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DEFINITIONS
This source file includes following definitions.
- mtrr_type_lookup
- get_mtrr_var_range
- fill_mtrr_var_range
- get_fixed_ranges
- mtrr_save_fixed_ranges
- print_fixed
- get_mtrr_state
- mtrr_state_warn
- mtrr_wrmsr
- k8_enable_fixed_iorrs
- set_fixed_range
- generic_get_free_region
- generic_get_mtrr
- set_fixed_ranges
- set_mtrr_var_ranges
- set_mtrr_state
- prepare_set
- post_set
- generic_set_all
- generic_set_mtrr
- generic_validate_add_page
- generic_have_wrcomb
- positive_have_wrcomb
/* This only handles 32bit MTRR on 32bit hosts. This is strictly wrong
because MTRRs can span upto 40 bits (36bits on most modern x86) */
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <asm/io.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
#include <asm/system.h>
#include <asm/cpufeature.h>
#include <asm/processor-flags.h>
#include <asm/tlbflush.h>
#include <asm/pat.h>
#include "mtrr.h"
struct mtrr_state {
struct mtrr_var_range var_ranges[MAX_VAR_RANGES];
mtrr_type fixed_ranges[NUM_FIXED_RANGES];
unsigned char enabled;
unsigned char have_fixed;
mtrr_type def_type;
};
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[] = {
{ MTRRfix64K_00000_MSR, 1 }, /* one 64k MTRR */
{ MTRRfix16K_80000_MSR, 2 }, /* two 16k MTRRs */
{ MTRRfix4K_C0000_MSR, 8 }, /* eight 4k MTRRs */
{}
};
static unsigned long smp_changes_mask;
static struct mtrr_state mtrr_state = {};
static int mtrr_state_set;
u64 mtrr_tom2;
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "mtrr."
static int mtrr_show;
module_param_named(show, mtrr_show, bool, 0);
/*
* Returns the effective MTRR type for the region
* Error returns:
* - 0xFE - when the range is "not entirely covered" by _any_ var range MTRR
* - 0xFF - when MTRR is not enabled
*/
u8 mtrr_type_lookup(u64 start, u64 end)
{
int i;
u64 base, mask;
u8 prev_match, curr_match;
if (!mtrr_state_set)
return 0xFF;
if (!mtrr_state.enabled)
return 0xFF;
/* Make end inclusive end, instead of exclusive */
end--;
/* Look in fixed ranges. Just return the type as per start */
if (mtrr_state.have_fixed && (start < 0x100000)) {
int idx;
if (start < 0x80000) {
idx = 0;
idx += (start >> 16);
return mtrr_state.fixed_ranges[idx];
} else if (start < 0xC0000) {
idx = 1 * 8;
idx += ((start - 0x80000) >> 14);
return mtrr_state.fixed_ranges[idx];
} else if (start < 0x1000000) {
idx = 3 * 8;
idx += ((start - 0xC0000) >> 12);
return mtrr_state.fixed_ranges[idx];
}
}
/*
* Look in variable ranges
* Look of multiple ranges matching this address and pick type
* as per MTRR precedence
*/
if (!(mtrr_state.enabled & 2)) {
return mtrr_state.def_type;
}
prev_match = 0xFF;
for (i = 0; i < num_var_ranges; ++i) {
unsigned short start_state, end_state;
if (!(mtrr_state.var_ranges[i].mask_lo & (1 << 11)))
continue;
base = (((u64)mtrr_state.var_ranges[i].base_hi) << 32) +
(mtrr_state.var_ranges[i].base_lo & PAGE_MASK);
mask = (((u64)mtrr_state.var_ranges[i].mask_hi) << 32) +
(mtrr_state.var_ranges[i].mask_lo & PAGE_MASK);
start_state = ((start & mask) == (base & mask));
end_state = ((end & mask) == (base & mask));
if (start_state != end_state)
return 0xFE;
if ((start & mask) != (base & mask)) {
continue;
}
curr_match = mtrr_state.var_ranges[i].base_lo & 0xff;
if (prev_match == 0xFF) {
prev_match = curr_match;
continue;
}
if (prev_match == MTRR_TYPE_UNCACHABLE ||
curr_match == MTRR_TYPE_UNCACHABLE) {
return MTRR_TYPE_UNCACHABLE;
}
if ((prev_match == MTRR_TYPE_WRBACK &&
curr_match == MTRR_TYPE_WRTHROUGH) ||
(prev_match == MTRR_TYPE_WRTHROUGH &&
curr_match == MTRR_TYPE_WRBACK)) {
prev_match = MTRR_TYPE_WRTHROUGH;
curr_match = MTRR_TYPE_WRTHROUGH;
}
if (prev_match != curr_match) {
return MTRR_TYPE_UNCACHABLE;
}
}
if (mtrr_tom2) {
if (start >= (1ULL<<32) && (end < mtrr_tom2))
return MTRR_TYPE_WRBACK;
}
if (prev_match != 0xFF)
return prev_match;
return mtrr_state.def_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;
rdmsr(MTRRfix64K_00000_MSR, p[0], p[1]);
for (i = 0; i < 2; i++)
rdmsr(MTRRfix16K_80000_MSR + i, p[2 + i * 2], p[3 + i * 2]);
for (i = 0; i < 8; i++)
rdmsr(MTRRfix4K_C0000_MSR + i, p[6 + i * 2], p[7 + i * 2]);
}
void mtrr_save_fixed_ranges(void *info)
{
if (cpu_has_mtrr)
get_fixed_ranges(mtrr_state.fixed_ranges);
}
static void print_fixed(unsigned base, unsigned step, const mtrr_type*types)
{
unsigned i;
for (i = 0; i < 8; ++i, ++types, base += step)
printk(KERN_INFO "MTRR %05X-%05X %s\n",
base, base + step - 1, mtrr_attrib_to_str(*types));
}
static void prepare_set(void);
static void post_set(void);
/* Grab all of the MTRR state for this CPU into *state */
void __init get_mtrr_state(void)
{
unsigned int i;
struct mtrr_var_range *vrs;
unsigned lo, dummy;
unsigned long flags;
vrs = mtrr_state.var_ranges;
rdmsr(MTRRcap_MSR, lo, dummy);
mtrr_state.have_fixed = (lo >> 8) & 1;
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(MTRRdefType_MSR, lo, dummy);
mtrr_state.def_type = (lo & 0xff);
mtrr_state.enabled = (lo & 0xc00) >> 10;
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_show) {
int high_width;
printk(KERN_INFO "MTRR default type: %s\n", mtrr_attrib_to_str(mtrr_state.def_type));
if (mtrr_state.have_fixed) {
printk(KERN_INFO "MTRR fixed ranges %sabled:\n",
mtrr_state.enabled & 1 ? "en" : "dis");
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);
}
printk(KERN_INFO "MTRR variable ranges %sabled:\n",
mtrr_state.enabled & 2 ? "en" : "dis");
high_width = ((size_or_mask ? ffs(size_or_mask) - 1 : 32) - (32 - PAGE_SHIFT) + 3) / 4;
for (i = 0; i < num_var_ranges; ++i) {
if (mtrr_state.var_ranges[i].mask_lo & (1 << 11))
printk(KERN_INFO "MTRR %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 & 0xff));
else
printk(KERN_INFO "MTRR %u disabled\n", i);
}
if (mtrr_tom2) {
printk(KERN_INFO "TOM2: %016llx aka %lldM\n",
mtrr_tom2, mtrr_tom2>>20);
}
}
mtrr_state_set = 1;
/* PAT setup for BP. We need to go through sync steps here */
local_irq_save(flags);
prepare_set();
pat_init();
post_set();
local_irq_restore(flags);
}
/* Some BIOS's are fucked 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)
printk(KERN_WARNING "mtrr: your CPUs had inconsistent fixed MTRR settings\n");
if (mask & MTRR_CHANGE_MASK_VARIABLE)
printk(KERN_WARNING "mtrr: your CPUs had inconsistent variable MTRR settings\n");
if (mask & MTRR_CHANGE_MASK_DEFTYPE)
printk(KERN_WARNING "mtrr: your CPUs had inconsistent MTRRdefType settings\n");
printk(KERN_INFO "mtrr: probably your BIOS does not setup all CPUs.\n");
printk(KERN_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)
printk(KERN_ERR
"MTRR: CPU %u: Writing MSR %x to %x:%x failed\n",
smp_processor_id(), msr, a, b);
}
/**
* Enable and allow read/write of extended fixed-range MTRR bits on K8 CPUs
* see AMD publication no. 24593, chapter 3.2.1 for more information
*/
static inline void k8_enable_fixed_iorrs(void)
{
unsigned lo, hi;
rdmsr(MSR_K8_SYSCFG, lo, hi);
mtrr_wrmsr(MSR_K8_SYSCFG, lo
| K8_MTRRFIXRANGE_DRAM_ENABLE
| K8_MTRRFIXRANGE_DRAM_MODIFY, hi);
}
/**
* 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
*
* If K8 extentions are wanted, update the K8 SYSCFG MSR also.
* See AMD publication no. 24593, chapter 7.8.1, page 233 for more information.
*/
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]) {
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
(boot_cpu_data.x86 >= 0x0f && boot_cpu_data.x86 <= 0x11) &&
((msrwords[0] | msrwords[1]) & K8_MTRR_RDMEM_WRMEM_MASK))
k8_enable_fixed_iorrs();
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)
{
int i, max;
mtrr_type ltype;
unsigned long lbase, lsize;
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, <ype);
if (lsize == 0)
return i;
}
return -ENOSPC;
}
static void generic_get_mtrr(unsigned int reg, unsigned long *base,
unsigned long *size, mtrr_type *type)
{
unsigned int mask_lo, mask_hi, base_lo, base_hi;
unsigned int tmp, hi;
rdmsr(MTRRphysMask_MSR(reg), mask_lo, mask_hi);
if ((mask_lo & 0x800) == 0) {
/* Invalid (i.e. free) range */
*base = 0;
*size = 0;
*type = 0;
return;
}
rdmsr(MTRRphysBase_MSR(reg), base_lo, base_hi);
/* Work out the shifted address mask. */
tmp = mask_hi << (32 - PAGE_SHIFT) | mask_lo >> PAGE_SHIFT;
mask_lo = size_or_mask | tmp;
/* Expand tmp with high bits to all 1s*/
hi = fls(tmp);
if (hi > 0) {
tmp |= ~((1<<(hi - 1)) - 1);
if (tmp != mask_lo) {
WARN_ONCE(1, KERN_INFO "mtrr: your BIOS has set up an incorrect mask, fixing it up.\n");
mask_lo = tmp;
}
}
/* This works correctly if size is a power of two, i.e. a
contiguous range. */
*size = -mask_lo;
*base = base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
*type = base_lo & 0xff;
}
/**
* 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;
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 & 0xfffff0ffUL) != (lo & 0xfffff0ffUL)
|| (vr->base_hi & (size_and_mask >> (32 - PAGE_SHIFT))) !=
(hi & (size_and_mask >> (32 - PAGE_SHIFT)))) {
mtrr_wrmsr(MTRRphysBase_MSR(index), vr->base_lo, vr->base_hi);
changed = true;
}
rdmsr(MTRRphysMask_MSR(index), lo, hi);
if ((vr->mask_lo & 0xfffff800UL) != (lo & 0xfffff800UL)
|| (vr->mask_hi & (size_and_mask >> (32 - PAGE_SHIFT))) !=
(hi & (size_and_mask >> (32 - PAGE_SHIFT)))) {
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.
* RETURNS: 0 if no changes made, else a mask indicating what was changed.
*/
static unsigned long set_mtrr_state(void)
{
unsigned int i;
unsigned long change_mask = 0;
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 & 0xff) != mtrr_state.def_type
|| ((deftype_lo & 0xc00) >> 10) != mtrr_state.enabled) {
deftype_lo = (deftype_lo & ~0xcff) | mtrr_state.def_type | (mtrr_state.enabled << 10);
change_mask |= MTRR_CHANGE_MASK_DEFTYPE;
}
return change_mask;
}
static unsigned long cr4 = 0;
static DEFINE_SPINLOCK(set_atomicity_lock);
/*
* Since we are disabling the cache don't allow any interrupts - they
* would run extremely slow and would only increase the pain. The caller must
* ensure that local interrupts are disabled and are reenabled after post_set()
* has been called.
*/
static void prepare_set(void) __acquires(set_atomicity_lock)
{
unsigned long cr0;
/* Note that this is not ideal, since the cache is only flushed/disabled
for this CPU while the MTRRs are changed, but changing this requires
more invasive changes to the way the kernel boots */
spin_lock(&set_atomicity_lock);
/* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */
cr0 = read_cr0() | X86_CR0_CD;
write_cr0(cr0);
wbinvd();
/* Save value of CR4 and clear Page Global Enable (bit 7) */
if ( cpu_has_pge ) {
cr4 = read_cr4();
write_cr4(cr4 & ~X86_CR4_PGE);
}
/* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
__flush_tlb();
/* Save MTRR state */
rdmsr(MTRRdefType_MSR, deftype_lo, deftype_hi);
/* Disable MTRRs, and set the default type to uncached */
mtrr_wrmsr(MTRRdefType_MSR, deftype_lo & ~0xcff, deftype_hi);
}
static void post_set(void) __releases(set_atomicity_lock)
{
/* Flush TLBs (no need to flush caches - they are disabled) */
__flush_tlb();
/* Intel (P6) standard MTRRs */
mtrr_wrmsr(MTRRdefType_MSR, deftype_lo, deftype_hi);
/* Enable caches */
write_cr0(read_cr0() & 0xbfffffff);
/* Restore value of CR4 */
if ( cpu_has_pge )
write_cr4(cr4);
spin_unlock(&set_atomicity_lock);
}
static void generic_set_all(void)
{
unsigned long mask, count;
unsigned long flags;
local_irq_save(flags);
prepare_set();
/* Actually set the state */
mask = set_mtrr_state();
/* also set PAT */
pat_init();
post_set();
local_irq_restore(flags);
/* 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;
}
}
static void generic_set_mtrr(unsigned int reg, unsigned long base,
unsigned long size, mtrr_type type)
/* [SUMMARY] 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.
*/
{
unsigned long flags;
struct mtrr_var_range *vr;
vr = &mtrr_state.var_ranges[reg];
local_irq_save(flags);
prepare_set();
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 & size_and_mask) >> (32 - PAGE_SHIFT);
vr->mask_lo = -size << PAGE_SHIFT | 0x800;
vr->mask_hi = (-size & size_and_mask) >> (32 - PAGE_SHIFT);
mtrr_wrmsr(MTRRphysBase_MSR(reg), vr->base_lo, vr->base_hi);
mtrr_wrmsr(MTRRphysMask_MSR(reg), vr->mask_lo, vr->mask_hi);
}
post_set();
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 (is_cpu(INTEL) && boot_cpu_data.x86 == 6 &&
boot_cpu_data.x86_model == 1 &&
boot_cpu_data.x86_mask <= 7) {
if (base & ((1 << (22 - PAGE_SHIFT)) - 1)) {
printk(KERN_WARNING "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)) {
printk(KERN_WARNING "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) {
printk(KERN_WARNING "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(MTRRcap_MSR, config, dummy);
return (config & (1 << 10));
}
int positive_have_wrcomb(void)
{
return 1;
}
/* generic structure...
*/
struct mtrr_ops generic_mtrr_ops = {
.use_intel_if = 1,
.set_all = generic_set_all,
.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,
};