492 lines
12 KiB
C
492 lines
12 KiB
C
/*
|
|
* Handle caching attributes in page tables (PAT)
|
|
*
|
|
* Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
|
|
* Suresh B Siddha <suresh.b.siddha@intel.com>
|
|
*
|
|
* Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen.
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/bootmem.h>
|
|
|
|
#include <asm/msr.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/page.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/pat.h>
|
|
#include <asm/e820.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/fcntl.h>
|
|
#include <asm/mtrr.h>
|
|
#include <asm/io.h>
|
|
|
|
#ifdef CONFIG_X86_PAT
|
|
int __read_mostly pat_enabled = 1;
|
|
|
|
void __cpuinit pat_disable(char *reason)
|
|
{
|
|
pat_enabled = 0;
|
|
printk(KERN_INFO "%s\n", reason);
|
|
}
|
|
|
|
static int __init nopat(char *str)
|
|
{
|
|
pat_disable("PAT support disabled.");
|
|
return 0;
|
|
}
|
|
early_param("nopat", nopat);
|
|
#endif
|
|
|
|
|
|
static int debug_enable;
|
|
static int __init pat_debug_setup(char *str)
|
|
{
|
|
debug_enable = 1;
|
|
return 0;
|
|
}
|
|
__setup("debugpat", pat_debug_setup);
|
|
|
|
#define dprintk(fmt, arg...) \
|
|
do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
|
|
|
|
|
|
static u64 __read_mostly boot_pat_state;
|
|
|
|
enum {
|
|
PAT_UC = 0, /* uncached */
|
|
PAT_WC = 1, /* Write combining */
|
|
PAT_WT = 4, /* Write Through */
|
|
PAT_WP = 5, /* Write Protected */
|
|
PAT_WB = 6, /* Write Back (default) */
|
|
PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
|
|
};
|
|
|
|
#define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
|
|
|
|
void pat_init(void)
|
|
{
|
|
u64 pat;
|
|
|
|
if (!pat_enabled)
|
|
return;
|
|
|
|
/* Paranoia check. */
|
|
if (!cpu_has_pat && boot_pat_state) {
|
|
/*
|
|
* If this happens we are on a secondary CPU, but
|
|
* switched to PAT on the boot CPU. We have no way to
|
|
* undo PAT.
|
|
*/
|
|
printk(KERN_ERR "PAT enabled, "
|
|
"but not supported by secondary CPU\n");
|
|
BUG();
|
|
}
|
|
|
|
/* Set PWT to Write-Combining. All other bits stay the same */
|
|
/*
|
|
* PTE encoding used in Linux:
|
|
* PAT
|
|
* |PCD
|
|
* ||PWT
|
|
* |||
|
|
* 000 WB _PAGE_CACHE_WB
|
|
* 001 WC _PAGE_CACHE_WC
|
|
* 010 UC- _PAGE_CACHE_UC_MINUS
|
|
* 011 UC _PAGE_CACHE_UC
|
|
* PAT bit unused
|
|
*/
|
|
pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
|
|
PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
|
|
|
|
/* Boot CPU check */
|
|
if (!boot_pat_state)
|
|
rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
|
|
|
|
wrmsrl(MSR_IA32_CR_PAT, pat);
|
|
printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
|
|
smp_processor_id(), boot_pat_state, pat);
|
|
}
|
|
|
|
#undef PAT
|
|
|
|
static char *cattr_name(unsigned long flags)
|
|
{
|
|
switch (flags & _PAGE_CACHE_MASK) {
|
|
case _PAGE_CACHE_UC: return "uncached";
|
|
case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
|
|
case _PAGE_CACHE_WB: return "write-back";
|
|
case _PAGE_CACHE_WC: return "write-combining";
|
|
default: return "broken";
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The global memtype list keeps track of memory type for specific
|
|
* physical memory areas. Conflicting memory types in different
|
|
* mappings can cause CPU cache corruption. To avoid this we keep track.
|
|
*
|
|
* The list is sorted based on starting address and can contain multiple
|
|
* entries for each address (this allows reference counting for overlapping
|
|
* areas). All the aliases have the same cache attributes of course.
|
|
* Zero attributes are represented as holes.
|
|
*
|
|
* Currently the data structure is a list because the number of mappings
|
|
* are expected to be relatively small. If this should be a problem
|
|
* it could be changed to a rbtree or similar.
|
|
*
|
|
* memtype_lock protects the whole list.
|
|
*/
|
|
|
|
struct memtype {
|
|
u64 start;
|
|
u64 end;
|
|
unsigned long type;
|
|
struct list_head nd;
|
|
};
|
|
|
|
static LIST_HEAD(memtype_list);
|
|
static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
|
|
|
|
/*
|
|
* Does intersection of PAT memory type and MTRR memory type and returns
|
|
* the resulting memory type as PAT understands it.
|
|
* (Type in pat and mtrr will not have same value)
|
|
* The intersection is based on "Effective Memory Type" tables in IA-32
|
|
* SDM vol 3a
|
|
*/
|
|
static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
|
|
{
|
|
/*
|
|
* Look for MTRR hint to get the effective type in case where PAT
|
|
* request is for WB.
|
|
*/
|
|
if (req_type == _PAGE_CACHE_WB) {
|
|
u8 mtrr_type;
|
|
|
|
mtrr_type = mtrr_type_lookup(start, end);
|
|
if (mtrr_type == MTRR_TYPE_UNCACHABLE)
|
|
return _PAGE_CACHE_UC;
|
|
if (mtrr_type == MTRR_TYPE_WRCOMB)
|
|
return _PAGE_CACHE_WC;
|
|
}
|
|
|
|
return req_type;
|
|
}
|
|
|
|
static int chk_conflict(struct memtype *new, struct memtype *entry,
|
|
unsigned long *type)
|
|
{
|
|
if (new->type != entry->type) {
|
|
if (type) {
|
|
new->type = entry->type;
|
|
*type = entry->type;
|
|
} else
|
|
goto conflict;
|
|
}
|
|
|
|
/* check overlaps with more than one entry in the list */
|
|
list_for_each_entry_continue(entry, &memtype_list, nd) {
|
|
if (new->end <= entry->start)
|
|
break;
|
|
else if (new->type != entry->type)
|
|
goto conflict;
|
|
}
|
|
return 0;
|
|
|
|
conflict:
|
|
printk(KERN_INFO "%s:%d conflicting memory types "
|
|
"%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
|
|
new->end, cattr_name(new->type), cattr_name(entry->type));
|
|
return -EBUSY;
|
|
}
|
|
|
|
/*
|
|
* req_type typically has one of the:
|
|
* - _PAGE_CACHE_WB
|
|
* - _PAGE_CACHE_WC
|
|
* - _PAGE_CACHE_UC_MINUS
|
|
* - _PAGE_CACHE_UC
|
|
*
|
|
* req_type will have a special case value '-1', when requester want to inherit
|
|
* the memory type from mtrr (if WB), existing PAT, defaulting to UC_MINUS.
|
|
*
|
|
* If new_type is NULL, function will return an error if it cannot reserve the
|
|
* region with req_type. If new_type is non-NULL, function will return
|
|
* available type in new_type in case of no error. In case of any error
|
|
* it will return a negative return value.
|
|
*/
|
|
int reserve_memtype(u64 start, u64 end, unsigned long req_type,
|
|
unsigned long *new_type)
|
|
{
|
|
struct memtype *new, *entry;
|
|
unsigned long actual_type;
|
|
struct list_head *where;
|
|
int err = 0;
|
|
|
|
BUG_ON(start >= end); /* end is exclusive */
|
|
|
|
if (!pat_enabled) {
|
|
/* This is identical to page table setting without PAT */
|
|
if (new_type) {
|
|
if (req_type == -1)
|
|
*new_type = _PAGE_CACHE_WB;
|
|
else
|
|
*new_type = req_type & _PAGE_CACHE_MASK;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Low ISA region is always mapped WB in page table. No need to track */
|
|
if (is_ISA_range(start, end - 1)) {
|
|
if (new_type)
|
|
*new_type = _PAGE_CACHE_WB;
|
|
return 0;
|
|
}
|
|
|
|
if (req_type == -1) {
|
|
/*
|
|
* Call mtrr_lookup to get the type hint. This is an
|
|
* optimization for /dev/mem mmap'ers into WB memory (BIOS
|
|
* tools and ACPI tools). Use WB request for WB memory and use
|
|
* UC_MINUS otherwise.
|
|
*/
|
|
u8 mtrr_type = mtrr_type_lookup(start, end);
|
|
|
|
if (mtrr_type == MTRR_TYPE_WRBACK)
|
|
actual_type = _PAGE_CACHE_WB;
|
|
else
|
|
actual_type = _PAGE_CACHE_UC_MINUS;
|
|
} else
|
|
actual_type = pat_x_mtrr_type(start, end,
|
|
req_type & _PAGE_CACHE_MASK);
|
|
|
|
new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
new->start = start;
|
|
new->end = end;
|
|
new->type = actual_type;
|
|
|
|
if (new_type)
|
|
*new_type = actual_type;
|
|
|
|
spin_lock(&memtype_lock);
|
|
|
|
/* Search for existing mapping that overlaps the current range */
|
|
where = NULL;
|
|
list_for_each_entry(entry, &memtype_list, nd) {
|
|
if (end <= entry->start) {
|
|
where = entry->nd.prev;
|
|
break;
|
|
} else if (start <= entry->start) { /* end > entry->start */
|
|
err = chk_conflict(new, entry, new_type);
|
|
if (!err) {
|
|
dprintk("Overlap at 0x%Lx-0x%Lx\n",
|
|
entry->start, entry->end);
|
|
where = entry->nd.prev;
|
|
}
|
|
break;
|
|
} else if (start < entry->end) { /* start > entry->start */
|
|
err = chk_conflict(new, entry, new_type);
|
|
if (!err) {
|
|
dprintk("Overlap at 0x%Lx-0x%Lx\n",
|
|
entry->start, entry->end);
|
|
where = &entry->nd;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (err) {
|
|
printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
|
|
"track %s, req %s\n",
|
|
start, end, cattr_name(new->type), cattr_name(req_type));
|
|
kfree(new);
|
|
spin_unlock(&memtype_lock);
|
|
return err;
|
|
}
|
|
|
|
if (where)
|
|
list_add(&new->nd, where);
|
|
else
|
|
list_add_tail(&new->nd, &memtype_list);
|
|
|
|
spin_unlock(&memtype_lock);
|
|
|
|
dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
|
|
start, end, cattr_name(new->type), cattr_name(req_type),
|
|
new_type ? cattr_name(*new_type) : "-");
|
|
|
|
return err;
|
|
}
|
|
|
|
int free_memtype(u64 start, u64 end)
|
|
{
|
|
struct memtype *entry;
|
|
int err = -EINVAL;
|
|
|
|
if (!pat_enabled)
|
|
return 0;
|
|
|
|
/* Low ISA region is always mapped WB. No need to track */
|
|
if (is_ISA_range(start, end - 1))
|
|
return 0;
|
|
|
|
spin_lock(&memtype_lock);
|
|
list_for_each_entry(entry, &memtype_list, nd) {
|
|
if (entry->start == start && entry->end == end) {
|
|
list_del(&entry->nd);
|
|
kfree(entry);
|
|
err = 0;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&memtype_lock);
|
|
|
|
if (err) {
|
|
printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
|
|
current->comm, current->pid, start, end);
|
|
}
|
|
|
|
dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
|
|
return err;
|
|
}
|
|
|
|
|
|
/*
|
|
* /dev/mem mmap interface. The memtype used for mapping varies:
|
|
* - Use UC for mappings with O_SYNC flag
|
|
* - Without O_SYNC flag, if there is any conflict in reserve_memtype,
|
|
* inherit the memtype from existing mapping.
|
|
* - Else use UC_MINUS memtype (for backward compatibility with existing
|
|
* X drivers.
|
|
*/
|
|
pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
|
|
unsigned long size, pgprot_t vma_prot)
|
|
{
|
|
return vma_prot;
|
|
}
|
|
|
|
#ifndef CONFIG_PROMISC_DEVMEM
|
|
/* This check is done in drivers/char/mem.c in case of !PROMISC_DEVMEM*/
|
|
static inline int range_is_allowed(unsigned long pfn, unsigned long size)
|
|
{
|
|
return 1;
|
|
}
|
|
#else
|
|
static inline int range_is_allowed(unsigned long pfn, unsigned long size)
|
|
{
|
|
u64 from = ((u64)pfn) << PAGE_SHIFT;
|
|
u64 to = from + size;
|
|
u64 cursor = from;
|
|
|
|
while (cursor < to) {
|
|
if (!devmem_is_allowed(pfn)) {
|
|
printk(KERN_INFO
|
|
"Program %s tried to access /dev/mem between %Lx->%Lx.\n",
|
|
current->comm, from, to);
|
|
return 0;
|
|
}
|
|
cursor += PAGE_SIZE;
|
|
pfn++;
|
|
}
|
|
return 1;
|
|
}
|
|
#endif /* CONFIG_PROMISC_DEVMEM */
|
|
|
|
int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
|
|
unsigned long size, pgprot_t *vma_prot)
|
|
{
|
|
u64 offset = ((u64) pfn) << PAGE_SHIFT;
|
|
unsigned long flags = _PAGE_CACHE_UC_MINUS;
|
|
int retval;
|
|
|
|
if (!range_is_allowed(pfn, size))
|
|
return 0;
|
|
|
|
if (file->f_flags & O_SYNC) {
|
|
flags = _PAGE_CACHE_UC;
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
/*
|
|
* On the PPro and successors, the MTRRs are used to set
|
|
* memory types for physical addresses outside main memory,
|
|
* so blindly setting UC or PWT on those pages is wrong.
|
|
* For Pentiums and earlier, the surround logic should disable
|
|
* caching for the high addresses through the KEN pin, but
|
|
* we maintain the tradition of paranoia in this code.
|
|
*/
|
|
if (!pat_enabled &&
|
|
!(boot_cpu_has(X86_FEATURE_MTRR) ||
|
|
boot_cpu_has(X86_FEATURE_K6_MTRR) ||
|
|
boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
|
|
boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
|
|
(pfn << PAGE_SHIFT) >= __pa(high_memory)) {
|
|
flags = _PAGE_CACHE_UC;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* With O_SYNC, we can only take UC mapping. Fail if we cannot.
|
|
* Without O_SYNC, we want to get
|
|
* - WB for WB-able memory and no other conflicting mappings
|
|
* - UC_MINUS for non-WB-able memory with no other conflicting mappings
|
|
* - Inherit from confliting mappings otherwise
|
|
*/
|
|
if (flags != _PAGE_CACHE_UC_MINUS) {
|
|
retval = reserve_memtype(offset, offset + size, flags, NULL);
|
|
} else {
|
|
retval = reserve_memtype(offset, offset + size, -1, &flags);
|
|
}
|
|
|
|
if (retval < 0)
|
|
return 0;
|
|
|
|
if (((pfn < max_low_pfn_mapped) ||
|
|
(pfn >= (1UL<<(32 - PAGE_SHIFT)) && pfn < max_pfn_mapped)) &&
|
|
ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
|
|
free_memtype(offset, offset + size);
|
|
printk(KERN_INFO
|
|
"%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
|
|
current->comm, current->pid,
|
|
cattr_name(flags),
|
|
offset, (unsigned long long)(offset + size));
|
|
return 0;
|
|
}
|
|
|
|
*vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
|
|
flags);
|
|
return 1;
|
|
}
|
|
|
|
void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
|
|
{
|
|
u64 addr = (u64)pfn << PAGE_SHIFT;
|
|
unsigned long flags;
|
|
unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
|
|
|
|
reserve_memtype(addr, addr + size, want_flags, &flags);
|
|
if (flags != want_flags) {
|
|
printk(KERN_INFO
|
|
"%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n",
|
|
current->comm, current->pid,
|
|
cattr_name(want_flags),
|
|
addr, (unsigned long long)(addr + size),
|
|
cattr_name(flags));
|
|
}
|
|
}
|
|
|
|
void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
|
|
{
|
|
u64 addr = (u64)pfn << PAGE_SHIFT;
|
|
|
|
free_memtype(addr, addr + size);
|
|
}
|