linux-kernel - Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b0b824bebb9ef13ce746f9914de83126b0386e23.camel@suse.de>
Date:   Wed, 11 Sep 2019 12:54:38 +0200
From:   Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
To:     catalin.marinas@....com, hch@....de, wahrenst@....net,
        marc.zyngier@....com, robh+dt@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-mm@...ck.org,
        linux-riscv@...ts.infradead.org, Will Deacon <will@...nel.org>
Cc:     f.fainelli@...il.com, robin.murphy@....com,
        linux-kernel@...r.kernel.org, mbrugger@...e.com,
        linux-rpi-kernel@...ts.infradead.org, phill@...pberrypi.org,
        m.szyprowski@...sung.com
Subject: Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32

On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote:
> +
>  /*
> - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). It
> - * currently assumes that for memory starting above 4G, 32-bit devices will
> - * use a DMA offset.
> + * Return the maximum physical address for a zone with a given address size
> + * limit. It currently assumes that for memory starting above 4G, 32-bit
> + * devices will use a DMA offset.
>   */
> -static phys_addr_t __init max_zone_dma32_phys(void)
> +static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
>  {
>         phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, 32);
> -       return min(offset + (1ULL << 32), memblock_end_of_DRAM());
> +       return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM());
>  }

Hi all,
while testing other code on top of this series on odd arm64 machines I found an
issue: when memblock_start_of_DRAM() != 0, max_zone_phys() isn't taking into
account the offset to the beginning of memory. This doesn't matter with
zone_bits == 32 but it does when zone_bits == 30.

I'll send a follow-up series.

Regards,
Nicolas


Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)