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Patch "arm64: Initialise high_memory global variable earlier" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 18, 2017

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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 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-initialise-high_memory-global-variable-earlier.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From f24e5834a2c3f6c5f814a417f858226f0a010ade Mon Sep 17 00:00:00 2001

From: Steve Capper <[email protected]>
Date: Mon, 4 Dec 2017 14:13:05 +0000
Subject: arm64: Initialise high_memory global variable earlier

From: Steve Capper <[email protected]>

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")
---
 arch/arm64/mm/init.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/init.c +2 -1
@@ -476,6 +476,8 @@ void __init arm64_memblock_init(void)
 
 	reserve_elfcorehdr();
 
+	high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
+
 	dma_contiguous_reserve(arm64_dma_phys_limit);
 
 	memblock_allow_resize();
@@ -502,7 +504,6 @@ 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 [email protected] are

queue-4.14/arm64-initialise-high_memory-global-variable-earlier.patch queue-4.14/arm64-mm-fix-pte_mkclean-pte_mkdirty-semantics.patch