diff options
Diffstat (limited to 'arch/sh/mm/mmap.c')
| -rw-r--r-- | arch/sh/mm/mmap.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c new file mode 100644 index 00000000..afeb710e --- /dev/null +++ b/arch/sh/mm/mmap.c @@ -0,0 +1,254 @@ +/* + * arch/sh/mm/mmap.c + * + * Copyright (C) 2008 - 2009 Paul Mundt + * + * 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. + */ +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/module.h> +#include <asm/page.h> +#include <asm/processor.h> + +unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ +EXPORT_SYMBOL(shm_align_mask); + +#ifdef CONFIG_MMU +/* + * To avoid cache aliases, we map the shared page with same color. + */ +static inline unsigned long COLOUR_ALIGN(unsigned long addr, + unsigned long pgoff) +{ + unsigned long base = (addr + shm_align_mask) & ~shm_align_mask; + unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask; + + return base + off; +} + +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; +} + +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; + unsigned long start_addr; + int do_colour_align; + + if (flags & MAP_FIXED) { + /* 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; + } + + if (unlikely(len > TASK_SIZE)) + return -ENOMEM; + + do_colour_align = 0; + if (filp || (flags & MAP_SHARED)) + do_colour_align = 1; + + if (addr) { + if (do_colour_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 (len > mm->cached_hole_size) { + start_addr = addr = mm->free_area_cache; + } else { + mm->cached_hole_size = 0; + start_addr = addr = TASK_UNMAPPED_BASE; + } + +full_search: + if (do_colour_align) + addr = COLOUR_ALIGN(addr, pgoff); + else + addr = PAGE_ALIGN(mm->free_area_cache); + + for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { + /* At this point: (!vma || addr < vma->vm_end). */ + if (unlikely(TASK_SIZE - len < addr)) { + /* + * Start a new search - just in case we missed + * some holes. + */ + if (start_addr != TASK_UNMAPPED_BASE) { + start_addr = addr = TASK_UNMAPPED_BASE; + mm->cached_hole_size = 0; + goto full_search; + } + return -ENOMEM; + } + if (likely(!vma || addr + len <= vma->vm_start)) { + /* + * Remember the place where we stopped the search: + */ + mm->free_area_cache = addr + len; + return addr; + } + if (addr + mm->cached_hole_size < vma->vm_start) + mm->cached_hole_size = vma->vm_start - addr; + + addr = vma->vm_end; + if (do_colour_align) + addr = COLOUR_ALIGN(addr, pgoff); + } +} + +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; + int do_colour_align; + + if (flags & MAP_FIXED) { + /* 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; + } + + if (unlikely(len > TASK_SIZE)) + return -ENOMEM; + + do_colour_align = 0; + if (filp || (flags & MAP_SHARED)) + do_colour_align = 1; + + /* requesting a specific address */ + if (addr) { + if (do_colour_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; + } + + /* 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 can't fit in requested address hole */ + addr = mm->free_area_cache; + if (do_colour_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) { + /* remember 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_colour_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)) { + /* remember 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_colour_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; +} +#endif /* CONFIG_MMU */ + +/* + * You really shouldn't be using read() or write() on /dev/mem. This + * might go away in the future. + */ +int valid_phys_addr_range(unsigned long addr, size_t count) +{ + if (addr < __MEMORY_START) + return 0; + if (addr + count > __pa(high_memory)) + return 0; + + return 1; +} + +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return 1; +} |