1 files changed, 101 insertions, 32 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 20070b7c573d..e83623ead441 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -41,36 +41,7 @@
  */
 static inline int uncached_access(struct file *file, unsigned long addr)
 {
-#if defined(__i386__) && !defined(__arch_um__)
-        /*
-         * On the PPro and successors, the MTRRs are used to set
-         * memory types for physical addresses outside main memory,
-         * so blindly setting PCD 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 (file->f_flags & O_SYNC)
-                return 1;
-        return !( 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) )
-          && addr >= __pa(high_memory);
-#elif defined(__x86_64__) && !defined(__arch_um__)
-        /* 
-         * This is broken because it can generate memory type aliases,
-         * which can cause cache corruptions
-         * But it is only available for root and we have to be bug-to-bug
-         * compatible with i386.
-         */
-        if (file->f_flags & O_SYNC)
-                return 1;
-        /* same behaviour as i386. PAT always set to cached and MTRRs control the
-           caching behaviour. 
-           Hopefully a full PAT implementation will fix that soon. */      
-        return 0;
-#elif defined(CONFIG_IA64)
+#if defined(CONFIG_IA64)
         /*
          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
          */
@@ -108,6 +79,36 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 }
 #endif
 
+#ifdef CONFIG_NONPROMISC_DEVMEM
+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;
+}
+#else
+static inline int range_is_allowed(unsigned long pfn, unsigned long size)
+{
+        return 1;
+}
+#endif
+
+void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr)
+{
+}
+
 /*
  * This funcion reads the *physical* memory. The f_pos points directly to the 
  * memory location. 
@@ -150,15 +151,25 @@ static ssize_t read_mem(struct file * file, char __user * buf,
 
                 sz = min_t(unsigned long, sz, count);
 
+                if (!range_is_allowed(p >> PAGE_SHIFT, count))
+                        return -EPERM;
+
                 /*
                  * On ia64 if a page has been mapped somewhere as
                  * uncached, then it must also be accessed uncached
                  * by the kernel or data corruption may occur
                  */
                 ptr = xlate_dev_mem_ptr(p);
+                if (!ptr)
+                        return -EFAULT;
 
-                if (copy_to_user(buf, ptr, sz))
+                if (copy_to_user(buf, ptr, sz)) {
+                        unxlate_dev_mem_ptr(p, ptr);
                         return -EFAULT;
+                }
+
+                unxlate_dev_mem_ptr(p, ptr);
+
                 buf += sz;
                 p += sz;
                 count -= sz;
@@ -207,20 +218,32 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
 
                 sz = min_t(unsigned long, sz, count);
 
+                if (!range_is_allowed(p >> PAGE_SHIFT, sz))
+                        return -EPERM;
+
                 /*
                  * On ia64 if a page has been mapped somewhere as
                  * uncached, then it must also be accessed uncached
                  * by the kernel or data corruption may occur
                  */
                 ptr = xlate_dev_mem_ptr(p);
+                if (!ptr) {
+                        if (written)
+                                break;
+                        return -EFAULT;
+                }
 
                 copied = copy_from_user(ptr, buf, sz);
                 if (copied) {
                         written += sz - copied;
+                        unxlate_dev_mem_ptr(p, ptr);
                         if (written)
                                 break;
                         return -EFAULT;
                 }
+
+                unxlate_dev_mem_ptr(p, ptr);
+
                 buf += sz;
                 p += sz;
                 count -= sz;
@@ -231,6 +254,12 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
         return written;
 }
 
+int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file,
+        unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
+{
+        return 1;
+}
+
 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT
 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                                      unsigned long size, pgprot_t vma_prot)
@@ -271,6 +300,35 @@ static inline int private_mapping_ok(struct vm_area_struct *vma)
 }
 #endif
 
+void __attribute__((weak))
+map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+        /* nothing. architectures can override. */
+}
+
+void __attribute__((weak))
+unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+        /* nothing. architectures can override. */
+}
+
+static void mmap_mem_open(struct vm_area_struct *vma)
+{
+        map_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+                        vma->vm_page_prot);
+}
+
+static void mmap_mem_close(struct vm_area_struct *vma)
+{
+        unmap_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+                        vma->vm_page_prot);
+}
+
+static struct vm_operations_struct mmap_mem_ops = {
+        .open  = mmap_mem_open,
+        .close = mmap_mem_close
+};
+
 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
         size_t size = vma->vm_end - vma->vm_start;
@@ -281,17 +339,28 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
         if (!private_mapping_ok(vma))
                 return -ENOSYS;
 
+        if (!range_is_allowed(vma->vm_pgoff, size))
+                return -EPERM;
+
+        if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
+                                                &vma->vm_page_prot))
+                return -EINVAL;
+
         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
                                                  size,
                                                  vma->vm_page_prot);
 
+        vma->vm_ops = &mmap_mem_ops;
+
         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
         if (remap_pfn_range(vma,
                             vma->vm_start,
                             vma->vm_pgoff,
                             size,
-                            vma->vm_page_prot))
+                            vma->vm_page_prot)) {
+                unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot);
                 return -EAGAIN;
+        }
         return 0;
 }