[PATCH] RISCV: Fix end PFN for low memory

[PATCH] RISCV: Fix end PFN for low memory

[Atish Patra]

Use memblock_end_of_DRAM which provides correct last low memory
PFN. Without that, DMA32 region becomes empty resulting in zero
pages being allocated for DMA32.

This patch is based on earlier patch from palmer which never
merged into 4.19. I just edited the commit text to make more
sense.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/kernel/setup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index db20dc63..a192bf8a 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -193,7 +193,7 @@ static void __init setup_bootmem(void)
 	BUG_ON(mem_size == 0);
 
 	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = pfn_base + PFN_DOWN(mem_size);
+	max_low_pfn = memblock_end_of_DRAM();
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	setup_initrd();
-- 
2.7.4

Re: [PATCH] RISCV: Fix end PFN for low memory

[Christoph Hellwig]

On Tue, Sep 11, 2018 at 11:30:18AM -0700, Atish Patra wrote:
> Use memblock_end_of_DRAM which provides correct last low memory
> PFN. Without that, DMA32 region becomes empty resulting in zero
> pages being allocated for DMA32.
> 
> This patch is based on earlier patch from palmer which never
> merged into 4.19. I just edited the commit text to make more
> sense.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Palmer, can you queue this up for 4.19?

Re: [PATCH] RISCV: Fix end PFN for low memory

[Atish Patra]

On 9/17/18 7:08 AM, Christoph Hellwig wrote:
> On Tue, Sep 11, 2018 at 11:30:18AM -0700, Atish Patra wrote:
>> Use memblock_end_of_DRAM which provides correct last low memory
>> PFN. Without that, DMA32 region becomes empty resulting in zero
>> pages being allocated for DMA32.
>>
>> This patch is based on earlier patch from palmer which never
>> merged into 4.19. I just edited the commit text to make more
>> sense.
> 
> Looks good,
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> Palmer, can you queue this up for 4.19?
> 
Hi Palmer,
I did not see this one pulled into your rc6 PR.
Not sure if it was intentional or just lost in heap of emails.


Regards,
Atish

Re: [PATCH] RISCV: Fix end PFN for low memory

[Palmer Dabbelt]

On Mon, 24 Sep 2018 13:55:04 PDT (-0700), atish.patra@wdc.com wrote:
> On 9/17/18 7:08 AM, Christoph Hellwig wrote:
>> On Tue, Sep 11, 2018 at 11:30:18AM -0700, Atish Patra wrote:
>>> Use memblock_end_of_DRAM which provides correct last low memory
>>> PFN. Without that, DMA32 region becomes empty resulting in zero
>>> pages being allocated for DMA32.
>>>
>>> This patch is based on earlier patch from palmer which never
>>> merged into 4.19. I just edited the commit text to make more
>>> sense.
>>
>> Looks good,
>>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>>
>> Palmer, can you queue this up for 4.19?
>>
> Hi Palmer,
> I did not see this one pulled into your rc6 PR.
> Not sure if it was intentional or just lost in heap of emails.

Looks like it got lost, sorry.  It's in my branch now, I might re-spin the rc6 
PR because it looks like I may have screwed it up, if not I'll put it in rc7.

Thanks for the ping!