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From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: Dave Young <dyoung@redhat.com>
Cc: Junichi Nomura <j-nomura@ce.jp.nec.com>,
	Borislav Petkov <bp@alien8.de>, "bhe@redhat.com" <bhe@redhat.com>,
	"kasong@redhat.com" <kasong@redhat.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
Date: Wed, 3 Apr 2019 17:02:11 +0800
Message-ID: <20190403090210.GH1555@localhost.localdomain> (raw)
In-Reply-To: <20190403082305.GG1555@localhost.localdomain>

On Wed, Apr 03, 2019 at 04:23:06PM +0800, Chao Fan wrote:
>On Wed, Apr 03, 2019 at 04:09:16PM +0800, Dave Young wrote:
>>On 04/03/19 at 03:21pm, Chao Fan wrote:
>>> On Wed, Apr 03, 2019 at 01:53:40PM +0800, Dave Young wrote:
>>> >On 04/03/19 at 01:35pm, Chao Fan wrote:
>>> >> On Tue, Apr 02, 2019 at 08:03:19PM +0800, Dave Young wrote:
>>> >> >On 04/01/19 at 12:08am, Junichi Nomura wrote:
[...]
>>> >
>>> >It is weird to me. Probably I need find out why I can not reproduce the
>>> >bug this patch is addressing first.
>>> 
>>> Hmm, is your laptop booted from EFI or legacy BIOS?
>>
>>EFI booted.
>>
>>> >
>>> >earlyprintk seems not working for me anymore, it is not easy to debug on
>>> >laptop now.
>>> 
>>> Another computer can help print the console message.
>>> I remeber you are good at debug on two computers.
>>
>>I used to use earlyprintk, but seems earlyprintk can not work so early.
>>So I only can try to comment out code manually.
>
>Ah, I got it. If you want to use earlyprintk to print message of
>get_rsdp_addr(), you should change some code.
>Because get_rsdp_addr() is called before earlyprintk initialed.
>
>I am still testing, but in my debug stage, I change like this:
>diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
>index c0d6c560df69..dbbe8d9a5792 100644
>--- a/arch/x86/boot/compressed/misc.c
>+++ b/arch/x86/boot/compressed/misc.c
>@@ -352,7 +352,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
>        boot_params->hdr.loadflags &= ~KASLR_FLAG;
>
>        /* Save RSDP address for later use. */
>-       boot_params->acpi_rsdp_addr = get_rsdp_addr();
>
>        sanitize_boot_params(boot_params);
>
>@@ -368,6 +367,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
>        cols = boot_params->screen_info.orig_video_cols;
>
>        console_init();
>+       boot_params->acpi_rsdp_addr = get_rsdp_addr();
>        debug_putstr("early console in extract_kernel\n");
>
>        free_mem_ptr     = heap;        /* Heap */
>
>Call this function after console_init().
>That will make earlyprintk works.
>
>>
>>It seems to be still some bug in early acpi code because if I 
>>return 0 in get rsdp function it just works.
>>
>>This guess make sense to me for now:
>>1. nokaslr does not work because it may only avoid randomization, but it
>>does not avoid running the early acpi parsing code.
>>
>>2. kexec does not work without the patch we talked about, because I just
>>reproduced Junichi reported bug, sometimes hang, or reset, it is
>>understandable.
>>
>>3. kexec does not work with the patch, so there is still bugs in the
>>code. 
>>
>>So several things to do is:
>>
>>Fix 1. (separate issue),  Baoquan or either of you may want to fix it :)
>
>For 1, I think it's not needed to fix. Since not only KASLR needs RSDP.
>So nokaslr should not stop the acpi parsing code.
>>
>>Fix 3.  need more debugging, have you or Junichi run tests on more real
>>hardware, maybe it is easier to reproduce on real hardware, I'm glad to
>>help to try test patch or provide any help. 
>
>I am still testing in real hardware.

Hi Dave,

I find a Fujitsu Desktop PC to test it.
Without this PATCH, it failed to kexec and kdump.
With this PATCH, it succeed to kexec.
But failed to kdump. From the log, I think it didn't jump to the second
kernel, just reboot after panic. I have not figured out what's the
problem, but it seems not caused by this PATCH.
So I still think this PATCH works for the Fujitsu Desktop PC.

As for your issue, I think there may be some problems related to specified
hardware. Are you using a Lenovo laptop?

And I am not sure how Nomura tested it.

Thanks,
Chao Fan

>
>Thanks,
>Chao Fan
>
>>
>>Thanks
>>Dave
>>
>>



  reply index

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-22 11:03 [PATCH] x86/boot: Use EFI setup data if provided Junichi Nomura
2019-03-22 15:23 ` Borislav Petkov
2019-03-25  0:27   ` Junichi Nomura
2019-03-25  6:01     ` Dave Young
2019-03-25  6:19       ` Dave Young
2019-03-25  6:45         ` Kairui Song
2019-03-25  6:47         ` Junichi Nomura
2019-03-25  6:59           ` Dave Young
2019-03-25  8:27             ` [PATCH v2] " Junichi Nomura
2019-03-25  8:54               ` Boris Petkov
2019-03-25  9:25                 ` [PATCH v2] x86/boot: Don't try to search RSDP from EFI when kexec-booted Junichi Nomura
2019-03-25 10:15                 ` [PATCH v2] x86/boot: Use EFI setup data if provided Dave Young
2019-03-25 10:36                   ` Junichi Nomura
2019-03-25 11:16                     ` Dave Young
2019-03-25 12:01                     ` Borislav Petkov
2019-03-25 12:23                       ` Dave Young
2019-03-25 12:32                         ` Borislav Petkov
2019-03-25 23:10                           ` Junichi Nomura
2019-03-26 12:46                             ` Dave Young
2019-03-26 13:57                             ` Borislav Petkov
2019-03-27  1:48                               ` bhe
2019-03-27 12:14                                 ` Borislav Petkov
2019-03-28  4:17                                 ` Junichi Nomura
2019-03-28  6:26                                   ` Chao Fan
2019-03-28  6:43                                   ` bhe
2019-03-28  7:43                                     ` Junichi Nomura
2019-03-28 15:52                                       ` Borislav Petkov
2019-03-29  3:05                                         ` Junichi Nomura
2019-03-29  8:39                                           ` Borislav Petkov
2019-03-29  9:05                                             ` Chao Fan
2019-03-29  9:16                                               ` Borislav Petkov
2019-03-29  9:37                                                 ` Junichi Nomura
2019-03-29  9:44                                                   ` Chao Fan
2019-03-29  9:56                                                     ` Junichi Nomura
2019-03-29  7:20                                         ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-03-29  7:49                                           ` bhe
2019-03-29  8:29                                           ` Chao Fan
2019-03-29  8:39                                             ` Junichi Nomura
2019-03-29  9:18                                               ` Chao Fan
2019-03-29  9:16                                             ` bhe
2019-03-29  9:20                                               ` Chao Fan
2019-04-01  0:08                                         ` [PATCH v2] " Junichi Nomura
2019-04-02  9:41                                           ` Chao Fan
2019-04-02  9:53                                             ` Junichi Nomura
2019-04-02 11:06                                               ` Chao Fan
2019-04-02 10:22                                                 ` Junichi Nomura
2019-04-02 12:03                                           ` Dave Young
2019-04-03  5:35                                             ` Chao Fan
2019-04-03  5:53                                               ` Dave Young
2019-04-03  6:39                                                 ` Dave Young
2019-04-03  7:30                                                   ` Chao Fan
2019-04-03  7:50                                                     ` bhe
2019-04-03  8:23                                                       ` Dave Young
2019-04-03  8:26                                                         ` Dave Young
2019-04-03 16:14                                                           ` Borislav Petkov
2019-04-04  1:02                                                             ` Chao Fan
2019-04-03  9:28                                                       ` Chao Fan
2019-04-03  7:21                                                 ` Chao Fan
2019-04-03  8:09                                                   ` Dave Young
2019-04-03  8:23                                                     ` Chao Fan
2019-04-03  9:02                                                       ` Chao Fan [this message]
2019-04-03  9:39                                                         ` Chao Fan
2019-04-04  1:23                                                         ` Junichi Nomura
2019-04-04  2:52                                                           ` Dave Young
2019-04-04  3:00                                                             ` bhe
2019-04-04  3:10                                                               ` bhe
2019-04-04  3:22                                                                 ` Dave Young
2019-04-04  6:41                                                                   ` Dave Young
2019-04-04  7:20                                                                     ` Chao Fan
2019-04-04  7:41                                                                       ` Dave Young
2019-04-04  7:48                                                                         ` Chao Fan
2019-04-04 12:22                                                                         ` Borislav Petkov
2019-04-04 14:08                                                                           ` Dave Young
2019-04-03  8:18                                                   ` Dave Young
2019-04-02 10:25                                         ` [PATCH v3] " Junichi Nomura
2019-04-04  7:32                                           ` Dave Young
2019-04-04 12:24                                             ` Borislav Petkov
2019-04-04 14:12                                               ` Dave Young
2019-04-04 14:41                                                 ` Borislav Petkov
2019-04-05  1:36                                                   ` Dave Young
2019-04-05  4:19                                             ` Junichi Nomura
2019-03-28 23:11                                       ` [PATCH v2] x86/boot: Use EFI setup data if provided bhe
2019-03-29  3:34                                         ` Junichi Nomura
2019-03-29  3:52                                           ` bhe
2019-03-29  5:16                                             ` Junichi Nomura
2019-03-25  7:27   ` [PATCH] " Baoquan He
2019-03-25  7:53     ` Borislav Petkov
2019-03-25  8:21       ` Baoquan He
2019-03-25  8:43         ` Thomas Gleixner
2019-03-25  9:03           ` Baoquan He

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