linux-kernel - Re: [PATCH] RAS/AMD/ATL: Add MI300 DRAM to Normalized address translation support

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Date: Thu, 1 Feb 2024 16:59:06 -0500
From: Yazen Ghannam <yazen.ghannam@....com>
To: Borislav Petkov <bp@...en8.de>
Cc: yazen.ghannam@....com, tony.luck@...el.com, linux-edac@...r.kernel.org,
 linux-kernel@...r.kernel.org, avadhut.naik@....com, john.allen@....com,
 muralidhara.mk@....com
Subject: Re: [PATCH] RAS/AMD/ATL: Add MI300 DRAM to Normalized address
 translation support

On 2/1/2024 10:05 AM, Borislav Petkov wrote:
> On Thu, Feb 01, 2024 at 09:35:13AM -0500, Yazen Ghannam wrote:
>> It's an operation on the bits within a value rather than between two values.
>>
>> BTW, I looked up "internal" in a thesaurus, and nothing seemed much better to me.
>>
>> Maybe something like "xor_bits_in_value()"? This has the verb-first style too.
> 
> Ah, ok, easy:
> 
> ---
> diff --git a/drivers/ras/amd/atl/umc.c b/drivers/ras/amd/atl/umc.c
> index 67dc186a1226..7e310d1dfcfc 100644
> --- a/drivers/ras/amd/atl/umc.c
> +++ b/drivers/ras/amd/atl/umc.c
> @@ -49,7 +49,8 @@ static u8 get_coh_st_inst_id_mi300(struct atl_err *err)
>   	return i;
>   }
>   
> -static u16 internal_bitwise_xor(u16 val)
> +/* XOR the bits in @val. */
> +static u16 bitwise_xor_bits(u16 val)
>   {
>   	u16 tmp = 0;
>   	u8 i;
> @@ -181,8 +182,8 @@ static unsigned long convert_dram_to_norm_addr_mi300(unsigned long addr)
>   		if (!addr_hash.bank[i].xor_enable)
>   			continue;
>   
> -		temp  = internal_bitwise_xor(col & addr_hash.bank[i].col_xor);
> -		temp ^= internal_bitwise_xor(row & addr_hash.bank[i].row_xor);
> +		temp  = bitwise_xor_bits(col & addr_hash.bank[i].col_xor);
> +		temp ^= bitwise_xor_bits(row & addr_hash.bank[i].row_xor);
>   		bank ^= temp << i;
>   	}
>   
> @@ -191,9 +192,9 @@ static unsigned long convert_dram_to_norm_addr_mi300(unsigned long addr)
>   		/* Bits SID[1:0] act as Bank[6:5] for PC hash, so apply them here. */
>   		bank |= sid << 5;
>   
> -		temp  = internal_bitwise_xor(col  & addr_hash.pc.col_xor);
> -		temp ^= internal_bitwise_xor(row  & addr_hash.pc.row_xor);
> -		temp ^= internal_bitwise_xor(bank & addr_hash.bank_xor);
> +		temp  = bitwise_xor_bits(col  & addr_hash.pc.col_xor);
> +		temp ^= bitwise_xor_bits(row  & addr_hash.pc.row_xor);
> +		temp ^= bitwise_xor_bits(bank & addr_hash.bank_xor);
>   		pc   ^= temp;
>   
>   		/* Drop SID bits for the sake of debug printing later. */
> 
> 

Yep, easy :) Looks good to me.

Thanks,
Yazen