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-rw-r--r--drivers/char/Kconfig9
-rw-r--r--drivers/char/mem.c10
2 files changed, 19 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 929d4fa73fd9..5dce3877eee5 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -80,6 +80,15 @@ config VT_HW_CONSOLE_BINDING
information. For framebuffer console users, please refer to
<file:Documentation/fb/fbcon.txt>.
+config DEVKMEM
+ bool "/dev/kmem virtual device support"
+ default y
+ help
+ Say Y here if you want to support the /dev/kmem device. The
+ /dev/kmem device is rarely used, but can be used for certain
+ kind of kernel debugging operations.
+ When in doubt, say "N".
+
config SERIAL_NONSTANDARD
bool "Non-standard serial port support"
depends on HAS_IOMEM
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index e83623ead441..934ffafedaea 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -364,6 +364,7 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
return 0;
}
+#ifdef CONFIG_DEVKMEM
static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
{
unsigned long pfn;
@@ -384,6 +385,7 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
vma->vm_pgoff = pfn;
return mmap_mem(file, vma);
}
+#endif
#ifdef CONFIG_CRASH_DUMP
/*
@@ -422,6 +424,7 @@ static ssize_t read_oldmem(struct file *file, char __user *buf,
extern long vread(char *buf, char *addr, unsigned long count);
extern long vwrite(char *buf, char *addr, unsigned long count);
+#ifdef CONFIG_DEVKMEM
/*
* This function reads the *virtual* memory as seen by the kernel.
*/
@@ -626,6 +629,7 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
*ppos = p;
return virtr + wrote;
}
+#endif
#ifdef CONFIG_DEVPORT
static ssize_t read_port(struct file * file, char __user * buf,
@@ -803,6 +807,7 @@ static const struct file_operations mem_fops = {
.get_unmapped_area = get_unmapped_area_mem,
};
+#ifdef CONFIG_DEVKMEM
static const struct file_operations kmem_fops = {
.llseek = memory_lseek,
.read = read_kmem,
@@ -811,6 +816,7 @@ static const struct file_operations kmem_fops = {
.open = open_kmem,
.get_unmapped_area = get_unmapped_area_mem,
};
+#endif
static const struct file_operations null_fops = {
.llseek = null_lseek,
@@ -889,11 +895,13 @@ static int memory_open(struct inode * inode, struct file * filp)
filp->f_mapping->backing_dev_info =
&directly_mappable_cdev_bdi;
break;
+#ifdef CONFIG_DEVKMEM
case 2:
filp->f_op = &kmem_fops;
filp->f_mapping->backing_dev_info =
&directly_mappable_cdev_bdi;
break;
+#endif
case 3:
filp->f_op = &null_fops;
break;
@@ -942,7 +950,9 @@ static const struct {
const struct file_operations *fops;
} devlist[] = { /* list of minor devices */
{1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
+#ifdef CONFIG_DEVKMEM
{2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
+#endif
{3, "null", S_IRUGO | S_IWUGO, &null_fops},
#ifdef CONFIG_DEVPORT
{4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},