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authorAndi Kleen <ak@suse.de>2006-01-17 07:03:38 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-16 23:18:35 -0800
commit8817210d4d968e58f7d93db2eecd17b20dd03d40 (patch)
tree4a4084011f348f44c388e1876e55c0d2a03f46b4 /arch/x86_64/mm
parent562795fe5770d0c7ee7fe269890e37d9fd475fdf (diff)
[PATCH] x86_64: Flexmap for 32bit and randomized mappings for 64bit
Another try at this. For 32bit follow the 32bit implementation from Ingo - mappings are growing down from the end of stack now and vary randomly by 1GB. Randomized mappings for 64bit just vary the normal mmap break by 1TB. I didn't bother implementing full flex mmap for 64bit because it shouldn't be needed there. Cc: mingo@elte.hu Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/mm')
-rw-r--r--arch/x86_64/mm/Makefile2
-rw-r--r--arch/x86_64/mm/mmap.c30
2 files changed, 31 insertions, 1 deletions
diff --git a/arch/x86_64/mm/Makefile b/arch/x86_64/mm/Makefile
index 1d232a87f113..d25ac86fe27a 100644
--- a/arch/x86_64/mm/Makefile
+++ b/arch/x86_64/mm/Makefile
@@ -2,7 +2,7 @@
# Makefile for the linux x86_64-specific parts of the memory manager.
#
-obj-y := init.o fault.o ioremap.o extable.o pageattr.o
+obj-y := init.o fault.o ioremap.o extable.o pageattr.o mmap.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_K8_NUMA) += k8topology.o
diff --git a/arch/x86_64/mm/mmap.c b/arch/x86_64/mm/mmap.c
new file mode 100644
index 000000000000..43e9b99bdf25
--- /dev/null
+++ b/arch/x86_64/mm/mmap.c
@@ -0,0 +1,30 @@
+/* Copyright 2005 Andi Kleen, SuSE Labs.
+ * Licensed under GPL, v.2
+ */
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/random.h>
+#include <asm/ia32.h>
+
+/* Notebook: move the mmap code from sys_x86_64.c over here. */
+
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (current_thread_info()->flags & _TIF_IA32)
+ return ia32_pick_mmap_layout(mm);
+#endif
+ mm->mmap_base = TASK_UNMAPPED_BASE;
+ if (current->flags & PF_RANDOMIZE) {
+ /* Add 28bit randomness which is about 40bits of address space
+ because mmap base has to be page aligned.
+ or ~1/128 of the total user VM
+ (total user address space is 47bits) */
+ unsigned rnd = get_random_int() & 0xfffffff;
+ mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
+ }
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ mm->unmap_area = arch_unmap_area;
+}
+