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arm64: Initialise high_memory global variable earlier

PATCH In review Steve Capper 2 participants 4 messages Dec 18, 2017 – Dec 20, 2017

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#0 lore raw

PATCH 1/1 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")
---
 arch/arm64/mm/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/arm64/mm/init.c +2 -1
index 43245e15413e..ed8affdf8f58 100644
@@ -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;
 }
 
Signature · 1 line
2.11.0
#1 lore raw

PATCH 1/1 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")
---
 arch/arm64/mm/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm64/mm/init.c +1 -1
index 4cb98aa8c27b..efd89ce4533d 100644
@@ -178,6 +178,7 @@ 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();
@@ -202,7 +203,6 @@ 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;
 }
 
Signature · 1 line
2.11.0
#2 lore raw

PATCH 1/1 arm64: Initialise high_memory global variable earlier

In reply to Steve Capper

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm64/mm/init.c +1 -1
index 380ebe705093..9b8b477c363d 100644
@@ -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();
 }
 
Signature · 1 line
2.11.0
#3 lore raw
In reply to Steve Capper
Quoted 5 lines · Steve Capper

Commit f24e5834a2c3f6c5f814a417f858226f0a010ade upstream.

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

Quoted 7 lines

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.

Thanks for all 3 of these, now queued up.

greg k-h