/* $OpenBSD: pcb.h,v 1.11 2022/10/21 18:55:42 miod 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. 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 */ #ifndef _MACHINE_PCB_H_ #define _MACHINE_PCB_H_ #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 -- probably not needed */ const char *lastcall; /* DEBUG -- name of last system call */ u_int64_t pcb_wcookie; /* the following MUST be aligned on a 64-bit boundary */ struct rwindow pcb_rw[PCB_MAXWIN]; /* saved windows */ u_int64_t pcb_rwsp[PCB_MAXWIN]; }; #ifndef _KERNEL /* Let gdb compile. We need fancier macros to make these make sense. */ #define pcb_psr pcb_pstate #define pcb_wim pcb_cwp #endif /* _KERNEL */ #endif /* _MACHINE_PCB_H_ */
