#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>
-int pat_wc_enabled = 1;
+#ifdef CONFIG_X86_PAT
+int __read_mostly pat_wc_enabled = 1;
-static u64 __read_mostly boot_pat_state;
-
-static int nopat(char *str)
+void __cpuinit pat_disable(char *reason)
{
pat_wc_enabled = 0;
- printk(KERN_INFO "x86: PAT support disabled.\n");
-
- return 0;
+ printk(KERN_INFO "%s\n", reason);
}
-early_param("nopat", nopat);
-static int pat_known_cpu(void)
+static int __init nopat(char *str)
{
- if (!pat_wc_enabled)
- return 0;
-
- if (cpu_has_pat)
- return 1;
-
- pat_wc_enabled = 0;
- printk(KERN_INFO "CPU and/or kernel does not support PAT.\n");
+ pat_disable("PAT support disabled.");
return 0;
}
+early_param("nopat", nopat);
+#endif
+
+static u64 __read_mostly boot_pat_state;
enum {
PAT_UC = 0, /* uncached */
{
u64 pat;
-#ifndef CONFIG_X86_PAT
- nopat(NULL);
-#endif
-
- /* Boot CPU enables PAT based on CPU feature */
- if (!smp_processor_id() && !pat_known_cpu())
+ if (!pat_wc_enabled)
return;
- /* APs enable PAT iff boot CPU has enabled it before */
- if (smp_processor_id() && !pat_wc_enabled)
- return;
+ /* Paranoia check. */
+ if (!cpu_has_pat) {
+ printk(KERN_ERR "PAT enabled, but CPU feature cleared\n");
+ /*
+ * Panic if this happens on the secondary CPU, and we
+ * switched to PAT on the boot CPU. We have no way to
+ * undo PAT.
+ */
+ BUG_ON(boot_pat_state);
+ }
/* Set PWT to Write-Combining. All other bits stay the same */
/*
PAT(4,WB) | PAT(5,WC) | PAT(6,UC_MINUS) | PAT(7,UC);
/* Boot CPU check */
- if (!smp_processor_id()) {
+ 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",
unsigned long pat_type;
u8 mtrr_type;
- mtrr_type = mtrr_type_lookup(start, end);
- if (mtrr_type == 0xFF) { /* MTRR not enabled */
- *ret_prot = prot;
- return 0;
- }
- if (mtrr_type == 0xFE) { /* MTRR match error */
- *ret_prot = _PAGE_CACHE_UC;
- return -1;
- }
- if (mtrr_type != MTRR_TYPE_UNCACHABLE &&
- mtrr_type != MTRR_TYPE_WRBACK &&
- mtrr_type != MTRR_TYPE_WRCOMB) { /* MTRR type unhandled */
- *ret_prot = _PAGE_CACHE_UC;
- return -1;
- }
-
pat_type = prot & _PAGE_CACHE_MASK;
prot &= (~_PAGE_CACHE_MASK);
- /* Currently doing intersection by hand. Optimize it later. */
+ /*
+ * We return the PAT request directly for types where PAT takes
+ * precedence with respect to MTRR and for UC_MINUS.
+ * Consistency checks with other PAT requests is done later
+ * while going through memtype list.
+ */
if (pat_type == _PAGE_CACHE_WC) {
*ret_prot = prot | _PAGE_CACHE_WC;
+ return 0;
} else if (pat_type == _PAGE_CACHE_UC_MINUS) {
*ret_prot = prot | _PAGE_CACHE_UC_MINUS;
- } else if (pat_type == _PAGE_CACHE_UC ||
- mtrr_type == MTRR_TYPE_UNCACHABLE) {
+ return 0;
+ } else if (pat_type == _PAGE_CACHE_UC) {
+ *ret_prot = prot | _PAGE_CACHE_UC;
+ return 0;
+ }
+
+ /*
+ * Look for MTRR hint to get the effective type in case where PAT
+ * request is for WB.
+ */
+ mtrr_type = mtrr_type_lookup(start, end);
+
+ if (mtrr_type == MTRR_TYPE_UNCACHABLE) {
*ret_prot = prot | _PAGE_CACHE_UC;
} else if (mtrr_type == MTRR_TYPE_WRCOMB) {
*ret_prot = prot | _PAGE_CACHE_WC;
return 0;
}
+/*
+ * 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 ret_type is NULL, function will return an error if it cannot reserve the
+ * region with req_type. If ret_type is non-null, function will return
+ * available type in ret_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 *ret_type)
{
/* Only track when pat_wc_enabled */
if (!pat_wc_enabled) {
- if (ret_type)
- *ret_type = req_type;
-
+ /* This is identical to page table setting without PAT */
+ if (ret_type) {
+ if (req_type == -1) {
+ *ret_type = _PAGE_CACHE_WB;
+ } else {
+ *ret_type = req_type;
+ }
+ }
return 0;
}
return 0;
}
- req_type &= _PAGE_CACHE_MASK;
- err = pat_x_mtrr_type(start, end, req_type, &actual_type);
+ 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) {
+ req_type = _PAGE_CACHE_WB;
+ actual_type = _PAGE_CACHE_WB;
+ } else {
+ req_type = _PAGE_CACHE_UC_MINUS;
+ actual_type = _PAGE_CACHE_UC_MINUS;
+ }
+ } else {
+ req_type &= _PAGE_CACHE_MASK;
+ err = pat_x_mtrr_type(start, end, req_type, &actual_type);
+ }
+
if (err) {
if (ret_type)
*ret_type = actual_type;
struct memtype *saved_ptr;
if (parse->start >= end) {
- printk("New Entry\n");
+ pr_debug("New Entry\n");
list_add(&new_entry->nd, parse->nd.prev);
new_entry = NULL;
break;
break;
}
- printk("Overlap at 0x%Lx-0x%Lx\n",
+ pr_debug("Overlap at 0x%Lx-0x%Lx\n",
saved_ptr->start, saved_ptr->end);
/* No conflict. Go ahead and add this new entry */
list_add(&new_entry->nd, saved_ptr->nd.prev);
break;
}
- printk("Overlap at 0x%Lx-0x%Lx\n",
- saved_ptr->start, saved_ptr->end);
+ pr_debug(KERN_INFO "Overlap at 0x%Lx-0x%Lx\n",
+ saved_ptr->start, saved_ptr->end);
/* No conflict. Go ahead and add this new entry */
list_add(&new_entry->nd, &saved_ptr->nd);
new_entry = NULL;
}
if (err) {
- printk(
+ printk(KERN_INFO
"reserve_memtype failed 0x%Lx-0x%Lx, track %s, req %s\n",
start, end, cattr_name(new_entry->type),
cattr_name(req_type));
if (new_entry) {
/* No conflict. Not yet added to the list. Add to the tail */
list_add_tail(&new_entry->nd, &memtype_list);
- printk("New Entry\n");
- }
+ pr_debug("New Entry\n");
+ }
if (ret_type) {
- printk(
+ pr_debug(
"reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
start, end, cattr_name(actual_type),
cattr_name(req_type), cattr_name(*ret_type));
} else {
- printk(
+ pr_debug(
"reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s\n",
start, end, cattr_name(actual_type),
cattr_name(req_type));
spin_unlock(&memtype_lock);
if (err) {
- printk(KERN_DEBUG "%s:%d freeing invalid memtype %Lx-%Lx\n",
+ printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
current->comm, current->pid, start, end);
}
- printk( "free_memtype request 0x%Lx-0x%Lx\n", start, end);
+ pr_debug("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;
+}
+
+#ifdef CONFIG_NONPROMISC_DEVMEM
+/* This check is done in drivers/char/mem.c in case of NONPROMISC_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_NONPROMISC_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_wc_enabled &&
+ ! ( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability)) &&
+ (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_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);
+}
+