Initial import

1 files changed, 288 insertions, 0 deletions

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
new file mode 100644
index 000000000..6e552af08
--- /dev/null
+++ b/arch/s390/mm/mmap.c
@@ -0,0 +1,288 @@
+/*
+ *  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 <linux/security.h>
+#include <asm/pgalloc.h>
+
+unsigned long mmap_rnd_mask;
+static unsigned long mmap_align_mask;
+
+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;
+}
+
+unsigned long arch_mmap_rnd(void)
+{
+	if (is_32bit_task())
+		return (get_random_int() & 0x7ff) << PAGE_SHIFT;
+	else
+		return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
+}
+
+static unsigned long mmap_base_legacy(unsigned long rnd)
+{
+	return TASK_UNMAPPED_BASE + rnd;
+}
+
+static inline 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;
+	gap &= PAGE_MASK;
+	return STACK_TOP - stack_maxrandom_size() - rnd - gap;
+}
+
+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;
+	struct vm_unmapped_area_info info;
+	int do_color_align;
+
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+
+	do_color_align = 0;
+	if (filp || (flags & MAP_SHARED))
+		do_color_align = !is_32bit_task();
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = mm->mmap_base;
+	info.high_limit = TASK_SIZE;
+	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	return vm_unmapped_area(&info);
+}
+
+unsigned long
+arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+			  const unsigned long len, const unsigned long pgoff,
+			  const unsigned long flags)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	unsigned long addr = addr0;
+	struct vm_unmapped_area_info info;
+	int do_color_align;
+
+	/* requested length too big for entire address space */
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	/* requesting a specific address */
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+				(!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+
+	do_color_align = 0;
+	if (filp || (flags & MAP_SHARED))
+		do_color_align = !is_32bit_task();
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+	info.high_limit = mm->mmap_base;
+	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	addr = vm_unmapped_area(&info);
+
+	/*
+	 * 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.
+	 */
+	if (addr & ~PAGE_MASK) {
+		VM_BUG_ON(addr != -ENOMEM);
+		info.flags = 0;
+		info.low_limit = TASK_UNMAPPED_BASE;
+		info.high_limit = TASK_SIZE;
+		addr = vm_unmapped_area(&info);
+	}
+
+	return addr;
+}
+
+int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
+{
+	if (is_compat_task() || (TASK_SIZE >= (1UL << 53)))
+		return 0;
+	if (!(flags & MAP_FIXED))
+		addr = 0;
+	if ((addr + len) >= TASK_SIZE)
+		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)
+{
+	unsigned long random_factor = 0UL;
+
+	if (current->flags & PF_RANDOMIZE)
+		random_factor = arch_mmap_rnd();
+
+	/*
+	 * 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 = mmap_base_legacy(random_factor);
+		mm->get_unmapped_area = s390_get_unmapped_area;
+	} else {
+		mm->mmap_base = mmap_base(random_factor);
+		mm->get_unmapped_area = s390_get_unmapped_area_topdown;
+	}
+}
+
+static int __init setup_mmap_rnd(void)
+{
+	struct cpuid cpu_id;
+
+	get_cpu_id(&cpu_id);
+	switch (cpu_id.machine) {
+	case 0x9672:
+	case 0x2064:
+	case 0x2066:
+	case 0x2084:
+	case 0x2086:
+	case 0x2094:
+	case 0x2096:
+	case 0x2097:
+	case 0x2098:
+	case 0x2817:
+	case 0x2818:
+	case 0x2827:
+	case 0x2828:
+		mmap_rnd_mask = 0x7ffUL;
+		mmap_align_mask = 0UL;
+		break;
+	case 0x2964:	/* z13 */
+	default:
+		mmap_rnd_mask = 0x3ff80UL;
+		mmap_align_mask = 0x7fUL;
+		break;
+	}
+	return 0;
+}
+early_initcall(setup_mmap_rnd);