linux-kernel - Re: [PATCH 1/4] riscv: Fix TASK_SIZE on 64-bit NOMMU

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Message-ID: <668ad9cf-08bf-92de-b70a-af36defda6e0@gmail.com>
Date: Wed, 27 Mar 2024 00:54:03 -0700
From: Bo Gan <ganboing@...il.com>
To: Jisheng Zhang <jszhang@...nel.org>,
 Samuel Holland <samuel.holland@...ive.com>
Cc: Palmer Dabbelt <palmer@...belt.com>, linux-riscv@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] riscv: Fix TASK_SIZE on 64-bit NOMMU

On 3/27/24 12:04 AM, Jisheng Zhang wrote:
> On Mon, Feb 26, 2024 at 04:34:46PM -0800, Samuel Holland wrote:
>> On NOMMU, userspace memory can come from anywhere in physical RAM. The
>> current definition of TASK_SIZE is wrong if any RAM exists above 4G,
>> causing spurious failures in the userspace access routines.
>>
>> Fixes: 6bd33e1ece52 ("riscv: add nommu support")
>> Fixes: c3f896dcf1e4 ("mm: switch the test_vmalloc module to use __vmalloc_node")
>> Signed-off-by: Samuel Holland <samuel.holland@...ive.com>
> 
> Reviewed-by: Jisheng Zhang <jszhang@...nel.org>
> 

Reviewed-by: Bo Gan <ganboing@...il.com>

Thanks for this patch! I'm doing something similar locally and it fixes the
linux nommu + musl libc build on my JH7110 S7 core.

Bo

>> ---
>>
>>   arch/riscv/include/asm/pgtable.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
>> index 0c94260b5d0c..a564a39e5676 100644
>> --- a/arch/riscv/include/asm/pgtable.h
>> +++ b/arch/riscv/include/asm/pgtable.h
>> @@ -882,7 +882,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
>>   #define PAGE_SHARED		__pgprot(0)
>>   #define PAGE_KERNEL		__pgprot(0)
>>   #define swapper_pg_dir		NULL
>> -#define TASK_SIZE		0xffffffffUL
>> +#define TASK_SIZE		_AC(-1, UL)
>>   #define VMALLOC_START		_AC(0, UL)
>>   #define VMALLOC_END		TASK_SIZE
>>   
>> -- 
>> 2.43.0
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> 
> _______________________________________________
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> linux-riscv@...ts.infradead.org
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> 

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