gems-kernel/source/THIRDPARTY/xnu/bsd/dev/mem.c
2024-06-03 11:29:39 -05:00

313 lines
7.9 KiB
C

/*
* Copyright (c) 2000-2016 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*-
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1982, 1986, 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, and code derived from software contributed to
* Berkeley by William Jolitz.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 $Hdr: mem.c 1.13 89/10/08$
* @(#)mem.c 8.1 (Berkeley) 6/11/93
*/
/*
* Memory special file
*/
#include <sys/param.h>
#include <sys/dir.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/vm.h>
#include <sys/uio_internal.h>
#include <kern/zalloc.h>
#include <mach/vm_types.h>
#include <mach/vm_param.h>
#include <vm/vm_kern.h> /* for kernel_map */
#include <libkern/section_keywords.h>
#include <pexpert/pexpert.h> /* for PE_parse_boot_argn */
boolean_t iskmemdev(dev_t dev);
#if CONFIG_DEV_KMEM
boolean_t dev_kmem_enabled;
boolean_t dev_kmem_mask_top_bit;
void dev_kmem_init(void);
#if defined(__x86_64__)
extern addr64_t kvtophys(vm_offset_t va);
#else
#error need kvtophys prototype
#endif
extern boolean_t kernacc(off_t, size_t );
#endif
static SECURITY_READ_ONLY_LATE(caddr_t) devzerobuf;
int mmread(dev_t dev, struct uio *uio);
int mmwrite(dev_t dev, struct uio *uio);
int mmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw);
int
mmread(dev_t dev, struct uio *uio)
{
return mmrw(dev, uio, UIO_READ);
}
int
mmwrite(dev_t dev, struct uio *uio)
{
return mmrw(dev, uio, UIO_WRITE);
}
int
mmioctl(dev_t dev, u_long cmd, __unused caddr_t data,
__unused int flag, __unused struct proc *p)
{
int minnum = minor(dev);
if (0 == minnum || 1 == minnum) {
/* /dev/mem and /dev/kmem */
#if CONFIG_DEV_KMEM
if (!dev_kmem_enabled) {
return ENODEV;
}
#else
return ENODEV;
#endif
}
switch (cmd) {
case FIONBIO:
case FIOASYNC:
/* OK to do nothing: we always return immediately */
break;
default:
return ENODEV;
}
return 0;
}
int
mmrw(dev_t dev, struct uio *uio, enum uio_rw rw)
{
user_size_t c;
int error = 0;
while (uio_resid(uio) > 0) {
uio_update(uio, 0);
switch (minor(dev)) {
/* minor device 0 is physical memory */
case 0:
return ENODEV;
/* minor device 1 is kernel memory */
case 1:
#if !CONFIG_DEV_KMEM
return ENODEV;
#else /* CONFIG_DEV_KMEM */
if (!dev_kmem_enabled) {
return ENODEV;
}
vm_address_t kaddr = (vm_address_t)uio->uio_offset;
if (dev_kmem_mask_top_bit) {
/*
* KVA addresses of the form 0xFFFFFF80AABBCCDD can't be
* represented as a signed off_t correctly. In these cases,
* 0x7FFFFF80AABBCCDD is passed in, and the top bit OR-ed
* on.
*/
const vm_address_t top_bit = (~((vm_address_t)0)) ^ (~((vm_address_t)0) >> 1UL);
if (kaddr & top_bit) {
/* top bit should not be set already */
return EFAULT;
}
kaddr |= top_bit;
}
c = uio_curriovlen(uio);
/* Do some sanity checking */
if ((kaddr > (VM_MAX_KERNEL_ADDRESS - c)) ||
(kaddr <= VM_MIN_KERNEL_AND_KEXT_ADDRESS)) {
goto fault;
}
if (!kernacc(kaddr, c)) {
goto fault;
}
error = uiomove((const char *)(uintptr_t)kaddr,
(int)c, uio);
if (error) {
break;
}
continue; /* Keep going until UIO is done */
#endif /* CONFIG_DEV_KMEM */
/* minor device 2 is EOF/RATHOLE */
case 2:
if (rw == UIO_READ) {
return 0;
}
c = uio_curriovlen(uio);
error = 0; /* Always succeeds, always consumes all input */
break;
case 3:
assert(devzerobuf != NULL);
if (uio->uio_rw == UIO_WRITE) {
c = uio_curriovlen(uio);
error = 0; /* Always succeeds, always consumes all input */
break;
}
c = MIN(uio_curriovlen(uio), PAGE_SIZE);
error = uiomove(devzerobuf, (int)c, uio);
if (error) {
break;
}
continue; /* Keep going until UIO is done */
default:
return ENODEV;
}
if (error) {
break;
}
uio_update(uio, c);
}
return error;
#if CONFIG_DEV_KMEM
fault:
return EFAULT;
#endif
}
__startup_func
static void
devzerobuf_init(void)
{
devzerobuf = zalloc_permanent(PAGE_SIZE, ZALIGN_NONE); /* zeroed */
}
STARTUP(ZALLOC, STARTUP_RANK_LAST, devzerobuf_init);
#if CONFIG_DEV_KMEM
void
dev_kmem_init(void)
{
uint32_t kmem;
if (PE_i_can_has_debugger(NULL) &&
PE_parse_boot_argn("kmem", &kmem, sizeof(kmem))) {
if (kmem & 0x1) {
dev_kmem_enabled = TRUE;
}
if (kmem & 0x2) {
dev_kmem_mask_top_bit = TRUE;
}
}
}
boolean_t
kernacc(
off_t start,
size_t len
)
{
off_t base;
off_t end;
base = trunc_page(start);
end = start + len;
while (base < end) {
if (kvtophys((vm_offset_t)base) == 0ULL) {
return FALSE;
}
base += page_size;
}
return TRUE;
}
#endif /* CONFIG_DEV_KMEM */
/*
* Returns true if dev is /dev/mem or /dev/kmem.
*/
boolean_t
iskmemdev(dev_t dev)
{
return major(dev) == 3 && minor(dev) < 2;
}