linux-kernel - Re: [PATCH] x86: only put e820 ram entries in resource tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <86802c440808251011k5c80a527la5066565b8cff6f5@mail.gmail.com>
Date:	Mon, 25 Aug 2008 10:11:32 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Vivek Goyal" <vgoyal@...hat.com>
Cc:	"Ingo Molnar" <mingo@...e.hu>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, "Bernhard Walle" <bwalle@...e.de>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH] x86: only put e820 ram entries in resource tree

On Mon, Aug 25, 2008 at 7:19 AM, Vivek Goyal <vgoyal@...hat.com> wrote:
> On Sun, Aug 24, 2008 at 03:44:57PM -0700, Yinghai Lu wrote:
>> may need user to have new kexec tools that could create e820 table
>> from /sys/firmware/memmap instead of /proc/iomem for second kernel
>>
>> Signed-off-by: Yinghai Lu <yhlu.kernel@...il.com>
>> Cc: Bernhard Walle <bwalle@...e.de>
>> Cc: Vivek Goyal <vgoyal@...hat.com>
>> Cc: "Eric W. Biederman" <ebiederm@...ssion.com>
>>
>> Index: linux-2.6/arch/x86/kernel/e820.c
>> ===================================================================
>> --- linux-2.6.orig/arch/x86/kernel/e820.c
>> +++ linux-2.6/arch/x86/kernel/e820.c
>> @@ -1279,6 +1279,10 @@ void __init e820_reserve_resources(void)
>>
>>       res = alloc_bootmem_low(sizeof(struct resource) * e820.nr_map);
>>       for (i = 0; i < e820.nr_map; i++) {
>> +             if (e820.map[i].type != E820_RAM) {
>> +                     res++;
>> +                     continue;
>> +             }
>>               end = e820.map[i].addr + e820.map[i].size - 1;
>>  #ifndef CONFIG_RESOURCES_64BIT
>>               if (end > 0x100000000ULL) {
>
> I think this will wipe out ACPI related entries also from /proc/iomem
> and kdump will be broken as second kernel needs to know about the ACPI
> areas.
>
> Though, if all these entries are available in /sys/firmware/memap then
> probably one can modify kexec-tools to grep RAM entries from /proc/iomem and
> rest of the entries from /sys/firmware/memmap.

/sys/firmware/memmap have all of them. though RAM entries from
/proc/iomem could be smaller than that in /sys/firmware/memmap because
of trimming from commandline.

YH
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/