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Subject: Re: [PATCH v3 2/6] powerpc/fsl_booke/64: introduce
 reloc_kernel_entry() helper
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,
        oss@buserror.net
Cc:     linux-kernel@vger.kernel.org, zhaohongjiang@huawei.com
References: <20200206025825.22934-1-yanaijie@huawei.com>
 <20200206025825.22934-3-yanaijie@huawei.com>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <da8c9b88-1d21-ed70-c6f1-343117b4075d@c-s.fr>
Date:   Thu, 20 Feb 2020 14:41:21 +0100
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Le 06/02/2020 à 03:58, Jason Yan a écrit :
> Like the 32bit code, we introduce reloc_kernel_entry() helper to prepare
> for the KASLR 64bit version. And move the C declaration of this function
> out of CONFIG_PPC32 and use long instead of int for the parameter 'addr'.
> 
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> Cc: Scott Wood <oss@buserror.net>
> 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>

Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>


> ---
>   arch/powerpc/kernel/exceptions-64e.S | 13 +++++++++++++
>   arch/powerpc/mm/mmu_decl.h           |  3 ++-
>   2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
> index e4076e3c072d..1b9b174bee86 100644
> --- a/arch/powerpc/kernel/exceptions-64e.S
> +++ b/arch/powerpc/kernel/exceptions-64e.S
> @@ -1679,3 +1679,16 @@ _GLOBAL(setup_ehv_ivors)
>   _GLOBAL(setup_lrat_ivor)
>   	SET_IVOR(42, 0x340) /* LRAT Error */
>   	blr
> +
> +/*
> + * Return to the start of the relocated kernel and run again
> + * r3 - virtual address of fdt
> + * r4 - entry of the kernel
> + */
> +_GLOBAL(reloc_kernel_entry)
> +	mfmsr	r7
> +	rlwinm	r7, r7, 0, ~(MSR_IS | MSR_DS)
> +
> +	mtspr	SPRN_SRR0,r4
> +	mtspr	SPRN_SRR1,r7
> +	rfi
> diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
> index 8e99649c24fc..3e1c85c7d10b 100644
> --- a/arch/powerpc/mm/mmu_decl.h
> +++ b/arch/powerpc/mm/mmu_decl.h
> @@ -140,9 +140,10 @@ extern void adjust_total_lowmem(void);
>   extern int switch_to_as1(void);
>   extern void restore_to_as0(int esel, int offset, void *dt_ptr, int bootcpu);
>   void create_kaslr_tlb_entry(int entry, unsigned long virt, phys_addr_t phys);
> -void reloc_kernel_entry(void *fdt, int addr);
>   extern int is_second_reloc;
>   #endif
> +
> +void reloc_kernel_entry(void *fdt, long addr);
>   extern void loadcam_entry(unsigned int index);
>   extern void loadcam_multi(int first_idx, int num, int tmp_idx);
>   
>