diff options
Diffstat (limited to 'arch/powerpc/mm/mmap.c')
| -rw-r--r-- | arch/powerpc/mm/mmap.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c index 4087705ba90f..2f1e44362198 100644 --- a/arch/powerpc/mm/mmap.c +++ b/arch/powerpc/mm/mmap.c @@ -26,6 +26,9 @@ #include <linux/mm.h> #include <linux/random.h> #include <linux/sched.h> +#include <linux/elf-randomize.h> +#include <linux/security.h> +#include <linux/mman.h> /* * Top of mmap area (just below the process stack). @@ -78,6 +81,111 @@ static inline unsigned long mmap_base(unsigned long rnd) return PAGE_ALIGN(TASK_SIZE - gap - rnd); } +#ifdef CONFIG_PPC_RADIX_MMU +/* + * Same function as generic code used only for radix, because we don't need to overload + * the generic one. But we will have to duplicate, because hash select + * HAVE_ARCH_UNMAPPED_AREA + */ +static unsigned long +radix__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; + struct vm_unmapped_area_info info; + + if (len > TASK_SIZE - mmap_min_addr) + return -ENOMEM; + + if (flags & MAP_FIXED) + return addr; + + if (addr) { + addr = PAGE_ALIGN(addr); + vma = find_vma(mm, addr); + if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && + (!vma || addr + len <= vma->vm_start)) + return addr; + } + + info.flags = 0; + info.length = len; + info.low_limit = mm->mmap_base; + info.high_limit = TASK_SIZE; + info.align_mask = 0; + return vm_unmapped_area(&info); +} + +static unsigned long +radix__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; + struct vm_unmapped_area_info info; + + /* requested length too big for entire address space */ + if (len > TASK_SIZE - mmap_min_addr) + return -ENOMEM; + + if (flags & MAP_FIXED) + return addr; + + /* requesting a specific address */ + if (addr) { + addr = PAGE_ALIGN(addr); + vma = find_vma(mm, addr); + if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && + (!vma || addr + len <= vma->vm_start)) + return addr; + } + + info.flags = VM_UNMAPPED_AREA_TOPDOWN; + info.length = len; + info.low_limit = max(PAGE_SIZE, mmap_min_addr); + info.high_limit = mm->mmap_base; + info.align_mask = 0; + addr = vm_unmapped_area(&info); + + /* + * 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. + */ + if (addr & ~PAGE_MASK) { + VM_BUG_ON(addr != -ENOMEM); + info.flags = 0; + info.low_limit = TASK_UNMAPPED_BASE; + info.high_limit = TASK_SIZE; + addr = vm_unmapped_area(&info); + } + + return addr; +} + +static void radix__arch_pick_mmap_layout(struct mm_struct *mm, + unsigned long random_factor) +{ + if (mmap_is_legacy()) { + mm->mmap_base = TASK_UNMAPPED_BASE; + mm->get_unmapped_area = radix__arch_get_unmapped_area; + } else { + mm->mmap_base = mmap_base(random_factor); + mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown; + } +} +#else +/* dummy */ +extern void radix__arch_pick_mmap_layout(struct mm_struct *mm, + unsigned long random_factor); +#endif /* * This function, called very early during the creation of a new * process VM image, sets up which VM layout function to use: @@ -89,6 +197,8 @@ void arch_pick_mmap_layout(struct mm_struct *mm) if (current->flags & PF_RANDOMIZE) random_factor = arch_mmap_rnd(); + if (radix_enabled()) + return radix__arch_pick_mmap_layout(mm, random_factor); /* * Fall back to the standard layout if the personality * bit is set, or if the expected stack growth is unlimited: |