1 files changed, 122 insertions, 0 deletions
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
new file mode 100644
index 00000000000..ae3c20a9556
--- /dev/null
+++ b/arch/mips/mm/mmap.c
@@ -0,0 +1,122 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011 Wind River Systems,
+ *   written by Ralf Baechle <ralf@linux-mips.org>
+ */
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+
+unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
+
+EXPORT_SYMBOL(shm_align_mask);
+
+#define COLOUR_ALIGN(addr,pgoff)				\
+	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
+	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
+
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+	unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+	struct vm_area_struct * vmm;
+	int do_color_align;
+
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED) {
+		/* Even MAP_FIXED mappings must reside within TASK_SIZE.  */
+		if (TASK_SIZE - len < addr)
+			return -EINVAL;
+
+		/*
+		 * We do not accept a shared mapping if it would violate
+		 * cache aliasing constraints.
+		 */
+		if ((flags & MAP_SHARED) &&
+		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
+			return -EINVAL;
+		return addr;
+	}
+
+	do_color_align = 0;
+	if (filp || (flags & MAP_SHARED))
+		do_color_align = 1;
+	if (addr) {
+		if (do_color_align)
+			addr = COLOUR_ALIGN(addr, pgoff);
+		else
+			addr = PAGE_ALIGN(addr);
+		vmm = find_vma(current->mm, addr);
+		if (TASK_SIZE - len >= addr &&
+		    (!vmm || addr + len <= vmm->vm_start))
+			return addr;
+	}
+	addr = current->mm->mmap_base;
+	if (do_color_align)
+		addr = COLOUR_ALIGN(addr, pgoff);
+	else
+		addr = PAGE_ALIGN(addr);
+
+	for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
+		/* At this point:  (!vmm || addr < vmm->vm_end). */
+		if (TASK_SIZE - len < addr)
+			return -ENOMEM;
+		if (!vmm || addr + len <= vmm->vm_start)
+			return addr;
+		addr = vmm->vm_end;
+		if (do_color_align)
+			addr = COLOUR_ALIGN(addr, pgoff);
+	}
+}
+
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+	unsigned long random_factor = 0UL;
+
+	if (current->flags & PF_RANDOMIZE) {
+		random_factor = get_random_int();
+		random_factor = random_factor << PAGE_SHIFT;
+		if (TASK_IS_32BIT_ADDR)
+			random_factor &= 0xfffffful;
+		else
+			random_factor &= 0xffffffful;
+	}
+
+	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
+	mm->get_unmapped_area = arch_get_unmapped_area;
+	mm->unmap_area = arch_unmap_area;
+}
+
+static inline unsigned long brk_rnd(void)
+{
+	unsigned long rnd = get_random_int();
+
+	rnd = rnd << PAGE_SHIFT;
+	/* 8MB for 32bit, 256MB for 64bit */
+	if (TASK_IS_32BIT_ADDR)
+		rnd = rnd & 0x7ffffful;
+	else
+		rnd = rnd & 0xffffffful;
+
+	return rnd;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+	unsigned long base = mm->brk;
+	unsigned long ret;
+
+	ret = PAGE_ALIGN(base + brk_rnd());
+
+	if (ret < mm->brk)
+		return mm->brk;
+
+	return ret;
+}