linux-kernel - Re: [PATCH] powerpc/xmon: replace sizeof calculations with ARRAY

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Message-ID: <62aa5231-ed31-43e2-84b7-d6b6ec86e78d@csgroup.eu>
Date: Wed, 30 Jul 2025 08:14:01 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Ruben Wauters <rubenru09@....com>,
 Madhavan Srinivasan <maddy@...ux.ibm.com>,
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>
Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
 kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] powerpc/xmon: replace sizeof calculations with ARRAY_SIZE
 macro



Le 20/07/2025 à 00:43, Ruben Wauters a écrit :
> [Vous ne recevez pas souvent de courriers de rubenru09@....com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
> 
> The calculations for operand/opcode/macro numbers are done in an
> identical manner to the already existing ARRAY_SIZE macro in
> linux/array_size.h
> 
> This patch replaces the sizeof calculations with the macro to make the
> code cleaner and more immediately obvious what it is doing.
> 
> Signed-off-by: Ruben Wauters <rubenru09@....com>
> ---
>   arch/powerpc/xmon/ppc-opc.c | 16 ++++++----------

This file is mostly taken from binutils, refer commit 08d96e0b127e 
("powerpc/xmon: Apply binutils changes to upgrade disassembly").

I think your change should be done in binutils then backported to the 
kernel. The more we diverge from binutils the worse it is.

Christophe


>   1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/xmon/ppc-opc.c b/arch/powerpc/xmon/ppc-opc.c
> index 0774d711453e..de9b4236728c 100644
> --- a/arch/powerpc/xmon/ppc-opc.c
> +++ b/arch/powerpc/xmon/ppc-opc.c
> @@ -954,8 +954,7 @@ const struct powerpc_operand powerpc_operands[] =
>     { 0xff, 11, NULL, NULL, PPC_OPERAND_SIGNOPT },
>   };
> 
> -const unsigned int num_powerpc_operands = (sizeof (powerpc_operands)
> -                                          / sizeof (powerpc_operands[0]));
> +const unsigned int num_powerpc_operands = ARRAY_SIZE(powerpc_operands);
> 
>   /* The functions used to insert and extract complicated operands.  */
> 
> @@ -6968,9 +6967,8 @@ const struct powerpc_opcode powerpc_opcodes[] = {
>   {"fcfidu.",    XRC(63,974,1),  XRA_MASK, POWER7|PPCA2, PPCVLE,         {FRT, FRB}},
>   };
> 
> -const int powerpc_num_opcodes =
> -  sizeof (powerpc_opcodes) / sizeof (powerpc_opcodes[0]);
> -
> +const int powerpc_num_opcodes = ARRAY_SIZE(powerpc_opcodes);
> +
>   /* The VLE opcode table.
> 
>      The format of this opcode table is the same as the main opcode table.  */
> @@ -7207,9 +7205,8 @@ const struct powerpc_opcode vle_opcodes[] = {
>   {"se_bl",      BD8(58,0,1),    BD8_MASK,       PPCVLE, 0,              {B8}},
>   };
> 
> -const int vle_num_opcodes =
> -  sizeof (vle_opcodes) / sizeof (vle_opcodes[0]);
> -
> +const int vle_num_opcodes = ARRAY_SIZE(vle_opcodes);
> +
>   /* The macro table.  This is only used by the assembler.  */
> 
>   /* The expressions of the form (-x ! 31) & (x | 31) have the value 0
> @@ -7276,5 +7273,4 @@ const struct powerpc_macro powerpc_macros[] = {
>   {"e_clrlslwi",4, PPCVLE, "e_rlwinm %0,%1,%3,(%2)-(%3),31-(%3)"},
>   };
> 
> -const int powerpc_num_macros =
> -  sizeof (powerpc_macros) / sizeof (powerpc_macros[0]);
> +const int powerpc_num_macros = ARRAY_SIZE(powerpc_macros);
> --
> 2.49.1
>