/*      $NetBSD: locore.s,v 1.91 2026/03/29 03:24:58 thorpej Exp $      */

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1980, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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.
 *
 *      from: Utah $Hdr: locore.s 1.66 92/12/22$
 *      @(#)locore.s    8.6 (Berkeley) 5/27/94
 */

#include "opt_compat_netbsd.h"
#include "opt_compat_sunos.h"
#include "opt_kgdb.h"
#include "opt_lockdebug.h"

#include "assym.h"
#include <machine/asm.h>
#include <machine/trap.h>

| Remember this is a fun project!

        .data
GLOBAL(mon_crp)
        .long   0,0

| This is for kvm_mkdb, and should be the address of the beginning
| of the kernel text segment (not necessarily the same as kernbase).
        .text
GLOBAL(kernel_text)

| This is the entry point, as well as the end of the temporary stack
| used during process switch (one 8K page ending at start)
ASGLOBAL(tmpstk)
ASGLOBAL(start)

| The first step, after disabling interrupts, is to map enough of the kernel
| into high virtual address space so that we can use position dependent code.
| This is a tricky task on the sun3x because the MMU is already enabled and
| the ROM monitor provides no indication of where the root MMU table is mapped.
| Therefore we must use one of the 68030's 'transparent translation' registers
| to define a range in the address space where the MMU translation is
| turned off.  Once this is complete we can modify the MMU table directly
| without the need for it to be mapped into virtual memory.
| All code must be position independent until otherwise noted, as the
| boot loader has loaded us into low memory but all the symbols in this
| code have been linked high.
        movw    #PSL_HIGHIPL,%sr        | no interrupts
        movl    #KERNBASE3X,%a5         | for vtop conversion
        lea     _C_LABEL(mon_crp),%a0   | where to store the CRP
        subl    %a5,%a0
        | Note: borrowing mon_crp for tt0 setup...
        movl    #0x3F8107,%a0@          | map the low 1GB v=p with the
        .long   0xf0100800              | transparent translation reg0
                                        | [ pmove a0@, tt0 ]
| In order to map the kernel into high memory we will copy the root table
| entry which maps the 16 megabytes of memory starting at 0x0 into the
| entry which maps the 16 megabytes starting at KERNBASE.
        pmove   %crp,%a0@               | Get monitor CPU root pointer
        movl    %a0@(4),%a1             | 2nd word is PA of level A table

        movl    %a1,%a0                 | compute the descriptor address
        addl    #0x3e0,%a1              | for VA starting at KERNBASE
        movl    %a0@,%a1@               | copy descriptor type
        movl    %a0@(4),%a1@(4)         | copy physical address

| Kernel is now double mapped at zero and KERNBASE.
| Force a long jump to the relocated code (high VA).
        movl    #IC_CLEAR,%d0           | Flush the I-cache
        movc    %d0,%cacr
        jmp L_high_code:l               | long jump

L_high_code:
| We are now running in the correctly relocated kernel, so
| we are no longer restricted to position-independent code.
| It is handy to leave transparent translation enabled while
| for the low 1GB while _bootstrap() is doing its thing.

| Do bootstrap stuff needed before main() gets called.
| Our boot loader leaves a copy of the kernel's exec header
| just before the start of the kernel text segment, so the
| kernel can sanity-check the DDB symbols at [end...esym].
| Pass the struct exec at tmpstk-32 to _bootstrap().
| Also, make sure the initial frame pointer is zero so that
| the backtrace algorithm used by KGDB terminates nicely.
|
| _bootstrap() returns lwp0 SP in %a0
        lea     _ASM_LABEL(tmpstk)-32,%sp
        jsr     _C_LABEL(_bootstrap)    | See locore2.c
        movl    %a0,%sp                 | now running on lwp0's stack
        movl    #0,%a6                  | terminate the stack back trace

| Now turn off the transparent translation of the low 1GB.
| (this also flushes the ATC)
        clrl    %sp@-
        .long   0xf0170800              | pmove sp@,tt0
        addql   #4,%sp

        jra     _C_LABEL(main)          | main() (never returns)

| That is all the assembly startup code we need on the sun3x!
| The rest of this is like the hp300/locore.s where possible.

/*
 * Interrupt handlers.  Most are auto-vectored,
 * and hard-wired the same way on all sun3 models.
 * Format in the stack is:
 *   %d0,%d1,%a0,%a1, sr, pc, vo
 */

/* clock: see clock.c */
#ifdef __ELF__
        .align  4
#else
        .align  2
#endif
GLOBAL(_isr_clock)
        INTERRUPT_SAVEREG
        jbsr    _C_LABEL(clock_intr)
        INTERRUPT_RESTOREREG
        jra     _ASM_LABEL(rei)

/*
 * Initialization is at the beginning of this file, because the
 * kernel entry point needs to be at zero for compatibility with
 * the Sun boot loader.  This works on Sun machines because the
 * interrupt vector table for reset is NOT at address zero.
 * (The MMU has a "boot" bit that forces access to the PROM)
 */

#ifdef DEBUG
        .data
ASGLOBAL(fulltflush)
        .long   0
ASGLOBAL(fullcflush)
        .long   0
        .text
#endif

/*
 * Load a new CPU Root Pointer (CRP) into the MMU.
 *      void    loadcrp(struct mmu_rootptr *);
 */
ENTRY(loadcrp)
        movl    %sp@(4),%a0             | arg1: &CRP
        movl    #CACHE_CLR,%d0
        movc    %d0,%cacr               | invalidate cache(s)
        pflusha                         | flush entire TLB
        pmove   %a0@,%crp               | load new user root pointer
        rts

ENTRY(getcrp)
        movl    %sp@(4),%a0             | arg1: &crp
        pmove   %crp,%a0@               | *crpp = %crp
        rts

/*
 * Get the physical address of the PTE for a given VA.
 */
ENTRY(ptest_addr)
        movl    %sp@(4),%a1             | VA
        ptestr  #5,%a1@,#7,%a0          | %a0 = addr of PTE
        movl    %a0,%d0                 | Result in %d0 (not a pointer return)
        rts

| Define some addresses, mostly so DDB can print useful info.
| Not using _C_LABEL() here because these symbols are never
| referenced by any C code, and if the leading underscore
| ever goes away, these lines turn into syntax errors...
        .set    _KERNBASE3X,KERNBASE3X
        .set    _MONSTART,SUN3X_MONSTART
        .set    _PROM_BASE,SUN3X_PROM_BASE
        .set    _MONEND,SUN3X_MONEND

|The end!