minix3/kernel/system/do_mcontext.c

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2020-02-21 00:59:27 +05:30
/* The kernel calls that are implemented in this file:
* m_type: SYS_SETMCONTEXT
* m_type: SYS_GETMCONTEXT
*
* The parameters for SYS_SETMCONTEXT kernel call are:
* m_lsys_krn_sys_setmcontext.endpt # proc endpoint doing call
* m_lsys_krn_sys_setmcontext.ctx_ptr # pointer to mcontext structure
*
* The parameters for SYS_GETMCONTEXT kernel call are:
* m_lsys_krn_sys_getmcontext.endpt # proc endpoint doing call
* m_lsys_krn_sys_getmcontext.ctx_ptr # pointer to mcontext structure
*/
#include "kernel/system.h"
#include <string.h>
#include <assert.h>
#include <machine/mcontext.h>
#if USE_MCONTEXT
/*===========================================================================*
* do_getmcontext *
*===========================================================================*/
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->m_lsys_krn_sys_getmcontext.endpt, &proc_nr))
return(EINVAL);
if (iskerneln(proc_nr)) return(EPERM);
rp = proc_addr(proc_nr);
#if defined(__i386__)
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->m_lsys_krn_sys_getmcontext.endpt,
m_ptr->m_lsys_krn_sys_getmcontext.ctx_ptr, KERNEL,
(vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
return(r);
mc.mc_flags = 0;
#if defined(__i386__)
/* Copy FPU state */
if (proc_used_fpu(rp)) {
/* make sure that the FPU context is saved into proc structure first */
save_fpu(rp);
mc.mc_flags = (rp->p_misc_flags & MF_FPU_INITIALIZED) ? _MC_FPU_SAVED : 0;
assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
memcpy(&(mc.__fpregs.__fp_reg_set), rp->p_seg.fpu_state, FPU_XFP_SIZE);
}
#endif
/* Copy the mcontext structure to the user's address space. */
if ((r = data_copy(KERNEL, (vir_bytes) &mc,
m_ptr->m_lsys_krn_sys_getmcontext.endpt,
m_ptr->m_lsys_krn_sys_getmcontext.ctx_ptr,
(phys_bytes) sizeof(mcontext_t))) != OK)
return(r);
return(OK);
}
/*===========================================================================*
* do_setmcontext *
*===========================================================================*/
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->m_lsys_krn_sys_setmcontext.endpt, &proc_nr)) return(EINVAL);
rp = proc_addr(proc_nr);
/* Get the mcontext structure into our address space. */
if ((r = data_copy(m_ptr->m_lsys_krn_sys_setmcontext.endpt,
m_ptr->m_lsys_krn_sys_setmcontext.ctx_ptr, KERNEL,
(vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
return(r);
#if defined(__i386__)
/* Copy FPU state */
if (mc.mc_flags & _MC_FPU_SAVED) {
rp->p_misc_flags |= MF_FPU_INITIALIZED;
assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
memcpy(rp->p_seg.fpu_state, &(mc.__fpregs.__fp_reg_set), FPU_XFP_SIZE);
} else
rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
/* force reloading FPU in either case */
release_fpu(rp);
#endif
return(OK);
}
#endif