linux-kernel - Re: [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup

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Date:   Tue, 1 Jun 2021 14:54:15 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Mike Rapoport <rppt@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-mips@...r.kernel.org,
        linux-mm@...ck.org, linux-s390@...r.kernel.org
Subject: Re: [RFC/RFT PATCH 2/5] memblock: introduce generic
 memblock_setup_resources()

On Mon, May 31, 2021 at 03:29:56PM +0300, Mike Rapoport wrote:
> +	code_resource.start = __pa_symbol(_text);
> +	code_resource.end = __pa_symbol(_etext)-1;
> +	rodata_resource.start = __pa_symbol(__start_rodata);
> +	rodata_resource.end = __pa_symbol(__end_rodata)-1;
> +	data_resource.start = __pa_symbol(_sdata);
> +	data_resource.end = __pa_symbol(_edata)-1;
> +	bss_resource.start = __pa_symbol(__bss_start);
> +	bss_resource.end = __pa_symbol(__bss_stop)-1;

This falls short on 32-bit ARM. The old code was:

-       kernel_code.start   = virt_to_phys(_text);
-       kernel_code.end     = virt_to_phys(__init_begin - 1);
-       kernel_data.start   = virt_to_phys(_sdata);                             
-       kernel_data.end     = virt_to_phys(_end - 1);                           

If I look at one of my kernels:

c0008000 T _text
c0b5b000 R __end_rodata
... exception and unwind tables live here ...
c0c00000 T __init_begin
c0e00000 D _sdata
c0e68870 D _edata
c0e68870 B __bss_start
c0e995d4 B __bss_stop
c0e995d4 B _end

So the original covers _text..__init_begin-1 which includes the
exception and unwind tables. Your version above omits these, which
leaves them exposed.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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