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/* $OpenBSD: db_memrw.c,v 1.10 2008/06/26 05:42:10 ray Exp $ */
/* $NetBSD: db_memrw.c,v 1.5 1997/06/10 18:48:47 veego Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Gordon W. Ross and Jason R. Thorpe.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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.
*/
/*
* Interface to the debugger for virtual memory read/write.
* This file is shared by DDB and KGDB, and must work even
* when only KGDB is included (thus no db_printf calls).
*
* To write in the text segment, we have to first make
* the page writable, do the write, then restore the PTE.
* For writes outside the text segment, and all reads,
* just do the access -- if it causes a fault, the debugger
* will recover with a longjmp to an appropriate place.
*
* ALERT! If you want to access device registers with a
* specific size, then the read/write functions have to
* make sure to do the correct sized pointer access.
*
* Modified from sun3 version for hp300 (and probably other m68ks, too)
* by Jason R. Thorpe <thorpej@NetBSD.ORG>.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <uvm/uvm_extern.h>
#include <machine/pte.h>
#include <machine/db_machdep.h>
#include <machine/cpu.h>
#include <ddb/db_access.h>
static void db_write_text(db_addr_t, size_t, char *);
/*
* Read bytes from kernel address space for debugger.
* This used to check for valid PTEs, but now that
* traps in DDB work correctly, "Just Do It!"
*/
void
db_read_bytes(addr, size, data)
db_addr_t addr;
size_t size;
char *data;
{
char *src = (char *)addr;
if (size == 4) {
*((int *)data) = *((int *)src);
return;
}
if (size == 2) {
*((short *)data) = *((short *)src);
return;
}
while (size > 0) {
--size;
*data++ = *src++;
}
}
/*
* Write bytes somewhere in kernel text.
* Makes text page writable temporarily.
* We're probably a little to cache-paranoid.
*/
static void
db_write_text(addr, size, data)
db_addr_t addr;
size_t size;
char *data;
{
char *dst, *odst;
pt_entry_t *pte, oldpte, tmppte;
vaddr_t pgva;
int limit;
if (size == 0)
return;
dst = (char *)addr;
do {
/*
* Get the VA for the page.
*/
pgva = trunc_page((vaddr_t)dst);
/*
* Save this destination address, for TLB
* flush.
*/
odst = dst;
/*
* Compute number of bytes that can be written
* with this mapping and subtract it from the
* total size.
*/
limit = NBPG - ((u_long)dst & PGOFSET);
if (limit > size)
limit = size;
size -= limit;
#ifdef M68K_MMU_HP
/*
* Flush the supervisor side of the VAC to
* prevent a cache hit on the old, read-only PTE.
* XXX Is this really necessary, or am I just
* paranoid?
*/
if (ectype == EC_VIRT)
DCIS();
#endif
/*
* Make the page writable. Note the mapping is
* cache-inhibited to save hair.
*/
pte = kvtopte(pgva);
oldpte = *pte;
if ((oldpte & PG_V) == 0) {
printf(" address %p not a valid page\n", dst);
return;
}
tmppte = (oldpte & ~PG_RO) | PG_RW | PG_CI;
*pte = tmppte;
TBIS((vaddr_t)odst);
/*
* Page is now writable. Do as much access as we
* can in this page.
*/
for (; limit > 0; limit--)
*dst++ = *data++;
/*
* Restore the old PTE.
*/
*pte = oldpte;
TBIS((vaddr_t)odst);
} while (size != 0);
/*
* Invalidate the instruction cache so our changes
* take effect.
*/
ICIA();
}
/*
* Write bytes to kernel address space for debugger.
*/
extern char kernel_text[], etext[];
void
db_write_bytes(addr, size, data)
db_addr_t addr;
size_t size;
char *data;
{
char *dst = (char *)addr;
/* If any part is in kernel text, use db_write_text() */
if ((dst < etext) && ((dst + size) > kernel_text)) {
db_write_text(addr, size, data);
return;
}
if (size == 4) {
*((int *)dst) = *((int *)data);
return;
}
if (size == 2) {
*((short *)dst) = *((short *)data);
return;
}
while (size > 0) {
--size;
*dst++ = *data++;
}
}
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