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/* $OpenBSD: pcb.h,v 1.2 2001/08/20 20:23:52 jason Exp $ */
/* $NetBSD: pcb.h,v 1.7 2000/12/29 17:12:05 eeh Exp $ */
/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)pcb.h 8.1 (Berkeley) 6/11/93
*/
#include <machine/reg.h>
#ifdef notyet
#define PCB_MAXWIN 32 /* architectural limit */
#else
#define PCB_MAXWIN 8 /* worried about u area sizes ... */
#endif
/*
* SPARC Process Control Block.
*
* pcb_uw is positive if there are any user windows that are
* are currently in the CPU windows rather than on the user
* stack. Whenever we are running in the kernel with traps
* enabled, we decrement pcb_uw for each ``push'' of a CPU
* register window into the stack, and we increment it for
* each ``pull'' from the stack into the CPU. (If traps are
* disabled, or if we are in user mode, pcb_uw is junk.)
*
* To ease computing pcb_uw on traps from user mode, we keep track
* of the log base 2 of the single bit that is set in %wim.
*
* If an overflow occurs while the associated user stack pages
* are invalid (paged out), we have to store the registers
* in a page that is locked in core while the process runs,
* i.e., right here in the pcb. We also need the stack pointer
* for the last such window (but only the last, as the others
* are in each window) and the count of windows saved. We
* cheat by having a whole window structure for that one %sp.
* Thus, to save window pcb_rw[i] to memory, we write it at
* pcb_rw[i + 1].rw_in[6].
*
* pcb_nsaved has three `kinds' of values. If 0, it means no
* registers are in the PCB (though if pcb_uw is positive,
* there may be the next time you look). If positive, it means
* there are no user registers in the CPU, but there are some
* saved in pcb_rw[]. As a special case, traps that needed
* assistance to pull user registers from the stack also store
* the registers in pcb_rw[], and set pcb_nsaved to -1. This
* special state is normally short-term: it can only last until the
* trap returns, and it can never persist across entry to user code.
*/
/*
* v9 addendum:
*
* Window handling between v8 and v9 has changed somewhat. There
* is no %wim. Instead, we have a %cwp, %cansave, %canrestore,
* %cleanwin, and %otherwin. By definition:
*
* %cansave + %canrestore + %otherwin = NWINDOWS - 2
*
* In addition, %cleanwin >= %canrestore since restorable windows
* are considered clean. This means that by storing %canrestore
* and %otherwin, we should be able to compute the values of all
* the other registers.
*
* The only other register we need to save is %cwp because it cannot
* be trivially computed from the other registers. The %cwp is
* stored in the %tstate register, but if the machine was in a register
* window spill/fill handler, the value of that %cwp may be off by
* as much as 2 register windows. We will also store %cwp. [We will
* try to steal pcb_uw or pcb_nsaved for this purpose eventually.]
*
* To calculate what registers are in the pcb, start with pcb_cwp
* and proceed to (pcb_cwp - pcb_canrestore) % NWINDOWS. These should
* be saved to their appropriate register windows. The client routine
* (trap handler) is responsible for saving pcb_cwp + 1 [%o1-%o7] in
* the trap frame or on the stack.
*
*
* Even more addendum:
*
* With the new system for keeping track of register windows we don't
* care about anything other than pcb_uw which keeps track of how many
* full windows we have. As soon as a flush traps, we dump all user
* windows to the pcb, handle the fault, then restore all user windows.
*
* XXX we are using pcb_nsaved as the counter. pcb_uw is still a mask.
* change this as soon as the new scheme is debugged.
*/
struct pcb {
u_int64_t pcb_sp; /* sp (%o6) when switch() was called */
u_int64_t pcb_pc; /* pc (%o7) when switch() was called */
caddr_t pcb_onfault; /* for copyin/out */
short pcb_pstate; /* %pstate when switch() was called -- may be useful if we support multiple memory models */
char pcb_nsaved; /* number of windows saved in pcb */
/* The rest is probably not needed except for pcb_rw */
char pcb_cwp; /* %cwp when switch() was called */
char pcb_pil; /* %pil when switch() was called -- prolly not needed */
const char *lastcall; /* DEBUG -- name of last system call */
/* the following MUST be aligned on a 64-bit boundary */
struct rwindow64 pcb_rw[PCB_MAXWIN]; /* saved windows */
};
/*
* The pcb is augmented with machine-dependent additional data for
* core dumps. Note that the trapframe here is a copy of the one
* from the top of the kernel stack (included here so that the kernel
* stack itself need not be dumped).
*/
struct md_coredump {
struct trapframe64 md_tf;
struct fpstate64 md_fpstate;
};
#ifdef _KERNEL
extern struct pcb *cpcb;
#else
/* Let gdb compile. We need fancier macros to make these make sense. */
#define pcb_psr pcb_pstate
#define pcb_wim pcb_cwp
#endif /* _KERNEL */
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