Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 9 Mar 2003 13:54:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 9 Mar 2003 13:54:14 -0500 Received: from [195.39.17.254] ([195.39.17.254]:2052 "EHLO Elf.ucw.cz") by vger.kernel.org with ESMTP id ; Sun, 9 Mar 2003 13:54:09 -0500 Date: Sat, 8 Mar 2003 00:19:54 +0100 From: Pavel Machek To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org Subject: Re: Reserving physical memory at boot time Message-ID: <20030307231954.GB164@elf.ucw.cz> References:

<32981.4.64.238.61.1046844111.squirrel@www.osdl.org> <20030306212607.GA173@elf.ucw.cz> <3E67D89B.1010308@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3E67D89B.1010308@zytor.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.3i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2825 Lines: 89 Hi! > > Really? So user has to know where ACPI tables are and specify less > > than that on mem= command line? That seems very > > counter-intuitive. [Ahha, its probaly okay because e820 saves you.] > > > > What do you pass on 4GB machine as mem= parameter? AFAIK those beasts > > have hole at 3.75G. [Hopefully bigmem machines have working e820 > > tables?] > > > > If you pass mem= you have to pass mem=3840M. Yes, it sucks, but if you > genuinely have a machine which is so fucked up that you can't rely on > the memory map the BIOS presents to you, you have problems to begin with. > > Oh yes, this is why GRUB passing the mem= parameter gratuitously was > beyond total and complete brainfuckage. Okay; which mem= options you want killed? What about this? Pavel --- clean/arch/i386/kernel/setup.c 2003-03-06 23:25:14.000000000 +0100 +++ linux/arch/i386/kernel/setup.c 2003-03-08 00:18:21.000000000 +0100 @@ -527,6 +527,9 @@ * to , overriding the bios size. * "mem=XXX[KkmM]@XXX[KkmM]" defines a memory region from * to +, overriding the bios size. + * + * HPA tells me bootloaders need to parse mem=, so no new + * option should be mem= */ if (c == ' ' && !memcmp(from, "mem=", 4)) { if (to != command_line) @@ -535,8 +538,24 @@ from += 9+4; clear_bit(X86_FEATURE_PSE, boot_cpu_data.x86_capability); disable_pse = 1; - } else if (!memcmp(from+4, "exactmap", 8)) { - from += 8+4; + } else { + /* If the user specifies memory size, we + * limit the BIOS-provided memory map to + * that size. exactmap can be used to specify + * the exact map. mem=number can be used to + * trim the existing memory map. + */ + unsigned long long start_at, mem_size; + + mem_size = memparse(from+4, &from); + } + } + + if (c == ' ' && !memcmp(from, "memmap=", 7)) { + if (to != command_line) + to--; + if (!memcmp(from+7, "exactmap", 8)) { + from += 8+7; e820.nr_map = 0; userdef = 1; } else { @@ -548,7 +567,7 @@ */ unsigned long long start_at, mem_size; - mem_size = memparse(from+4, &from); + mem_size = memparse(from+7, &from); if (*from == '@') { start_at = memparse(from+1, &from); add_memory_region(start_at, mem_size, E820_RAM); @@ -565,6 +584,7 @@ } } + /* "acpi=off" disables both ACPI table parsing and interpreter init */ if (c == ' ' && !memcmp(from, "acpi=off", 8)) acpi_disabled = 1; -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/