[PATCH v3.18 backport] arm64: Initialise high_memory global variable earlier

[PATCH v3.18 backport] arm64: Initialise high_memory global variable earlier

[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.

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;
 }
 
-- 
2.11.0

[PATCH v4.4 backport] arm64: Initialise high_memory global variable earlier

[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.

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 4cb98aa8c27b..efd89ce4533d 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -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;
 }
 
-- 
2.11.0

[PATCH v4.9 backport] arm64: Initialise high_memory global variable earlier

[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.

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 380ebe705093..9b8b477c363d 100644
--- 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();
 }
 
-- 
2.11.0

Re: [PATCH v3.18 backport] arm64: Initialise high_memory global variable earlier

[Greg KH]

On Mon, Dec 18, 2017 at 05:11:03PM +0000, Steve Capper wrote:
> 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.

Thanks for all 3 of these, now queued up.

greg k-h