Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / arc / mm / mmap.c

diff --git a/kernel/arch/arc/mm/mmap.c b/kernel/arch/arc/mm/mmap.c
new file mode 100644 (file)
index 0000000..2e06d56
--- /dev/null
+++ b/kernel/arch/arc/mm/mmap.c
@@ -0,0 +1,78 @@
+/*
+ * ARC700 mmap
+ *
+ * (started from arm version - for VIPT alias handling)
+ *
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <asm/cacheflush.h>
+
+#define COLOUR_ALIGN(addr, pgoff)                      \
+       ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +      \
+        (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
+
+/*
+ * Ensure that shared mappings are correctly aligned to
+ * avoid aliasing issues with VIPT caches.
+ * We need to ensure that
+ * a specific page of an object is always mapped at a multiple of
+ * SHMLBA bytes.
+ */
+unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
+               unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+       int do_align = 0;
+       int aliasing = cache_is_vipt_aliasing();
+       struct vm_unmapped_area_info info;
+
+       /*
+        * We only need to do colour alignment if D cache aliases.
+        */
+       if (aliasing)
+               do_align = filp || (flags & MAP_SHARED);
+
+       /*
+        * We enforce the MAP_FIXED case.
+        */
+       if (flags & MAP_FIXED) {
+               if (aliasing && flags & MAP_SHARED &&
+                   (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
+                       return -EINVAL;
+               return addr;
+       }
+
+       if (len > TASK_SIZE)
+               return -ENOMEM;
+
+       if (addr) {
+               if (do_align)
+                       addr = COLOUR_ALIGN(addr, pgoff);
+               else
+                       addr = PAGE_ALIGN(addr);
+
+               vma = find_vma(mm, addr);
+               if (TASK_SIZE - len >= addr &&
+                   (!vma || addr + len <= vma->vm_start))
+                       return addr;
+       }
+
+       info.flags = 0;
+       info.length = len;
+       info.low_limit = mm->mmap_base;
+       info.high_limit = TASK_SIZE;
+       info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+       info.align_offset = pgoff << PAGE_SHIFT;
+       return vm_unmapped_area(&info);
+}