trim_start, trim_size, E820_RAM,
981 * mtrr_trim_uncached_memory - trim RAM not covered by MTRRs
982 * @end_pfn: ending page frame number
984 * Some buggy BIOSes don't setup the MTRRs properly for systems with certain
985 * memory configurations. This routine checks that the highest MTRR matches
986 * the end of memory, to make sure the MTRRs having a write back type cover
987 * all of the memory the kernel is intending to use. If not, it'll trim any
988 * memory off the end by adjusting end_pfn, removing it from the kernel's
989 * allocation pools, warning the user with an obnoxious message.
991 int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
993 unsigned long i, base, size, highest_pfn = 0, def, dummy;
997 /* extra one for all 0 */
998 int num[MTRR_NUM_TYPES + 1];
1000 * Make sure we only trim uncachable memory on machines that
1001 * support the Intel MTRR architecture:
1003 if (!is_cpu(INTEL) || disable_mtrr_trim)
1005 rdmsr(MTRRdefType_MSR, def, dummy);
1007 if (def != MTRR_TYPE_UNCACHABLE)
1010 /* get it and store it aside */
1011 memset(range_state, 0, sizeof(range_state));
1012 for (i = 0; i < num_var_ranges; i++) {
1013 mtrr_if->get(i, &base, &size, &type);
1014 range_state[i].base_pfn = base;
1015 range_state[i].size_pfn = size;
1016 range_state[i].type = type;
1019 /* Find highest cached pfn */
1020 for (i = 0; i < num_var_ranges; i++) {
1021 type = range_state[i].type;
1022 if (type != MTRR_TYPE_WRBACK)
1024 base = range_state[i].base_pfn;
1025 size = range_state[i].size_pfn;
1026 if (highest_pfn < base + size)
1027 highest_pfn = base + size;
1030 /* kvm/qemu doesn't have mtrr set right, don't trim them all */
1032 printk(KERN_INFO "CPU MTRRs all blank - virtualized system.\n");
1036 /* check entries number */
1037 memset(num, 0, sizeof(num));
1038 for (i = 0; i < num_var_ranges; i++) {
1039 type = range_state[i].type;
1040 if (type >= MTRR_NUM_TYPES)
1042 size = range_state[i].size_pfn;
1044 type = MTRR_NUM_TYPES;
1048 /* no entry for WB? */
1049 if (!num[MTRR_TYPE_WRBACK])
1052 /* check if we only had WB and UC */
1053 if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
1054 num_var_ranges - num[MTRR_NUM_TYPES])
1057 memset(range, 0, sizeof(range));
1060 range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
1061 range[nr_range].end = (mtrr_tom2 >> PAGE_SHIFT) - 1;
1062 if (highest_pfn < range[nr_range].end + 1)
1063 highest_pfn = range[nr_range].end + 1;
1066 nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);
1068 total_trim_size = 0;
1069 /* check the head */
1071 total_trim_size += real_trim_memory(0, range[0].start);
1072 /* check the holes */
1073 for (i = 0; i < nr_range - 1; i++) {
1074 if (range[i].end + 1 < range[i+1].start)
1075 total_trim_size += real_trim_memory(range[i].end + 1,
1080 if (range[i].end + 1 < end_pfn)
1081 total_trim_size += real_trim_memory(range[i].end + 1,
1084 if (total_trim_size) {
1085 printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover"
1086 " all of memory, losing %lluMB of RAM.\n",
1087 total_trim_size >> 20);
1089 if (!changed_by_mtrr_cleanup)
1092 printk(KERN_INFO "update e820 for mtrr\n");