curcpu(9) [netbsd man page]

CURPROC(9)						   BSD Kernel Developer's Manual						CURPROC(9)

NAME

     curproc, curcpu, curlwp -- current process, processor, and LWP

SYNOPSIS

     #include <sys/proc.h>

     struct cpu_info *
     curcpu(void);

     struct proc *
     curproc(void);

     struct lwp *
     curlwp(void);

DESCRIPTION

     The following macros can be used to retrieve the current processor, process, and light-weight process (LWP), respectively:

	   1.	The machine-dependent curcpu() macro returns a pointer to a cpu_info structure containing information of the CPU that this thread
		is running on.

	   2.	The machine-independent curproc() macro refers to a pointer to the process currently running on this CPU.

	   3.	The curlwp() macro expands to a pointer to lwp structure, containing information about the current LWP.  This macro is machine-
		independent, but machine-dependent <machine/cpu.h> may redefine it.

SEE ALSO

     cpu_number(9), proc_find(9)

BSD
								   July 1, 2010 							       BSD

CPU_SWITCHTO(9) 					   BSD Kernel Developer's Manual					   CPU_SWITCHTO(9)

NAME

     cpu_switchto -- machine-dependent LWP context switching interface

SYNOPSIS

     #include <sys/cpu.h>

     lwp_t *
     cpu_switchto(lwp_t *oldlwp, lwp_t *newlwp, bool returning);

DESCRIPTION

     The cpu_switchto() function saves the context of the LWP which is currently running on the processor, and restores the context of the LWP
     specified by newlwp.

     Remarks:

	   1.	cpu_switchto() does not switch address spaces.

	   2.	cpu_switchto() sets curlwp(9) to newlwp.  If the architecture does non-interlocked adaptive mutex release, cpu_switchto() does an
		equivalent of membar_producer(3), before and after the modification of curlwp(9).

	   3.	cpu_switchto() should be called at IPL_SCHED.  When the function returns, the caller should lower the priority level as soon as
		possible.

	   4.	cpu_switchto() might be called with spin mutexes held.

     The function takes the following arguments.

	   oldlwp      Specify the LWP from which the switch is going to be made, i.e., the calling LWP.  If it was NULL, the context of the LWP
		       currently running on this processor is not saved.

	   newlwp      Specify the LWP to which to switch.  It must not be NULL.

	   returning   Only meaningful if the architecture implements fast software interrupts.  If true, it indicates that oldlwp is a soft
		       interrupt LWP that is blocking.	It is a good indication that any kind of address space or user activity can be completely
		       ignored.  For example: ras_lookup(9), cache flushes, TLB wirings, adjusting lazy FPU state.  All that is required is to
		       restore the register state and stack, and return to the interrupted LWP.

RETURN VALUES

     The cpu_switchto() function does not return until another LWP calls cpu_switchto().  It returns the oldlwp argument of the cpu_switchto()
     which is called to switch back to our LWP.  It is either a LWP which called cpu_switchto() to switch to us or NULL in case the LWP was exit-
     ing.

SEE ALSO

     membar_producer(3), swapcontext(3), intro(9), mutex(9), spl(9)

BSD
								   June 2, 2011 							       BSD