minix/kernel/system/do_mcontext.c

   1 /* The kernel calls that are implemented in this file:
   2  *   m_type:    SYS_SETMCONTEXT
   3  *   m_type:    SYS_GETMCONTEXT
   4  *
   5  * The parameters for SYS_SETMCONTEXT kernel call are:
   6  *   m_lsys_krn_sys_setmcontext.endpt   # proc endpoint doing call
   7  *   m_lsys_krn_sys_setmcontext.ctx_ptr # pointer to mcontext structure
   8  *
   9  * The parameters for SYS_GETMCONTEXT kernel call are:
  10  *   m_lsys_krn_sys_getmcontext.endpt   # proc endpoint doing call
  11  *   m_lsys_krn_sys_getmcontext.ctx_ptr # pointer to mcontext structure
  12  */
  13
  14 #include "kernel/system.h"
  15 #include <string.h>
  16 #include <assert.h>
  17 #include <machine/mcontext.h>
  18
  19 #if USE_MCONTEXT
  20 /*===========================================================================*
  21  *                            do_getmcontext                                 *
  22  *===========================================================================*/
  23 int do_getmcontext(struct proc * caller, message * m_ptr)
  24 {
  25 /* Retrieve machine context of a process */
  26
  27   register struct proc *rp;
  28   int proc_nr, r;
  29   mcontext_t mc;
  30
  31   if (!isokendpt(m_ptr->m_lsys_krn_sys_getmcontext.endpt, &proc_nr))
  32         return(EINVAL);
  33   if (iskerneln(proc_nr)) return(EPERM);
  34   rp = proc_addr(proc_nr);
  35
  36 #if defined(__i386__)
  37   if (!proc_used_fpu(rp))
  38         return(OK);     /* No state to copy */
  39 #endif
  40
  41   /* Get the mcontext structure into our address space.  */
  42   if ((r = data_copy(m_ptr->m_lsys_krn_sys_getmcontext.endpt,
  43                 m_ptr->m_lsys_krn_sys_getmcontext.ctx_ptr, KERNEL,
  44                 (vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
  45         return(r);
  46
  47   mc.mc_flags = 0;
  48 #if defined(__i386__)
  49   /* Copy FPU state */
  50   if (proc_used_fpu(rp)) {
  51         /* make sure that the FPU context is saved into proc structure first */
  52         save_fpu(rp);
  53         mc.mc_flags = (rp->p_misc_flags & MF_FPU_INITIALIZED) ? _MC_FPU_SAVED : 0;
  54         assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
  55         memcpy(&(mc.__fpregs.__fp_reg_set), rp->p_seg.fpu_state, FPU_XFP_SIZE);
  56   }
  57 #endif
  58
  59
  60   /* Copy the mcontext structure to the user's address space. */
  61   if ((r = data_copy(KERNEL, (vir_bytes) &mc,
  62         m_ptr->m_lsys_krn_sys_getmcontext.endpt,
  63         m_ptr->m_lsys_krn_sys_getmcontext.ctx_ptr,
  64         (phys_bytes) sizeof(mcontext_t))) != OK)
  65         return(r);
  66
  67   return(OK);
  68 }
  69
  70
  71 /*===========================================================================*
  72  *                            do_setmcontext                                 *
  73  *===========================================================================*/
  74 int do_setmcontext(struct proc * caller, message * m_ptr)
  75 {
  76 /* Set machine context of a process */
  77
  78   register struct proc *rp;
  79   int proc_nr, r;
  80   mcontext_t mc;
  81
  82   if (!isokendpt(m_ptr->m_lsys_krn_sys_setmcontext.endpt, &proc_nr)) return(EINVAL);
  83   rp = proc_addr(proc_nr);
  84
  85   /* Get the mcontext structure into our address space.  */
  86   if ((r = data_copy(m_ptr->m_lsys_krn_sys_setmcontext.endpt,
  87                 m_ptr->m_lsys_krn_sys_setmcontext.ctx_ptr, KERNEL,
  88                 (vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
  89         return(r);
  90
  91 #if defined(__i386__)
  92   /* Copy FPU state */
  93   if (mc.mc_flags & _MC_FPU_SAVED) {
  94         rp->p_misc_flags |= MF_FPU_INITIALIZED;
  95         assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
  96         memcpy(rp->p_seg.fpu_state, &(mc.__fpregs.__fp_reg_set), FPU_XFP_SIZE);
  97   } else
  98         rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
  99   /* force reloading FPU in either case */
 100   release_fpu(rp);
 101 #endif
 102
 103   return(OK);
 104 }
 105
 106 #endif