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 these kernel calls are:
   6  *     m1_i1:   PR_ENDPT        # proc endpoint doing call
   7  *     m1_p1:   PR_MEM_PTR      # pointer to mcontext structure
   8  *
   9  */
  10
  11 #include "kernel/system.h"
  12 #include <string.h>
  13 #include <machine/mcontext.h>
  14
  15 #if USE_MCONTEXT
  16 /*===========================================================================*
  17  *                            do_getmcontext                                 *
  18  *===========================================================================*/
  19 int do_getmcontext(struct proc * caller, message * m_ptr)
  20 {
  21 /* Retrieve machine context of a process */
  22
  23   register struct proc *rp;
  24   int proc_nr, r;
  25   mcontext_t mc;
  26
  27   if (! isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
  28   if (iskerneln(proc_nr)) return(EPERM);
  29   rp = proc_addr(proc_nr);
  30
  31 #if defined(__i386__)
  32   if (!proc_used_fpu(rp))
  33         return(OK);     /* No state to copy */
  34 #endif
  35
  36   /* Get the mcontext structure into our address space.  */
  37   if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
  38                 (vir_bytes) &mc, (phys_bytes) sizeof(struct __mcontext))) != OK)
  39         return(r);
  40
  41 #if defined(__i386__)
  42   /* Copy FPU state */
  43   mc.mc_fpu_flags = 0;
  44   if (proc_used_fpu(rp)) {
  45         /* make sure that the FPU context is saved into proc structure first */
  46         save_fpu(rp);
  47         mc.mc_fpu_flags = rp->p_misc_flags & MF_FPU_INITIALIZED;
  48         memcpy(&(mc.mc_fpu_state), rp->p_seg.fpu_state, FPU_XFP_SIZE);
  49   }
  50 #endif
  51
  52
  53   /* Copy the mcontext structure to the user's address space. */
  54   if ((r = data_copy(KERNEL, (vir_bytes) &mc, m_ptr->PR_ENDPT,
  55         (vir_bytes) m_ptr->PR_CTX_PTR,
  56         (phys_bytes) sizeof(struct __mcontext))) != OK)
  57         return(r);
  58
  59   return(OK);
  60 }
  61
  62
  63 /*===========================================================================*
  64  *                            do_setmcontext                                 *
  65  *===========================================================================*/
  66 int do_setmcontext(struct proc * caller, message * m_ptr)
  67 {
  68 /* Set machine context of a process */
  69
  70   register struct proc *rp;
  71   int proc_nr, r;
  72   mcontext_t mc;
  73
  74   if (!isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
  75   rp = proc_addr(proc_nr);
  76
  77   /* Get the mcontext structure into our address space.  */
  78   if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
  79                 (vir_bytes) &mc, (phys_bytes) sizeof(struct __mcontext))) != OK)
  80         return(r);
  81
  82 #if defined(__i386__)
  83   /* Copy FPU state */
  84   if (mc.mc_fpu_flags & MF_FPU_INITIALIZED) {
  85         rp->p_misc_flags |= MF_FPU_INITIALIZED;
  86         memcpy(rp->p_seg.fpu_state, &(mc.mc_fpu_state), FPU_XFP_SIZE);
  87   } else
  88         rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
  89   /* force reloading FPU in either case */
  90   release_fpu(rp);
  91 #endif
  92
  93   return(OK);
  94 }
  95
  96 #endif