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    Subject[PATCH -mm v2 10/11] mm: remove ARM arch_get_unmapped_area functions
    Date
    Remove the ARM special variants of arch_get_unmapped_area since the
    generic functions should now be able to handle everything.

    ARM only needs page colouring if cache_is_vipt_aliasing; leave
    shm_align_mask at PAGE_SIZE-1 unless we need colouring.

    Untested because I have no ARM hardware.

    Cc: Russell King <linux@arm.linux.org.uk>
    Signed-off-by: Rik van Riel <riel@redhat.com>
    ---
    arch/arm/include/asm/pgtable.h | 6 -
    arch/arm/mm/init.c | 4 +
    arch/arm/mm/mmap.c | 217 ----------------------------------------
    3 files changed, 4 insertions(+), 223 deletions(-)

    diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
    index f66626d..6754183 100644
    --- a/arch/arm/include/asm/pgtable.h
    +++ b/arch/arm/include/asm/pgtable.h
    @@ -296,12 +296,6 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
    #include <asm-generic/pgtable.h>

    /*
    - * We provide our own arch_get_unmapped_area to cope with VIPT caches.
    - */
    -#define HAVE_ARCH_UNMAPPED_AREA
    -#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
    -
    -/*
    * remap a physical page `pfn' of size `size' with page protection `prot'
    * into virtual address `from'
    */
    diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
    index f54d592..abaf862 100644
    --- a/arch/arm/mm/init.c
    +++ b/arch/arm/mm/init.c
    @@ -600,6 +600,10 @@ void __init mem_init(void)
    extern u32 itcm_end;
    #endif

    + /* Tell the page colouring code what we need. */
    + if (cache_is_vipt_aliasing())
    + shm_align_mask = SHMLBA - 1;
    +
    max_mapnr = pfn_to_page(max_pfn + PHYS_PFN_OFFSET) - mem_map;

    /* this will put all unused low memory onto the freelists */
    diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
    index ce8cb19..d90969b 100644
    --- a/arch/arm/mm/mmap.c
    +++ b/arch/arm/mm/mmap.c
    @@ -11,22 +11,6 @@
    #include <linux/random.h>
    #include <asm/cachetype.h>

    -static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
    - unsigned long pgoff)
    -{
    - unsigned long base = addr & ~(SHMLBA-1);
    - unsigned long off = (pgoff << PAGE_SHIFT) & (SHMLBA-1);
    -
    - if (base + off <= addr)
    - return base + off;
    -
    - return base - off;
    -}
    -
    -#define COLOUR_ALIGN(addr,pgoff) \
    - ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
    - (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
    -
    /* gap between mmap and stack */
    #define MIN_GAP (128*1024*1024UL)
    #define MAX_GAP ((TASK_SIZE)/6*5)
    @@ -54,207 +38,6 @@ static unsigned long mmap_base(unsigned long rnd)
    return PAGE_ALIGN(TASK_SIZE - gap - rnd);
    }

    -/*
    - * We need to ensure that shared mappings are correctly aligned to
    - * avoid aliasing issues with VIPT caches. We need to ensure that
    - * a specific page of an object is always mapped at a multiple of
    - * SHMLBA bytes.
    - *
    - * We unconditionally provide this function for all cases, however
    - * in the VIVT case, we optimise out the alignment rules.
    - */
    -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_align = 0;
    - int aliasing = cache_is_vipt_aliasing();
    -
    - /*
    - * We only need to do colour alignment if either the I or D
    - * caches alias.
    - */
    - if (aliasing)
    - do_align = filp || (flags & MAP_SHARED);
    -
    - /*
    - * We enforce the MAP_FIXED case.
    - */
    - if (flags & MAP_FIXED) {
    - if (aliasing && flags & MAP_SHARED &&
    - (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
    - return -EINVAL;
    - return addr;
    - }
    -
    - if (len > TASK_SIZE)
    - return -ENOMEM;
    -
    - if (addr) {
    - if (do_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 {
    - start_addr = addr = mm->mmap_base;
    - mm->cached_hole_size = 0;
    - }
    -
    -full_search:
    - if (do_align)
    - addr = COLOUR_ALIGN(addr, pgoff);
    - else
    - addr = PAGE_ALIGN(addr);
    -
    - for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
    - /* At this point: (!vma || addr < vma->vm_end). */
    - if (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 (!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_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_align = 0;
    - int aliasing = cache_is_vipt_aliasing();
    -
    - /*
    - * We only need to do colour alignment if either the I or D
    - * caches alias.
    - */
    - if (aliasing)
    - do_align = filp || (flags & MAP_SHARED);
    -
    - /* requested length too big for entire address space */
    - if (len > TASK_SIZE)
    - return -ENOMEM;
    -
    - if (flags & MAP_FIXED) {
    - if (aliasing && flags & MAP_SHARED &&
    - (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
    - return -EINVAL;
    - return addr;
    - }
    -
    - /* requesting a specific address */
    - if (addr) {
    - if (do_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_align) {
    - unsigned long base = COLOUR_ALIGN_DOWN(addr - len, pgoff);
    - addr = base + len;
    - }
    -
    - /* make sure it can fit in the remaining address space */
    - if (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 (mm->mmap_base < len)
    - goto bottomup;
    -
    - addr = mm->mmap_base - len;
    - if (do_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 (!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_align)
    - addr = COLOUR_ALIGN_DOWN(addr, pgoff);
    - } while (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;
    -}
    -
    void arch_pick_mmap_layout(struct mm_struct *mm)
    {
    unsigned long random_factor = 0UL;
    --
    1.7.7.6


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