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phys(2) [bsd man page]

PHYS(2) 							System Calls Manual							   PHYS(2)

NAME
phys - allow a process to access physical addresses (2BSD) SYNOPSIS
phys(segreg, size, physaddr) unsigned int segreg, size, physaddr; DESCRIPTION
The argument segreg specifies a process virtual (data-space) address range of 8K bytes starting at virtual address segregx8K bytes. This address range is mapped into physical address physaddrx64 bytes. Only the first sizex64 bytes of this mapping is addressable. If size is zero, any previous mapping of this virtual address range is nullified. For example, the call phys(7, 1, 0177775); will map virtual addresses 0160000-0160077 into physical addresses 017777500-017777577. In particular, virtual address 0160060 is the PDP-11 console located at physical address 017777560. This call may only be executed by the super-user. ERRORS
[EPERM] The process's effective user ID is not the super-user. [EINVAL] Segreg is less than 0 or greater than 7. [EINVAL] Size is less than 0 or greater than 128. SEE ALSO
PDP-11 segmentation hardware BUGS
On systems with ENABLE/34(tm) memory mapping boards, phys cannot be used to map in the I/O page. This system call is very dangerous. It is not considered a permanent part of the system. Phys is unique to the PDP-11 and 2BSD; its use is discouraged. 3rd Berkeley Distribution January 22, 1987 PHYS(2)

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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)

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