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authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /arch/mips/mm/mmap.c
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff)
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure.
Diffstat (limited to 'arch/mips/mm/mmap.c')
-rw-r--r--arch/mips/mm/mmap.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
new file mode 100644
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--- /dev/null
+++ b/arch/mips/mm/mmap.c
@@ -0,0 +1,271 @@
+/*
+ * 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/compiler.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/personality.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+
+unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
+EXPORT_SYMBOL(shm_align_mask);
+
+/* gap between mmap and stack */
+#define MIN_GAP (128*1024*1024UL)
+#define MAX_GAP ((TASK_SIZE)/6*5)
+
+static int mmap_is_legacy(void)
+{
+ if (current->personality & ADDR_COMPAT_LAYOUT)
+ return 1;
+
+ if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
+ return 1;
+
+ return sysctl_legacy_va_layout;
+}
+
+static unsigned long mmap_base(unsigned long rnd)
+{
+ unsigned long gap = rlimit(RLIMIT_STACK);
+
+ if (gap < MIN_GAP)
+ gap = MIN_GAP;
+ else if (gap > MAX_GAP)
+ gap = MAX_GAP;
+
+ return PAGE_ALIGN(TASK_SIZE - gap - rnd);
+}
+
+static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
+ unsigned long pgoff)
+{
+ unsigned long base = addr & ~shm_align_mask;
+ unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
+
+ if (base + off <= addr)
+ return base + off;
+
+ return base - off;
+}
+
+#define COLOUR_ALIGN(addr, pgoff) \
+ ((((addr) + shm_align_mask) & ~shm_align_mask) + \
+ (((pgoff) << PAGE_SHIFT) & shm_align_mask))
+
+enum mmap_allocation_direction {UP, DOWN};
+
+static unsigned long arch_get_unmapped_area_common(struct file *filp,
+ unsigned long addr0, unsigned long len, unsigned long pgoff,
+ unsigned long flags, enum mmap_allocation_direction dir)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long addr = addr0;
+ int do_color_align;
+
+ if (unlikely(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;
+
+ /* requesting a specific address */
+ if (addr) {
+ if (do_color_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;
+ }
+
+ if (dir == UP) {
+ addr = mm->mmap_base;
+ if (do_color_align)
+ addr = COLOUR_ALIGN(addr, pgoff);
+ else
+ addr = PAGE_ALIGN(addr);
+
+ for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr)
+ return -ENOMEM;
+ if (!vma || addr + len <= vma->vm_start)
+ return addr;
+ addr = vma->vm_end;
+ if (do_color_align)
+ addr = COLOUR_ALIGN(addr, pgoff);
+ }
+ } else {
+ /* check if free_area_cache is useful for us */
+ if (len <= mm->cached_hole_size) {
+ mm->cached_hole_size = 0;
+ mm->free_area_cache = mm->mmap_base;
+ }
+
+ /*
+ * either no address requested, or the mapping can't fit into
+ * the requested address hole
+ */
+ addr = mm->free_area_cache;
+ if (do_color_align) {
+ unsigned long base =
+ COLOUR_ALIGN_DOWN(addr - len, pgoff);
+ addr = base + len;
+ }
+
+ /* make sure it can fit in the remaining address space */
+ if (likely(addr > len)) {
+ vma = find_vma(mm, addr - len);
+ if (!vma || addr <= vma->vm_start) {
+ /* cache the address as a hint for next time */
+ return mm->free_area_cache = addr - len;
+ }
+ }
+
+ if (unlikely(mm->mmap_base < len))
+ goto bottomup;
+
+ addr = mm->mmap_base - len;
+ if (do_color_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+
+ do {
+ /*
+ * Lookup failure means no vma is above this address,
+ * else if new region fits below vma->vm_start,
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+ if (likely(!vma || addr + len <= vma->vm_start)) {
+ /* cache the address as a hint for next time */
+ return mm->free_area_cache = addr;
+ }
+
+ /* remember the largest hole we saw so far */
+ if (addr + mm->cached_hole_size < vma->vm_start)
+ mm->cached_hole_size = vma->vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+ addr = vma->vm_start - len;
+ if (do_color_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+ } while (likely(len < vma->vm_start));
+
+bottomup:
+ /*
+ * A failed mmap() very likely causes application failure,
+ * so fall back to the bottom-up function here. This scenario
+ * can happen with large stack limits and large mmap()
+ * allocations.
+ */
+ mm->cached_hole_size = ~0UL;
+ mm->free_area_cache = TASK_UNMAPPED_BASE;
+ addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+ /*
+ * Restore the topdown base:
+ */
+ mm->free_area_cache = mm->mmap_base;
+ mm->cached_hole_size = ~0UL;
+
+ return addr;
+ }
+}
+
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ return arch_get_unmapped_area_common(filp,
+ addr0, len, pgoff, flags, UP);
+}
+
+/*
+ * There is no need to export this but sched.h declares the function as
+ * extern so making it static here results in an error.
+ */
+unsigned long arch_get_unmapped_area_topdown(struct file *filp,
+ unsigned long addr0, unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ return arch_get_unmapped_area_common(filp,
+ addr0, len, pgoff, flags, DOWN);
+}
+
+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;
+ }
+
+ if (mmap_is_legacy()) {
+ mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ mm->unmap_area = arch_unmap_area;
+ } else {
+ mm->mmap_base = mmap_base(random_factor);
+ mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+ mm->unmap_area = arch_unmap_area_topdown;
+ }
+}
+
+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;
+}