- 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
81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/* The kernel call implemented in this file:
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* m_type: SYS_CLEAR
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*
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* The parameters for this kernel call are:
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* m1_i1: PR_ENDPT (endpoint of process to clean up)
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*/
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#include "kernel/system.h"
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#include <minix/endpoint.h>
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#if USE_CLEAR
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/*===========================================================================*
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* do_clear *
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*===========================================================================*/
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PUBLIC int do_clear(struct proc * caller, message * m_ptr)
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{
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/* Handle sys_clear. Only the PM can request other process slots to be cleared
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* when a process has exited.
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* The routine to clean up a process table slot cancels outstanding timers,
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* possibly removes the process from the message queues, and resets certain
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* process table fields to the default values.
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*/
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struct proc *rc;
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int exit_p;
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int i;
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if(!isokendpt(m_ptr->PR_ENDPT, &exit_p)) { /* get exiting process */
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return EINVAL;
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}
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rc = proc_addr(exit_p); /* clean up */
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release_address_space(rc);
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/* Don't clear if already cleared. */
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if(isemptyp(rc)) return OK;
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/* Check the table with IRQ hooks to see if hooks should be released. */
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for (i=0; i < NR_IRQ_HOOKS; i++) {
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if (rc->p_endpoint == irq_hooks[i].proc_nr_e) {
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rm_irq_handler(&irq_hooks[i]); /* remove interrupt handler */
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irq_hooks[i].proc_nr_e = NONE; /* mark hook as free */
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}
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}
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/* Remove the process' ability to send and receive messages */
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clear_endpoint(rc);
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/* Turn off any alarm timers at the clock. */
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reset_timer(&priv(rc)->s_alarm_timer);
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/* Make sure that the exiting process is no longer scheduled,
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* and mark slot as FREE. Also mark saved fpu contents as not significant.
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*/
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RTS_SETFLAGS(rc, RTS_SLOT_FREE);
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rc->p_misc_flags &= ~MF_FPU_INITIALIZED;
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/* Release the process table slot. If this is a system process, also
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* release its privilege structure. Further cleanup is not needed at
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* this point. All important fields are reinitialized when the
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* slots are assigned to another, new process.
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*/
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if (priv(rc)->s_flags & SYS_PROC) priv(rc)->s_proc_nr = NONE;
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#if 0
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/* Clean up virtual memory */
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if (rc->p_misc_flags & MF_VM) {
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vm_map_default(rc);
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}
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#endif
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/* release FPU */
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if (fpu_owner == rc)
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release_fpu();
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return OK;
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}
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#endif /* USE_CLEAR */
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