bd5d4df4dc
commit 791ab8b2e3db0c6e4295467d10398800ec29144c upstream. 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> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.