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