arch/um/kernel/uaccess_user.c

   1 /*
   2  * Copyright (C) 2001 Chris Emerson (cemerson@chiark.greenend.org.uk)
   3  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include <setjmp.h>
   8 #include <string.h>
   9
  10 /* These are here rather than tt/uaccess.c because skas mode needs them in
  11  * order to do SIGBUS recovery when a tmpfs mount runs out of room.
  12  */
  13
  14 unsigned long __do_user_copy(void *to, const void *from, int n,
  15                              void **fault_addr, void **fault_catcher,
  16                              void (*op)(void *to, const void *from,
  17                                         int n), int *faulted_out)
  18 {
  19         unsigned long *faddrp = (unsigned long *) fault_addr, ret;
  20
  21         sigjmp_buf jbuf;
  22         *fault_catcher = &jbuf;
  23         if(sigsetjmp(jbuf, 1) == 0){
  24                 (*op)(to, from, n);
  25                 ret = 0;
  26                 *faulted_out = 0;
  27         }
  28         else {
  29                 ret = *faddrp;
  30                 *faulted_out = 1;
  31         }
  32         *fault_addr = NULL;
  33         *fault_catcher = NULL;
  34         return ret;
  35 }
  36
  37 void __do_copy(void *to, const void *from, int n)
  38 {
  39         memcpy(to, from, n);
  40 }
  41
  42
  43 int __do_copy_to_user(void *to, const void *from, int n,
  44                       void **fault_addr, void **fault_catcher)
  45 {
  46         unsigned long fault;
  47         int faulted;
  48
  49         fault = __do_user_copy(to, from, n, fault_addr, fault_catcher,
  50                                __do_copy, &faulted);
  51         if(!faulted) return(0);
  52         else return(n - (fault - (unsigned long) to));
  53 }
  54
  55 /*
  56  * Overrides for Emacs so that we follow Linus's tabbing style.
  57  * Emacs will notice this stuff at the end of the file and automatically
  58  * adjust the settings for this buffer only.  This must remain at the end
  59  * of the file.
  60  * ---------------------------------------------------------------------------
  61  * Local variables:
  62  * c-file-style: "linux"
  63  * End:
  64  */