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Subject: Re: [PATCH v5 0/6] implement KASLR for powerpc/fsl_booke/64
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>,
        <dja@axtens.net>
References: <20200330022023.3691-1-yanaijie@huawei.com>
From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <433bb006-aa45-524d-c57e-79657d01c685@huawei.com>
Date:   Mon, 13 Apr 2020 09:23:23 +0800
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ping...

?? 2020/3/30 10:20, Jason Yan д??:
> 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&state=*
> 
> 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.
> 
> v4->v5:
>    Fix "-Werror=maybe-uninitialized" compile error.
>    Fix typo "similar as" -> "similar to".
> v3->v4:
>    Do not define __kaslr_offset as a fixed symbol. Reference __run_at_load and
>      __kaslr_offset by symbol instead of magic offsets.
>    Use IS_ENABLED(CONFIG_PPC32) instead of #ifdef CONFIG_PPC32.
>    Change kaslr-booke32 to kaslr-booke in index.rst
>    Switch some instructions to 64-bit.
> 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
> 
>   Documentation/powerpc/index.rst               |  2 +-
>   .../{kaslr-booke32.rst => kaslr-booke.rst}    | 35 ++++++-
>   arch/powerpc/Kconfig                          |  2 +-
>   arch/powerpc/kernel/exceptions-64e.S          | 23 +++++
>   arch/powerpc/kernel/head_64.S                 | 13 +++
>   arch/powerpc/kernel/setup_64.c                |  3 +
>   arch/powerpc/mm/mmu_decl.h                    | 23 +++--
>   arch/powerpc/mm/nohash/kaslr_booke.c          | 91 +++++++++++++------
>   8 files changed, 147 insertions(+), 45 deletions(-)
>   rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%)
>