From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/arm/mm/mmap.c | 240 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 240 insertions(+) create mode 100644 arch/arm/mm/mmap.c (limited to 'arch/arm/mm/mmap.c') diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c new file mode 100644 index 000000000..407dc7865 --- /dev/null +++ b/arch/arm/mm/mmap.c @@ -0,0 +1,240 @@ +/* + * linux/arch/arm/mm/mmap.c + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define COLOUR_ALIGN(addr,pgoff) \ + ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ + (((pgoff)<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); +} + +/* + * 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; + int do_align = 0; + int aliasing = cache_is_vipt_aliasing(); + struct vm_unmapped_area_info info; + + /* + * 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; + } + + info.flags = 0; + info.length = len; + info.low_limit = mm->mmap_base; + info.high_limit = TASK_SIZE; + info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; + info.align_offset = pgoff << PAGE_SHIFT; + return vm_unmapped_area(&info); +} + +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(); + struct vm_unmapped_area_info info; + + /* + * 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; + } + + info.flags = VM_UNMAPPED_AREA_TOPDOWN; + info.length = len; + info.low_limit = FIRST_USER_ADDRESS; + info.high_limit = mm->mmap_base; + info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; + info.align_offset = pgoff << PAGE_SHIFT; + 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 = mm->mmap_base; + info.high_limit = TASK_SIZE; + addr = vm_unmapped_area(&info); + } + + return addr; +} + +unsigned long arch_mmap_rnd(void) +{ + unsigned long rnd; + + /* 8 bits of randomness in 20 address space bits */ + rnd = (unsigned long)get_random_int() % (1 << 8); + + return rnd << PAGE_SHIFT; +} + +void arch_pick_mmap_layout(struct mm_struct *mm) +{ + unsigned long random_factor = 0UL; + + if (current->flags & PF_RANDOMIZE) + random_factor = arch_mmap_rnd(); + + if (mmap_is_legacy()) { + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; + mm->get_unmapped_area = arch_get_unmapped_area; + } else { + mm->mmap_base = mmap_base(random_factor); + mm->get_unmapped_area = arch_get_unmapped_area_topdown; + } +} + +/* + * You really shouldn't be using read() or write() on /dev/mem. This + * might go away in the future. + */ +int valid_phys_addr_range(phys_addr_t addr, size_t size) +{ + if (addr < PHYS_OFFSET) + return 0; + if (addr + size > __pa(high_memory - 1) + 1) + return 0; + + return 1; +} + +/* + * Do not allow /dev/mem mappings beyond the supported physical range. + */ +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT)); +} + +#ifdef CONFIG_STRICT_DEVMEM + +#include + +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain + * address is valid. The argument is a physical page number. + * We mimic x86 here by disallowing access to system RAM as well as + * device-exclusive MMIO regions. This effectively disable read()/write() + * on /dev/mem. + */ +int devmem_is_allowed(unsigned long pfn) +{ + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pfn)) + return 1; + return 0; +} + +#endif -- cgit v1.2.3-54-g00ecf