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Diffstat (limited to 'arch/s390/mm/mmap.c')
| -rw-r--r-- | arch/s390/mm/mmap.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c new file mode 100644 index 00000000..2857c484 --- /dev/null +++ b/arch/s390/mm/mmap.c @@ -0,0 +1,178 @@ +/* + * 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; + } +} + +#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; + } +} + +#endif |