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Subject: Re: [PATCH v3 0/6] implement KASLR for powerpc/fsl_booke/64
From:   Jason Yan <yanaijie@huawei.com>
To:     <mpe@ellerman.id.au>, <linuxppc-dev@lists.ozlabs.org>,
        <diana.craciun@nxp.com>, <christophe.leroy@c-s.fr>,
        <benh@kernel.crashing.org>, <paulus@samba.org>,
        <npiggin@gmail.com>, <keescook@chromium.org>,
        <kernel-hardening@lists.openwall.com>, <oss@buserror.net>
CC:     <linux-kernel@vger.kernel.org>, <zhaohongjiang@huawei.com>
References: <20200206025825.22934-1-yanaijie@huawei.com>
 <636f16fd-cc7b-ee2e-7496-c06bdc10c7af@huawei.com>
Message-ID: <c20b8e8b-5e70-4897-85c3-2d8d3c5454d7@huawei.com>
Date:   Thu, 20 Feb 2020 11:33:12 +0800
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ping...

on 2020/2/13 11:00, Jason Yan wrote:
> Hi everyone, any comments or suggestions?
> 
> Thanks,
> Jason
> 
> on 2020/2/6 10:58, Jason Yan wrote:
>> This is a try to implement KASLR for Freescale BookE64 which is based on
>> my earlier implementation for Freescale BookE32:
>> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718
>>
>> The implementation for Freescale BookE64 is similar as BookE32. One
>> difference is that Freescale BookE64 set up a TLB mapping of 1G during
>> booting. Another difference is that ppc64 needs the kernel to be
>> 64K-aligned. So we can randomize the kernel in this 1G mapping and make
>> it 64K-aligned. This can save some code to creat another TLB map at
>> early boot. The disadvantage is that we only have about 1G/64K = 16384
>> slots to put the kernel in.
>>
>>      KERNELBASE
>>
>>            64K                     |--> kernel <--|
>>             |                      |              |
>>          +--+--+--+    +--+--+--+--+--+--+--+--+--+    +--+--+
>>          |  |  |  |....|  |  |  |  |  |  |  |  |  |....|  |  |
>>          +--+--+--+    +--+--+--+--+--+--+--+--+--+    +--+--+
>>          |                         |                        1G
>>          |----->   offset    <-----|
>>
>>                                kernstart_virt_addr
>>
>> I'm not sure if the slot numbers is enough or the design has any
>> defects. If you have some better ideas, I would be happy to hear that.
>>
>> Thank you all.
>>
>> v2->v3:
>>    Fix build error when KASLR is disabled.
>> v1->v2:
>>    Add __kaslr_offset for the secondary cpu boot up.
>>
>> Jason Yan (6):
>>    powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and
>>      kaslr_early_init()
>>    powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper
>>    powerpc/fsl_booke/64: implement KASLR for fsl_booke64
>>    powerpc/fsl_booke/64: do not clear the BSS for the second pass
>>    powerpc/fsl_booke/64: clear the original kernel if randomized
>>    powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst
>>      and add 64bit part
>>
>>   .../{kaslr-booke32.rst => kaslr-booke.rst}    | 35 +++++++--
>>   arch/powerpc/Kconfig                          |  2 +-
>>   arch/powerpc/kernel/exceptions-64e.S          | 23 ++++++
>>   arch/powerpc/kernel/head_64.S                 | 14 ++++
>>   arch/powerpc/kernel/setup_64.c                |  4 +-
>>   arch/powerpc/mm/mmu_decl.h                    | 19 ++---
>>   arch/powerpc/mm/nohash/kaslr_booke.c          | 71 +++++++++++++------
>>   7 files changed, 132 insertions(+), 36 deletions(-)
>>   rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} 
>> (59%)
>>
> 
> 
> .