arch/x86_64/kernel/sys_x86_64.c

   1 /*
   2  * linux/arch/x86_64/kernel/sys_x86_64.c
   3  */
   4
   5 #include <linux/errno.h>
   6 #include <linux/sched.h>
   7 #include <linux/syscalls.h>
   8 #include <linux/mm.h>
   9 #include <linux/smp.h>
  10 #include <linux/smp_lock.h>
  11 #include <linux/sem.h>
  12 #include <linux/msg.h>
  13 #include <linux/shm.h>
  14 #include <linux/stat.h>
  15 #include <linux/mman.h>
  16 #include <linux/file.h>
  17 #include <linux/utsname.h>
  18 #include <linux/personality.h>
  19
  20 #include <asm/uaccess.h>
  21 #include <asm/ia32.h>
  22
  23 /*
  24  * sys_pipe() is the normal C calling standard for creating
  25  * a pipe. It's not the way Unix traditionally does this, though.
  26  */
  27 asmlinkage long sys_pipe(int __user *fildes)
  28 {
  29         int fd[2];
  30         int error;
  31
  32         error = do_pipe(fd);
  33         if (!error) {
  34                 if (copy_to_user(fildes, fd, 2*sizeof(int)))
  35                         error = -EFAULT;
  36         }
  37         return error;
  38 }
  39
  40 asmlinkage long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags,
  41         unsigned long fd, unsigned long off)
  42 {
  43         long error;
  44         struct file * file;
  45
  46         error = -EINVAL;
  47         if (off & ~PAGE_MASK)
  48                 goto out;
  49
  50         error = -EBADF;
  51         file = NULL;
  52         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  53         if (!(flags & MAP_ANONYMOUS)) {
  54                 file = fget(fd);
  55                 if (!file)
  56                         goto out;
  57         }
  58         down_write(&current->mm->mmap_sem);
  59         error = do_mmap_pgoff(file, addr, len, prot, flags, off >> PAGE_SHIFT);
  60         up_write(&current->mm->mmap_sem);
  61
  62         if (file)
  63                 fput(file);
  64 out:
  65         return error;
  66 }
  67
  68 static void find_start_end(unsigned long flags, unsigned long *begin,
  69                            unsigned long *end)
  70 {
  71         if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
  72                 /* This is usually used needed to map code in small
  73                    model, so it needs to be in the first 31bit. Limit
  74                    it to that.  This means we need to move the
  75                    unmapped base down for this case. This can give
  76                    conflicts with the heap, but we assume that glibc
  77                    malloc knows how to fall back to mmap. Give it 1GB
  78                    of playground for now. -AK */
  79                 *begin = 0x40000000;
  80                 *end = 0x80000000;
  81         } else {
  82                 *begin = TASK_UNMAPPED_BASE;
  83                 *end = TASK_SIZE;
  84         }
  85 }
  86
  87 unsigned long
  88 arch_get_unmapped_area(struct file *filp, unsigned long addr,
  89                 unsigned long len, unsigned long pgoff, unsigned long flags)
  90 {
  91         struct mm_struct *mm = current->mm;
  92         struct vm_area_struct *vma;
  93         unsigned long start_addr;
  94         unsigned long begin, end;
  95
  96         find_start_end(flags, &begin, &end);
  97
  98         if (len > end)
  99                 return -ENOMEM;
 100
 101         if (addr) {
 102                 addr = PAGE_ALIGN(addr);
 103                 vma = find_vma(mm, addr);
 104                 if (end - len >= addr &&
 105                     (!vma || addr + len <= vma->vm_start))
 106                         return addr;
 107         }
 108         if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
 109             && len <= mm->cached_hole_size) {
 110                 mm->cached_hole_size = 0;
 111                 mm->free_area_cache = begin;
 112         }
 113         addr = mm->free_area_cache;
 114         if (addr < begin)
 115                 addr = begin;
 116         start_addr = addr;
 117
 118 full_search:
 119         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 120                 /* At this point:  (!vma || addr < vma->vm_end). */
 121                 if (end - len < addr) {
 122                         /*
 123                          * Start a new search - just in case we missed
 124                          * some holes.
 125                          */
 126                         if (start_addr != begin) {
 127                                 start_addr = addr = begin;
 128                                 mm->cached_hole_size = 0;
 129                                 goto full_search;
 130                         }
 131                         return -ENOMEM;
 132                 }
 133                 if (!vma || addr + len <= vma->vm_start) {
 134                         /*
 135                          * Remember the place where we stopped the search:
 136                          */
 137                         mm->free_area_cache = addr + len;
 138                         return addr;
 139                 }
 140                 if (addr + mm->cached_hole_size < vma->vm_start)
 141                         mm->cached_hole_size = vma->vm_start - addr;
 142
 143                 addr = vma->vm_end;
 144         }
 145 }
 146
 147 asmlinkage long sys_uname(struct new_utsname __user * name)
 148 {
 149         int err;
 150         down_read(&uts_sem);
 151         err = copy_to_user(name, &system_utsname, sizeof (*name));
 152         up_read(&uts_sem);
 153         if (personality(current->personality) == PER_LINUX32)
 154                 err |= copy_to_user(&name->machine, "i686", 5);
 155         return err ? -EFAULT : 0;
 156 }