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 #include <linux/elf.h> 18 19 #include <asm/ia32.h> 20 #include <asm/syscalls.h> 21 22 /* 23 * Align a virtual address to avoid aliasing in the I$ on AMD F15h. 24 * 25 * @flags denotes the allocation direction - bottomup or topdown - 26 * or vDSO; see call sites below. 27 */ 28 unsigned long align_addr(unsigned long addr, struct file *filp, 29 enum align_flags flags) 30 { 31 unsigned long tmp_addr; 32 33 /* handle 32- and 64-bit case with a single conditional */ 34 if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32()))) 35 return addr; 36 37 if (!(current->flags & PF_RANDOMIZE)) 38 return addr; 39 40 if (!((flags & ALIGN_VDSO) || filp)) 41 return addr; 42 43 tmp_addr = addr; 44 45 /* 46 * We need an address which is <= than the original 47 * one only when in topdown direction. 48 */ 49 if (!(flags & ALIGN_TOPDOWN)) 50 tmp_addr += va_align.mask; 51 52 tmp_addr &= ~va_align.mask; 53 54 return tmp_addr; 55 } 56 57 static int __init control_va_addr_alignment(char *str) 58 { 59 /* guard against enabling this on other CPU families */ 60 if (va_align.flags < 0) 61 return 1; 62 63 if (*str == 0) 64 return 1; 65 66 if (*str == '=') 67 str++; 68 69 if (!strcmp(str, "32")) 70 va_align.flags = ALIGN_VA_32; 71 else if (!strcmp(str, "64")) 72 va_align.flags = ALIGN_VA_64; 73 else if (!strcmp(str, "off")) 74 va_align.flags = 0; 75 else if (!strcmp(str, "on")) 76 va_align.flags = ALIGN_VA_32 | ALIGN_VA_64; 77 else 78 return 0; 79 80 return 1; 81 } 82 __setup("align_va_addr", control_va_addr_alignment); 83 84 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, 85 unsigned long, prot, unsigned long, flags, 86 unsigned long, fd, unsigned long, off) 87 { 88 long error; 89 error = -EINVAL; 90 if (off & ~PAGE_MASK) 91 goto out; 92 93 error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); 94 out: 95 return error; 96 } 97 98 static void find_start_end(unsigned long flags, unsigned long *begin, 99 unsigned long *end) 100 { 101 if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) { 102 unsigned long new_begin; 103 /* This is usually used needed to map code in small 104 model, so it needs to be in the first 31bit. Limit 105 it to that. This means we need to move the 106 unmapped base down for this case. This can give 107 conflicts with the heap, but we assume that glibc 108 malloc knows how to fall back to mmap. Give it 1GB 109 of playground for now. -AK */ 110 *begin = 0x40000000; 111 *end = 0x80000000; 112 if (current->flags & PF_RANDOMIZE) { 113 new_begin = randomize_range(*begin, *begin + 0x02000000, 0); 114 if (new_begin) 115 *begin = new_begin; 116 } 117 } else { 118 *begin = TASK_UNMAPPED_BASE; 119 *end = TASK_SIZE; 120 } 121 } 122 123 unsigned long 124 arch_get_unmapped_area(struct file *filp, unsigned long addr, 125 unsigned long len, unsigned long pgoff, unsigned long flags) 126 { 127 struct mm_struct *mm = current->mm; 128 struct vm_area_struct *vma; 129 unsigned long start_addr; 130 unsigned long begin, end; 131 132 if (flags & MAP_FIXED) 133 return addr; 134 135 find_start_end(flags, &begin, &end); 136 137 if (len > end) 138 return -ENOMEM; 139 140 if (addr) { 141 addr = PAGE_ALIGN(addr); 142 vma = find_vma(mm, addr); 143 if (end - len >= addr && 144 (!vma || addr + len <= vma->vm_start)) 145 return addr; 146 } 147 if (((flags & MAP_32BIT) || test_thread_flag(TIF_ADDR32)) 148 && len <= mm->cached_hole_size) { 149 mm->cached_hole_size = 0; 150 mm->free_area_cache = begin; 151 } 152 addr = mm->free_area_cache; 153 if (addr < begin) 154 addr = begin; 155 start_addr = addr; 156 157 full_search: 158 159 addr = align_addr(addr, filp, 0); 160 161 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 162 /* At this point: (!vma || addr < vma->vm_end). */ 163 if (end - len < addr) { 164 /* 165 * Start a new search - just in case we missed 166 * some holes. 167 */ 168 if (start_addr != begin) { 169 start_addr = addr = begin; 170 mm->cached_hole_size = 0; 171 goto full_search; 172 } 173 return -ENOMEM; 174 } 175 if (!vma || addr + len <= vma->vm_start) { 176 /* 177 * Remember the place where we stopped the search: 178 */ 179 mm->free_area_cache = addr + len; 180 return addr; 181 } 182 if (addr + mm->cached_hole_size < vma->vm_start) 183 mm->cached_hole_size = vma->vm_start - addr; 184 185 addr = vma->vm_end; 186 addr = align_addr(addr, filp, 0); 187 } 188 } 189 190 191 unsigned long 192 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 193 const unsigned long len, const unsigned long pgoff, 194 const unsigned long flags) 195 { 196 struct vm_area_struct *vma; 197 struct mm_struct *mm = current->mm; 198 unsigned long addr = addr0, start_addr; 199 200 /* requested length too big for entire address space */ 201 if (len > TASK_SIZE) 202 return -ENOMEM; 203 204 if (flags & MAP_FIXED) 205 return addr; 206 207 /* for MAP_32BIT mappings we force the legact mmap base */ 208 if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) 209 goto bottomup; 210 211 /* requesting a specific address */ 212 if (addr) { 213 addr = PAGE_ALIGN(addr); 214 vma = find_vma(mm, addr); 215 if (TASK_SIZE - len >= addr && 216 (!vma || addr + len <= vma->vm_start)) 217 return addr; 218 } 219 220 /* check if free_area_cache is useful for us */ 221 if (len <= mm->cached_hole_size) { 222 mm->cached_hole_size = 0; 223 mm->free_area_cache = mm->mmap_base; 224 } 225 226 try_again: 227 /* either no address requested or can't fit in requested address hole */ 228 start_addr = addr = mm->free_area_cache; 229 230 if (addr < len) 231 goto fail; 232 233 addr -= len; 234 do { 235 addr = align_addr(addr, filp, ALIGN_TOPDOWN); 236 237 /* 238 * Lookup failure means no vma is above this address, 239 * else if new region fits below vma->vm_start, 240 * return with success: 241 */ 242 vma = find_vma(mm, addr); 243 if (!vma || addr+len <= vma->vm_start) 244 /* remember the address as a hint for next time */ 245 return mm->free_area_cache = addr; 246 247 /* remember the largest hole we saw so far */ 248 if (addr + mm->cached_hole_size < vma->vm_start) 249 mm->cached_hole_size = vma->vm_start - addr; 250 251 /* try just below the current vma->vm_start */ 252 addr = vma->vm_start-len; 253 } while (len < vma->vm_start); 254 255 fail: 256 /* 257 * if hint left us with no space for the requested 258 * mapping then try again: 259 */ 260 if (start_addr != mm->mmap_base) { 261 mm->free_area_cache = mm->mmap_base; 262 mm->cached_hole_size = 0; 263 goto try_again; 264 } 265 266 bottomup: 267 /* 268 * A failed mmap() very likely causes application failure, 269 * so fall back to the bottom-up function here. This scenario 270 * can happen with large stack limits and large mmap() 271 * allocations. 272 */ 273 mm->cached_hole_size = ~0UL; 274 mm->free_area_cache = TASK_UNMAPPED_BASE; 275 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); 276 /* 277 * Restore the topdown base: 278 */ 279 mm->free_area_cache = mm->mmap_base; 280 mm->cached_hole_size = ~0UL; 281 282 return addr; 283 } 284