linux-kernel - Re: [PATCH] powerpc: wire up memtest

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Message-ID: <871s9euw4m.fsf@concordia.ellerman.id.au>
Date:   Fri, 28 Sep 2018 13:41:13 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Christophe Leroy <christophe.leroy@....fr>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] powerpc: wire up memtest

Christophe Leroy <christophe.leroy@....fr> writes:
> Add call to early_memtest() so that kernel compiled with
> CONFIG_MEMTEST really perform memtest at startup when requested
> via 'memtest' boot parameter.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
>  arch/powerpc/kernel/setup-common.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index 93fa0c99681e..904b728eb20d 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -33,6 +33,7 @@
>  #include <linux/serial_8250.h>
>  #include <linux/percpu.h>
>  #include <linux/memblock.h>
> +#include <linux/bootmem.h>
>  #include <linux/of_platform.h>
>  #include <linux/hugetlb.h>
>  #include <asm/debugfs.h>
> @@ -917,6 +918,8 @@ void __init setup_arch(char **cmdline_p)
>  	/* Parse memory topology */
>  	mem_topology_setup();
>  
> +	early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT);

On a ppc64le VM this boils down to early_memtest(0, 0) for me.

I think it's too early, we don't set up max_low_pfn until
initmem_init().

If I move it after initmem_init() then it does something more useful:

early_memtest: # of tests: 17
  0x0000000001450580 - 0x0000000001450800 pattern 4c494e5558726c7a
  0x0000000001450c00 - 0x0000000003600000 pattern 4c494e5558726c7a
  0x00000000047c0000 - 0x000000002fff0000 pattern 4c494e5558726c7a
  0x0000000030000000 - 0x000000003ff24000 pattern 4c494e5558726c7a
  0x000000003fff4000 - 0x000000003fff4c00 pattern 4c494e5558726c7a
  0x000000003fff5000 - 0x000000003fff5300 pattern 4c494e5558726c7a
  0x000000003fff5c00 - 0x000000003fff5f00 pattern 4c494e5558726c7a
  0x000000003fff6800 - 0x000000003fff6b00 pattern 4c494e5558726c7a
  0x000000003fff7400 - 0x000000003fff7700 pattern 4c494e5558726c7a
  0x000000003fff8000 - 0x000000003fff8300 pattern 4c494e5558726c7a
  0x000000003fff8c00 - 0x000000003fff8f00 pattern 4c494e5558726c7a
  0x000000003fff9800 - 0x000000003fff9b00 pattern 4c494e5558726c7a
  0x000000003fffa400 - 0x000000003fffa700 pattern 4c494e5558726c7a
  0x000000003fffb000 - 0x000000003fffb300 pattern 4c494e5558726c7a
  0x000000003fffbc00 - 0x000000003fffbf00 pattern 4c494e5558726c7a
  0x000000003fffc800 - 0x000000003fffcb00 pattern 4c494e5558726c7a
  0x000000003fffd400 - 0x000000003fffd700 pattern 4c494e5558726c7a
  0x000000003fffe000 - 0x000000003fffe100 pattern 4c494e5558726c7a
  0x0000000040000000 - 0x00000000ffc10000 pattern 4c494e5558726c7a
  0x00000000fffa0000 - 0x00000000fffa5b00 pattern 4c494e5558726c7a
  0x0000000100000000 - 0x00000001ffbe0000 pattern 4c494e5558726c7a
  0x00000001fff60000 - 0x00000001fff61b00 pattern 4c494e5558726c7a
  0x00000001fffec000 - 0x00000001fffec4b8 pattern 4c494e5558726c7a
  0x00000001fffec524 - 0x00000001fffec528 pattern 4c494e5558726c7a


cheers