lkml.org 
[lkml]   [2020]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] mm/memblock: export max_pfn for kernel modules
On Thu, Jun 04, 2020 at 12:11:32AM +0800, Miles Chen wrote:
> max_pfn is uesd to get the highest pfn in the system. Drivers like
> drivers/iommu/mtk_iommu.c checks max_pfn to see if it should enable
> its "4GB mode".
>
> This patch exports the max_pfn symbol, so we can build the driver as
> a kernel module.

You can use totalram_pages(), like e.g.
drivers/media/platform/mtk-vpu/mtk_vpu.c:

$ git grep -np totalram_pages drivers/media/
drivers/media/platform/mtk-vpu/mtk_vpu.c=779=static int mtk_vpu_probe(struct platform_device *pdev)
drivers/media/platform/mtk-vpu/mtk_vpu.c:861: vpu->enable_4GB = !!(totalram_pages() > (SZ_2G >> PAGE_SHIFT));


> Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> ---
> mm/memblock.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index c79ba6f9920c..3b2b21ecebb6 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -99,6 +99,7 @@ EXPORT_SYMBOL(contig_page_data);
> unsigned long max_low_pfn;
> unsigned long min_low_pfn;
> unsigned long max_pfn;
> +EXPORT_SYMBOL(max_pfn);
> unsigned long long max_possible_pfn;
>
> static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
> --
> 2.18.0

--
Sincerely yours,
Mike.

\
 
 \ /
  Last update: 2020-06-03 19:07    [W:0.044 / U:1.896 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site