// SPDX-License-Identifier: GPL-2.0-only
/*
 * This only handles 32bit MTRR on 32bit hosts. This is strictly wrong
 * because MTRRs can span up to 40 bits (36bits on most modern x86)
 */

#include <linux/export.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/cc_platform.h>
#include <linux/string_choices.h>
#include <asm/processor-flags.h>
#include <asm/cacheinfo.h>
#include <asm/cpufeature.h>
#include <asm/cpu_device_id.h>
#include <asm/hypervisor.h>
#include <asm/mshyperv.h>
#include <asm/tlbflush.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
#include <asm/memtype.h>

#include "mtrr.h"

struct fixed_range_block {
        int base_msr;           /* start address of an MTRR block */
        int ranges;             /* number of MTRRs in this block  */
};

static struct fixed_range_block fixed_range_blocks[] = {
        { MSR_MTRRfix64K_00000, 1 }, /* one   64k MTRR  */
        { MSR_MTRRfix16K_80000, 2 }, /* two   16k MTRRs */
        { MSR_MTRRfix4K_C0000,  8 }, /* eight  4k MTRRs */
        {}
};

struct cache_map {
        u64 start;
        u64 end;
        u64 flags;
        u64 type:8;
        u64 fixed:1;
};

bool mtrr_debug;

static int __init mtrr_param_setup(char *str)
{
        int rc = 0;

        if (!str)
                return -EINVAL;
        if (!strcmp(str, "debug"))
                mtrr_debug = true;
        else
                rc = -EINVAL;

        return rc;
}
early_param("mtrr", mtrr_param_setup);

/*
 * CACHE_MAP_MAX is the maximum number of memory ranges in cache_map, where
 * no 2 adjacent ranges have the same cache mode (those would be merged).
 * The number is based on the worst case:
 * - no two adjacent fixed MTRRs share the same cache mode
 * - one variable MTRR is spanning a huge area with mode WB
 * - 255 variable MTRRs with mode UC all overlap with the WB MTRR, creating 2
 *   additional ranges each (result like "ababababa...aba" with a = WB, b = UC),
 *   accounting for MTRR_MAX_VAR_RANGES * 2 - 1 range entries
 * - a TOP_MEM2 area (even with overlapping an UC MTRR can't add 2 range entries
 *   to the possible maximum, as it always starts at 4GB, thus it can't be in
 *   the middle of that MTRR, unless that MTRR starts at 0, which would remove
 *   the initial "a" from the "abababa" pattern above)
 * The map won't contain ranges with no matching MTRR (those fall back to the
 * default cache mode).
 */
#define CACHE_MAP_MAX   (MTRR_NUM_FIXED_RANGES + MTRR_MAX_VAR_RANGES * 2)

static struct cache_map init_cache_map[CACHE_MAP_MAX] __initdata;
static struct cache_map *cache_map __refdata = init_cache_map;
static unsigned int cache_map_size = CACHE_MAP_MAX;
static unsigned int cache_map_n;
static unsigned int cache_map_fixed;

static unsigned long smp_changes_mask;
static int mtrr_state_set;
u64 mtrr_tom2;

struct mtrr_state_type mtrr_state;

/* Reserved bits in the high portion of the MTRRphysBaseN MSR. */
u32 phys_hi_rsvd;

/*
 * BIOS is expected to clear MtrrFixDramModEn bit, see for example
 * "BIOS and Kernel Developer's Guide for the AMD Athlon 64 and AMD
 * Opteron Processors" (26094 Rev. 3.30 February 2006), section
 * "13.2.1.2 SYSCFG Register": "The MtrrFixDramModEn bit should be set
 * to 1 during BIOS initialization of the fixed MTRRs, then cleared to
 * 0 for operation."
 */
static inline void k8_check_syscfg_dram_mod_en(void)
{
        u32 lo, hi;

        if (!((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&
              (boot_cpu_data.x86 >= 0x0f)))
                return;

        if (cc_platform_has(CC_ATTR_HOST_SEV_SNP))
                return;

        rdmsr(MSR_AMD64_SYSCFG, lo, hi);
        if (lo & K8_MTRRFIXRANGE_DRAM_MODIFY) {
                pr_err(FW_WARN "MTRR: CPU %u: SYSCFG[MtrrFixDramModEn]"
                       " not cleared by BIOS, clearing this bit\n",
                       smp_processor_id());
                lo &= ~K8_MTRRFIXRANGE_DRAM_MODIFY;
                mtrr_wrmsr(MSR_AMD64_SYSCFG, lo, hi);
        }
}

/* Get the size of contiguous MTRR range */
static u64 get_mtrr_size(u64 mask)
{
        u64 size;

        mask |= (u64)phys_hi_rsvd << 32;
        size = -mask;

        return size;
}

static u8 get_var_mtrr_state(unsigned int reg, u64 *start, u64 *size)
{
        struct mtrr_var_range *mtrr = mtrr_state.var_ranges + reg;

        if (!(mtrr->mask_lo & MTRR_PHYSMASK_V))
                return MTRR_TYPE_INVALID;

        *start = (((u64)mtrr->base_hi) << 32) + (mtrr->base_lo & PAGE_MASK);
        *size = get_mtrr_size((((u64)mtrr->mask_hi) << 32) +
                              (mtrr->mask_lo & PAGE_MASK));

        return mtrr->base_lo & MTRR_PHYSBASE_TYPE;
}

static u8 get_effective_type(u8 type1, u8 type2)
{
        if (type1 == MTRR_TYPE_UNCACHABLE || type2 == MTRR_TYPE_UNCACHABLE)
                return MTRR_TYPE_UNCACHABLE;

        if ((type1 == MTRR_TYPE_WRBACK && type2 == MTRR_TYPE_WRTHROUGH) ||
            (type1 == MTRR_TYPE_WRTHROUGH && type2 == MTRR_TYPE_WRBACK))
                return MTRR_TYPE_WRTHROUGH;

        if (type1 != type2)
                return MTRR_TYPE_UNCACHABLE;

        return type1;
}

static void rm_map_entry_at(int idx)
{
        cache_map_n--;
        if (cache_map_n > idx) {
                memmove(cache_map + idx, cache_map + idx + 1,
                        sizeof(*cache_map) * (cache_map_n - idx));
        }
}

/*
 * Add an entry into cache_map at a specific index.  Merges adjacent entries if
 * appropriate.  Return the number of merges for correcting the scan index
 * (this is needed as merging will reduce the number of entries, which will
 * result in skipping entries in future iterations if the scan index isn't
 * corrected).
 * Note that the corrected index can never go below -1 (resulting in being 0 in
 * the next scan iteration), as "2" is returned only if the current index is
 * larger than zero.
 */
static int add_map_entry_at(u64 start, u64 end, u8 type, int idx)
{
        bool merge_prev = false, merge_next = false;

        if (start >= end)
                return 0;

        if (idx > 0) {
                struct cache_map *prev = cache_map + idx - 1;

                if (!prev->fixed && start == prev->end && type == prev->type)
                        merge_prev = true;
        }

        if (idx < cache_map_n) {
                struct cache_map *next = cache_map + idx;

                if (!next->fixed && end == next->start && type == next->type)
                        merge_next = true;
        }

        if (merge_prev && merge_next) {
                cache_map[idx - 1].end = cache_map[idx].end;
                rm_map_entry_at(idx);
                return 2;
        }
        if (merge_prev) {
                cache_map[idx - 1].end = end;
                return 1;
        }
        if (merge_next) {
                cache_map[idx].start = start;
                return 1;
        }

        /* Sanity check: the array should NEVER be too small! */
        if (cache_map_n == cache_map_size) {
                WARN(1, "MTRR cache mode memory map exhausted!\n");
                cache_map_n = cache_map_fixed;
                return 0;
        }

        if (cache_map_n > idx) {
                memmove(cache_map + idx + 1, cache_map + idx,
                        sizeof(*cache_map) * (cache_map_n - idx));
        }

        cache_map[idx].start = start;
        cache_map[idx].end = end;
        cache_map[idx].type = type;
        cache_map[idx].fixed = 0;
        cache_map_n++;

        return 0;
}

/* Clear a part of an entry. Return 1 if start of entry is still valid. */
static int clr_map_range_at(u64 start, u64 end, int idx)
{
        int ret = start != cache_map[idx].start;
        u64 tmp;

        if (start == cache_map[idx].start && end == cache_map[idx].end) {
                rm_map_entry_at(idx);
        } else if (start == cache_map[idx].start) {
                cache_map[idx].start = end;
        } else if (end == cache_map[idx].end) {
                cache_map[idx].end = start;
        } else {
                tmp = cache_map[idx].end;
                cache_map[idx].end = start;
                add_map_entry_at(end, tmp, cache_map[idx].type, idx + 1);
        }

        return ret;
}

/*
 * Add MTRR to the map.  The current map is scanned and each part of the MTRR
 * either overlapping with an existing entry or with a hole in the map is
 * handled separately.
 */
static void add_map_entry(u64 start, u64 end, u8 type)
{
        u8 new_type, old_type;
        u64 tmp;
        int i;

        for (i = 0; i < cache_map_n && start < end; i++) {
                if (start >= cache_map[i].end)
                        continue;

                if (start < cache_map[i].start) {
                        /* Region start has no overlap. */
                        tmp = min(end, cache_map[i].start);
                        i -= add_map_entry_at(start, tmp,  type, i);
                        start = tmp;
                        continue;
                }

                new_type = get_effective_type(type, cache_map[i].type);
                old_type = cache_map[i].type;

                if (cache_map[i].fixed || new_type == old_type) {
                        /* Cut off start of new entry. */
                        start = cache_map[i].end;
                        continue;
                }

                /* Handle only overlapping part of region. */
                tmp = min(end, cache_map[i].end);
                i += clr_map_range_at(start, tmp, i);
                i -= add_map_entry_at(start, tmp, new_type, i);
                start = tmp;
        }

        /* Add rest of region after last map entry (rest might be empty). */
        add_map_entry_at(start, end, type, i);
}

/* Add variable MTRRs to cache map. */
static void map_add_var(void)
{
        u64 start, size;
        unsigned int i;
        u8 type;

        /*
         * Add AMD TOP_MEM2 area.  Can't be added in mtrr_build_map(), as it
         * needs to be added again when rebuilding the map due to potentially
         * having moved as a result of variable MTRRs for memory below 4GB.
         */
        if (mtrr_tom2) {
                add_map_entry(BIT_ULL(32), mtrr_tom2, MTRR_TYPE_WRBACK);
                cache_map[cache_map_n - 1].fixed = 1;
        }

        for (i = 0; i < num_var_ranges; i++) {
                type = get_var_mtrr_state(i, &start, &size);
                if (type != MTRR_TYPE_INVALID)
                        add_map_entry(start, start + size, type);
        }
}

/*
 * Rebuild map by replacing variable entries.  Needs to be called when MTRR
 * registers are being changed after boot, as such changes could include
 * removals of registers, which are complicated to handle without rebuild of
 * the map.
 */
void generic_rebuild_map(void)
{
        if (mtrr_if != &generic_mtrr_ops)
                return;

        cache_map_n = cache_map_fixed;

        map_add_var();
}

static unsigned int __init get_cache_map_size(void)
{
        return cache_map_fixed + 2 * num_var_ranges + (mtrr_tom2 != 0);
}

/* Build the cache_map containing the cache modes per memory range. */
void __init mtrr_build_map(void)
{
        u64 start, end, size;
        unsigned int i;
        u8 type;

        /* Add fixed MTRRs, optimize for adjacent entries with same type. */
        if (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED) {
                /*
                 * Start with 64k size fixed entries, preset 1st one (hence the
                 * loop below is starting with index 1).
                 */
                start = 0;
                end = size = 0x10000;
                type = mtrr_state.fixed_ranges[0];

                for (i = 1; i < MTRR_NUM_FIXED_RANGES; i++) {
                        /* 8 64k entries, then 16 16k ones, rest 4k. */
                        if (i == 8 || i == 24)
                                size >>= 2;

                        if (mtrr_state.fixed_ranges[i] != type) {
                                add_map_entry(start, end, type);
                                start = end;
                                type = mtrr_state.fixed_ranges[i];
                        }
                        end += size;
                }
                add_map_entry(start, end, type);
        }

        /* Mark fixed, they take precedence. */
        for (i = 0; i < cache_map_n; i++)
                cache_map[i].fixed = 1;
        cache_map_fixed = cache_map_n;

        map_add_var();

        pr_info("MTRR map: %u entries (%u fixed + %u variable; max %u), built from %u variable MTRRs\n",
                cache_map_n, cache_map_fixed, cache_map_n - cache_map_fixed,
                get_cache_map_size(), num_var_ranges + (mtrr_tom2 != 0));

        if (mtrr_debug) {
                for (i = 0; i < cache_map_n; i++) {
                        pr_info("%3u: %016llx-%016llx %s\n", i,
                                cache_map[i].start, cache_map[i].end - 1,
                                mtrr_attrib_to_str(cache_map[i].type));
                }
        }
}

/* Copy the cache_map from __initdata memory to dynamically allocated one. */
void __init mtrr_copy_map(void)
{
        unsigned int new_size = get_cache_map_size();

        if (!mtrr_state.enabled || !new_size) {
                cache_map = NULL;
                return;
        }

        mutex_lock(&mtrr_mutex);

        cache_map = kzalloc_objs(*cache_map, new_size);
        if (cache_map) {
                memmove(cache_map, init_cache_map,
                        cache_map_n * sizeof(*cache_map));
                cache_map_size = new_size;
        } else {
                mtrr_state.enabled = 0;
                pr_err("MTRRs disabled due to allocation failure for lookup map.\n");
        }

        mutex_unlock(&mtrr_mutex);
}

/**
 * guest_force_mtrr_state - set static MTRR state for a guest
 *
 * Used to set MTRR state via different means (e.g. with data obtained from
 * a hypervisor).
 * Is allowed only for special cases when running virtualized. Must be called
 * from the x86_init.hyper.init_platform() hook.  It can be called only once.
 * The MTRR state can't be changed afterwards.  To ensure that, X86_FEATURE_MTRR
 * is cleared.
 *
 * @var: MTRR variable range array to use
 * @num_var: length of the @var array
 * @def_type: default caching type
 */
void guest_force_mtrr_state(struct mtrr_var_range *var, unsigned int num_var,
                            mtrr_type def_type)
{
        unsigned int i;

        /* Only allowed to be called once before mtrr_bp_init(). */
        if (WARN_ON_ONCE(mtrr_state_set))
                return;

        /* Only allowed when running virtualized. */
        if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
                return;

        /*
         * Only allowed for special virtualization cases:
         * - when running as Hyper-V, SEV-SNP guest using vTOM
         * - when running as Xen PV guest
         * - when running as SEV-SNP or TDX guest to avoid unnecessary
         *   VMM communication/Virtualization exceptions (#VC, #VE)
         */
        if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP) &&
            !hv_is_isolation_supported() &&
            !cpu_feature_enabled(X86_FEATURE_XENPV) &&
            !cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
                return;

        /* Disable MTRR in order to disable MTRR modifications. */
        setup_clear_cpu_cap(X86_FEATURE_MTRR);

        if (var) {
                if (num_var > MTRR_MAX_VAR_RANGES) {
                        pr_warn("Trying to overwrite MTRR state with %u variable entries\n",
                                num_var);
                        num_var = MTRR_MAX_VAR_RANGES;
                }
                for (i = 0; i < num_var; i++)
                        mtrr_state.var_ranges[i] = var[i];
                num_var_ranges = num_var;
        }

        mtrr_state.def_type = def_type;
        mtrr_state.enabled |= MTRR_STATE_MTRR_ENABLED;

        mtrr_state_set = 1;
}

static u8 type_merge(u8 type, u8 new_type, u8 *uniform)
{
        u8 effective_type;

        if (type == MTRR_TYPE_INVALID)
                return new_type;

        effective_type = get_effective_type(type, new_type);
        if (type != effective_type)
                *uniform = 0;

        return effective_type;
}

/**
 * mtrr_type_lookup - look up memory type in MTRR
 *
 * @start: Begin of the physical address range
 * @end: End of the physical address range
 * @uniform: output argument:
 *  - 1: the returned MTRR type is valid for the whole region
 *  - 0: otherwise
 *
 * Return Values:
 * MTRR_TYPE_(type)  - The effective MTRR type for the region
 * MTRR_TYPE_INVALID - MTRR is disabled
 */
u8 mtrr_type_lookup(u64 start, u64 end, u8 *uniform)
{
        u8 type = MTRR_TYPE_INVALID;
        unsigned int i;

        if (!mtrr_state_set) {
                /* Uniformity is unknown. */
                *uniform = 0;
                return MTRR_TYPE_UNCACHABLE;
        }

        *uniform = 1;

        if (!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED))
                return MTRR_TYPE_UNCACHABLE;

        for (i = 0; i < cache_map_n && start < end; i++) {
                /* Region after current map entry? -> continue with next one. */
                if (start >= cache_map[i].end)
                        continue;

                /* Start of region not covered by current map entry? */
                if (start < cache_map[i].start) {
                        /* At least some part of region has default type. */
                        type = type_merge(type, mtrr_state.def_type, uniform);
                        /* End of region not covered, too? -> lookup done. */
                        if (end <= cache_map[i].start)
                                return type;
                }

                /* At least part of region covered by map entry. */
                type = type_merge(type, cache_map[i].type, uniform);

                start = cache_map[i].end;
        }

        /* End of region past last entry in map? -> use default type. */
        if (start < end)
                type = type_merge(type, mtrr_state.def_type, uniform);

        return type;
}

/* Get the MSR pair relating to a var range */
static void
get_mtrr_var_range(unsigned int index, struct mtrr_var_range *vr)
{
        rdmsr(MTRRphysBase_MSR(index), vr->base_lo, vr->base_hi);
        rdmsr(MTRRphysMask_MSR(index), vr->mask_lo, vr->mask_hi);
}

/* Fill the MSR pair relating to a var range */
void fill_mtrr_var_range(unsigned int index,
                u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi)
{
        struct mtrr_var_range *vr;

        vr = mtrr_state.var_ranges;

        vr[index].base_lo = base_lo;
        vr[index].base_hi = base_hi;
        vr[index].mask_lo = mask_lo;
        vr[index].mask_hi = mask_hi;
}

static void get_fixed_ranges(mtrr_type *frs)
{
        unsigned int *p = (unsigned int *)frs;
        int i;

        k8_check_syscfg_dram_mod_en();

        rdmsr(MSR_MTRRfix64K_00000, p[0], p[1]);

        for (i = 0; i < 2; i++)
                rdmsr(MSR_MTRRfix16K_80000 + i, p[2 + i * 2], p[3 + i * 2]);
        for (i = 0; i < 8; i++)
                rdmsr(MSR_MTRRfix4K_C0000 + i, p[6 + i * 2], p[7 + i * 2]);
}

void mtrr_save_fixed_ranges(void *info)
{
        if (mtrr_state.have_fixed)
                get_fixed_ranges(mtrr_state.fixed_ranges);
}

static unsigned __initdata last_fixed_start;
static unsigned __initdata last_fixed_end;
static mtrr_type __initdata last_fixed_type;

static void __init print_fixed_last(void)
{
        if (!last_fixed_end)
                return;

        pr_info("  %05X-%05X %s\n", last_fixed_start,
                last_fixed_end - 1, mtrr_attrib_to_str(last_fixed_type));

        last_fixed_end = 0;
}

static void __init update_fixed_last(unsigned base, unsigned end,
                                     mtrr_type type)
{
        last_fixed_start = base;
        last_fixed_end = end;
        last_fixed_type = type;
}

static void __init
print_fixed(unsigned base, unsigned step, const mtrr_type *types)
{
        unsigned i;

        for (i = 0; i < 8; ++i, ++types, base += step) {
                if (last_fixed_end == 0) {
                        update_fixed_last(base, base + step, *types);
                        continue;
                }
                if (last_fixed_end == base && last_fixed_type == *types) {
                        last_fixed_end = base + step;
                        continue;
                }
                /* new segments: gap or different type */
                print_fixed_last();
                update_fixed_last(base, base + step, *types);
        }
}

static void __init print_mtrr_state(void)
{
        unsigned int i;
        int high_width;

        pr_info("MTRR default type: %s\n",
                mtrr_attrib_to_str(mtrr_state.def_type));
        if (mtrr_state.have_fixed) {
                pr_info("MTRR fixed ranges %s:\n",
                        str_enabled_disabled(
                         (mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED) &&
                         (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)));
                print_fixed(0x00000, 0x10000, mtrr_state.fixed_ranges + 0);
                for (i = 0; i < 2; ++i)
                        print_fixed(0x80000 + i * 0x20000, 0x04000,
                                    mtrr_state.fixed_ranges + (i + 1) * 8);
                for (i = 0; i < 8; ++i)
                        print_fixed(0xC0000 + i * 0x08000, 0x01000,
                                    mtrr_state.fixed_ranges + (i + 3) * 8);

                /* tail */
                print_fixed_last();
        }
        pr_info("MTRR variable ranges %s:\n",
                str_enabled_disabled(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED));
        high_width = (boot_cpu_data.x86_phys_bits - (32 - PAGE_SHIFT) + 3) / 4;

        for (i = 0; i < num_var_ranges; ++i) {
                if (mtrr_state.var_ranges[i].mask_lo & MTRR_PHYSMASK_V)
                        pr_info("  %u base %0*X%05X000 mask %0*X%05X000 %s\n",
                                i,
                                high_width,
                                mtrr_state.var_ranges[i].base_hi,
                                mtrr_state.var_ranges[i].base_lo >> 12,
                                high_width,
                                mtrr_state.var_ranges[i].mask_hi,
                                mtrr_state.var_ranges[i].mask_lo >> 12,
                                mtrr_attrib_to_str(mtrr_state.var_ranges[i].base_lo &
                                                    MTRR_PHYSBASE_TYPE));
                else
                        pr_info("  %u disabled\n", i);
        }
        if (mtrr_tom2)
                pr_info("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);
}

/* Grab all of the MTRR state for this CPU into *state */
bool __init get_mtrr_state(void)
{
        struct mtrr_var_range *vrs;
        unsigned lo, dummy;
        unsigned int i;

        vrs = mtrr_state.var_ranges;

        rdmsr(MSR_MTRRcap, lo, dummy);
        mtrr_state.have_fixed = lo & MTRR_CAP_FIX;

        for (i = 0; i < num_var_ranges; i++)
                get_mtrr_var_range(i, &vrs[i]);
        if (mtrr_state.have_fixed)
                get_fixed_ranges(mtrr_state.fixed_ranges);

        rdmsr(MSR_MTRRdefType, lo, dummy);
        mtrr_state.def_type = lo & MTRR_DEF_TYPE_TYPE;
        mtrr_state.enabled = (lo & MTRR_DEF_TYPE_ENABLE) >> MTRR_STATE_SHIFT;

        if (amd_special_default_mtrr()) {
                unsigned low, high;

                /* TOP_MEM2 */
                rdmsr(MSR_K8_TOP_MEM2, low, high);
                mtrr_tom2 = high;
                mtrr_tom2 <<= 32;
                mtrr_tom2 |= low;
                mtrr_tom2 &= 0xffffff800000ULL;
        }

        if (mtrr_debug)
                print_mtrr_state();

        mtrr_state_set = 1;

        return !!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED);
}

/* Some BIOS's are messed up and don't set all MTRRs the same! */
void __init mtrr_state_warn(void)
{
        unsigned long mask = smp_changes_mask;

        if (!mask)
                return;
        if (mask & MTRR_CHANGE_MASK_FIXED)
                pr_warn("mtrr: your CPUs had inconsistent fixed MTRR settings\n");
        if (mask & MTRR_CHANGE_MASK_VARIABLE)
                pr_warn("mtrr: your CPUs had inconsistent variable MTRR settings\n");
        if (mask & MTRR_CHANGE_MASK_DEFTYPE)
                pr_warn("mtrr: your CPUs had inconsistent MTRRdefType settings\n");

        pr_info("mtrr: probably your BIOS does not setup all CPUs.\n");
        pr_info("mtrr: corrected configuration.\n");
}

/*
 * Doesn't attempt to pass an error out to MTRR users
 * because it's quite complicated in some cases and probably not
 * worth it because the best error handling is to ignore it.
 */
void mtrr_wrmsr(unsigned msr, unsigned a, unsigned b)
{
        if (wrmsr_safe(msr, a, b) < 0) {
                pr_err("MTRR: CPU %u: Writing MSR %x to %x:%x failed\n",
                        smp_processor_id(), msr, a, b);
        }
}

/**
 * set_fixed_range - checks & updates a fixed-range MTRR if it
 *                   differs from the value it should have
 * @msr: MSR address of the MTTR which should be checked and updated
 * @changed: pointer which indicates whether the MTRR needed to be changed
 * @msrwords: pointer to the MSR values which the MSR should have
 */
static void set_fixed_range(int msr, bool *changed, unsigned int *msrwords)
{
        unsigned lo, hi;

        rdmsr(msr, lo, hi);

        if (lo != msrwords[0] || hi != msrwords[1]) {
                mtrr_wrmsr(msr, msrwords[0], msrwords[1]);
                *changed = true;
        }
}

/**
 * generic_get_free_region - Get a free MTRR.
 * @base: The starting (base) address of the region.
 * @size: The size (in bytes) of the region.
 * @replace_reg: mtrr index to be replaced; set to invalid value if none.
 *
 * Returns: The index of the region on success, else negative on error.
 */
int
generic_get_free_region(unsigned long base, unsigned long size, int replace_reg)
{
        unsigned long lbase, lsize;
        mtrr_type ltype;
        int i, max;

        max = num_var_ranges;
        if (replace_reg >= 0 && replace_reg < max)
                return replace_reg;

        for (i = 0; i < max; ++i) {
                mtrr_if->get(i, &lbase, &lsize, &ltype);
                if (lsize == 0)
                        return i;
        }

        return -ENOSPC;
}

static void generic_get_mtrr(unsigned int reg, unsigned long *base,
                             unsigned long *size, mtrr_type *type)
{
        u32 mask_lo, mask_hi, base_lo, base_hi;
        unsigned int hi;
        u64 tmp, mask;

        /*
         * get_mtrr doesn't need to update mtrr_state, also it could be called
         * from any cpu, so try to print it out directly.
         */
        get_cpu();

        rdmsr(MTRRphysMask_MSR(reg), mask_lo, mask_hi);

        if (!(mask_lo & MTRR_PHYSMASK_V)) {
                /*  Invalid (i.e. free) range */
                *base = 0;
                *size = 0;
                *type = 0;
                goto out_put_cpu;
        }

        rdmsr(MTRRphysBase_MSR(reg), base_lo, base_hi);

        /* Work out the shifted address mask: */
        tmp = (u64)mask_hi << 32 | (mask_lo & PAGE_MASK);
        mask = (u64)phys_hi_rsvd << 32 | tmp;

        /* Expand tmp with high bits to all 1s: */
        hi = fls64(tmp);
        if (hi > 0) {
                tmp |= ~((1ULL<<(hi - 1)) - 1);

                if (tmp != mask) {
                        pr_warn("mtrr: your BIOS has configured an incorrect mask, fixing it.\n");
                        add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
                        mask = tmp;
                }
        }

        /*
         * This works correctly if size is a power of two, i.e. a
         * contiguous range:
         */
        *size = -mask >> PAGE_SHIFT;
        *base = (u64)base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
        *type = base_lo & MTRR_PHYSBASE_TYPE;

out_put_cpu:
        put_cpu();
}

/**
 * set_fixed_ranges - checks & updates the fixed-range MTRRs if they
 *                    differ from the saved set
 * @frs: pointer to fixed-range MTRR values, saved by get_fixed_ranges()
 */
static int set_fixed_ranges(mtrr_type *frs)
{
        unsigned long long *saved = (unsigned long long *)frs;
        bool changed = false;
        int block = -1, range;

        k8_check_syscfg_dram_mod_en();

        while (fixed_range_blocks[++block].ranges) {
                for (range = 0; range < fixed_range_blocks[block].ranges; range++)
                        set_fixed_range(fixed_range_blocks[block].base_msr + range,
                                        &changed, (unsigned int *)saved++);
        }

        return changed;
}

/*
 * Set the MSR pair relating to a var range.
 * Returns true if changes are made.
 */
static bool set_mtrr_var_ranges(unsigned int index, struct mtrr_var_range *vr)
{
        unsigned int lo, hi;
        bool changed = false;

        rdmsr(MTRRphysBase_MSR(index), lo, hi);
        if ((vr->base_lo & ~MTRR_PHYSBASE_RSVD) != (lo & ~MTRR_PHYSBASE_RSVD)
            || (vr->base_hi & ~phys_hi_rsvd) != (hi & ~phys_hi_rsvd)) {

                mtrr_wrmsr(MTRRphysBase_MSR(index), vr->base_lo, vr->base_hi);
                changed = true;
        }

        rdmsr(MTRRphysMask_MSR(index), lo, hi);

        if ((vr->mask_lo & ~MTRR_PHYSMASK_RSVD) != (lo & ~MTRR_PHYSMASK_RSVD)
            || (vr->mask_hi & ~phys_hi_rsvd) != (hi & ~phys_hi_rsvd)) {
                mtrr_wrmsr(MTRRphysMask_MSR(index), vr->mask_lo, vr->mask_hi);
                changed = true;
        }
        return changed;
}

static u32 deftype_lo, deftype_hi;

/**
 * set_mtrr_state - Set the MTRR state for this CPU.
 *
 * NOTE: The CPU must already be in a safe state for MTRR changes, including
 *       measures that only a single CPU can be active in set_mtrr_state() in
 *       order to not be subject to races for usage of deftype_lo. This is
 *       accomplished by taking cache_disable_lock.
 * RETURNS: 0 if no changes made, else a mask indicating what was changed.
 */
static unsigned long set_mtrr_state(void)
{
        unsigned long change_mask = 0;
        unsigned int i;

        for (i = 0; i < num_var_ranges; i++) {
                if (set_mtrr_var_ranges(i, &mtrr_state.var_ranges[i]))
                        change_mask |= MTRR_CHANGE_MASK_VARIABLE;
        }

        if (mtrr_state.have_fixed && set_fixed_ranges(mtrr_state.fixed_ranges))
                change_mask |= MTRR_CHANGE_MASK_FIXED;

        /*
         * Set_mtrr_restore restores the old value of MTRRdefType,
         * so to set it we fiddle with the saved value:
         */
        if ((deftype_lo & MTRR_DEF_TYPE_TYPE) != mtrr_state.def_type ||
            ((deftype_lo & MTRR_DEF_TYPE_ENABLE) >> MTRR_STATE_SHIFT) != mtrr_state.enabled) {

                deftype_lo = (deftype_lo & MTRR_DEF_TYPE_DISABLE) |
                             mtrr_state.def_type |
                             (mtrr_state.enabled << MTRR_STATE_SHIFT);
                change_mask |= MTRR_CHANGE_MASK_DEFTYPE;
        }

        return change_mask;
}

void mtrr_disable(void)
{
        /* Save MTRR state */
        rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);

        /* Disable MTRRs, and set the default type to uncached */
        mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & MTRR_DEF_TYPE_DISABLE, deftype_hi);
}

void mtrr_enable(void)
{
        /* Intel (P6) standard MTRRs */
        mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
}

void mtrr_generic_set_state(void)
{
        unsigned long mask, count;

        /* Actually set the state */
        mask = set_mtrr_state();

        /* Use the atomic bitops to update the global mask */
        for (count = 0; count < sizeof(mask) * 8; ++count) {
                if (mask & 0x01)
                        set_bit(count, &smp_changes_mask);
                mask >>= 1;
        }
}

/**
 * generic_set_mtrr - set variable MTRR register on the local CPU.
 *
 * @reg: The register to set.
 * @base: The base address of the region.
 * @size: The size of the region. If this is 0 the region is disabled.
 * @type: The type of the region.
 *
 * Returns nothing.
 */
static void generic_set_mtrr(unsigned int reg, unsigned long base,
                             unsigned long size, mtrr_type type)
{
        unsigned long flags;
        struct mtrr_var_range *vr;

        vr = &mtrr_state.var_ranges[reg];

        local_irq_save(flags);
        cache_disable();

        if (size == 0) {
                /*
                 * The invalid bit is kept in the mask, so we simply
                 * clear the relevant mask register to disable a range.
                 */
                mtrr_wrmsr(MTRRphysMask_MSR(reg), 0, 0);
                memset(vr, 0, sizeof(struct mtrr_var_range));
        } else {
                vr->base_lo = base << PAGE_SHIFT | type;
                vr->base_hi = (base >> (32 - PAGE_SHIFT)) & ~phys_hi_rsvd;
                vr->mask_lo = -size << PAGE_SHIFT | MTRR_PHYSMASK_V;
                vr->mask_hi = (-size >> (32 - PAGE_SHIFT)) & ~phys_hi_rsvd;

                mtrr_wrmsr(MTRRphysBase_MSR(reg), vr->base_lo, vr->base_hi);
                mtrr_wrmsr(MTRRphysMask_MSR(reg), vr->mask_lo, vr->mask_hi);
        }

        cache_enable();
        local_irq_restore(flags);
}

int generic_validate_add_page(unsigned long base, unsigned long size,
                              unsigned int type)
{
        unsigned long lbase, last;

        /*
         * For Intel PPro stepping <= 7
         * must be 4 MiB aligned and not touch 0x70000000 -> 0x7003FFFF
         */
        if (mtrr_if == &generic_mtrr_ops && boot_cpu_data.x86_vfm == INTEL_PENTIUM_PRO &&
            boot_cpu_data.x86_stepping <= 7) {
                if (base & ((1 << (22 - PAGE_SHIFT)) - 1)) {
                        pr_warn("mtrr: base(0x%lx000) is not 4 MiB aligned\n", base);
                        return -EINVAL;
                }
                if (!(base + size < 0x70000 || base > 0x7003F) &&
                    (type == MTRR_TYPE_WRCOMB
                     || type == MTRR_TYPE_WRBACK)) {
                        pr_warn("mtrr: writable mtrr between 0x70000000 and 0x7003FFFF may hang the CPU.\n");
                        return -EINVAL;
                }
        }

        /*
         * Check upper bits of base and last are equal and lower bits are 0
         * for base and 1 for last
         */
        last = base + size - 1;
        for (lbase = base; !(lbase & 1) && (last & 1);
             lbase = lbase >> 1, last = last >> 1)
                ;
        if (lbase != last) {
                pr_warn("mtrr: base(0x%lx000) is not aligned on a size(0x%lx000) boundary\n", base, size);
                return -EINVAL;
        }
        return 0;
}

static int generic_have_wrcomb(void)
{
        unsigned long config, dummy;
        rdmsr(MSR_MTRRcap, config, dummy);
        return config & MTRR_CAP_WC;
}

int positive_have_wrcomb(void)
{
        return 1;
}

/*
 * Generic structure...
 */
const struct mtrr_ops generic_mtrr_ops = {
        .get                    = generic_get_mtrr,
        .get_free_region        = generic_get_free_region,
        .set                    = generic_set_mtrr,
        .validate_add_page      = generic_validate_add_page,
        .have_wrcomb            = generic_have_wrcomb,
};