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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2008-04-26 11:32:12 -0700
committerIngo Molnar <mingo@elte.hu>2008-04-26 21:28:29 +0200
commit0124cecfc85a6664b1ad5f1d28cf0ab8df66fc42 (patch)
treedfbbb8cf4a294ed52dc9a224ccb57ea601d25532
parent4a27214d7be31e122db4102166f49ec15958e8e9 (diff)
x86, PAT: disable /dev/mem mmap RAM with PAT
disable /dev/mem mmap of RAM with PAT. It makes things safer and eliminates aliasing. A future improvement would be to avoid the range_is_allowed duplication. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/mm/pat.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 9851265e4d6..e7ca7fc48d1 100644
--- 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>
@@ -477,6 +478,33 @@ 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)
{
@@ -485,6 +513,9 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
unsigned long ret_flags;
int retval;
+ if (!range_is_allowed(pfn, size))
+ return 0;
+
if (file->f_flags & O_SYNC) {
flags = _PAGE_CACHE_UC;
}