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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/s390/mm/mmap.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/s390/mm/mmap.c')
-rw-r--r--arch/s390/mm/mmap.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
new file mode 100644
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+++ b/arch/s390/mm/mmap.c
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+/*
+ * linux/arch/s390/mm/mmap.c
+ *
+ * flexible mmap layout support
+ *
+ * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ *
+ * Started by Ingo Molnar <mingo@elte.hu>
+ */
+
+#include <linux/personality.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/compat.h>
+#include <asm/pgalloc.h>
+
+static unsigned long stack_maxrandom_size(void)
+{
+ if (!(current->flags & PF_RANDOMIZE))
+ return 0;
+ if (current->personality & ADDR_NO_RANDOMIZE)
+ return 0;
+ return STACK_RND_MASK << PAGE_SHIFT;
+}
+
+/*
+ * Top of mmap area (just below the process stack).
+ *
+ * Leave at least a ~32 MB hole.
+ */
+#define MIN_GAP (32*1024*1024)
+#define MAX_GAP (STACK_TOP/6*5)
+
+static inline 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_rnd(void)
+{
+ if (!(current->flags & PF_RANDOMIZE))
+ return 0;
+ /* 8MB randomization for mmap_base */
+ return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
+}
+
+static inline unsigned long mmap_base(void)
+{
+ unsigned long gap = rlimit(RLIMIT_STACK);
+
+ if (gap < MIN_GAP)
+ gap = MIN_GAP;
+ else if (gap > MAX_GAP)
+ gap = MAX_GAP;
+ gap &= PAGE_MASK;
+ return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
+}
+
+#ifndef CONFIG_64BIT
+
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+ /*
+ * Fall back to the standard layout if the personality
+ * bit is set, or if the expected stack growth is unlimited:
+ */
+ if (mmap_is_legacy()) {
+ mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ mm->unmap_area = arch_unmap_area;
+ } else {
+ mm->mmap_base = mmap_base();
+ mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+ mm->unmap_area = arch_unmap_area_topdown;
+ }
+}
+EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
+
+#else
+
+int s390_mmap_check(unsigned long addr, unsigned long len)
+{
+ if (!is_compat_task() &&
+ len >= TASK_SIZE && TASK_SIZE < (1UL << 53))
+ return crst_table_upgrade(current->mm, 1UL << 53);
+ return 0;
+}
+
+static unsigned long
+s390_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long area;
+ int rc;
+
+ area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
+ if (!(area & ~PAGE_MASK))
+ return area;
+ if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
+ /* Upgrade the page table to 4 levels and retry. */
+ rc = crst_table_upgrade(mm, 1UL << 53);
+ if (rc)
+ return (unsigned long) rc;
+ area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
+ }
+ return area;
+}
+
+static unsigned long
+s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
+ const unsigned long len, const unsigned long pgoff,
+ const unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long area;
+ int rc;
+
+ area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
+ if (!(area & ~PAGE_MASK))
+ return area;
+ if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
+ /* Upgrade the page table to 4 levels and retry. */
+ rc = crst_table_upgrade(mm, 1UL << 53);
+ if (rc)
+ return (unsigned long) rc;
+ area = arch_get_unmapped_area_topdown(filp, addr, len,
+ pgoff, flags);
+ }
+ return area;
+}
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+ /*
+ * Fall back to the standard layout if the personality
+ * bit is set, or if the expected stack growth is unlimited:
+ */
+ if (mmap_is_legacy()) {
+ mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->get_unmapped_area = s390_get_unmapped_area;
+ mm->unmap_area = arch_unmap_area;
+ } else {
+ mm->mmap_base = mmap_base();
+ mm->get_unmapped_area = s390_get_unmapped_area_topdown;
+ mm->unmap_area = arch_unmap_area_topdown;
+ }
+}
+EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
+
+#endif