This is a note to let you know that I've just added the patch titled

arm64: Initialise high_memory global variable earlier

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: arm64-initialise-high_memory-global-variable-earlier.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From f24e5834a2c3f6c5f814a417f858226f0a010ade Mon Sep 17 00:00:00 2001

From: Steve Capper steve.capper@arm.com Date: Mon, 4 Dec 2017 14:13:05 +0000 Subject: arm64: Initialise high_memory global variable earlier

From: Steve Capper steve.capper@arm.com

commit f24e5834a2c3f6c5f814a417f858226f0a010ade upstream.

The high_memory global variable is used by cma_declare_contiguous(.) before it is defined.

We don't notice this as we compute __pa(high_memory - 1), and it looks like we're processing a VA from the direct linear map.

This problem becomes apparent when we flip the kernel virtual address space and the linear map is moved to the bottom of the kernel VA space.

This patch moves the initialisation of high_memory before it used.

Fixes: f7426b983a6a ("mm: cma: adjust address limit to avoid hitting low/high memory boundary") Signed-off-by: Steve Capper steve.capper@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/arm64/mm/init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -296,6 +296,7 @@ void __init arm64_memblock_init(void) arm64_dma_phys_limit = max_zone_dma_phys(); else arm64_dma_phys_limit = PHYS_MASK + 1; + high_memory = __va(memblock_end_of_DRAM() - 1) + 1; dma_contiguous_reserve(arm64_dma_phys_limit);

memblock_allow_resize(); @@ -322,7 +323,6 @@ void __init bootmem_init(void) sparse_init(); zone_sizes_init(min, max);

- high_memory = __va((max << PAGE_SHIFT) - 1) + 1; memblock_dump_all(); }

Patches currently in stable-queue which might be from steve.capper@arm.com are

queue-4.9/arm64-initialise-high_memory-global-variable-earlier.patch