diff options
Diffstat (limited to 'arch/mips/mm')
| -rw-r--r-- | arch/mips/mm/Makefile | 3 | ||||
| -rw-r--r-- | arch/mips/mm/mmap.c | 122 |
2 files changed, 124 insertions, 1 deletions
diff --git a/arch/mips/mm/Makefile b/arch/mips/mm/Makefile index eb4463689fa..4d8c1623eee 100644 --- a/arch/mips/mm/Makefile +++ b/arch/mips/mm/Makefile @@ -3,7 +3,8 @@ # obj-y += cache.o dma-default.o extable.o fault.o \ - init.o tlbex.o tlbex-fault.o uasm.o page.o + init.o mmap.o tlbex.o tlbex-fault.o uasm.o \ + page.o obj-$(CONFIG_32BIT) += ioremap.o pgtable-32.o obj-$(CONFIG_64BIT) += pgtable-64.o diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c new file mode 100644 index 00000000000..ae3c20a9556 --- /dev/null +++ b/arch/mips/mm/mmap.c @@ -0,0 +1,122 @@ +/* + * 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/errno.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/module.h> +#include <linux/random.h> +#include <linux/sched.h> + +unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ + +EXPORT_SYMBOL(shm_align_mask); + +#define COLOUR_ALIGN(addr,pgoff) \ + ((((addr) + shm_align_mask) & ~shm_align_mask) + \ + (((pgoff) << PAGE_SHIFT) & shm_align_mask)) + +unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + struct vm_area_struct * vmm; + int do_color_align; + + if (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; + if (addr) { + if (do_color_align) + addr = COLOUR_ALIGN(addr, pgoff); + else + addr = PAGE_ALIGN(addr); + vmm = find_vma(current->mm, addr); + if (TASK_SIZE - len >= addr && + (!vmm || addr + len <= vmm->vm_start)) + return addr; + } + addr = current->mm->mmap_base; + if (do_color_align) + addr = COLOUR_ALIGN(addr, pgoff); + else + addr = PAGE_ALIGN(addr); + + for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) { + /* At this point: (!vmm || addr < vmm->vm_end). */ + if (TASK_SIZE - len < addr) + return -ENOMEM; + if (!vmm || addr + len <= vmm->vm_start) + return addr; + addr = vmm->vm_end; + if (do_color_align) + addr = COLOUR_ALIGN(addr, pgoff); + } +} + +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; + } + + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; + mm->get_unmapped_area = arch_get_unmapped_area; + mm->unmap_area = arch_unmap_area; +} + +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; +} |