aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--Documentation/sysctl/kernel.txt14
-rw-r--r--include/linux/mm.h6
-rw-r--r--kernel/sysctl.c11
3 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 57baff5bdb80..62044945a118 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -41,6 +41,7 @@ show up in /proc/sys/kernel:
- kptr_restrict
- kstack_depth_to_print [ X86 only ]
- l2cr [ PPC only ]
+- mmap_rnd_bits
- modprobe ==> Documentation/debugging-modules.txt
- modules_disabled
- msg_next_id [ sysv ipc ]
@@ -386,6 +387,19 @@ This flag controls the L2 cache of G3 processor boards. If
==============================================================
+mmap_rnd_bits:
+
+This value can be used to select the number of bits to use to
+determine the random offset to the base address of vma regions
+resulting from mmap allocations on architectures which support
+tuning address space randomization. This value will be bounded
+by the architecture's minimum and maximum supported values.
+
+This value can be changed after boot using the
+/proc/sys/kernel/mmap_rnd_bits tunable
+
+==============================================================
+
modules_disabled:
A toggle value indicating if modules are allowed to be loaded
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 18a4997dcde7..1fb49a650c17 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -48,6 +48,12 @@ extern int sysctl_legacy_va_layout;
#define sysctl_legacy_va_layout 0
#endif
+#ifdef CONFIG_ARCH_MMAP_RND_BITS
+extern int mmap_rnd_bits_min;
+extern int mmap_rnd_bits_max;
+extern int mmap_rnd_bits;
+#endif
+
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 78af9692e0a4..a6de89ef2191 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1106,6 +1106,17 @@ static struct ctl_table kern_table[] = {
.proc_handler = proc_dointvec,
},
#endif
+#ifdef CONFIG_ARCH_MMAP_RND_BITS
+ {
+ .procname = "mmap_rnd_bits",
+ .data = &mmap_rnd_bits,
+ .maxlen = sizeof(mmap_rnd_bits),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &mmap_rnd_bits_min,
+ .extra2 = &mmap_rnd_bits_max,
+ },
+#endif
{ }
};