linux-kernel - Re: [PATCH] clocksource/arm_arch_timer: add __ro_after_init and _

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Message-ID: <e6179eb3-2439-ea34-db2e-307db048e6e6@linaro.org>
Date:   Wed, 31 Mar 2021 18:14:36 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Jisheng Zhang <Jisheng.Zhang@...aptics.com>,
        Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clocksource/arm_arch_timer: add __ro_after_init and
 __init

Hi,


On 30/03/2021 08:04, Jisheng Zhang wrote:
> Some functions are not needed after booting, so mark them as __init
> to move them to the .init section.
> 
> Some global variables are never modified after init, so can be
> __ro_after_init.
> 
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>

Mar[ck] ? Any comment on this change ?



> ---
>  drivers/clocksource/arm_arch_timer.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index d0177824c518..1b885964fb34 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -51,7 +51,7 @@
>  
>  static unsigned arch_timers_present __initdata;
>  
> -static void __iomem *arch_counter_base;
> +static void __iomem *arch_counter_base __ro_after_init;
>  
>  struct arch_timer {
>  	void __iomem *base;
> @@ -60,15 +60,16 @@ struct arch_timer {
>  
>  #define to_arch_timer(e) container_of(e, struct arch_timer, evt)
>  
> -static u32 arch_timer_rate;
> -static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI];
> +static u32 arch_timer_rate __ro_after_init;
> +u32 arch_timer_rate1 __ro_after_init;
> +static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI] __ro_after_init;
>  
>  static struct clock_event_device __percpu *arch_timer_evt;
>  
> -static enum arch_timer_ppi_nr arch_timer_uses_ppi = ARCH_TIMER_VIRT_PPI;
> -static bool arch_timer_c3stop;
> -static bool arch_timer_mem_use_virtual;
> -static bool arch_counter_suspend_stop;
> +static enum arch_timer_ppi_nr arch_timer_uses_ppi __ro_after_init = ARCH_TIMER_VIRT_PPI;
> +static bool arch_timer_c3stop __ro_after_init;
> +static bool arch_timer_mem_use_virtual __ro_after_init;
> +static bool arch_counter_suspend_stop __ro_after_init;
>  #ifdef CONFIG_GENERIC_GETTIMEOFDAY
>  static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_ARCHTIMER;
>  #else
> @@ -76,7 +77,7 @@ static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_NONE;
>  #endif /* CONFIG_GENERIC_GETTIMEOFDAY */
>  
>  static cpumask_t evtstrm_available = CPU_MASK_NONE;
> -static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
> +static bool evtstrm_enable __ro_after_init = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
>  
>  static int __init early_evtstrm_cfg(char *buf)
>  {
> @@ -176,7 +177,7 @@ static notrace u64 arch_counter_get_cntvct(void)
>   * to exist on arm64. arm doesn't use this before DT is probed so even
>   * if we don't have the cp15 accessors we won't have a problem.
>   */
> -u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
> +u64 (*arch_timer_read_counter)(void) __ro_after_init = arch_counter_get_cntvct;
>  EXPORT_SYMBOL_GPL(arch_timer_read_counter);
>  
>  static u64 arch_counter_read(struct clocksource *cs)
> @@ -925,7 +926,7 @@ static int validate_timer_rate(void)
>   * rate was probed first, and don't verify that others match. If the first node
>   * probed has a clock-frequency property, this overrides the HW register.
>   */
> -static void arch_timer_of_configure_rate(u32 rate, struct device_node *np)
> +static void __init arch_timer_of_configure_rate(u32 rate, struct device_node *np)
>  {
>  	/* Who has more than one independent system counter? */
>  	if (arch_timer_rate)
> @@ -939,7 +940,7 @@ static void arch_timer_of_configure_rate(u32 rate, struct device_node *np)
>  		pr_warn("frequency not available\n");
>  }
>  
> -static void arch_timer_banner(unsigned type)
> +static void __init arch_timer_banner(unsigned type)
>  {
>  	pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
>  		type & ARCH_TIMER_TYPE_CP15 ? "cp15" : "",
> 


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