os161/kern/arch/mips/include/specialreg.h
2015-12-23 00:50:04 +00:00

118 lines
5.2 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* 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 UNIVERSITY 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 UNIVERSITY 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.
*/
#ifndef _MIPS_SPECIALREG_H_
#define _MIPS_SPECIALREG_H_
/*
* Coprocessor 0 (system processor) register numbers
*/
#define c0_index $0 /* TLB entry index register */
#define c0_random $1 /* TLB random slot register */
#define c0_entrylo $2 /* TLB entry contents (low-order half) */
/* c0_entrylo0 $2 */ /* MIPS-II and up only */
/* c0_entrylo1 $3 */ /* MIPS-II and up only */
#define c0_context $4 /* some precomputed pagetable stuff */
/* c0_pagemask $5 */ /* MIPS-II and up only */
/* c0_wired $6 */ /* MIPS-II and up only */
#define c0_vaddr $8 /* virtual addr of failing memory access */
#define c0_count $9 /* cycle counter (MIPS-II and up) */
#define c0_entryhi $10 /* TLB entry contents (high-order half) */
#define c0_compare $11 /* on-chip timer control (MIPS-II and up) */
#define c0_status $12 /* processor status register */
#define c0_cause $13 /* exception cause register */
#define c0_epc $14 /* exception PC register */
#define c0_prid $15 /* processor ID register */
/* c0_config $16 */ /* MIPS-II and up only */
/* c0_lladdr $17 */ /* MIPS-II and up only */
/* c0_watchlo $18 */ /* MIPS-II and up only */
/* c0_watchhi $19 */ /* MIPS-II and up only */
/*
* Mode bits in c0_status
*/
#define CST_IEc 0x00000001 /* current: interrupt enable */
#define CST_KUc 0x00000002 /* current: user mode */
#define CST_IEp 0x00000004 /* previous: interrupt enable */
#define CST_KUp 0x00000008 /* previous: user mode */
#define CST_IEo 0x00000010 /* old: interrupt enable */
#define CST_KUo 0x00000020 /* old: user mode */
#define CST_MODEMASK 0x0000003f /* mask for the above */
#define CST_IRQMASK 0x0000ff00 /* mask for the individual irq enable bits */
#define CST_BEV 0x00400000 /* bootstrap exception vectors flag */
/*
* Fields of the c0_cause register
*/
#define CCA_UTLB 0x00000001 /* true if UTLB exception (set by our asm) */
#define CCA_CODE 0x0000003c /* EX_foo in trapframe.h */
#define CCA_IRQS 0x0000ff00 /* Currently pending interrupts */
#define CCA_COPN 0x30000000 /* Coprocessor number for EX_CPU */
#define CCA_JD 0x80000000 /* True if exception happened in jump delay */
#define CCA_CODESHIFT 2 /* shift for CCA_CODE field */
/*
* Fields of the c0_index register
*/
#define CIN_P 0x80000000 /* nonzero -> TLB probe found nothing */
#define CIN_INDEX 0x00003f00 /* 6-bit index into TLB */
#define CIN_INDEXSHIFT 8 /* shift for CIN_INDEX field */
/*
* Fields of the c0_context register
*
* The intent of c0_context is that you can manage virtually-mapped
* page tables in kseg2; then you load the base address of the current
* page table into c0_context. On a TLB miss the failing address is
* masked and shifted and appears in the VSHIFT field, and c0_context
* thereby contains the address of the page table entry you need to
* load into the TLB. This can be used to make TLB refill very fast.
*
* However, in OS/161 we use CTX_PTBASE to hold the current CPU
* number. This (or something like it) is fairly important to have and
* there's no other good place in the chip to put it. See discussions
* elsewhere.
*/
#define CTX_VSHIFT 0x001ffffc /* shifted/masked copy of c0_vaddr */
#define CTX_PTBASE 0xffe00000 /* page table base address */
#define CTX_PTBASESHIFT 21 /* shift for CTX_PBASE field */
/*
* Hardwired exception handler addresses.
*/
#define EXADDR_UTLB 0x80000000
#define EXADDR_GENERAL 0x80000080
#endif /* _MIPS_SPECIALREG_H_ */