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From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/9] kexec_file_load implementation for PowerPC
Date: Thu, 16 Jun 2016 16:55:33 -0300	[thread overview]
Message-ID: <17475630.nMjKSPkg4b@hactar> (raw)
In-Reply-To: <1466056110.5400.8.camel@ellerman.id.au>

Am Donnerstag, 16 Juni 2016, 15:48:30 schrieb Michael Ellerman:
> On Tue, 2016-06-14 at 11:59 -0300, Thiago Jung Bauermann wrote:
> > Hello,
> > 
> > This patch series implements the kexec_file_load system call on PowerPC.
> 
> Can you tell me what this syscall does and why I would want it?

Sorry, should have provided the motivation when I posted the patches.

This system call moves the reading of the kernel, initrd and the device tree 
from the userspace kexec tool to the kernel. This is needed if you want to 
do one or both of the following:

1. only allow loading of signed kernels.
2. "measure" (i.e., record the hashes of) the kernel, initrd, kernel command 
line and other boot inputs for the  Integrity Measurement Architecture 
subsystem.

The above are the functions kexec already has built into kexec_file_load. I 
will soon post a set of patches which will allow a third feature:

3. have IMA pass-on its event log (where integrity measurements are 
registered) accross kexec to the second kernel, so that the event history is 
preserved.

Because OpenPower uses an intermediary Linux instance as a boot loader 
(skiroot), feature 1 is needed to implement secure boot for the platform, 
while features 2 and 3 are needed to implement trusted boot.

There's an LWN article giving more context on the origins of the system 
call, if you are interested:

https://lwn.net/Articles/603116/

-- 
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center

      reply	other threads:[~2016-06-16 19:55 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-14 14:59 Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 1/9] kexec_file: Remove unused members from struct kexec_buf Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 2/9] kexec_file: Generalize kexec_add_buffer Thiago Jung Bauermann
2016-06-15  7:33   ` Dave Young
2016-06-15 16:21     ` Thiago Jung Bauermann
2016-06-16  1:58       ` Dave Young
2016-06-16 20:39         ` Thiago Jung Bauermann
2016-06-17  7:35           ` Dave Young
2016-06-17 20:51             ` Thiago Jung Bauermann
2016-06-20  2:26               ` Dave Young
2016-06-20 16:01                 ` Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 3/9] kexec_file: Factor out kexec_locate_mem_hole from kexec_add_buffer Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 4/9] powerpc: Factor out relocation code from module_64.c to elf_util_64.c Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 5/9] powerpc: Generalize elf64_apply_relocate_add Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 6/9] powerpc: Add functions to read ELF files of any endianness Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 7/9] powerpc: Implement kexec_file_load Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 8/9] powerpc: Add support for loading ELF kernels with kexec_file_load Thiago Jung Bauermann
2016-06-14 14:59 ` [PATCH v2 9/9] powerpc: Add purgatory for kexec_file_load implementation Thiago Jung Bauermann
2016-06-16  5:48 ` [PATCH v2 0/9] kexec_file_load implementation for PowerPC Michael Ellerman
2016-06-16 19:55   ` Thiago Jung Bauermann [this message]

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