linux-kernel - Re: [PATCH] unicore32: Stop printing the virtual memory layout

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Date:   Tue, 28 Aug 2018 07:30:33 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Guan Xuetao <gxt@....edu.cn>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] unicore32: Stop printing the virtual memory layout

On Tue, Aug 28, 2018 at 7:23 AM, Geert Uytterhoeven
<geert+renesas@...der.be> wrote:
> Since commit ad67b74d2469d9b8 ("printk: hash addresses printed with
> %p"), the virtual memory layout printed during boot up contains "ptrval"
> instead of actual addresses.
>
> Instead of changing the printing to "%px", and leaking virtual memory
> layout information again, just remove the printing completely, cfr. e.g.
> commits 071929dbdd865f77 ("arm64: Stop printing the virtual memory
> layout") and  31833332f7987636 ("m68k/mm: Stop printing the virtual
> memory layout").
>
> All interesting information (actual section sizes) is already printed by
> mem_init_print_info() just above anyway.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

Nice!

Reviewed-by: Kees Cook <keescook@...omium.org>

-Kees

> ---
>  arch/unicore32/mm/init.c | 24 ------------------------
>  1 file changed, 24 deletions(-)
>
> diff --git a/arch/unicore32/mm/init.c b/arch/unicore32/mm/init.c
> index f4950fbfe57493c7..1662058c272a5917 100644
> --- a/arch/unicore32/mm/init.c
> +++ b/arch/unicore32/mm/init.c
> @@ -344,30 +344,6 @@ void __init mem_init(void)
>         free_all_bootmem();
>
>         mem_init_print_info(NULL);
> -       printk(KERN_NOTICE "Virtual kernel memory layout:\n"
> -               "    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
> -               "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> -               "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> -               "    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> -               "      .init : 0x%p" " - 0x%p" "   (%4d kB)\n"
> -               "      .text : 0x%p" " - 0x%p" "   (%4d kB)\n"
> -               "      .data : 0x%p" " - 0x%p" "   (%4d kB)\n",
> -
> -               VECTORS_BASE, VECTORS_BASE + PAGE_SIZE,
> -               DIV_ROUND_UP(PAGE_SIZE, SZ_1K),
> -               VMALLOC_START, VMALLOC_END,
> -               DIV_ROUND_UP((VMALLOC_END - VMALLOC_START), SZ_1M),
> -               PAGE_OFFSET, (unsigned long)high_memory,
> -               DIV_ROUND_UP(((unsigned long)high_memory - PAGE_OFFSET), SZ_1M),
> -               MODULES_VADDR, MODULES_END,
> -               DIV_ROUND_UP((MODULES_END - MODULES_VADDR), SZ_1M),
> -
> -               __init_begin, __init_end,
> -               DIV_ROUND_UP((__init_end - __init_begin), SZ_1K),
> -               _stext, _etext,
> -               DIV_ROUND_UP((_etext - _stext), SZ_1K),
> -               _sdata, _edata,
> -               DIV_ROUND_UP((_edata - _sdata), SZ_1K));
>
>         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
>         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
> --
> 2.17.1
>



-- 
Kees Cook
Pixel Security