Re: [PATCH 1/2] powerpc/sstep: Consistently use one define to check arch bit width

[LEROY Christophe]

Le 29/07/2026 à 22:49, Link Mauve a écrit :
> Previously, both CONFIG_PPC64 and __powerpc64__ were being used to check
> whether we were on 32-bit or on 64-bit PowerPC, sometimes in a single
> function.
> 
> I picked __powerpc64__ since it was used six times as much as
> CONFIG_PPC64 in this file, but could be convinced to use the other one
> if there is any reason to prefer it.

Well, we tend to use the other as much as possible:

$ git grep -w -e "#ifdef CONFIG_PPC64" -e "defined(CONFIG_PPC64)" | wc -l
368
$ git grep -w -e "#ifdef __powerpc64__"  | wc -l
118

Allthough in most cases you can use one or the other, they don't mean 
the same.

CONFIG_PPC64 means you are building a 64 bit kernel.
__powerpc64__ means you are building 64 bit code.

In a 64 bit kernel you can have 32 bit code, for instance the vdso32.

If you look into include/asm/feature-fixups.h for instance you have :

#if defined(CONFIG_PPC64) && !defined(__powerpc64__)
/* 64 bits kernel, 32 bits code (ie. vdso32) */
#define FTR_ENTRY_LONG		.8byte
#define FTR_ENTRY_OFFSET	.long 0xffffffff; .long
#elif defined(CONFIG_PPC64)
#define FTR_ENTRY_LONG		.8byte
#define FTR_ENTRY_OFFSET	.8byte
#else
#define FTR_ENTRY_LONG		.long
#define FTR_ENTRY_OFFSET	.long
#endif

Unless you are a good reason to use __powerpc64__ it is often better to 
use CONFIG_PPC64

Christophe

> 
> Signed-off-by: Link Mauve <linkmauve@xxxxxxxxxxxx>
> ---
>   arch/powerpc/lib/sstep.c | 16 ++++++++--------
>   1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index f0d6aa657c1a..597a0d841fe8 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -15,7 +15,7 @@
>   #include <asm/cputable.h>
>   #include <asm/disassemble.h>
>   
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   /* Bits in SRR1 that are copied from MSR */
>   #define MSR_MASK	0xffffffff87c0ffffUL
>   #else
> @@ -1256,7 +1256,7 @@ static nokprobe_inline void do_popcnt(const struct pt_regs *regs,
>   	op->val = out;	/* popcntd */
>   }
>   
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   static nokprobe_inline void do_bpermd(const struct pt_regs *regs,
>   				      struct instruction_op *op,
>   				      unsigned long v1, unsigned long v2)
> @@ -1273,7 +1273,7 @@ static nokprobe_inline void do_bpermd(const struct pt_regs *regs,
>   	}
>   	op->val = perm;
>   }
> -#endif /* CONFIG_PPC64 */
> +#endif /* __powerpc64__ */
>   /*
>    * The size parameter adjusts the equivalent prty instruction.
>    * prtyw = 32, prtyd = 64
> @@ -1340,7 +1340,7 @@ static nokprobe_inline int trap_compare(long v1, long v2)
>   int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
>   		  ppc_inst_t instr)
>   {
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   	unsigned int suffixopcode, prefixtype, prefix_r;
>   #endif
>   	unsigned int opcode, ra, rb, rc, rd, spr, u;
> @@ -1739,7 +1739,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
>   			op->reg = rd;
>   			op->val = 0xffffffff & ~(MSR_ME | MSR_LE);
>   			return 0;
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   		case 178:	/* mtmsrd */
>   			if (user_mode(regs))
>   				goto priv;
> @@ -2054,7 +2054,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
>   		case 186:	/* prtyd */
>   			do_prty(regs, op, regs->gpr[rd], 64);
>   			goto logical_done_nocc;
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   		case 252:	/* bpermd */
>   			do_bpermd(regs, op, regs->gpr[rd], regs->gpr[rb]);
>   			goto logical_done_nocc;
> @@ -2082,7 +2082,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
>   		case 476:	/* nand */
>   			op->val = ~(regs->gpr[rd] & regs->gpr[rb]);
>   			goto logical_done;
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   		case 506:	/* popcntd */
>   			do_popcnt(regs, op, regs->gpr[rd], 64);
>   			goto logical_done_nocc;
> @@ -3247,7 +3247,7 @@ void emulate_update_regs(struct pt_regs *regs, struct instruction_op *op)
>   		case BARRIER_EIEIO:
>   			eieio();
>   			break;
> -#ifdef CONFIG_PPC64
> +#ifdef __powerpc64__
>   		case BARRIER_LWSYNC:
>   			asm volatile("lwsync" : : : "memory");
>   			break;