arm64: Ignore any DMA offsets in the max_zone_phys() calculation

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Currently, the kernel assumes that if RAM starts above 32-bit (or
zone_bits), there is still a ZONE_DMA/DMA32 at the bottom of the RAM and
such constrained devices have a hardwired DMA offset. In practice, we
haven't noticed any such hardware so let's assume that we can expand
ZONE_DMA32 to the available memory if no RAM below 4GB. Similarly,
ZONE_DMA is expanded to the 4GB limit if no RAM addressable by
zone_bits.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20201118185809.1078362-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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This commit is contained in:

Catalin Marinas 2020-11-18 18:58:09 +00:00

parent f8394f232b

commit 791ab8b2e3

1 changed files with 12 additions and 5 deletions

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arch/arm64/mm/init.c

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