- RTS_VMINHIBIT flag is used to stop process while VM is fiddling with its pagetables - more generic way of sending synchronous scheduling events among cpus - do the x-cpu smp sched calls only if the target process is runnable. If it is not, it cannot be running and it cannot become runnable this CPU holds the BKL
76 lines
2.3 KiB
C
76 lines
2.3 KiB
C
/* The kernel call implemented in this file:
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* m_type: SYS_RUNCTL
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*
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* The parameters for this kernel call are:
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* m1_i1: RC_ENDPT process number to control
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* m1_i2: RC_ACTION stop or resume the process
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* m1_i3: RC_FLAGS request flags
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*/
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#include "kernel/system.h"
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#include <assert.h>
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#if USE_RUNCTL
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/*===========================================================================*
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* do_runctl *
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*===========================================================================*/
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PUBLIC int do_runctl(struct proc * caller, message * m_ptr)
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{
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/* Control a process's RTS_PROC_STOP flag. Used for process management.
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* If the process is queued sending a message or stopped for system call
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* tracing, and the RC_DELAY request flag is given, set MF_SIG_DELAY instead
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* of RTS_PROC_STOP, and send a SIGSNDELAY signal later when the process is done
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* sending (ending the delay). Used by PM for safe signal delivery.
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*/
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int proc_nr, action, flags;
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register struct proc *rp;
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/* Extract the message parameters and do sanity checking. */
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if (!isokendpt(m_ptr->RC_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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action = m_ptr->RC_ACTION;
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flags = m_ptr->RC_FLAGS;
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/* Is the target sending or syscall-traced? Then set MF_SIG_DELAY instead.
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* Do this only when the RC_DELAY flag is set in the request flags field.
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* The process will not become runnable before PM has called SYS_ENDKSIG.
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* Note that asynchronous messages are not covered: a process using SENDA
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* should not also install signal handlers *and* expect POSIX compliance.
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*/
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if (action == RC_STOP && (flags & RC_DELAY)) {
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if (RTS_ISSET(rp, RTS_SENDING) || (rp->p_misc_flags & MF_SC_DEFER))
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rp->p_misc_flags |= MF_SIG_DELAY;
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if (rp->p_misc_flags & MF_SIG_DELAY)
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return (EBUSY);
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}
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/* Either set or clear the stop flag. */
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switch (action) {
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case RC_STOP:
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#if CONFIG_SMP
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/* check if we must stop a process on a different CPU */
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if (rp->p_cpu != cpuid) {
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smp_schedule_stop_proc(rp);
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break;
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}
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#endif
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RTS_SET(rp, RTS_PROC_STOP);
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break;
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case RC_RESUME:
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assert(RTS_ISSET(rp, RTS_PROC_STOP));
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RTS_UNSET(rp, RTS_PROC_STOP);
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break;
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default:
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return(EINVAL);
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}
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return(OK);
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}
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#endif /* USE_RUNCTL */
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