arch/um/sys-x86_64/syscalls.c

   1 /*
   2  * Copyright 2003 PathScale, Inc.
   3  *
   4  * Licensed under the GPL
   5  */
   6
   7 #include "linux/linkage.h"
   8 #include "linux/slab.h"
   9 #include "linux/shm.h"
  10 #include "linux/utsname.h"
  11 #include "linux/personality.h"
  12 #include "asm/uaccess.h"
  13 #define __FRAME_OFFSETS
  14 #include "asm/ptrace.h"
  15 #include "asm/unistd.h"
  16 #include "asm/prctl.h" /* XXX This should get the constants from libc */
  17 #include "choose-mode.h"
  18 #include "kern.h"
  19 #include "os.h"
  20
  21 asmlinkage long sys_uname64(struct new_utsname __user * name)
  22 {
  23         int err;
  24         down_read(&uts_sem);
  25         err = copy_to_user(name, utsname(), sizeof (*name));
  26         up_read(&uts_sem);
  27         if (personality(current->personality) == PER_LINUX32)
  28                 err |= copy_to_user(&name->machine, "i686", 5);
  29         return err ? -EFAULT : 0;
  30 }
  31
  32 #ifdef CONFIG_MODE_TT
  33 extern long arch_prctl(int code, unsigned long addr);
  34
  35 static long arch_prctl_tt(int code, unsigned long addr)
  36 {
  37         unsigned long tmp;
  38         long ret;
  39
  40         switch(code){
  41         case ARCH_SET_GS:
  42         case ARCH_SET_FS:
  43                 ret = arch_prctl(code, addr);
  44                 break;
  45         case ARCH_GET_FS:
  46         case ARCH_GET_GS:
  47                 ret = arch_prctl(code, (unsigned long) &tmp);
  48                 if(!ret)
  49                         ret = put_user(tmp, (long __user *)addr);
  50                 break;
  51         default:
  52                 ret = -EINVAL;
  53                 break;
  54         }
  55
  56         return(ret);
  57 }
  58 #endif
  59
  60 #ifdef CONFIG_MODE_SKAS
  61
  62 long arch_prctl_skas(struct task_struct *task, int code,
  63                      unsigned long __user *addr)
  64 {
  65         unsigned long *ptr = addr, tmp;
  66         long ret;
  67         int pid = task->mm->context.skas.id.u.pid;
  68
  69         /*
  70          * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
  71          * be safe), we need to call arch_prctl on the host because
  72          * setting %fs may result in something else happening (like a
  73          * GDT or thread.fs being set instead).  So, we let the host
  74          * fiddle the registers and thread struct and restore the
  75          * registers afterwards.
  76          *
  77          * So, the saved registers are stored to the process (this
  78          * needed because a stub may have been the last thing to run),
  79          * arch_prctl is run on the host, then the registers are read
  80          * back.
  81          */
  82         switch(code){
  83         case ARCH_SET_FS:
  84         case ARCH_SET_GS:
  85                 restore_registers(pid, &current->thread.regs.regs);
  86                 break;
  87         case ARCH_GET_FS:
  88         case ARCH_GET_GS:
  89                 /*
  90                  * With these two, we read to a local pointer and
  91                  * put_user it to the userspace pointer that we were
  92                  * given.  If addr isn't valid (because it hasn't been
  93                  * faulted in or is just bogus), we want put_user to
  94                  * fault it in (or return -EFAULT) instead of having
  95                  * the host return -EFAULT.
  96                  */
  97                 ptr = &tmp;
  98         }
  99
 100         ret = os_arch_prctl(pid, code, ptr);
 101         if(ret)
 102                 return ret;
 103
 104         switch(code){
 105         case ARCH_SET_FS:
 106                 current->thread.arch.fs = (unsigned long) ptr;
 107                 save_registers(pid, &current->thread.regs.regs);
 108                 break;
 109         case ARCH_SET_GS:
 110                 save_registers(pid, &current->thread.regs.regs);
 111                 break;
 112         case ARCH_GET_FS:
 113                 ret = put_user(tmp, addr);
 114                 break;
 115         case ARCH_GET_GS:
 116                 ret = put_user(tmp, addr);
 117                 break;
 118         }
 119
 120         return ret;
 121 }
 122 #endif
 123
 124 long sys_arch_prctl(int code, unsigned long addr)
 125 {
 126         return CHOOSE_MODE_PROC(arch_prctl_tt, arch_prctl_skas, current, code,
 127                                 (unsigned long __user *) addr);
 128 }
 129
 130 long sys_clone(unsigned long clone_flags, unsigned long newsp,
 131                void __user *parent_tid, void __user *child_tid)
 132 {
 133         long ret;
 134
 135         if (!newsp)
 136                 newsp = UPT_SP(&current->thread.regs.regs);
 137         current->thread.forking = 1;
 138         ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
 139                       child_tid);
 140         current->thread.forking = 0;
 141         return ret;
 142 }
 143
 144 void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
 145 {
 146         if((to->thread.arch.fs == 0) || (to->mm == NULL))
 147                 return;
 148
 149         arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
 150 }