arm64: Initialise high_memory global variable earlier

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>

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 43245e15413e79552a32311af2a484210cb5fa32..ed8affdf8f58b0f3b5c393071a327646ebd877f4 100644 (file)
--- 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;
 }