Make /dev/mem configurable, as we don't want it.

Signed-off-by: Brian Swetland <swetland@google.com>

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index a9bb5db..0e6dde2 100644 (file)
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -6,6 +6,19 @@ menu "Character devices"
 
 source "drivers/tty/Kconfig"
 
+config DEVMEM
+       bool "Memory device driver"
+       default y
+       help
+         The memory driver provides two character devices, mem and kmem, which
+         provide access to the system's memory. The mem device is a view of
+         physical memory, and each byte in the device corresponds to the
+         matching physical address. The kmem device is the same as mem, but
+         the addresses correspond to the kernel's virtual address space rather
+         than physical memory. These devices are standard parts of a Linux
+         system and most users should say Y here. You might say N if very
+         security conscience or memory is tight.
+
 config DEVKMEM
        bool "/dev/kmem virtual device support"
        default y

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 436a990..a9d8616 100644 (file)
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -56,6 +56,7 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 }
 #endif
 
+#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM)
 #ifdef CONFIG_STRICT_DEVMEM
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
@@ -81,7 +82,9 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
        return 1;
 }
 #endif
+#endif
 
+#ifdef CONFIG_DEVMEM
 void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 {
 }
@@ -208,6 +211,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf,
        *ppos += written;
        return written;
 }
+#endif /* CONFIG_DEVMEM */
+
+#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM)
 
 int __weak phys_mem_access_prot_allowed(struct file *file,
        unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
@@ -329,6 +335,7 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma)
        }
        return 0;
 }
+#endif /* CONFIG_DEVMEM */
 
 #ifdef CONFIG_DEVKMEM
 static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
@@ -693,6 +700,8 @@ static loff_t null_lseek(struct file *file, loff_t offset, int orig)
        return file->f_pos = 0;
 }
 
+#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT)
+
 /*
  * The memory devices use the full 32/64 bits of the offset, and so we cannot
  * check against negative addresses: they are ok. The return value is weird,
@@ -726,10 +735,14 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
        return ret;
 }
 
+#endif
+
+#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT)
 static int open_port(struct inode * inode, struct file * filp)
 {
        return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
 }
+#endif
 
 #define zero_lseek     null_lseek
 #define full_lseek      null_lseek
@@ -739,6 +752,7 @@ static int open_port(struct inode * inode, struct file * filp)
 #define open_kmem      open_mem
 #define open_oldmem    open_mem
 
+#ifdef CONFIG_DEVMEM
 static const struct file_operations mem_fops = {
        .llseek         = memory_lseek,
        .read           = read_mem,
@@ -747,6 +761,7 @@ static const struct file_operations mem_fops = {
        .open           = open_mem,
        .get_unmapped_area = get_unmapped_area_mem,
 };
+#endif
 
 #ifdef CONFIG_DEVKMEM
 static const struct file_operations kmem_fops = {
@@ -838,7 +853,9 @@ static const struct memdev {
        const struct file_operations *fops;
        struct backing_dev_info *dev_info;
 } devlist[] = {
+#ifdef CONFIG_DEVMEM
         [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
+#endif
 #ifdef CONFIG_DEVKMEM
         [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
 #endif