209 lines
5.4 KiB
C
209 lines
5.4 KiB
C
/* $NetBSD: db_memrw.c,v 1.4 1997/06/10 19:36:55 veego Exp $ */
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/*-
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* Copyright (c) 1996 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Gordon W. Ross and Jeremy Cooper.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Interface to the debugger for virtual memory read/write.
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* This file is shared by DDB and KGDB, and must work even
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* when only KGDB is included (thus no db_printf calls).
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*
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* To write in the text segment, we have to first make
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* the page writable, do the write, then restore the PTE.
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* For writes outside the text segment, and all reads,
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* just do the access -- if it causes a fault, the debugger
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* will recover with a longjmp to an appropriate place.
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*
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* ALERT! If you want to access device registers with a
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* specific size, then the read/write functions have to
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* make sure to do the correct sized pointer access.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <vm/vm.h>
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#include <machine/pte.h>
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#include <machine/db_machdep.h>
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#include <machine/machdep.h>
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#include <ddb/db_access.h>
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extern char etext[]; /* defined by the linker */
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extern char kernel_text[]; /* locore.s */
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static void db_write_text __P((char *, size_t size, char *));
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/*
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* Read bytes from kernel address space for debugger.
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* This used to check for valid PTEs, but now that
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* traps in DDB work correctly, "Just Do It!"
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*/
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void
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db_read_bytes(addr, size, data)
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vm_offset_t addr;
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register size_t size;
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register char *data;
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{
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register char *src = (char*)addr;
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if (size == 4) {
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*((int*)data) = *((int*)src);
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return;
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}
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if (size == 2) {
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*((short*)data) = *((short*)src);
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return;
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}
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while (size > 0) {
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--size;
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*data++ = *src++;
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}
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}
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/*
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* Write bytes somewhere in kernel text.
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* Makes text page writable temporarily.
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*
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* XXX - Look at the hp300 version of this. -gwr
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*/
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static void
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db_write_text(dst, size, data)
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register char *dst;
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register size_t size;
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register char *data;
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{
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int oldpte, tmppte;
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vm_offset_t pgva, prevpg;
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/* Prevent restoring a garbage PTE. */
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if (size <= 0)
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return;
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pgva = m68k_trunc_page((long)dst);
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goto firstpage;
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do {
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/*
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* If we are on a new page, restore the PTE
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* for the previous page, and make the new
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* page writable.
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*/
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pgva = m68k_trunc_page((long)dst);
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if (pgva != prevpg) {
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/* Restore old PTE and flush the cache. */
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set_pte(prevpg, oldpte);
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TBIS(prevpg);
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firstpage:
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/*
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* Flush the VAC to prevent a cache hit
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* on the old, read-only PTE.
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*/
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#ifdef HAVECACHE
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if (cache_size)
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cache_flush_page(pgva);
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#endif
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oldpte = get_pte(pgva);
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if ((oldpte & MMU_DT_MASK) == 0) {
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printf(" address %p not a valid page\n", dst);
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return;
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}
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/* Remove any write protect bit, and add
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* a cache inhibit bit.
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*/
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tmppte = oldpte;
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tmppte &= ~MMU_SHORT_PTE_WP;
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tmppte |= MMU_SHORT_PTE_CI;
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set_pte(pgva, tmppte);
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TBIS(pgva);
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prevpg = pgva;
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}
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/* Now we can write in this page of kernel text... */
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*dst++ = *data++;
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} while (--size > 0);
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/* Restore old PTE for the last page touched. */
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set_pte(prevpg, oldpte);
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TBIS(prevpg);
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/* Finally, clear the instruction cache. */
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ICIA();
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}
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/*
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* Write bytes to kernel address space for debugger.
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*/
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void
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db_write_bytes(addr, size, data)
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vm_offset_t addr;
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register size_t size;
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register char *data;
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{
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register char *dst = (char *)addr;
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/* If any part is in kernel text, use db_write_text() */
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if ((dst < etext) && ((dst + size) > kernel_text)) {
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db_write_text(dst, size, data);
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return;
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}
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if (size == 4) {
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*((int*)dst) = *((int*)data);
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return;
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}
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if (size == 2) {
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*((short*)dst) = *((short*)data);
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return;
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}
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while (size > 0) {
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--size;
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*dst++ = *data++;
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}
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}
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