cbc9586c13
- FPU context is stored only if conflict between 2 FPU users or while exporting context of a process to userspace while it is the active user of FPU - FPU has its owner (fpu_owner) which points to the process whose state is currently loaded in FPU - the FPU exception is only turned on when scheduling a process which is not the owner of FPU - FPU state is restored for the process that generated the FPU exception. This process runs immediately without letting scheduler to pick a new process to resolve the FPU conflict asap, to minimize the FPU thrashing and FPU exception hadler execution - faster all non-FPU-exception kernel entries as FPU state is not checked nor saved - removed MF_USED_FPU flag, only MF_FPU_INITIALIZED remains to signal that a process has used FPU in the past
103 lines
2.9 KiB
C
103 lines
2.9 KiB
C
/* 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
|
|
*
|
|
*/
|
|
|
|
#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)
|
|
if (!(rp->p_misc_flags & MF_FPU_INITIALIZED))
|
|
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 (rp->p_misc_flags & MF_FPU_INITIALIZED) {
|
|
/* 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
|