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Subject: Re: [RFC PATCH 06/10] powerpc/fsl_booke/32: implement KASLR
 infrastructure
To:     Jason Yan <yanaijie@huawei.com>, mpe@ellerman.id.au,
        linuxppc-dev@lists.ozlabs.org, diana.craciun@nxp.com,
        benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com,
        keescook@chromium.org, kernel-hardening@lists.openwall.com
Cc:     linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com,
        yebin10@huawei.com, thunder.leizhen@huawei.com,
        jingxiangfeng@huawei.com, fanchengyang@huawei.com
References: <20190717080621.40424-1-yanaijie@huawei.com>
 <20190717080621.40424-7-yanaijie@huawei.com>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <e3f287fc-c4d8-e0c2-90ba-ddfa3cb57e29@c-s.fr>
Date:   Mon, 29 Jul 2019 13:16:21 +0200
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Le 17/07/2019 à 10:06, Jason Yan a écrit :
> This patch add support to boot kernel from places other than KERNELBASE.
> Since CONFIG_RELOCATABLE has already supported, what we need to do is
> map or copy kernel to a proper place and relocate. Freescale Book-E
> parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1
> entries are not suitable to map the kernel directly in a randomized
> region, so we chose to copy the kernel to a proper place and restart to
> relocate.
> 
> The offset of the kernel was not randomized yet(a fixed 64M is set). We
> will randomize it in the next patch.
> 
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> Cc: Diana Craciun <diana.craciun@nxp.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Kees Cook <keescook@chromium.org>
> ---
>   arch/powerpc/Kconfig                          | 11 +++
>   arch/powerpc/kernel/Makefile                  |  1 +
>   arch/powerpc/kernel/early_32.c                |  2 +-
>   arch/powerpc/kernel/fsl_booke_entry_mapping.S | 13 ++-
>   arch/powerpc/kernel/head_fsl_booke.S          | 15 +++-
>   arch/powerpc/kernel/kaslr_booke.c             | 83 +++++++++++++++++++
>   arch/powerpc/mm/mmu_decl.h                    |  6 ++
>   arch/powerpc/mm/nohash/fsl_booke.c            |  7 +-
>   8 files changed, 125 insertions(+), 13 deletions(-)
>   create mode 100644 arch/powerpc/kernel/kaslr_booke.c
> 

[...]

> diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
> index dae8e9177574..754ae1e69f92 100644
> --- a/arch/powerpc/mm/mmu_decl.h
> +++ b/arch/powerpc/mm/mmu_decl.h
> @@ -148,6 +148,12 @@ extern void reloc_kernel_entry(void *fdt, int addr);
>   extern void loadcam_entry(unsigned int index);
>   extern void loadcam_multi(int first_idx, int num, int tmp_idx);
>   
> +#ifdef CONFIG_RANDOMIZE_BASE
> +extern void kaslr_early_init(void *dt_ptr, phys_addr_t size);

No superflous 'extern' keyword.

Christophe

> +#else
> +static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {}
> +#endif
> +
>   struct tlbcam {
>   	u32	MAS0;
>   	u32	MAS1;