minix/kernel/system/do_mcontext.c

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/* The kernel calls that are implemented in this file:
* m_type: SYS_SETMCONTEXT
* m_type: SYS_GETMCONTEXT
*
* The parameters for these kernel calls are:
* m1_i1: PR_ENDPT # proc endpoint doing call
* m1_p1: PR_MEM_PTR # pointer to mcontext structure
*
*/
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#include "kernel/system.h"
#include <string.h>
#include <machine/mcontext.h>
#if USE_MCONTEXT
/*===========================================================================*
* do_getmcontext *
*===========================================================================*/
PUBLIC int do_getmcontext(struct proc * caller, message * m_ptr)
{
/* Retrieve machine context of a process */
register struct proc *rp;
int proc_nr, r;
mcontext_t mc;
if (! isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
if (iskerneln(proc_nr)) return(EPERM);
rp = proc_addr(proc_nr);
#if (_MINIX_CHIP == _CHIP_INTEL)
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if (!proc_used_fpu(rp))
return(OK); /* No state to copy */
#endif
/* Get the mcontext structure into our address space. */
if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
(vir_bytes) &mc, (phys_bytes) sizeof(struct __mcontext))) != OK)
return(r);
#if (_MINIX_CHIP == _CHIP_INTEL)
/* Copy FPU state */
mc.mc_fpu_flags = 0;
if (proc_used_fpu(rp)) {
/* make sure that the FPU context is saved into proc structure first */
if (fpu_owner == rp) {
disable_fpu_exception();
save_fpu(rp);
}
mc.mc_fpu_flags = 0 | rp->p_misc_flags & MF_FPU_INITIALIZED;
memcpy(&(mc.mc_fpu_state), rp->p_fpu_state.fpu_save_area_p,
FPU_XFP_SIZE);
}
#endif
/* Copy the mcontext structure to the user's address space. */
if ((r = data_copy(KERNEL, (vir_bytes) &mc, m_ptr->PR_ENDPT,
(vir_bytes) m_ptr->PR_CTX_PTR,
(phys_bytes) sizeof(struct __mcontext))) != OK)
return(r);
return(OK);
}
/*===========================================================================*
* do_setmcontext *
*===========================================================================*/
PUBLIC int do_setmcontext(struct proc * caller, message * m_ptr)
{
/* Set machine context of a process */
register struct proc *rp;
int proc_nr, r;
mcontext_t mc;
if (!isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
rp = proc_addr(proc_nr);
/* Get the mcontext structure into our address space. */
if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
(vir_bytes) &mc, (phys_bytes) sizeof(struct __mcontext))) != OK)
return(r);
#if (_MINIX_CHIP == _CHIP_INTEL)
/* Copy FPU state */
if (mc.mc_fpu_flags & MF_FPU_INITIALIZED) {
rp->p_misc_flags |= MF_FPU_INITIALIZED;
memcpy(rp->p_fpu_state.fpu_save_area_p, &(mc.mc_fpu_state),
FPU_XFP_SIZE);
} else
rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
/* force reloading FPU in either case */
if (fpu_owner == rp)
release_fpu();
#endif
return(OK);
}
#endif