[PATCH v5sub1 8/8] arm64: allow kernel Image to be loaded anywhere in physical memory

On Mon, Feb 01, 2016 at 06:57:05PM +0100, Ard Biesheuvel wrote:

On 1 February 2016 at 18:31, Catalin Marinas [off-list ref] wrote:

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On Mon, Feb 01, 2016 at 11:54:53AM +0100, Ard Biesheuvel wrote:

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Note that limiting memory using mem= is not unambiguous anymore after
this change, considering that the kernel may be at the top of physical
memory, and clipping from the bottom rather than the top will discard
any 32-bit DMA addressable memory first. To deal with this, the handling
of mem= is reimplemented to clip top down, but take special care not to
clip memory that covers the kernel image.

I may have forgotten the reason - why do we need to avoid clipping the
memory that covers the kernel image? It's already mapped in the vmalloc
area, so we wouldn't need it in the linear map as well.

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I don't care about efficiency, I was hoping to avoid the additional
arm64-specific memory clipping but it seems that it could easily get
more complicated. So let's leave as it is.

Alternatively, we could simply apply the memory limit as before, and
add back the [__init_begin, _end] interval right afterwards using
memblock_add()

If the code ends up simpler, yes, I'm fine with it.

-- 
Catalin