linux-kernel - Re: [PATCH 6/9] MIPS: Remove "weak" from get_c0_compare

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Message-ID: <55A38698.8080206@imgtec.com>
Date:	Mon, 13 Jul 2015 10:36:24 +0100
From:	James Hogan <james.hogan@...tec.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>,
	Ralf Baechle <ralf@...ux-mips.org>
CC:	Andrew Bresticker <abrestic@...omium.org>,
	<linux-mips@...ux-mips.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/9] MIPS: Remove "weak" from get_c0_compare_int() declaration

On 13/07/15 00:11, Bjorn Helgaas wrote:
> Weak header file declarations are error-prone because they make every
> definition weak, and the linker chooses one based on link order (see
> 10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
> decl")).
> 
> get_c0_compare_int() is defined in several files.  Each definition is weak,
> so I assume Kconfig prevents two or more from being included.  The caller
> contains default code used when get_c0_compare_int() isn't defined at all.
> 
> Add a weak get_c0_compare_int() definition with the default code and remove
> the weak annotation from the declaration.
> 
> Then the platform implementations will be strong and will override the weak
> default.  If multiple platforms are ever configured in, we'll get a link
> error instead of calling a random platform's implementation.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>

Reviewed-by: James Hogan <james.hogan@...tec.com>

Cheers
James

> ---
>  arch/mips/include/asm/time.h |    2 +-
>  arch/mips/kernel/cevt-r4k.c  |   11 +++++++----
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h
> index ce6a7d5..44a9c3a 100644
> --- a/arch/mips/include/asm/time.h
> +++ b/arch/mips/include/asm/time.h
> @@ -51,7 +51,7 @@ extern int get_c0_perfcount_int(void);
>  /*
>   * Initialize the calling CPU's compare interrupt as clockevent device
>   */
> -extern unsigned int __weak get_c0_compare_int(void);
> +extern unsigned int get_c0_compare_int(void);
>  extern int r4k_clockevent_init(void);
>  
>  static inline int mips_clockevent_init(void)
> diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
> index d70c4d8..cc7cc46 100644
> --- a/arch/mips/kernel/cevt-r4k.c
> +++ b/arch/mips/kernel/cevt-r4k.c
> @@ -174,6 +174,11 @@ int c0_compare_int_usable(void)
>  	return 1;
>  }
>  
> +unsigned int __weak get_c0_compare_int(void)
> +{
> +	return MIPS_CPU_IRQ_BASE + cp0_compare_irq;
> +}
> +
>  int r4k_clockevent_init(void)
>  {
>  	unsigned int cpu = smp_processor_id();
> @@ -189,11 +194,9 @@ int r4k_clockevent_init(void)
>  	/*
>  	 * With vectored interrupts things are getting platform specific.
>  	 * get_c0_compare_int is a hook to allow a platform to return the
> -	 * interrupt number of it's liking.
> +	 * interrupt number of its liking.
>  	 */
> -	irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
> -	if (get_c0_compare_int)
> -		irq = get_c0_compare_int();
> +	irq = get_c0_compare_int();
>  
>  	cd = &per_cpu(mips_clockevent_device, cpu);
>  
> 


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