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.

Cc: stable@vger.kernel.org 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 --- arch/arm64/mm/init.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 43245e15413e..ed8affdf8f58 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -155,6 +155,8 @@ void __init arm64_memblock_init(void) /* 4GB maximum for 32-bit only capable devices */ if (IS_ENABLED(CONFIG_ZONE_DMA)) dma_phys_limit = max_zone_dma_phys(); + + high_memory = __va(memblock_end_of_DRAM() - 1) + 1; dma_contiguous_reserve(dma_phys_limit);

memblock_allow_resize(); @@ -177,7 +179,6 @@ void __init bootmem_init(void) sparse_init(); zone_sizes_init(min, max);

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