1 /*- 2 * Copyright 2018 Toomas Soome <tsoome@me.com> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #include <stand.h> 30 #include "libi386.h" 31 32 /* 33 * The idea is borrowed from pxe.c and zfsimpl.c. The original buffer 34 * space in pxe.c was 2x 0x2000. Allocating it from BSS will give us needed 35 * memory below 1MB and usable for real mode calls. 36 * 37 * Note the allocations and frees are to be done in reverse order (LIFO). 38 */ 39 40 static char bio_buffer[BIO_BUFFER_SIZE]; 41 static char *bio_buffer_end = bio_buffer + BIO_BUFFER_SIZE; 42 static char *bio_buffer_ptr = bio_buffer; 43 44 void * 45 bio_alloc(size_t size) 46 { 47 char *ptr; 48 49 ptr = bio_buffer_ptr; 50 if (ptr + size > bio_buffer_end) 51 return (NULL); 52 bio_buffer_ptr += size; 53 54 return (ptr); 55 } 56 57 void 58 bio_free(void *ptr, size_t size) 59 { 60 61 if (ptr == NULL) 62 return; 63 64 bio_buffer_ptr -= size; 65 if (bio_buffer_ptr != ptr) 66 panic("bio_alloc()/bio_free() mismatch\n"); 67 } 68