Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux...

[deliverable/linux.git] / arch / x86 / mm / pat.c

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index ef8b64b89c7d27447aefe7a4b68a7e8748b42b25..60adbe22efa0d66e3885cbb39ed5f65c521a8fde 100644 (file)
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -16,6 +16,7 @@
 #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>
@@ -24,31 +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 __init 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 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 */
@@ -65,17 +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 */
        /*
@@ -94,9 +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",
@@ -334,7 +329,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
                                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);
@@ -386,8 +381,8 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
                                break;
                        }
 
-                       printk(KERN_INFO "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;
@@ -477,14 +472,43 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
        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;
-       unsigned long ret_flags;
        int retval;
 
+       if (!range_is_allowed(pfn, size))
+               return 0;
+
        if (file->f_flags & O_SYNC) {
                flags = _PAGE_CACHE_UC;
        }
@@ -518,14 +542,12 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
        if (flags != _PAGE_CACHE_UC_MINUS) {
                retval = reserve_memtype(offset, offset + size, flags, NULL);
        } else {
-               retval = reserve_memtype(offset, offset + size, -1, &ret_flags);
+               retval = reserve_memtype(offset, offset + size, -1, &flags);
        }
 
        if (retval < 0)
                return 0;
 
-       flags = ret_flags;
-
        if (pfn <= max_pfn_mapped &&
             ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
                free_memtype(offset, offset + size);