Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/mm/mmap.c |
| 3 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | #include <linux/fs.h> |
| 5 | #include <linux/mm.h> |
| 6 | #include <linux/mman.h> |
| 7 | #include <linux/shm.h> |
Alexey Dobriyan | e8edc6e | 2007-05-21 01:22:52 +0400 | [diff] [blame] | 8 | #include <linux/sched.h> |
Russell King | 09d9bae | 2008-09-05 14:08:44 +0100 | [diff] [blame] | 9 | #include <linux/io.h> |
Nicolas Pitre | cc92c28 | 2010-06-14 21:16:19 -0400 | [diff] [blame] | 10 | #include <linux/random.h> |
Russell King | 0ba8b9b | 2008-08-10 18:08:10 +0100 | [diff] [blame] | 11 | #include <asm/cputype.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <asm/system.h> |
| 13 | |
| 14 | #define COLOUR_ALIGN(addr,pgoff) \ |
| 15 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ |
| 16 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) |
| 17 | |
| 18 | /* |
| 19 | * We need to ensure that shared mappings are correctly aligned to |
| 20 | * avoid aliasing issues with VIPT caches. We need to ensure that |
| 21 | * a specific page of an object is always mapped at a multiple of |
| 22 | * SHMLBA bytes. |
| 23 | * |
| 24 | * We unconditionally provide this function for all cases, however |
| 25 | * in the VIVT case, we optimise out the alignment rules. |
| 26 | */ |
| 27 | unsigned long |
| 28 | arch_get_unmapped_area(struct file *filp, unsigned long addr, |
| 29 | unsigned long len, unsigned long pgoff, unsigned long flags) |
| 30 | { |
| 31 | struct mm_struct *mm = current->mm; |
| 32 | struct vm_area_struct *vma; |
| 33 | unsigned long start_addr; |
Russell King | e399b1a | 2011-01-17 15:08:32 +0000 | [diff] [blame] | 34 | #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | unsigned int cache_type; |
| 36 | int do_align = 0, aliasing = 0; |
| 37 | |
| 38 | /* |
| 39 | * We only need to do colour alignment if either the I or D |
| 40 | * caches alias. This is indicated by bits 9 and 21 of the |
| 41 | * cache type register. |
| 42 | */ |
Russell King | 0ba8b9b | 2008-08-10 18:08:10 +0100 | [diff] [blame] | 43 | cache_type = read_cpuid_cachetype(); |
| 44 | if (cache_type != read_cpuid_id()) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | aliasing = (cache_type | cache_type >> 12) & (1 << 11); |
| 46 | if (aliasing) |
| 47 | do_align = filp || flags & MAP_SHARED; |
| 48 | } |
| 49 | #else |
| 50 | #define do_align 0 |
| 51 | #define aliasing 0 |
| 52 | #endif |
| 53 | |
| 54 | /* |
Benjamin Herrenschmidt | acec0ac | 2007-05-06 14:50:07 -0700 | [diff] [blame] | 55 | * We enforce the MAP_FIXED case. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | */ |
| 57 | if (flags & MAP_FIXED) { |
Al Viro | e77414e | 2009-12-05 15:10:44 -0500 | [diff] [blame] | 58 | if (aliasing && flags & MAP_SHARED && |
| 59 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | return -EINVAL; |
| 61 | return addr; |
| 62 | } |
| 63 | |
| 64 | if (len > TASK_SIZE) |
| 65 | return -ENOMEM; |
| 66 | |
| 67 | if (addr) { |
| 68 | if (do_align) |
| 69 | addr = COLOUR_ALIGN(addr, pgoff); |
| 70 | else |
| 71 | addr = PAGE_ALIGN(addr); |
| 72 | |
| 73 | vma = find_vma(mm, addr); |
| 74 | if (TASK_SIZE - len >= addr && |
| 75 | (!vma || addr + len <= vma->vm_start)) |
| 76 | return addr; |
| 77 | } |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 78 | if (len > mm->cached_hole_size) { |
| 79 | start_addr = addr = mm->free_area_cache; |
| 80 | } else { |
| 81 | start_addr = addr = TASK_UNMAPPED_BASE; |
| 82 | mm->cached_hole_size = 0; |
| 83 | } |
Nicolas Pitre | cc92c28 | 2010-06-14 21:16:19 -0400 | [diff] [blame] | 84 | /* 8 bits of randomness in 20 address space bits */ |
| 85 | if (current->flags & PF_RANDOMIZE) |
| 86 | addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | |
| 88 | full_search: |
| 89 | if (do_align) |
| 90 | addr = COLOUR_ALIGN(addr, pgoff); |
| 91 | else |
| 92 | addr = PAGE_ALIGN(addr); |
| 93 | |
| 94 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { |
| 95 | /* At this point: (!vma || addr < vma->vm_end). */ |
| 96 | if (TASK_SIZE - len < addr) { |
| 97 | /* |
| 98 | * Start a new search - just in case we missed |
| 99 | * some holes. |
| 100 | */ |
| 101 | if (start_addr != TASK_UNMAPPED_BASE) { |
| 102 | start_addr = addr = TASK_UNMAPPED_BASE; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 103 | mm->cached_hole_size = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | goto full_search; |
| 105 | } |
| 106 | return -ENOMEM; |
| 107 | } |
| 108 | if (!vma || addr + len <= vma->vm_start) { |
| 109 | /* |
| 110 | * Remember the place where we stopped the search: |
| 111 | */ |
| 112 | mm->free_area_cache = addr + len; |
| 113 | return addr; |
| 114 | } |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 115 | if (addr + mm->cached_hole_size < vma->vm_start) |
| 116 | mm->cached_hole_size = vma->vm_start - addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | addr = vma->vm_end; |
| 118 | if (do_align) |
| 119 | addr = COLOUR_ALIGN(addr, pgoff); |
| 120 | } |
| 121 | } |
| 122 | |
Lennert Buytenhek | 51635ad | 2006-09-16 10:50:22 +0100 | [diff] [blame] | 123 | |
| 124 | /* |
| 125 | * You really shouldn't be using read() or write() on /dev/mem. This |
| 126 | * might go away in the future. |
| 127 | */ |
| 128 | int valid_phys_addr_range(unsigned long addr, size_t size) |
| 129 | { |
Alexandre Rusev | 9ae3ae0 | 2008-02-26 18:42:10 +0100 | [diff] [blame] | 130 | if (addr < PHYS_OFFSET) |
| 131 | return 0; |
Greg Ungerer | 6806bfe | 2009-10-02 00:45:28 +0100 | [diff] [blame] | 132 | if (addr + size > __pa(high_memory - 1) + 1) |
Lennert Buytenhek | 51635ad | 2006-09-16 10:50:22 +0100 | [diff] [blame] | 133 | return 0; |
| 134 | |
| 135 | return 1; |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * We don't use supersection mappings for mmap() on /dev/mem, which |
| 140 | * means that we can't map the memory area above the 4G barrier into |
| 141 | * userspace. |
| 142 | */ |
| 143 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
| 144 | { |
| 145 | return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); |
| 146 | } |
Nicolas Pitre | 087aaff | 2010-09-22 18:34:36 -0400 | [diff] [blame] | 147 | |
| 148 | #ifdef CONFIG_STRICT_DEVMEM |
| 149 | |
| 150 | #include <linux/ioport.h> |
| 151 | |
| 152 | /* |
| 153 | * devmem_is_allowed() checks to see if /dev/mem access to a certain |
| 154 | * address is valid. The argument is a physical page number. |
| 155 | * We mimic x86 here by disallowing access to system RAM as well as |
| 156 | * device-exclusive MMIO regions. This effectively disable read()/write() |
| 157 | * on /dev/mem. |
| 158 | */ |
| 159 | int devmem_is_allowed(unsigned long pfn) |
| 160 | { |
| 161 | if (iomem_is_exclusive(pfn << PAGE_SHIFT)) |
| 162 | return 0; |
| 163 | if (!page_is_ram(pfn)) |
| 164 | return 1; |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | #endif |