/* 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 <asm/io.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
#include <asm/system.h>
#include <asm/cpufeature.h>
#include <asm/tlbflush.h>
#include "mtrr.h"
struct mtrr_state {
struct mtrr_var_range *var_ranges;
mtrr_type fixed_ranges[NUM_FIXED_RANGES];
unsigned char enabled;
mtrr_type def_type;
};
static unsigned long smp_changes_mask;
static struct mtrr_state mtrr_state = {};
/* Get the MSR pair relating to a var range */
static void __init
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);
}
static void __init
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]);
}
/* 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;
if (!mtrr_state.var_ranges) {
mtrr_state.var_ranges = kmalloc(num_var_ranges * sizeof (struct mtrr_var_range),
GFP_KERNEL);
if (!mtrr_state.var_ranges)
return;
}
vrs = mtrr_state.var_ranges;
for (i = 0; i < num_var_ranges; i++)
get_mtrr_var_range(i, &vrs[i]);
get_fixed_ranges(mtrr_state.fixed_ranges);
rdmsr(MTRRdefType_MSR, lo, dummy);
mtrr_state.def_type = (lo & 0xff);
mtrr_state.enabled = (lo & 0xc00) >> 10;
}
/* 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);
}
int generic_get_free_region(unsigned long base, unsigned long size)
/* [SUMMARY] Get a free MTRR.
<base> The starting (base) address of the region.
<size> The size (in bytes) of the region.
[RETURNS] The index of the region on success, else -1 on error.
*/
{
int i, max;
mtrr_type ltype;
unsigned long lbase;
unsigned lsize;
max = num_var_ranges;
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 int *size, mtrr_type * type)
{
unsigned int mask_lo, mask_hi, base_lo, base_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. */
mask_lo = size_or_mask | mask_hi << (32 - PAGE_SHIFT)
| mask_lo >> PAGE_SHIFT;
/* 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;
}
static int set_fixed_ranges(mtrr_type * frs)
{
unsigned int *p = (unsigned int *) frs;
int changed = FALSE;
int i;
unsigned int lo, hi;
rdmsr(MTRRfix64K_00000_MSR, lo, hi);
if (p[0] != lo || p[1] != hi) {
mtrr_wrmsr(MTRRfix64K_00000_MSR, p[0], p[1]);
changed = TRUE;
}
for (i = 0; i < 2; i++) {
rdmsr(MTRRfix16K_80000_MSR + i, lo, hi);
if (p[2 + i * 2] != lo || p[3 + i * 2] != hi) {
mtrr_wrmsr(MTRRfix16K_80000_MSR + i, p[2 + i * 2],
p[3 + i * 2]);
changed = TRUE;
}
}
for (i = 0; i < 8; i++) {
rdmsr(MTRRfix4K_C0000_MSR + i, lo, hi);
if (p[6 + i * 2] != lo || p[7 + i * 2] != hi) {
mtrr_wrmsr(MTRRfix4K_C0000_MSR + i, p[6 + i * 2],
p[7 + i * 2]);
changed = TRUE;
}
}
return changed;
}
/* Set the MSR pair relating to a var range. Returns TRUE if
changes are made */
static int set_mtrr_var_ranges(unsigned int index, struct mtrr_var_range *vr)
{
unsigned int lo, hi;
int 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 unsigned long set_mtrr_state(u32 deftype_lo, u32 deftype_hi)
/* [SUMMARY] Set the MTRR state for this CPU.
<state> The MTRR state information to read.
<ctxt> Some relevant CPU context.
[NOTE] The CPU must already be in a safe state for MTRR changes.
[RETURNS] 0 if no changes made, else a mask indication what was changed.
*/
{
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 (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 |= (mtrr_state.def_type | mtrr_state.enabled << 10);
change_mask |= MTRR_CHANGE_MASK_DEFTYPE;
}
return change_mask;
}
static unsigned long cr4 = 0;
static u32 deftype_lo, deftype_hi;
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() | 0x40000000; /* set CD flag */
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 & 0xf300UL, 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(deftype_lo,deftype_hi);
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.
<do_safe> If TRUE, do the change safely. If FALSE, safety measures should
be done externally.
[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 < 0x70000000 || base > 0x7003FFFF) &&
(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;
}
}
if (base + size < 0x100) {
printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
base, size);
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,
};
