1 #include <linux/errno.h> 2 #include <linux/sched.h> 3 #include <linux/syscalls.h> 4 #include <linux/mm.h> 5 #include <linux/fs.h> 6 #include <linux/smp.h> 7 #include <linux/sem.h> 8 #include <linux/msg.h> 9 #include <linux/shm.h> 10 #include <linux/stat.h> 11 #include <linux/mman.h> 12 #include <linux/file.h> 13 #include <linux/utsname.h> 14 #include <linux/personality.h> 15 #include <linux/random.h> 16 #include <linux/uaccess.h> 17 18 #include <asm/ia32.h> 19 #include <asm/syscalls.h> 20 21 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, 22 unsigned long, prot, unsigned long, flags, 23 unsigned long, fd, unsigned long, off) 24 { 25 long error; 26 error = -EINVAL; 27 if (off & ~PAGE_MASK) 28 goto out; 29 30 error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); 31 out: 32 return error; 33 } 34 35 static void find_start_end(unsigned long flags, unsigned long *begin, 36 unsigned long *end) 37 { 38 if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) { 39 unsigned long new_begin; 40 /* This is usually used needed to map code in small 41 model, so it needs to be in the first 31bit. Limit 42 it to that. This means we need to move the 43 unmapped base down for this case. This can give 44 conflicts with the heap, but we assume that glibc 45 malloc knows how to fall back to mmap. Give it 1GB 46 of playground for now. -AK */ 47 *begin = 0x40000000; 48 *end = 0x80000000; 49 if (current->flags & PF_RANDOMIZE) { 50 new_begin = randomize_range(*begin, *begin + 0x02000000, 0); 51 if (new_begin) 52 *begin = new_begin; 53 } 54 } else { 55 *begin = TASK_UNMAPPED_BASE; 56 *end = TASK_SIZE; 57 } 58 } 59 60 unsigned long 61 arch_get_unmapped_area(struct file *filp, unsigned long addr, 62 unsigned long len, unsigned long pgoff, unsigned long flags) 63 { 64 struct mm_struct *mm = current->mm; 65 struct vm_area_struct *vma; 66 unsigned long start_addr; 67 unsigned long begin, end; 68 69 if (flags & MAP_FIXED) 70 return addr; 71 72 find_start_end(flags, &begin, &end); 73 74 if (len > end) 75 return -ENOMEM; 76 77 if (addr) { 78 addr = PAGE_ALIGN(addr); 79 vma = find_vma(mm, addr); 80 if (end - len >= addr && 81 (!vma || addr + len <= vma->vm_start)) 82 return addr; 83 } 84 if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32)) 85 && len <= mm->cached_hole_size) { 86 mm->cached_hole_size = 0; 87 mm->free_area_cache = begin; 88 } 89 addr = mm->free_area_cache; 90 if (addr < begin) 91 addr = begin; 92 start_addr = addr; 93 94 full_search: 95 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 96 /* At this point: (!vma || addr < vma->vm_end). */ 97 if (end - len < addr) { 98 /* 99 * Start a new search - just in case we missed 100 * some holes. 101 */ 102 if (start_addr != begin) { 103 start_addr = addr = begin; 104 mm->cached_hole_size = 0; 105 goto full_search; 106 } 107 return -ENOMEM; 108 } 109 if (!vma || addr + len <= vma->vm_start) { 110 /* 111 * Remember the place where we stopped the search: 112 */ 113 mm->free_area_cache = addr + len; 114 return addr; 115 } 116 if (addr + mm->cached_hole_size < vma->vm_start) 117 mm->cached_hole_size = vma->vm_start - addr; 118 119 addr = vma->vm_end; 120 } 121 } 122 123 124 unsigned long 125 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 126 const unsigned long len, const unsigned long pgoff, 127 const unsigned long flags) 128 { 129 struct vm_area_struct *vma; 130 struct mm_struct *mm = current->mm; 131 unsigned long addr = addr0; 132 133 /* requested length too big for entire address space */ 134 if (len > TASK_SIZE) 135 return -ENOMEM; 136 137 if (flags & MAP_FIXED) 138 return addr; 139 140 /* for MAP_32BIT mappings we force the legact mmap base */ 141 if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) 142 goto bottomup; 143 144 /* requesting a specific address */ 145 if (addr) { 146 addr = PAGE_ALIGN(addr); 147 vma = find_vma(mm, addr); 148 if (TASK_SIZE - len >= addr && 149 (!vma || addr + len <= vma->vm_start)) 150 return addr; 151 } 152 153 /* check if free_area_cache is useful for us */ 154 if (len <= mm->cached_hole_size) { 155 mm->cached_hole_size = 0; 156 mm->free_area_cache = mm->mmap_base; 157 } 158 159 /* either no address requested or can't fit in requested address hole */ 160 addr = mm->free_area_cache; 161 162 /* make sure it can fit in the remaining address space */ 163 if (addr > len) { 164 vma = find_vma(mm, addr-len); 165 if (!vma || addr <= vma->vm_start) 166 /* remember the address as a hint for next time */ 167 return mm->free_area_cache = addr-len; 168 } 169 170 if (mm->mmap_base < len) 171 goto bottomup; 172 173 addr = mm->mmap_base-len; 174 175 do { 176 /* 177 * Lookup failure means no vma is above this address, 178 * else if new region fits below vma->vm_start, 179 * return with success: 180 */ 181 vma = find_vma(mm, addr); 182 if (!vma || addr+len <= vma->vm_start) 183 /* remember the address as a hint for next time */ 184 return mm->free_area_cache = addr; 185 186 /* remember the largest hole we saw so far */ 187 if (addr + mm->cached_hole_size < vma->vm_start) 188 mm->cached_hole_size = vma->vm_start - addr; 189 190 /* try just below the current vma->vm_start */ 191 addr = vma->vm_start-len; 192 } while (len < vma->vm_start); 193 194 bottomup: 195 /* 196 * A failed mmap() very likely causes application failure, 197 * so fall back to the bottom-up function here. This scenario 198 * can happen with large stack limits and large mmap() 199 * allocations. 200 */ 201 mm->cached_hole_size = ~0UL; 202 mm->free_area_cache = TASK_UNMAPPED_BASE; 203 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); 204 /* 205 * Restore the topdown base: 206 */ 207 mm->free_area_cache = mm->mmap_base; 208 mm->cached_hole_size = ~0UL; 209 210 return addr; 211 } 212