linux-kernel - Re: [PATCH v2 1/1] initrd: move initrd_start calculate within linear mapping range check

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Message-ID: <20190319153114.GI59586@arrakis.emea.arm.com>
Date:   Tue, 19 Mar 2019 15:31:14 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     pierre Kuo <vichy.kuo@...il.com>
Cc:     steven.price@....com, will.deacon@....com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/1] initrd: move initrd_start calculate within linear
 mapping range check

On Thu, Mar 14, 2019 at 11:20:47AM +0800, pierre Kuo wrote:
> in the previous case, initrd_start and initrd_end can be successfully
> returned either (base < memblock_start_of_DRAM()) or (base + size >
> memblock_start_of_DRAM() + linear_region_size).
> 
> That means even linear mapping range check fail for initrd_start and
> initrd_end, it still can get virtual address. Here we put
> initrd_start/initrd_end to be calculated only when linear mapping check
> pass.
> 
> Fixes: c756c592e442 ("arm64: Utilize phys_initrd_start/phys_initrd_size")

For future versions, please also cc the author of the original commit
you are fixing.

> Reviewed-by: Steven Price <steven.price@....com>
> Signed-off-by: pierre Kuo <vichy.kuo@...il.com>
> ---
> Changes in v2:
> - add Fixes tag
> 
>  arch/arm64/mm/init.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 7205a9085b4d..1adf418de685 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -425,6 +425,9 @@ void __init arm64_memblock_init(void)
>  			memblock_remove(base, size); /* clear MEMBLOCK_ flags */
>  			memblock_add(base, size);
>  			memblock_reserve(base, size);
> +			/* the generic initrd code expects virtual addresses */
> +			initrd_start = __phys_to_virt(phys_initrd_start);
> +			initrd_end = initrd_start + phys_initrd_size;
>  		}
>  	}
>  
> @@ -450,11 +453,6 @@ void __init arm64_memblock_init(void)
>  	 * pagetables with memblock.
>  	 */
>  	memblock_reserve(__pa_symbol(_text), _end - _text);
> -	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
> -		/* the generic initrd code expects virtual addresses */
> -		initrd_start = __phys_to_virt(phys_initrd_start);
> -		initrd_end = initrd_start + phys_initrd_size;
> -	}

With CONFIG_RANDOMIZE_BASE we can get a further change to memstart_addr
after the place where you moved the initrd_{start,end} setting, which
would result in a different value for __phys_to_virt(phys_initrd_start).

-- 
Catalin