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Subject: Re: [PATCH 02/14] MIPS: memblock: Surely map BSS kernel memory
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To:     Serge Semin <fancer.lancer@gmail.com>, <ralf@linux-mips.org>,
        <miodrag.dinic@mips.com>, <jhogan@kernel.org>,
        <goran.ferenc@mips.com>, <david.daney@cavium.com>,
        <paul.gortmaker@windriver.com>, <paul.burton@mips.com>,
        <alex.belits@cavium.com>, <Steven.Hill@cavium.com>
CC:     <alexander.sverdlin@nokia.com>, <kumba@gentoo.org>,
        <marcin.nowakowski@mips.com>, <James.hogan@mips.com>,
        <Peter.Wotton@mips.com>, <Sergey.Semin@t-platforms.ru>,
        <linux-mips@linux-mips.org>, <linux-kernel@vger.kernel.org>
References: <20180117222312.14763-1-fancer.lancer@gmail.com>
 <20180117222312.14763-3-fancer.lancer@gmail.com>
From:   Matt Redfearn <matt.redfearn@mips.com>
Message-ID: <3fbb8850-bf34-d698-299a-f1cd62d063ae@mips.com>
Date:   Mon, 22 Jan 2018 16:35:26 +0000
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Hi Serge,

On 17/01/18 22:23, Serge Semin wrote:
> The current MIPS code makes sure the kernel code/data/init
> sections are in the maps, but BSS should also be there.

Quite right - it should. But this was protected against by reserving all 
bootmem up to the _end symbol here:
http://elixir.free-electrons.com/linux/v4.15-rc8/source/arch/mips/kernel/setup.c#L388
Which you remove in the next patch in this series. I'm not sure it is 
worth disentangling the reserved_end stuff from the next patch to make 
this into a single logical change of reserving just .bss rather than 
everything below _end.

Reviewed-by: Matt Redfearn <matt.redfearn@mips.com>

Thanks,
Matt

> 
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
> ---
>   arch/mips/kernel/setup.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 76e9e2075..0d21c9e04 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -845,6 +845,9 @@ static void __init arch_mem_init(char **cmdline_p)
>   	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
>   			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
>   			 BOOT_MEM_INIT_RAM);
> +	arch_mem_addpart(PFN_DOWN(__pa_symbol(&__bss_start)) << PAGE_SHIFT,
> +			 PFN_UP(__pa_symbol(&__bss_stop)) << PAGE_SHIFT,
> +			 BOOT_MEM_RAM);
>   
>   	pr_info("Determined physical RAM map:\n");
>   	print_memory_map();
>