linux-kernel - Re: [PATCH v5 04/22] drivers/perf: riscv: Use BIT macro for shifting operations

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Date: Thu, 4 Apr 2024 13:08:11 +0200
From: Andrew Jones <ajones@...tanamicro.com>
To: Atish Patra <atishp@...osinc.com>
Cc: linux-kernel@...r.kernel.org, Ajay Kaher <akaher@...are.com>, 
	Alexandre Ghiti <alexghiti@...osinc.com>, Alexey Makhalov <amakhalov@...are.com>, 
	Anup Patel <anup@...infault.org>, Conor Dooley <conor.dooley@...rochip.com>, 
	Juergen Gross <jgross@...e.com>, kvm-riscv@...ts.infradead.org, kvm@...r.kernel.org, 
	linux-kselftest@...r.kernel.org, linux-riscv@...ts.infradead.org, 
	Mark Rutland <mark.rutland@....com>, Palmer Dabbelt <palmer@...belt.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, Paul Walmsley <paul.walmsley@...ive.com>, 
	Shuah Khan <shuah@...nel.org>, virtualization@...ts.linux.dev, 
	VMware PV-Drivers Reviewers <pv-drivers@...are.com>, Will Deacon <will@...nel.org>, x86@...nel.org
Subject: Re: [PATCH v5 04/22] drivers/perf: riscv: Use BIT macro for shifting
 operations

On Wed, Apr 03, 2024 at 01:04:33AM -0700, Atish Patra wrote:
> It is a good practice to use BIT() instead of (1UL << x).

(1UL << x) isn't generally a problem. The problem is with (1 << x).

> Replace the current usages with BIT().
> 
> Signed-off-by: Atish Patra <atishp@...osinc.com>
> ---
>  arch/riscv/include/asm/sbi.h | 20 ++++++++++----------
>  drivers/perf/riscv_pmu_sbi.c |  2 +-
>  2 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> index ef8311dafb91..4afa2cd01bae 100644
> --- a/arch/riscv/include/asm/sbi.h
> +++ b/arch/riscv/include/asm/sbi.h
> @@ -233,20 +233,20 @@ enum sbi_pmu_ctr_type {
>  #define SBI_PMU_EVENT_IDX_INVALID 0xFFFFFFFF
>  
>  /* Flags defined for config matching function */
> -#define SBI_PMU_CFG_FLAG_SKIP_MATCH	(1 << 0)
> -#define SBI_PMU_CFG_FLAG_CLEAR_VALUE	(1 << 1)
> -#define SBI_PMU_CFG_FLAG_AUTO_START	(1 << 2)
> -#define SBI_PMU_CFG_FLAG_SET_VUINH	(1 << 3)
> -#define SBI_PMU_CFG_FLAG_SET_VSINH	(1 << 4)
> -#define SBI_PMU_CFG_FLAG_SET_UINH	(1 << 5)
> -#define SBI_PMU_CFG_FLAG_SET_SINH	(1 << 6)
> -#define SBI_PMU_CFG_FLAG_SET_MINH	(1 << 7)
> +#define SBI_PMU_CFG_FLAG_SKIP_MATCH	BIT(0)
> +#define SBI_PMU_CFG_FLAG_CLEAR_VALUE	BIT(1)
> +#define SBI_PMU_CFG_FLAG_AUTO_START	BIT(2)
> +#define SBI_PMU_CFG_FLAG_SET_VUINH	BIT(3)
> +#define SBI_PMU_CFG_FLAG_SET_VSINH	BIT(4)
> +#define SBI_PMU_CFG_FLAG_SET_UINH	BIT(5)
> +#define SBI_PMU_CFG_FLAG_SET_SINH	BIT(6)
> +#define SBI_PMU_CFG_FLAG_SET_MINH	BIT(7)
>  
>  /* Flags defined for counter start function */
> -#define SBI_PMU_START_FLAG_SET_INIT_VALUE (1 << 0)
> +#define SBI_PMU_START_FLAG_SET_INIT_VALUE BIT(0)
>  
>  /* Flags defined for counter stop function */
> -#define SBI_PMU_STOP_FLAG_RESET (1 << 0)
> +#define SBI_PMU_STOP_FLAG_RESET BIT(0)
>  
>  enum sbi_ext_dbcn_fid {
>  	SBI_EXT_DBCN_CONSOLE_WRITE = 0,
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index babf1b9a4dbe..a83ae82301e3 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -386,7 +386,7 @@ static int pmu_sbi_ctr_get_idx(struct perf_event *event)
>  			cmask = 1;
>  		} else if (event->attr.config == PERF_COUNT_HW_INSTRUCTIONS) {
>  			cflags |= SBI_PMU_CFG_FLAG_SKIP_MATCH;
> -			cmask = 1UL << (CSR_INSTRET - CSR_CYCLE);
> +			cmask = BIT(CSR_INSTRET - CSR_CYCLE);
>  		}
>  	}
>  
> -- 
> 2.34.1
>

Other than the commit message,

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>

Thanks,
drew