freebsd-dev/stand/i386/libi386/bio.c
Toomas Soome 46aedfa274 Add Copyright.
Reported by:	Rodney W. Grimes
2018-12-30 15:34:12 +00:00

68 lines
2.1 KiB
C

/*-
* Copyright 2018 Toomas Soome <tsoome@me.com>
*
* 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 AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include "libi386.h"
/*
* The idea is borrowed from pxe.c and zfsimpl.c. The original buffer
* space in pxe.c was 2x 0x2000. Allocating it from BSS will give us needed
* memory below 1MB and usable for real mode calls.
*
* Note the allocations and frees are to be done in reverse order (LIFO).
*/
static char bio_buffer[BIO_BUFFER_SIZE];
static char *bio_buffer_end = bio_buffer + BIO_BUFFER_SIZE;
static char *bio_buffer_ptr = bio_buffer;
void *
bio_alloc(size_t size)
{
char *ptr;
ptr = bio_buffer_ptr;
if (ptr + size > bio_buffer_end)
return (NULL);
bio_buffer_ptr += size;
return (ptr);
}
void
bio_free(void *ptr, size_t size)
{
if (ptr == NULL)
return;
bio_buffer_ptr -= size;
if (bio_buffer_ptr != ptr)
panic("bio_alloc()/bio_free() mismatch\n");
}