198 lines
5.2 KiB
C
198 lines
5.2 KiB
C
/* $NetBSD: db_memrw.c,v 1.7 2005/12/11 12:19:16 christos 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/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: db_memrw.c,v 1.7 2005/12/11 12:19:16 christos Exp $");
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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 <uvm/uvm_extern.h>
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#include <machine/db_machdep.h>
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#include <machine/pte.h>
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#include <sun2/sun2/machdep.h>
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#include <sun2/sun2/control.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(char *, size_t size, const 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(db_addr_t addr, size_t size, char *data)
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{
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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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static void
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db_write_text(char *dst, size_t size, const char *data)
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{
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int oldpte, tmppte;
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vaddr_t pgva, prevpg;
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int old_ctx;
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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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old_ctx = get_context();
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set_context(0);
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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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/*
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* Restore old PTE. No cache flush,
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* because the tmp PTE has no-cache.
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*/
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set_pte(prevpg, oldpte);
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firstpage:
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oldpte = get_pte(pgva);
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if ((oldpte & PG_VALID) == 0) {
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printf(" address %p not a valid page\n", dst);
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set_context(old_ctx);
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return;
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}
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/*
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* Make the pte writable and non-cached.
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*/
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tmppte = oldpte;
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tmppte |= (PG_WRITE | PG_NC);
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set_pte(pgva, tmppte);
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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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set_context(old_ctx);
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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(db_addr_t addr, size_t size, const char *data)
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{
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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) = *((const int *)data);
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return;
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}
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if (size == 2) {
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*((short *)dst) = *((const 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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