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

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Date: Thu, 1 Feb 2024 16:05:43 +0100
From: Borislav Petkov <bp@...en8.de>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: 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 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. */


-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette