vtop(9r) [osf1 man page]

vtop(9r)																  vtop(9r)

NAME

       vtop - General: Converts any virtual address to a physical address

SYNOPSIS

       vm_offset_t vtop(
	       struct proc *proc_p,
	       vm_offset_t virt_addr );

ARGUMENTS

       Specifies  a  pointer  to  a  proc  structure.  The vtop routine uses the proc structure pointer to obtain the pmap.  Specifies the virtual
       address that vtop converts to a physical address.

DESCRIPTION

       The vtop routine converts a specified virtual address to a physical address.

CAUTIONS

       The vtop routine panics and displays the following message on the console terminal if the proc structure pointer you pass is NULL  and  the
       virtual address is in user space:

       vtop: user address passed with null proc pointer

RETURN VALUES

       Upon successful completion, vtop returns the physical address associated with the specified virtual address.

																	  vtop(9r)

KSEG_TO_PHYS(9r)														  KSEG_TO_PHYS(9r)

NAME

       KSEG_TO_PHYS - General: Converts a kernel-unmapped virtual address to a physical address

SYNOPSIS

       vm_offset_t KSEG_TO_PHYS(
	       vm_offset_t addr );

ARGUMENTS

       Specifies the buffer virtual address to convert to a physical address.

DESCRIPTION

       The  KSEG_TO_PHYS  routine  converts  a	kernel-unmapped virtual address to a kernel physical address. Device drivers can use this physical
       address in DMA operations. Prior to calling KSEG_TO_PHYS, device driver writers often call one  of  the	following  routines  to  determine
       whether the address passed is a virtual address in the addressed kernel segment: IS_KSEG_VA

	      Determines if the specified address is located in the kernel-unmapped address space.  IS_SEG0_VA

	      Determines if the specified address is located in the user-mapped address space.	IS_SEG1_VA

	      Determines if the specified address is located in the kernel-mapped address space.

RETURN VALUES

       Upon successful completion, KSEG_TO_PHYS returns the physical address.

EXAMPLE

       The following code fragment shows a call to KSEG_TO_PHYS:

       .  .  .

       caddr_t virt_addr;  [1] unsigned phys_addr; [2]

       .  .  .

	   if(IS_KSEG_VA(virt_addr)) { [3]
	       phys_addr = KSEG_TO_PHYS(virt_addr); [4]

       .  .  .

       Declares  a  variable  to  store  the  user  buffer's  virtual  address.   Declares  a  variable  to store the physical address returned by
       KSEG_TO_PHYS.  Before calling KSEG_TO_PHYS, calls IS_KSEG_VA to determine if the virtual address is from the kernel-unmapped address space.
       If  the virtual address is from the kernel-unmapped address space, then calls KSEG_TO_PHYS to convert the address to a corresponding physi-
       cal address.

SEE ALSO

       Routines: IS_KSEG_VA(9r), PHYS_TO_KSEG(9r)

																  KSEG_TO_PHYS(9r)