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/fs.h>
  10 #include <linux/smp.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         if (flags & MAP_FIXED)
  97                 return addr;
  98
  99         find_start_end(flags, &begin, &end);
 100
 101         if (len > end)
 102                 return -ENOMEM;
 103
 104         if (addr) {
 105                 addr = PAGE_ALIGN(addr);
 106                 vma = find_vma(mm, addr);
 107                 if (end - len >= addr &&
 108                     (!vma || addr + len <= vma->vm_start))
 109                         return addr;
 110         }
 111         if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
 112             && len <= mm->cached_hole_size) {
 113                 mm->cached_hole_size = 0;
 114                 mm->free_area_cache = begin;
 115         }
 116         addr = mm->free_area_cache;
 117         if (addr < begin)
 118                 addr = begin;
 119         start_addr = addr;
 120
 121 full_search:
 122         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 123                 /* At this point:  (!vma || addr < vma->vm_end). */
 124                 if (end - len < addr) {
 125                         /*
 126                          * Start a new search - just in case we missed
 127                          * some holes.
 128                          */
 129                         if (start_addr != begin) {
 130                                 start_addr = addr = begin;
 131                                 mm->cached_hole_size = 0;
 132                                 goto full_search;
 133                         }
 134                         return -ENOMEM;
 135                 }
 136                 if (!vma || addr + len <= vma->vm_start) {
 137                         /*
 138                          * Remember the place where we stopped the search:
 139                          */
 140                         mm->free_area_cache = addr + len;
 141                         return addr;
 142                 }
 143                 if (addr + mm->cached_hole_size < vma->vm_start)
 144                         mm->cached_hole_size = vma->vm_start - addr;
 145
 146                 addr = vma->vm_end;
 147         }
 148 }
 149
 150 asmlinkage long sys_uname(struct new_utsname __user * name)
 151 {
 152         int err;
 153         down_read(&uts_sem);
 154         err = copy_to_user(name, utsname(), sizeof (*name));
 155         up_read(&uts_sem);
 156         if (personality(current->personality) == PER_LINUX32)
 157                 err |= copy_to_user(&name->machine, "i686", 5);
 158         return err ? -EFAULT : 0;
 159 }