1*22028508SToomas Soome /*
2*22028508SToomas Soome * Copyright 2018 Toomas Soome <tsoome@me.com>
3*22028508SToomas Soome *
4*22028508SToomas Soome * Redistribution and use in source and binary forms, with or without
5*22028508SToomas Soome * modification, are permitted provided that the following conditions
6*22028508SToomas Soome * are met:
7*22028508SToomas Soome * 1. Redistributions of source code must retain the above copyright
8*22028508SToomas Soome * notice, this list of conditions and the following disclaimer.
9*22028508SToomas Soome * 2. Redistributions in binary form must reproduce the above copyright
10*22028508SToomas Soome * notice, this list of conditions and the following disclaimer in the
11*22028508SToomas Soome * documentation and/or other materials provided with the distribution.
12*22028508SToomas Soome *
13*22028508SToomas Soome * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14*22028508SToomas Soome * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15*22028508SToomas Soome * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16*22028508SToomas Soome * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17*22028508SToomas Soome * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18*22028508SToomas Soome * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19*22028508SToomas Soome * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20*22028508SToomas Soome * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21*22028508SToomas Soome * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22*22028508SToomas Soome * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23*22028508SToomas Soome * SUCH DAMAGE.
24*22028508SToomas Soome */
25*22028508SToomas Soome
26*22028508SToomas Soome #include <sys/cdefs.h>
27*22028508SToomas Soome #include <stand.h>
28*22028508SToomas Soome #include <libi386.h>
29*22028508SToomas Soome
30*22028508SToomas Soome /*
31*22028508SToomas Soome * The idea is borrowed from pxe.c and zfsimpl.c. The original buffer
32*22028508SToomas Soome * space in pxe.c was 2x 0x2000. Allocating it from BSS will give us needed
33*22028508SToomas Soome * memory below 1MB and usable for real mode calls.
34*22028508SToomas Soome *
35*22028508SToomas Soome * Note the allocations and frees are to be done in reverse order (LIFO).
36*22028508SToomas Soome */
37*22028508SToomas Soome
38*22028508SToomas Soome #define BIO_BUFFER_SIZE 0x4000
39*22028508SToomas Soome static char bio_buffer[BIO_BUFFER_SIZE];
40*22028508SToomas Soome static char *bio_buffer_end = bio_buffer + BIO_BUFFER_SIZE;
41*22028508SToomas Soome static char *bio_buffer_ptr = bio_buffer;
42*22028508SToomas Soome
43*22028508SToomas Soome void *
bio_alloc(size_t size)44*22028508SToomas Soome bio_alloc(size_t size)
45*22028508SToomas Soome {
46*22028508SToomas Soome char *ptr;
47*22028508SToomas Soome
48*22028508SToomas Soome ptr = bio_buffer_ptr;
49*22028508SToomas Soome if (ptr + size > bio_buffer_end)
50*22028508SToomas Soome return (NULL);
51*22028508SToomas Soome bio_buffer_ptr += size;
52*22028508SToomas Soome
53*22028508SToomas Soome return (ptr);
54*22028508SToomas Soome }
55*22028508SToomas Soome
56*22028508SToomas Soome void
bio_free(void * ptr,size_t size)57*22028508SToomas Soome bio_free(void *ptr, size_t size)
58*22028508SToomas Soome {
59*22028508SToomas Soome
60*22028508SToomas Soome if (ptr == NULL)
61*22028508SToomas Soome return;
62*22028508SToomas Soome
63*22028508SToomas Soome bio_buffer_ptr -= size;
64*22028508SToomas Soome if (bio_buffer_ptr != ptr)
65*22028508SToomas Soome panic("bio_alloc()/bio_free() mismatch");
66*22028508SToomas Soome }
67