From: "H. Peter Anvin" <hpa@zytor.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Borislav Petkov <bp@alien8.de>, Jan Kiszka <jan.kiszka@web.de>,
Jason Wessel <jason.wessel@windriver.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v7u1 00/31] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G
Date: Wed, 16 Jan 2013 09:38:10 -0800 [thread overview]
Message-ID: <50F6E582.60905@zytor.com> (raw)
In-Reply-To: <CAE9FiQUYi_Bp2DW-G3Ht=Xz1rk+xks+NZe+-nAmvh4xR4dxVwA@mail.gmail.com>
On 01/16/2013 09:31 AM, Yinghai Lu wrote:
>
> rom af4f3bc044d1556f89bd488c7ea75e2a162bb273 Mon Sep 17 00:00:00 2001
> From: Yinghai Lu <yinghai@kernel.org>
> Date: Mon, 14 Jan 2013 21:11:05 -0800
> Subject: [PATCH] x86, mm: Fix page table early allocation offset checking
>
> During debugging loading kernel above 4G, found that one page is not used
> in pre-allocated BRK area for early page allocation.
>
> pgt_buf_top is address that can not be used, so should check if that new
> end is above that top, otherwise last page will not be used.
>
The first sentence here doesn't parse, and this description doesn't give
any hint to anyone who is researching this code in say, five years, what
problems this caused.
I can't really figure it out, either; from looking at the thread and the
patch I'm assuming the problem is somehow that the code failed to use
the last page in the brk buffer, which somehow lead to a Xen boot
failure... but the bits from here to there are totally unclear.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2013-01-16 17:38 UTC|newest]
Thread overview: 199+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-04 0:48 [PATCH v7u1 00/31] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 01/31] x86, mm: Fix page table early allocation offset checking Yinghai Lu
2013-01-04 7:17 ` Borislav Petkov
2013-01-04 21:50 ` Yinghai Lu
2013-01-05 13:05 ` Borislav Petkov
2013-01-15 12:27 ` Stefano Stabellini
2013-01-04 0:48 ` [PATCH v7u1 02/31] x86, 64bit, mm: make pgd next calculation consistent with pud/pmd Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 03/31] x86, realmode: set real_mode permissions early Yinghai Lu
2013-01-04 20:15 ` Borislav Petkov
2013-01-04 20:58 ` Yinghai Lu
2013-01-04 21:04 ` Borislav Petkov
2013-01-04 22:13 ` Yinghai Lu
2013-01-05 13:25 ` Borislav Petkov
2013-01-07 12:40 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 04/31] x86, 64bit, mm: add generic kernel/ident mapping helper Yinghai Lu
2013-01-04 21:19 ` Borislav Petkov
2013-01-04 22:19 ` Yinghai Lu
2013-01-05 13:21 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 05/31] x86, 64bit: copy zero-page early Yinghai Lu
2013-01-07 15:53 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 06/31] x86, 64bit, realmode: use init_level4_pgt to set trapmoline_pgt directly Yinghai Lu
2013-01-04 17:18 ` Sakkinen, Jarkko
2013-01-04 22:01 ` Yinghai Lu
2013-01-05 9:59 ` Sakkinen, Jarkko
2013-01-07 15:54 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 07/31] x86, realmode: Separate real_mode reserve and setup Yinghai Lu
2013-01-04 17:18 ` Sakkinen, Jarkko
2013-01-07 15:54 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 08/31] x86, 64bit: early #PF handler set page table Yinghai Lu
2013-01-07 15:55 ` Borislav Petkov
2013-01-10 1:56 ` Yinghai Lu
2013-01-10 12:19 ` Borislav Petkov
2013-01-10 17:05 ` Yinghai Lu
2013-01-10 20:27 ` Borislav Petkov
2013-01-12 22:04 ` H. Peter Anvin
2013-01-04 0:48 ` [PATCH v7u1 09/31] x86, 64bit: #PF handler set page to cover 2M only Yinghai Lu
2013-01-09 22:57 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 10/31] x86, 64bit: Don't set max_pfn_mapped wrong value early on native path Yinghai Lu
2013-01-11 12:13 ` Borislav Petkov
2013-01-11 16:42 ` Yinghai Lu
2013-01-11 16:52 ` Borislav Petkov
2013-01-15 13:48 ` Stefano Stabellini
2013-01-15 15:22 ` Konrad Rzeszutek Wilk
2013-01-15 15:59 ` Stefano Stabellini
2013-01-15 16:37 ` Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 11/31] x86: Merge early_reserve_initrd for 32bit and 64bit Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 12/31] x86: add get_ramdisk_image/size() Yinghai Lu
2013-01-07 15:56 ` Borislav Petkov
2013-01-10 1:53 ` Yinghai Lu
2013-01-10 12:13 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 13/31] x86, boot: add get_cmd_line_ptr() Yinghai Lu
2013-01-07 15:56 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 14/31] x86, boot: move checking of cmd_line_ptr out of common path Yinghai Lu
2013-01-07 16:00 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 15/31] x86, boot: pass cmd_line_ptr with unsigned long instead Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 16/31] x86, boot: move verify_cpu.S and no_longmode down Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 17/31] x86, boot: Move lldt/ltr out of 64bit code section Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 18/31] x86, kexec: remove 1024G limitation for kexec buffer on 64bit Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 19/31] x86, kexec: set ident mapping for kernel that is above max_pfn Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 20/31] x86, kexec: replace ident_mapping_init and init_level4_page Yinghai Lu
2013-01-04 21:01 ` Borislav Petkov
2013-01-04 22:04 ` Yinghai Lu
2013-01-05 13:24 ` Borislav Petkov
2013-01-10 1:26 ` Yinghai Lu
2013-01-10 11:59 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 21/31] x86, kexec: only set ident mapping for ram Yinghai Lu
2013-01-13 12:56 ` Borislav Petkov
2013-01-14 5:46 ` Yinghai Lu
2013-01-14 9:53 ` Borislav Petkov
2013-01-14 18:17 ` Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 22/31] x86, boot: add fields to support load bzImage and ramdisk above 4G Yinghai Lu
2013-01-13 21:41 ` Borislav Petkov
2013-01-14 5:37 ` Yinghai Lu
2013-01-14 9:43 ` Borislav Petkov
2013-01-14 23:06 ` Yinghai Lu
2013-01-14 17:49 ` H. Peter Anvin
2013-01-14 18:57 ` Yinghai Lu
2013-01-14 18:59 ` H. Peter Anvin
2013-01-14 19:19 ` Yinghai Lu
2013-01-14 19:50 ` Yinghai Lu
2013-01-14 19:56 ` H. Peter Anvin
2013-01-14 20:05 ` Yinghai Lu
2013-01-15 6:17 ` Yinghai Lu
2013-01-15 15:50 ` Borislav Petkov
2013-01-15 16:03 ` Yinghai Lu
2013-01-15 16:48 ` Borislav Petkov
2013-01-15 18:43 ` Yinghai Lu
2013-01-15 19:49 ` Borislav Petkov
2013-01-15 20:16 ` Yinghai Lu
2013-01-15 20:28 ` Borislav Petkov
2013-01-14 20:05 ` Borislav Petkov
2013-01-14 20:14 ` Yinghai Lu
2013-01-14 20:26 ` Borislav Petkov
2013-01-14 22:38 ` Yinghai Lu
2013-01-14 23:11 ` Borislav Petkov
2013-01-15 1:04 ` Yinghai Lu
2013-01-14 23:10 ` H. Peter Anvin
2013-01-14 23:21 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 23/31] x86, boot: update comments about entries for 64bit image Yinghai Lu
2013-01-14 11:20 ` Borislav Petkov
2013-01-14 18:35 ` Yinghai Lu
2013-01-14 18:37 ` Yinghai Lu
2013-01-14 18:46 ` Borislav Petkov
2013-01-14 20:01 ` Yinghai Lu
2013-01-14 18:43 ` Borislav Petkov
2013-01-04 0:48 ` [PATCH v7u1 24/31] x86, boot: Not need to check setup_header version for setup_data Yinghai Lu
2013-01-14 11:26 ` Borislav Petkov
2013-01-14 17:37 ` H. Peter Anvin
2013-01-14 18:04 ` Borislav Petkov
2013-01-14 18:42 ` H. Peter Anvin
2013-01-04 0:48 ` [PATCH v7u1 25/31] memblock: add memblock_mem_size() Yinghai Lu
2013-01-14 20:42 ` H. Peter Anvin
2013-01-14 22:28 ` Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 26/31] x86: Don't enable swiotlb if there is not enough ram for it Yinghai Lu
2013-01-04 16:05 ` Konrad Rzeszutek Wilk
2013-01-04 19:57 ` Yinghai Lu
2013-01-04 17:50 ` Shuah Khan
2013-01-04 20:34 ` Yinghai Lu
2013-01-04 21:02 ` Shuah Khan
2013-01-04 22:10 ` Yinghai Lu
2013-01-04 22:26 ` Shuah Khan
2013-01-04 22:34 ` Yinghai Lu
2013-01-04 22:47 ` Eric W. Biederman
2013-01-04 22:56 ` Shuah Khan
2013-01-04 23:00 ` Yinghai Lu
2013-01-04 23:21 ` Shuah Khan
2013-01-04 23:55 ` Yinghai Lu
2013-01-05 2:02 ` Shuah Khan
2013-01-05 4:10 ` Yinghai Lu
2013-01-05 22:04 ` Shuah Khan
2013-01-04 22:58 ` Yinghai Lu
2013-01-07 15:26 ` Konrad Rzeszutek Wilk
2013-01-07 17:02 ` Shuah Khan
2013-01-07 19:29 ` Konrad Rzeszutek Wilk
2013-01-08 2:22 ` Eric W. Biederman
2013-01-08 2:48 ` Konrad Rzeszutek Wilk
2013-01-08 3:03 ` Eric W. Biederman
2013-01-08 3:01 ` Yinghai Lu
2013-01-08 3:13 ` Eric W. Biederman
2013-01-08 3:50 ` Yinghai Lu
2013-01-08 23:40 ` Yinghai Lu
2013-01-09 0:04 ` Eric W. Biederman
2013-01-09 0:43 ` Konrad Rzeszutek Wilk
2013-01-09 0:56 ` Yinghai Lu
2013-01-09 0:58 ` Eric W. Biederman
2013-01-09 1:07 ` Yinghai Lu
2013-01-09 1:12 ` Yinghai Lu
2013-01-09 2:31 ` Eric W. Biederman
2013-01-09 13:24 ` Konrad Rzeszutek Wilk
2013-01-09 17:27 ` Yinghai Lu
2013-01-09 18:01 ` Shuah Khan
2013-01-09 19:13 ` Yinghai Lu
2013-01-09 21:00 ` Eric W. Biederman
2013-01-09 21:15 ` Yinghai Lu
2013-01-10 23:07 ` Yinghai Lu
2013-01-10 23:15 ` Eric W. Biederman
2013-01-10 23:55 ` Yinghai Lu
2013-01-11 16:35 ` Konrad Rzeszutek Wilk
2013-01-11 16:52 ` Yinghai Lu
2013-01-11 17:49 ` Yinghai Lu
2013-01-15 6:19 ` Yinghai Lu
2013-01-18 15:55 ` Konrad Rzeszutek Wilk
2013-01-24 15:39 ` Konrad Rzeszutek Wilk
2013-01-24 16:51 ` Shuah Khan
2013-01-24 19:22 ` Shuah Khan
2013-01-24 21:50 ` Yinghai Lu
2013-01-29 2:27 ` Shuah Khan
2013-01-29 3:44 ` Yinghai Lu
2013-01-31 19:28 ` Shuah Khan
2013-01-31 19:35 ` H. Peter Anvin
2013-01-09 13:12 ` Konrad Rzeszutek Wilk
2013-01-07 20:32 ` Yinghai Lu
2013-01-07 21:30 ` Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 27/31] x86, kdump: remove crashkernel range find limit for 64bit Yinghai Lu
2013-01-14 15:43 ` Borislav Petkov
2013-01-14 18:18 ` Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 28/31] x86: add Crash kernel low reservation Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 29/31] x86: Merge early kernel reserve for 32bit and 64bit Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 30/31] x86, 64bit, mm: Mark data/bss/brk to nx Yinghai Lu
2013-01-04 0:48 ` [PATCH v7u1 31/31] x86, 64bit, mm: hibernate use generic mapping_init Yinghai Lu
2013-01-04 11:43 ` Rafael J. Wysocki
2013-01-04 21:59 ` Yinghai Lu
2013-01-04 22:07 ` Rafael J. Wysocki
2013-01-04 7:09 ` [PATCH v7u1 00/31] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G Borislav Petkov
2013-01-04 21:44 ` Yinghai Lu
2013-01-14 20:45 ` H. Peter Anvin
2013-01-14 22:44 ` Yinghai Lu
2013-01-14 23:16 ` H. Peter Anvin
2013-01-14 23:39 ` David Woodhouse
2013-01-14 23:50 ` H. Peter Anvin
2013-01-15 0:12 ` David Woodhouse
2013-01-15 12:19 ` Stefano Stabellini
2013-01-15 16:43 ` Yinghai Lu
2013-01-15 19:28 ` Yinghai Lu
2013-01-16 11:32 ` Stefano Stabellini
2013-01-16 17:31 ` Yinghai Lu
2013-01-16 17:38 ` H. Peter Anvin [this message]
2013-01-16 18:20 ` Yinghai Lu
2013-01-17 2:35 ` Yinghai Lu
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