summaryrefslogtreecommitdiffstats
path: root/arch/mips/mm/mmap.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/mm/mmap.c')
-rw-r--r--arch/mips/mm/mmap.c122
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;
+}