x86: separate mtrr cleanup/mtrr_e820 trim to separate file

Impact: cleanup

mtrr main.c is too big, seperate mtrr cleanup and mtrr e820 trim
code to another file.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B87C7B.80809@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1089 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
new file mode 100644
index 000000000000..58b58bbf7eb3
--- /dev/null
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -0,0 +1,1089 @@
+/*  MTRR (Memory Type Range Register) cleanup
+
+    Copyright (C) 2009 Yinghai Lu
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/mutex.h>
+#include <linux/sort.h>
+
+#include <asm/e820.h>
+#include <asm/mtrr.h>
+#include <asm/uaccess.h>
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/kvm_para.h>
+#include "mtrr.h"
+
+/* should be related to MTRR_VAR_RANGES nums */
+#define RANGE_NUM 256
+
+struct res_range {
+        unsigned long start;
+        unsigned long end;
+};
+
+static int __init
+add_range(struct res_range *range, int nr_range, unsigned long start,
+                              unsigned long end)
+{
+        /* out of slots */
+        if (nr_range >= RANGE_NUM)
+                return nr_range;
+
+        range[nr_range].start = start;
+        range[nr_range].end = end;
+
+        nr_range++;
+
+        return nr_range;
+}
+
+static int __init
+add_range_with_merge(struct res_range *range, int nr_range, unsigned long start,
+                              unsigned long end)
+{
+        int i;
+
+        /* try to merge it with old one */
+        for (i = 0; i < nr_range; i++) {
+                unsigned long final_start, final_end;
+                unsigned long common_start, common_end;
+
+                if (!range[i].end)
+                        continue;
+
+                common_start = max(range[i].start, start);
+                common_end = min(range[i].end, end);
+                if (common_start > common_end + 1)
+                        continue;
+
+                final_start = min(range[i].start, start);
+                final_end = max(range[i].end, end);
+
+                range[i].start = final_start;
+                range[i].end =  final_end;
+                return nr_range;
+        }
+
+        /* need to add that */
+        return add_range(range, nr_range, start, end);
+}
+
+static void __init
+subtract_range(struct res_range *range, unsigned long start, unsigned long end)
+{
+        int i, j;
+
+        for (j = 0; j < RANGE_NUM; j++) {
+                if (!range[j].end)
+                        continue;
+
+                if (start <= range[j].start && end >= range[j].end) {
+                        range[j].start = 0;
+                        range[j].end = 0;
+                        continue;
+                }
+
+                if (start <= range[j].start && end < range[j].end &&
+                    range[j].start < end + 1) {
+                        range[j].start = end + 1;
+                        continue;
+                }
+
+
+                if (start > range[j].start && end >= range[j].end &&
+                    range[j].end > start - 1) {
+                        range[j].end = start - 1;
+                        continue;
+                }
+
+                if (start > range[j].start && end < range[j].end) {
+                        /* find the new spare */
+                        for (i = 0; i < RANGE_NUM; i++) {
+                                if (range[i].end == 0)
+                                        break;
+                        }
+                        if (i < RANGE_NUM) {
+                                range[i].end = range[j].end;
+                                range[i].start = end + 1;
+                        } else {
+                                printk(KERN_ERR "run of slot in ranges\n");
+                        }
+                        range[j].end = start - 1;
+                        continue;
+                }
+        }
+}
+
+static int __init cmp_range(const void *x1, const void *x2)
+{
+        const struct res_range *r1 = x1;
+        const struct res_range *r2 = x2;
+        long start1, start2;
+
+        start1 = r1->start;
+        start2 = r2->start;
+
+        return start1 - start2;
+}
+
+struct var_mtrr_range_state {
+        unsigned long base_pfn;
+        unsigned long size_pfn;
+        mtrr_type type;
+};
+
+static struct var_mtrr_range_state __initdata range_state[RANGE_NUM];
+static int __initdata debug_print;
+
+static int __init
+x86_get_mtrr_mem_range(struct res_range *range, int nr_range,
+                       unsigned long extra_remove_base,
+                       unsigned long extra_remove_size)
+{
+        unsigned long i, base, size;
+        mtrr_type type;
+
+        for (i = 0; i < num_var_ranges; i++) {
+                type = range_state[i].type;
+                if (type != MTRR_TYPE_WRBACK)
+                        continue;
+                base = range_state[i].base_pfn;
+                size = range_state[i].size_pfn;
+                nr_range = add_range_with_merge(range, nr_range, base,
+                                                base + size - 1);
+        }
+        if (debug_print) {
+                printk(KERN_DEBUG "After WB checking\n");
+                for (i = 0; i < nr_range; i++)
+                        printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
+                                 range[i].start, range[i].end + 1);
+        }
+
+        /* take out UC ranges */
+        for (i = 0; i < num_var_ranges; i++) {
+                type = range_state[i].type;
+                if (type != MTRR_TYPE_UNCACHABLE &&
+                    type != MTRR_TYPE_WRPROT)
+                        continue;
+                size = range_state[i].size_pfn;
+                if (!size)
+                        continue;
+                base = range_state[i].base_pfn;
+                subtract_range(range, base, base + size - 1);
+        }
+        if (extra_remove_size)
+                subtract_range(range, extra_remove_base,
+                                 extra_remove_base + extra_remove_size  - 1);
+
+        /* get new range num */
+        nr_range = 0;
+        for (i = 0; i < RANGE_NUM; i++) {
+                if (!range[i].end)
+                        continue;
+                nr_range++;
+        }
+        if  (debug_print) {
+                printk(KERN_DEBUG "After UC checking\n");
+                for (i = 0; i < nr_range; i++)
+                        printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
+                                 range[i].start, range[i].end + 1);
+        }
+
+        /* sort the ranges */
+        sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
+        if  (debug_print) {
+                printk(KERN_DEBUG "After sorting\n");
+                for (i = 0; i < nr_range; i++)
+                        printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
+                                 range[i].start, range[i].end + 1);
+        }
+
+        /* clear those is not used */
+        for (i = nr_range; i < RANGE_NUM; i++)
+                memset(&range[i], 0, sizeof(range[i]));
+
+        return nr_range;
+}
+
+static struct res_range __initdata range[RANGE_NUM];
+static int __initdata nr_range;
+
+#ifdef CONFIG_MTRR_SANITIZER
+
+static unsigned long __init sum_ranges(struct res_range *range, int nr_range)
+{
+        unsigned long sum;
+        int i;
+
+        sum = 0;
+        for (i = 0; i < nr_range; i++)
+                sum += range[i].end + 1 - range[i].start;
+
+        return sum;
+}
+
+static int enable_mtrr_cleanup __initdata =
+        CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT;
+
+static int __init disable_mtrr_cleanup_setup(char *str)
+{
+        enable_mtrr_cleanup = 0;
+        return 0;
+}
+early_param("disable_mtrr_cleanup", disable_mtrr_cleanup_setup);
+
+static int __init enable_mtrr_cleanup_setup(char *str)
+{
+        enable_mtrr_cleanup = 1;
+        return 0;
+}
+early_param("enable_mtrr_cleanup", enable_mtrr_cleanup_setup);
+
+static int __init mtrr_cleanup_debug_setup(char *str)
+{
+        debug_print = 1;
+        return 0;
+}
+early_param("mtrr_cleanup_debug", mtrr_cleanup_debug_setup);
+
+struct var_mtrr_state {
+        unsigned long   range_startk;
+        unsigned long   range_sizek;
+        unsigned long   chunk_sizek;
+        unsigned long   gran_sizek;
+        unsigned int    reg;
+};
+
+static void __init
+set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
+                unsigned char type, unsigned int address_bits)
+{
+        u32 base_lo, base_hi, mask_lo, mask_hi;
+        u64 base, mask;
+
+        if (!sizek) {
+                fill_mtrr_var_range(reg, 0, 0, 0, 0);
+                return;
+        }
+
+        mask = (1ULL << address_bits) - 1;
+        mask &= ~((((u64)sizek) << 10) - 1);
+
+        base  = ((u64)basek) << 10;
+
+        base |= type;
+        mask |= 0x800;
+
+        base_lo = base & ((1ULL<<32) - 1);
+        base_hi = base >> 32;
+
+        mask_lo = mask & ((1ULL<<32) - 1);
+        mask_hi = mask >> 32;
+
+        fill_mtrr_var_range(reg, base_lo, base_hi, mask_lo, mask_hi);
+}
+
+static void __init
+save_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
+                unsigned char type)
+{
+        range_state[reg].base_pfn = basek >> (PAGE_SHIFT - 10);
+        range_state[reg].size_pfn = sizek >> (PAGE_SHIFT - 10);
+        range_state[reg].type = type;
+}
+
+static void __init
+set_var_mtrr_all(unsigned int address_bits)
+{
+        unsigned long basek, sizek;
+        unsigned char type;
+        unsigned int reg;
+
+        for (reg = 0; reg < num_var_ranges; reg++) {
+                basek = range_state[reg].base_pfn << (PAGE_SHIFT - 10);
+                sizek = range_state[reg].size_pfn << (PAGE_SHIFT - 10);
+                type = range_state[reg].type;
+
+                set_var_mtrr(reg, basek, sizek, type, address_bits);
+        }
+}
+
+static unsigned long to_size_factor(unsigned long sizek, char *factorp)
+{
+        char factor;
+        unsigned long base = sizek;
+
+        if (base & ((1<<10) - 1)) {
+                /* not MB alignment */
+                factor = 'K';
+        } else if (base & ((1<<20) - 1)) {
+                factor = 'M';
+                base >>= 10;
+        } else {
+                factor = 'G';
+                base >>= 20;
+        }
+
+        *factorp = factor;
+
+        return base;
+}
+
+static unsigned int __init
+range_to_mtrr(unsigned int reg, unsigned long range_startk,
+              unsigned long range_sizek, unsigned char type)
+{
+        if (!range_sizek || (reg >= num_var_ranges))
+                return reg;
+
+        while (range_sizek) {
+                unsigned long max_align, align;
+                unsigned long sizek;
+
+                /* Compute the maximum size I can make a range */
+                if (range_startk)
+                        max_align = ffs(range_startk) - 1;
+                else
+                        max_align = 32;
+                align = fls(range_sizek) - 1;
+                if (align > max_align)
+                        align = max_align;
+
+                sizek = 1 << align;
+                if (debug_print) {
+                        char start_factor = 'K', size_factor = 'K';
+                        unsigned long start_base, size_base;
+
+                        start_base = to_size_factor(range_startk,
+                                                         &start_factor),
+                        size_base = to_size_factor(sizek, &size_factor),
+
+                        printk(KERN_DEBUG "Setting variable MTRR %d, "
+                                "base: %ld%cB, range: %ld%cB, type %s\n",
+                                reg, start_base, start_factor,
+                                size_base, size_factor,
+                                (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
+                                   ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other")
+                                );
+                }
+                save_var_mtrr(reg++, range_startk, sizek, type);
+                range_startk += sizek;
+                range_sizek -= sizek;
+                if (reg >= num_var_ranges)
+                        break;
+        }
+        return reg;
+}
+
+static unsigned __init
+range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
+                        unsigned long sizek)
+{
+        unsigned long hole_basek, hole_sizek;
+        unsigned long second_basek, second_sizek;
+        unsigned long range0_basek, range0_sizek;
+        unsigned long range_basek, range_sizek;
+        unsigned long chunk_sizek;
+        unsigned long gran_sizek;
+
+        hole_basek = 0;
+        hole_sizek = 0;
+        second_basek = 0;
+        second_sizek = 0;
+        chunk_sizek = state->chunk_sizek;
+        gran_sizek = state->gran_sizek;
+
+        /* align with gran size, prevent small block used up MTRRs */
+        range_basek = ALIGN(state->range_startk, gran_sizek);
+        if ((range_basek > basek) && basek)
+                return second_sizek;
+        state->range_sizek -= (range_basek - state->range_startk);
+        range_sizek = ALIGN(state->range_sizek, gran_sizek);
+
+        while (range_sizek > state->range_sizek) {
+                range_sizek -= gran_sizek;
+                if (!range_sizek)
+                        return 0;
+        }
+        state->range_sizek = range_sizek;
+
+        /* try to append some small hole */
+        range0_basek = state->range_startk;
+        range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
+
+        /* no increase */
+        if (range0_sizek == state->range_sizek) {
+                if (debug_print)
+                        printk(KERN_DEBUG "rangeX: %016lx - %016lx\n",
+                                range0_basek<<10,
+                                (range0_basek + state->range_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, range0_basek,
+                                state->range_sizek, MTRR_TYPE_WRBACK);
+                return 0;
+        }
+
+        /* only cut back, when it is not the last */
+        if (sizek) {
+                while (range0_basek + range0_sizek > (basek + sizek)) {
+                        if (range0_sizek >= chunk_sizek)
+                                range0_sizek -= chunk_sizek;
+                        else
+                                range0_sizek = 0;
+
+                        if (!range0_sizek)
+                                break;
+                }
+        }
+
+second_try:
+        range_basek = range0_basek + range0_sizek;
+
+        /* one hole in the middle */
+        if (range_basek > basek && range_basek <= (basek + sizek))
+                second_sizek = range_basek - basek;
+
+        if (range0_sizek > state->range_sizek) {
+
+                /* one hole in middle or at end */
+                hole_sizek = range0_sizek - state->range_sizek - second_sizek;
+
+                /* hole size should be less than half of range0 size */
+                if (hole_sizek >= (range0_sizek >> 1) &&
+                    range0_sizek >= chunk_sizek) {
+                        range0_sizek -= chunk_sizek;
+                        second_sizek = 0;
+                        hole_sizek = 0;
+
+                        goto second_try;
+                }
+        }
+
+        if (range0_sizek) {
+                if (debug_print)
+                        printk(KERN_DEBUG "range0: %016lx - %016lx\n",
+                                range0_basek<<10,
+                                (range0_basek + range0_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, range0_basek,
+                                range0_sizek, MTRR_TYPE_WRBACK);
+        }
+
+        if (range0_sizek < state->range_sizek) {
+                /* need to handle left over */
+                range_sizek = state->range_sizek - range0_sizek;
+
+                if (debug_print)
+                        printk(KERN_DEBUG "range: %016lx - %016lx\n",
+                                 range_basek<<10,
+                                 (range_basek + range_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, range_basek,
+                                 range_sizek, MTRR_TYPE_WRBACK);
+        }
+
+        if (hole_sizek) {
+                hole_basek = range_basek - hole_sizek - second_sizek;
+                if (debug_print)
+                        printk(KERN_DEBUG "hole: %016lx - %016lx\n",
+                                 hole_basek<<10,
+                                 (hole_basek + hole_sizek)<<10);
+                state->reg = range_to_mtrr(state->reg, hole_basek,
+                                 hole_sizek, MTRR_TYPE_UNCACHABLE);
+        }
+
+        return second_sizek;
+}
+
+static void __init
+set_var_mtrr_range(struct var_mtrr_state *state, unsigned long base_pfn,
+                   unsigned long size_pfn)
+{
+        unsigned long basek, sizek;
+        unsigned long second_sizek = 0;
+
+        if (state->reg >= num_var_ranges)
+                return;
+
+        basek = base_pfn << (PAGE_SHIFT - 10);
+        sizek = size_pfn << (PAGE_SHIFT - 10);
+
+        /* See if I can merge with the last range */
+        if ((basek <= 1024) ||
+            (state->range_startk + state->range_sizek == basek)) {
+                unsigned long endk = basek + sizek;
+                state->range_sizek = endk - state->range_startk;
+                return;
+        }
+        /* Write the range mtrrs */
+        if (state->range_sizek != 0)
+                second_sizek = range_to_mtrr_with_hole(state, basek, sizek);
+
+        /* Allocate an msr */
+        state->range_startk = basek + second_sizek;
+        state->range_sizek  = sizek - second_sizek;
+}
+
+/* mininum size of mtrr block that can take hole */
+static u64 mtrr_chunk_size __initdata = (256ULL<<20);
+
+static int __init parse_mtrr_chunk_size_opt(char *p)
+{
+        if (!p)
+                return -EINVAL;
+        mtrr_chunk_size = memparse(p, &p);
+        return 0;
+}
+early_param("mtrr_chunk_size", parse_mtrr_chunk_size_opt);
+
+/* granity of mtrr of block */
+static u64 mtrr_gran_size __initdata;
+
+static int __init parse_mtrr_gran_size_opt(char *p)
+{
+        if (!p)
+                return -EINVAL;
+        mtrr_gran_size = memparse(p, &p);
+        return 0;
+}
+early_param("mtrr_gran_size", parse_mtrr_gran_size_opt);
+
+static int nr_mtrr_spare_reg __initdata =
+                                 CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT;
+
+static int __init parse_mtrr_spare_reg(char *arg)
+{
+        if (arg)
+                nr_mtrr_spare_reg = simple_strtoul(arg, NULL, 0);
+        return 0;
+}
+
+early_param("mtrr_spare_reg_nr", parse_mtrr_spare_reg);
+
+static int __init
+x86_setup_var_mtrrs(struct res_range *range, int nr_range,
+                    u64 chunk_size, u64 gran_size)
+{
+        struct var_mtrr_state var_state;
+        int i;
+        int num_reg;
+
+        var_state.range_startk  = 0;
+        var_state.range_sizek   = 0;
+        var_state.reg           = 0;
+        var_state.chunk_sizek   = chunk_size >> 10;
+        var_state.gran_sizek    = gran_size >> 10;
+
+        memset(range_state, 0, sizeof(range_state));
+
+        /* Write the range etc */
+        for (i = 0; i < nr_range; i++)
+                set_var_mtrr_range(&var_state, range[i].start,
+                                   range[i].end - range[i].start + 1);
+
+        /* Write the last range */
+        if (var_state.range_sizek != 0)
+                range_to_mtrr_with_hole(&var_state, 0, 0);
+
+        num_reg = var_state.reg;
+        /* Clear out the extra MTRR's */
+        while (var_state.reg < num_var_ranges) {
+                save_var_mtrr(var_state.reg, 0, 0, 0);
+                var_state.reg++;
+        }
+
+        return num_reg;
+}
+
+struct mtrr_cleanup_result {
+        unsigned long gran_sizek;
+        unsigned long chunk_sizek;
+        unsigned long lose_cover_sizek;
+        unsigned int num_reg;
+        int bad;
+};
+
+/*
+ * gran_size: 64K, 128K, 256K, 512K, 1M, 2M, ..., 2G
+ * chunk size: gran_size, ..., 2G
+ * so we need (1+16)*8
+ */
+#define NUM_RESULT      136
+#define PSHIFT          (PAGE_SHIFT - 10)
+
+static struct mtrr_cleanup_result __initdata result[NUM_RESULT];
+static unsigned long __initdata min_loss_pfn[RANGE_NUM];
+
+static void __init print_out_mtrr_range_state(void)
+{
+        int i;
+        char start_factor = 'K', size_factor = 'K';
+        unsigned long start_base, size_base;
+        mtrr_type type;
+
+        for (i = 0; i < num_var_ranges; i++) {
+
+                size_base = range_state[i].size_pfn << (PAGE_SHIFT - 10);
+                if (!size_base)
+                        continue;
+
+                size_base = to_size_factor(size_base, &size_factor),
+                start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
+                start_base = to_size_factor(start_base, &start_factor),
+                type = range_state[i].type;
+
+                printk(KERN_DEBUG "reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
+                        i, start_base, start_factor,
+                        size_base, size_factor,
+                        (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
+                            ((type == MTRR_TYPE_WRPROT) ? "WP" :
+                             ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other"))
+                        );
+        }
+}
+
+static int __init mtrr_need_cleanup(void)
+{
+        int i;
+        mtrr_type type;
+        unsigned long size;
+        /* extra one for all 0 */
+        int num[MTRR_NUM_TYPES + 1];
+
+        /* check entries number */
+        memset(num, 0, sizeof(num));
+        for (i = 0; i < num_var_ranges; i++) {
+                type = range_state[i].type;
+                size = range_state[i].size_pfn;
+                if (type >= MTRR_NUM_TYPES)
+                        continue;
+                if (!size)
+                        type = MTRR_NUM_TYPES;
+                if (type == MTRR_TYPE_WRPROT)
+                        type = MTRR_TYPE_UNCACHABLE;
+                num[type]++;
+        }
+
+        /* check if we got UC entries */
+        if (!num[MTRR_TYPE_UNCACHABLE])
+                return 0;
+
+        /* check if we only had WB and UC */
+        if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
+                num_var_ranges - num[MTRR_NUM_TYPES])
+                return 0;
+
+        return 1;
+}
+
+static unsigned long __initdata range_sums;
+static void __init mtrr_calc_range_state(u64 chunk_size, u64 gran_size,
+                                         unsigned long extra_remove_base,
+                                         unsigned long extra_remove_size,
+                                         int i)
+{
+        int num_reg;
+        static struct res_range range_new[RANGE_NUM];
+        static int nr_range_new;
+        unsigned long range_sums_new;
+
+        /* convert ranges to var ranges state */
+        num_reg = x86_setup_var_mtrrs(range, nr_range,
+                                                chunk_size, gran_size);
+
+        /* we got new setting in range_state, check it */
+        memset(range_new, 0, sizeof(range_new));
+        nr_range_new = x86_get_mtrr_mem_range(range_new, 0,
+                                extra_remove_base, extra_remove_size);
+        range_sums_new = sum_ranges(range_new, nr_range_new);
+
+        result[i].chunk_sizek = chunk_size >> 10;
+        result[i].gran_sizek = gran_size >> 10;
+        result[i].num_reg = num_reg;
+        if (range_sums < range_sums_new) {
+                result[i].lose_cover_sizek =
+                        (range_sums_new - range_sums) << PSHIFT;
+                result[i].bad = 1;
+        } else
+                result[i].lose_cover_sizek =
+                        (range_sums - range_sums_new) << PSHIFT;
+
+        /* double check it */
+        if (!result[i].bad && !result[i].lose_cover_sizek) {
+                if (nr_range_new != nr_range ||
+                        memcmp(range, range_new, sizeof(range)))
+                                result[i].bad = 1;
+        }
+
+        if (!result[i].bad && (range_sums - range_sums_new <
+                                min_loss_pfn[num_reg])) {
+                min_loss_pfn[num_reg] =
+                        range_sums - range_sums_new;
+        }
+}
+
+static void __init mtrr_print_out_one_result(int i)
+{
+        char gran_factor, chunk_factor, lose_factor;
+        unsigned long gran_base, chunk_base, lose_base;
+
+        gran_base = to_size_factor(result[i].gran_sizek, &gran_factor),
+        chunk_base = to_size_factor(result[i].chunk_sizek, &chunk_factor),
+        lose_base = to_size_factor(result[i].lose_cover_sizek, &lose_factor),
+        printk(KERN_INFO "%sgran_size: %ld%c \tchunk_size: %ld%c \t",
+                        result[i].bad ? "*BAD*" : " ",
+                        gran_base, gran_factor, chunk_base, chunk_factor);
+        printk(KERN_CONT "num_reg: %d  \tlose cover RAM: %s%ld%c\n",
+                        result[i].num_reg, result[i].bad ? "-" : "",
+                        lose_base, lose_factor);
+}
+
+static int __init mtrr_search_optimal_index(void)
+{
+        int i;
+        int num_reg_good;
+        int index_good;
+
+        if (nr_mtrr_spare_reg >= num_var_ranges)
+                nr_mtrr_spare_reg = num_var_ranges - 1;
+        num_reg_good = -1;
+        for (i = num_var_ranges - nr_mtrr_spare_reg; i > 0; i--) {
+                if (!min_loss_pfn[i])
+                        num_reg_good = i;
+        }
+
+        index_good = -1;
+        if (num_reg_good != -1) {
+                for (i = 0; i < NUM_RESULT; i++) {
+                        if (!result[i].bad &&
+                            result[i].num_reg == num_reg_good &&
+                            !result[i].lose_cover_sizek) {
+                                index_good = i;
+                                break;
+                        }
+                }
+        }
+
+        return index_good;
+}
+
+
+int __init mtrr_cleanup(unsigned address_bits)
+{
+        unsigned long extra_remove_base, extra_remove_size;
+        unsigned long base, size, def, dummy;
+        mtrr_type type;
+        u64 chunk_size, gran_size;
+        int index_good;
+        int i;
+
+        if (!is_cpu(INTEL) || enable_mtrr_cleanup < 1)
+                return 0;
+        rdmsr(MTRRdefType_MSR, def, dummy);
+        def &= 0xff;
+        if (def != MTRR_TYPE_UNCACHABLE)
+                return 0;
+
+        /* get it and store it aside */
+        memset(range_state, 0, sizeof(range_state));
+        for (i = 0; i < num_var_ranges; i++) {
+                mtrr_if->get(i, &base, &size, &type);
+                range_state[i].base_pfn = base;
+                range_state[i].size_pfn = size;
+                range_state[i].type = type;
+        }
+
+        /* check if we need handle it and can handle it */
+        if (!mtrr_need_cleanup())
+                return 0;
+
+        /* print original var MTRRs at first, for debugging: */
+        printk(KERN_DEBUG "original variable MTRRs\n");
+        print_out_mtrr_range_state();
+
+        memset(range, 0, sizeof(range));
+        extra_remove_size = 0;
+        extra_remove_base = 1 << (32 - PAGE_SHIFT);
+        if (mtrr_tom2)
+                extra_remove_size =
+                        (mtrr_tom2 >> PAGE_SHIFT) - extra_remove_base;
+        nr_range = x86_get_mtrr_mem_range(range, 0, extra_remove_base,
+                                          extra_remove_size);
+        /*
+         * [0, 1M) should always be coverred by var mtrr with WB
+         * and fixed mtrrs should take effective before var mtrr for it
+         */
+        nr_range = add_range_with_merge(range, nr_range, 0,
+                                        (1ULL<<(20 - PAGE_SHIFT)) - 1);
+        /* sort the ranges */
+        sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
+
+        range_sums = sum_ranges(range, nr_range);
+        printk(KERN_INFO "total RAM coverred: %ldM\n",
+               range_sums >> (20 - PAGE_SHIFT));
+
+        if (mtrr_chunk_size && mtrr_gran_size) {
+                i = 0;
+                mtrr_calc_range_state(mtrr_chunk_size, mtrr_gran_size,
+                                      extra_remove_base, extra_remove_size, i);
+
+                mtrr_print_out_one_result(i);
+
+                if (!result[i].bad) {
+                        set_var_mtrr_all(address_bits);
+                        printk(KERN_DEBUG "New variable MTRRs\n");
+                        print_out_mtrr_range_state();
+                        return 1;
+                }
+                printk(KERN_INFO "invalid mtrr_gran_size or mtrr_chunk_size, "
+                       "will find optimal one\n");
+        }
+
+        i = 0;
+        memset(min_loss_pfn, 0xff, sizeof(min_loss_pfn));
+        memset(result, 0, sizeof(result));
+        for (gran_size = (1ULL<<16); gran_size < (1ULL<<32); gran_size <<= 1) {
+
+                for (chunk_size = gran_size; chunk_size < (1ULL<<32);
+                     chunk_size <<= 1) {
+
+                        if (i >= NUM_RESULT)
+                                continue;
+
+                        mtrr_calc_range_state(chunk_size, gran_size,
+                                      extra_remove_base, extra_remove_size, i);
+                        if (debug_print) {
+                                mtrr_print_out_one_result(i);
+                                printk(KERN_INFO "\n");
+                        }
+
+                        i++;
+                }
+        }
+
+        /* try to find the optimal index */
+        index_good = mtrr_search_optimal_index();
+
+        if (index_good != -1) {
+                printk(KERN_INFO "Found optimal setting for mtrr clean up\n");
+                i = index_good;
+                mtrr_print_out_one_result(i);
+
+                /* convert ranges to var ranges state */
+                chunk_size = result[i].chunk_sizek;
+                chunk_size <<= 10;
+                gran_size = result[i].gran_sizek;
+                gran_size <<= 10;
+                x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
+                set_var_mtrr_all(address_bits);
+                printk(KERN_DEBUG "New variable MTRRs\n");
+                print_out_mtrr_range_state();
+                return 1;
+        } else {
+                /* print out all */
+                for (i = 0; i < NUM_RESULT; i++)
+                        mtrr_print_out_one_result(i);
+        }
+
+        printk(KERN_INFO "mtrr_cleanup: can not find optimal value\n");
+        printk(KERN_INFO "please specify mtrr_gran_size/mtrr_chunk_size\n");
+
+        return 0;
+}
+#else
+int __init mtrr_cleanup(unsigned address_bits)
+{
+        return 0;
+}
+#endif
+
+static int disable_mtrr_trim;
+
+static int __init disable_mtrr_trim_setup(char *str)
+{
+        disable_mtrr_trim = 1;
+        return 0;
+}
+early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
+
+/*
+ * Newer AMD K8s and later CPUs have a special magic MSR way to force WB
+ * for memory >4GB. Check for that here.
+ * Note this won't check if the MTRRs < 4GB where the magic bit doesn't
+ * apply to are wrong, but so far we don't know of any such case in the wild.
+ */
+#define Tom2Enabled (1U << 21)
+#define Tom2ForceMemTypeWB (1U << 22)
+
+int __init amd_special_default_mtrr(void)
+{
+        u32 l, h;
+
+        if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+                return 0;
+        if (boot_cpu_data.x86 < 0xf || boot_cpu_data.x86 > 0x11)
+                return 0;
+        /* In case some hypervisor doesn't pass SYSCFG through */
+        if (rdmsr_safe(MSR_K8_SYSCFG, &l, &h) < 0)
+                return 0;
+        /*
+         * Memory between 4GB and top of mem is forced WB by this magic bit.
+         * Reserved before K8RevF, but should be zero there.
+         */
+        if ((l & (Tom2Enabled | Tom2ForceMemTypeWB)) ==
+                 (Tom2Enabled | Tom2ForceMemTypeWB))
+                return 1;
+        return 0;
+}
+
+static u64 __init real_trim_memory(unsigned long start_pfn,
+                                   unsigned long limit_pfn)
+{
+        u64 trim_start, trim_size;
+        trim_start = start_pfn;
+        trim_start <<= PAGE_SHIFT;
+        trim_size = limit_pfn;
+        trim_size <<= PAGE_SHIFT;
+        trim_size -= trim_start;
+
+        return e820_update_range(trim_start, trim_size, E820_RAM,
+                                E820_RESERVED);
+}
+/**
+ * mtrr_trim_uncached_memory - trim RAM not covered by MTRRs
+ * @end_pfn: ending page frame number
+ *
+ * Some buggy BIOSes don't setup the MTRRs properly for systems with certain
+ * memory configurations.  This routine checks that the highest MTRR matches
+ * the end of memory, to make sure the MTRRs having a write back type cover
+ * all of the memory the kernel is intending to use. If not, it'll trim any
+ * memory off the end by adjusting end_pfn, removing it from the kernel's
+ * allocation pools, warning the user with an obnoxious message.
+ */
+int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
+{
+        unsigned long i, base, size, highest_pfn = 0, def, dummy;
+        mtrr_type type;
+        u64 total_trim_size;
+
+        /* extra one for all 0 */
+        int num[MTRR_NUM_TYPES + 1];
+        /*
+         * Make sure we only trim uncachable memory on machines that
+         * support the Intel MTRR architecture:
+         */
+        if (!is_cpu(INTEL) || disable_mtrr_trim)
+                return 0;
+        rdmsr(MTRRdefType_MSR, def, dummy);
+        def &= 0xff;
+        if (def != MTRR_TYPE_UNCACHABLE)
+                return 0;
+
+        /* get it and store it aside */
+        memset(range_state, 0, sizeof(range_state));
+        for (i = 0; i < num_var_ranges; i++) {
+                mtrr_if->get(i, &base, &size, &type);
+                range_state[i].base_pfn = base;
+                range_state[i].size_pfn = size;
+                range_state[i].type = type;
+        }
+
+        /* Find highest cached pfn */
+        for (i = 0; i < num_var_ranges; i++) {
+                type = range_state[i].type;
+                if (type != MTRR_TYPE_WRBACK)
+                        continue;
+                base = range_state[i].base_pfn;
+                size = range_state[i].size_pfn;
+                if (highest_pfn < base + size)
+                        highest_pfn = base + size;
+        }
+
+        /* kvm/qemu doesn't have mtrr set right, don't trim them all */
+        if (!highest_pfn) {
+                printk(KERN_INFO "CPU MTRRs all blank - virtualized system.\n");
+                return 0;
+        }
+
+        /* check entries number */
+        memset(num, 0, sizeof(num));
+        for (i = 0; i < num_var_ranges; i++) {
+                type = range_state[i].type;
+                if (type >= MTRR_NUM_TYPES)
+                        continue;
+                size = range_state[i].size_pfn;
+                if (!size)
+                        type = MTRR_NUM_TYPES;
+                num[type]++;
+        }
+
+        /* no entry for WB? */
+        if (!num[MTRR_TYPE_WRBACK])
+                return 0;
+
+        /* check if we only had WB and UC */
+        if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
+                num_var_ranges - num[MTRR_NUM_TYPES])
+                return 0;
+
+        memset(range, 0, sizeof(range));
+        nr_range = 0;
+        if (mtrr_tom2) {
+                range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
+                range[nr_range].end = (mtrr_tom2 >> PAGE_SHIFT) - 1;
+                if (highest_pfn < range[nr_range].end + 1)
+                        highest_pfn = range[nr_range].end + 1;
+                nr_range++;
+        }
+        nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);
+
+        total_trim_size = 0;
+        /* check the head */
+        if (range[0].start)
+                total_trim_size += real_trim_memory(0, range[0].start);
+        /* check the holes */
+        for (i = 0; i < nr_range - 1; i++) {
+                if (range[i].end + 1 < range[i+1].start)
+                        total_trim_size += real_trim_memory(range[i].end + 1,
+                                                            range[i+1].start);
+        }
+        /* check the top */
+        i = nr_range - 1;
+        if (range[i].end + 1 < end_pfn)
+                total_trim_size += real_trim_memory(range[i].end + 1,
+                                                         end_pfn);
+
+        if (total_trim_size) {
+                printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover"
+                        " all of memory, losing %lluMB of RAM.\n",
+                        total_trim_size >> 20);
+
+                if (!changed_by_mtrr_cleanup)
+                        WARN_ON(1);
+
+                printk(KERN_INFO "update e820 for mtrr\n");
+                update_e820();
+
+                return 1;
+        }
+
+        return 0;
+}
+