Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 48 insertions, 55 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 277446cd30b6..06b7a1c90fb8 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -25,31 +25,24 @@
 #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 */
@@ -66,17 +59,19 @@ void pat_init(void)
 {
         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 */
         /*
@@ -95,9 +90,8 @@ void pat_init(void)
               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",
@@ -157,32 +151,33 @@ static int pat_x_mtrr_type(u64 start, u64 end, unsigned long prot,
         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;
@@ -239,14 +234,12 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
 
         if (req_type == -1) {
                 /*
-                 * Special case where caller wants to inherit from mtrr or
-                 * existing pat mapping, defaulting to UC_MINUS in case of
-                 * no match.
+                 * 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 == 0xFE) { /* MTRR match error */
-                        err = -1;
-                }
 
                 if (mtrr_type == MTRR_TYPE_WRBACK) {
                         req_type = _PAGE_CACHE_WB;
@@ -561,7 +554,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
                 "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
                         current->comm, current->pid,
                         cattr_name(flags),
-                        offset, offset + size);
+                        offset, (unsigned long long)(offset + size));
                 return 0;
         }
 
@@ -582,7 +575,7 @@ void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
                 "%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n",
                         current->comm, current->pid,
                         cattr_name(want_flags),
-                        addr, addr + size,
+                        addr, (unsigned long long)(addr + size),
                         cattr_name(flags));
         }
 }