From: Ard Biesheuvel <ardb@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>, Will Deacon <will@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jeremy Linton <jeremy.linton@arm.com>,
iommu@lists.linux-foundation.org,
Rob Herring <robh+dt@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-rpi-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/5] arm64: mm: Move zone_dma_bits initialization into zone_sizes_init()
Date: Mon, 12 Oct 2020 16:23:47 +0200 [thread overview]
Message-ID: <CAMj1kXFUH7gv-dPVNM8xa5SBHhSndCQu4QFy5os2vAkaO_yecg@mail.gmail.com> (raw)
In-Reply-To: <20201012113748.GE9844@gaia>
On Mon, 12 Oct 2020 at 13:37, Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Sat, Oct 10, 2020 at 05:12:31PM +0200, Nicolas Saenz Julienne wrote:
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index f6902a2b4ea6..0eca5865dcb1 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -196,14 +196,16 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
> > unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
> >
> > #ifdef CONFIG_ZONE_DMA
> > + zone_dma_bits = ARM64_ZONE_DMA_BITS;
> > +
> > if (IS_ENABLED(CONFIG_ACPI)) {
> > extern unsigned int acpi_iort_get_zone_dma_size(void);
> >
> > zone_dma_bits = min(zone_dma_bits,
> > acpi_iort_get_zone_dma_size());
> > - arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
> > }
> >
> > + arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
> > max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
> > #endif
> > #ifdef CONFIG_ZONE_DMA32
> > @@ -394,11 +396,6 @@ void __init arm64_memblock_init(void)
> >
> > early_init_fdt_scan_reserved_mem();
> >
> > - if (IS_ENABLED(CONFIG_ZONE_DMA)) {
> > - zone_dma_bits = ARM64_ZONE_DMA_BITS;
> > - arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
> > - }
>
> arm64_dma_phys_limit is used by memblock_alloc_low() (via
> ARCH_LOW_ADDRESS_LIMIT). I think it's too late to leave its
> initialisation to zone_sizes_init().
>
The only generic caller of memblock_alloc_low() is swiotlb_init(),
which is called much later. So at that point, we definitely need
ARCH_LOW_ADDRESS_LIMIT to be set correctly, but that means doing it in
zone_sizes_init() is early enough.
So the only problematic reference seems to be crashkernel_reserve() afaict.
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next prev parent reply other threads:[~2020-10-12 14:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-10 15:12 [PATCH v2 0/5] arm64: Default to 32-bit wide ZONE_DMA Nicolas Saenz Julienne
2020-10-10 15:12 ` [PATCH v2 1/5] arm64: mm: Move zone_dma_bits initialization into zone_sizes_init() Nicolas Saenz Julienne
2020-10-12 11:37 ` Catalin Marinas
2020-10-12 14:23 ` Ard Biesheuvel [this message]
2020-10-10 15:12 ` [PATCH v2 2/5] of/address: Introduce of_dma_lower_bus_limit() Nicolas Saenz Julienne
2020-10-11 7:47 ` Ard Biesheuvel
2020-10-14 11:34 ` Nicolas Saenz Julienne
2020-10-12 15:25 ` Rob Herring
2020-10-14 11:52 ` Nicolas Saenz Julienne
2020-10-14 12:23 ` Rob Herring
2020-10-10 15:12 ` [PATCH v2 3/5] dma-direct: Turn zone_dma_bits default value into a define Nicolas Saenz Julienne
2020-10-10 15:12 ` [PATCH v2 4/5] arm64: mm: Dynamically resize zone_dma_bits based on system's constraints Nicolas Saenz Julienne
2020-10-10 15:12 ` [PATCH v2 5/5] mm: Update DMA zones description Nicolas Saenz Julienne
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