diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 7e40f3778179..b2202a68cf0f 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -414,6 +414,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, * constraints placed on us by the cache architecture. */ #define HAVE_ARCH_UNMAPPED_AREA +#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN /* * No page table caches to initialise diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index ae3c20a9556e..9ff5d0fac556 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -17,21 +18,65 @@ unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ EXPORT_SYMBOL(shm_align_mask); +/* gap between mmap and stack */ +#define MIN_GAP (128*1024*1024UL) +#define MAX_GAP ((TASK_SIZE)/6*5) + +static 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_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; + + return PAGE_ALIGN(TASK_SIZE - gap - rnd); +} + +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; +} + #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) +enum mmap_allocation_direction {UP, DOWN}; + +static unsigned long arch_get_unmapped_area_foo(struct file *filp, + unsigned long addr0, unsigned long len, unsigned long pgoff, + unsigned long flags, enum mmap_allocation_direction dir) { - struct vm_area_struct * vmm; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long addr = addr0; int do_color_align; - if (len > TASK_SIZE) + if (unlikely(len > TASK_SIZE)) return -ENOMEM; if (flags & MAP_FIXED) { - /* Even MAP_FIXED mappings must reside within TASK_SIZE. */ + /* Even MAP_FIXED mappings must reside within TASK_SIZE */ if (TASK_SIZE - len < addr) return -EINVAL; @@ -48,32 +93,128 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, do_color_align = 0; if (filp || (flags & MAP_SHARED)) do_color_align = 1; + + /* requesting a specific address */ 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) + vma = find_vma(mm, addr); + if (TASK_SIZE - len >= addr && + (!vma || addr + len <= vma->vm_start)) return addr; - addr = vmm->vm_end; - if (do_color_align) - addr = COLOUR_ALIGN(addr, pgoff); } + + if (dir == UP) { + addr = mm->mmap_base; + if (do_color_align) + addr = COLOUR_ALIGN(addr, pgoff); + else + addr = PAGE_ALIGN(addr); + + for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) { + /* At this point: (!vma || addr < vma->vm_end). */ + if (TASK_SIZE - len < addr) + return -ENOMEM; + if (!vma || addr + len <= vma->vm_start) + return addr; + addr = vma->vm_end; + if (do_color_align) + addr = COLOUR_ALIGN(addr, pgoff); + } + } else { + /* 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_color_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_color_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_color_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; + } +} + +unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + return arch_get_unmapped_area_foo(filp, + addr0, len, pgoff, flags, UP); +} + +/* + * There is no need to export this but sched.h declares the function as + * extern so making it static here results in an error. + */ +unsigned long arch_get_unmapped_area_topdown(struct file *filp, + unsigned long addr0, unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + return arch_get_unmapped_area_foo(filp, + addr0, len, pgoff, flags, DOWN); } void arch_pick_mmap_layout(struct mm_struct *mm) @@ -89,9 +230,15 @@ void arch_pick_mmap_layout(struct mm_struct *mm) 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; + if (mmap_is_legacy()) { + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; + mm->get_unmapped_area = arch_get_unmapped_area; + mm->unmap_area = arch_unmap_area; + } else { + mm->mmap_base = mmap_base(random_factor); + mm->get_unmapped_area = arch_get_unmapped_area_topdown; + mm->unmap_area = arch_unmap_area_topdown; + } } static inline unsigned long brk_rnd(void)