/* $NetBSD: biosmemx.S,v 1.11.8.1 2024/09/03 15:23:40 martin Exp $ */ /* * Copyright (c) 1997, 1999 * Matthias Drochner. All rights reserved. * * 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 ``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 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 .text /* * int getextmem2(int buffer[2]) * * return: 0=OK, -1=error * buffer[0]: extmem kBytes below 16M (max 15M/1024) * buffer[1]: extmem above 16M, in 64k units */ ENTRY(getextmem2) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %edx push %esi push %edi call _C_LABEL(prot_to_real) .code16 xorl %ebx,%ebx movl $0xe801,%eax int $0x15 pushf movw %si,%ax orw %si,%bx jz 1f /* if zero use configured values */ movw %cx,%ax /* k below 16M (max 0x3c00 = 15MB) */ movw %dx,%bx /* 64k above 16M */ 1: popf setc %bl calll _C_LABEL(real_to_prot) .code32 movl 8(%ebp),%edi xorl %eax,%eax movw %cx,%ax stosl movw %dx,%ax stosl movb %bl,%al cbw pop %edi pop %esi popl %edx popl %ecx popl %ebx popl %ebp ret /* * int getmementry(int *iterator, int buffer[6]) * * return: 0=ok, else error * buffer[0]: start of memory chunk * buffer[2]: length (bytes) * buffer[4]: type * buffer[5]: ACPI 3.0 Extended Attributes bitfield (unused) * * Some buggy BIOSes may write to 24 bytes even if only 20 were requested. * Therefore, the buffer is defined for 6 elements to avoid stack buffer * overruns. See PR install/49470. * * More details can be found in the: * * Advanced Configuration and Power Interface (ACPI) * Specification, Release 6.5, 2022-08-29, UEFI Forum, Inc., * Sec. 15.1 `INT 15H E820H - Query System Address Map', * pp. 756-757 * https://uefi.org/sites/default/files/resources/ACPI_Spec_6_5_Aug29.pdf#page=824 * https://uefi.org/specs/ACPI/6.5/15_System_Address_Map_Interfaces.html#int-15h-e820h-query-system-address-map * * as well as this OSDev.org wiki page: * * https://wiki.osdev.org/Detecting_Memory_(x86)#BIOS_Function:_INT_0x15,_EAX_=_0xE820 */ ENTRY(getmementry) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %edx push %esi push %edi movl 8(%ebp),%eax movl 0(%eax),%ebx /* index */ movl $20,%ecx /* Buffer size */ movl $0x534d4150,%edx /* "SMAP" */ movl 12(%ebp),%edi /* buffer address */ call _C_LABEL(prot_to_real) .code16 push %di shrl $4,%edi mov %ds,%ax add %di,%ax mov %ax,%es pop %di and $0xf,%di /* buffer address now in ES:DI */ movl $0xe820,%eax /* Some BIOS check EAX value */ int $0x15 setc %cl calll _C_LABEL(real_to_prot) .code32 movl 8(%ebp),%eax movl %ebx,0(%eax) /* updated index */ xorl %eax,%eax movb %cl,%al pop %edi pop %esi popl %edx popl %ecx popl %ebx popl %ebp ret /* * int biosA20(void) * * return: 0=ok, else error */ ENTRY(biosA20) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %edx push %esi push %edi call _C_LABEL(prot_to_real) .code16 movl $0x2401,%eax int $0x15 setc %cl calll _C_LABEL(real_to_prot) .code32 movzbl %cl,%eax pop %edi pop %esi popl %edx popl %ecx popl %ebx popl %ebp ret