linux-kernel - Re: [RFC PATCH 4/5] arm64: smp: move the pen to a header file

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Date:	Tue, 14 Apr 2015 16:59:41 +0100
From:	Mark Rutland <mark.rutland@....com>
To:	Kumar Gala <galak@...eaurora.org>
Cc:	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
	Catalin Marinas <Catalin.Marinas@....com>,
	Will Deacon <Will.Deacon@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"arm@...nel.org" <arm@...nel.org>,
	Abhimanyu Kapur <abhimany@...eaurora.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RFC PATCH 4/5] arm64: smp: move the pen to a header file

On Thu, Apr 09, 2015 at 06:37:10PM +0100, Kumar Gala wrote:
> From: Abhimanyu Kapur <abhimany@...eaurora.org>
> 
> Move the secondary_pen_release variable and the secondary_holding_pen
> entry function to asm/smp_plat.h so that the other cpu ops implementations
> can share them.

If anything, this should all be moved into smp_spin_table.c, and made
static.

We made a mistake with the pen (and allowing multiple CPUs to enter the
kernel at once). That mistake shouldn't be spread further.

Mark.

> 
> Signed-off-by: Abhimanyu Kapur <abhimany@...eaurora.org>
> Signed-off-by: Kumar Gala <galak@...eaurora.org>
> ---
>  arch/arm64/include/asm/smp_plat.h  | 2 ++
>  arch/arm64/kernel/smp.c            | 1 +
>  arch/arm64/kernel/smp_spin_table.c | 3 ---
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/smp_plat.h b/arch/arm64/include/asm/smp_plat.h
> index 59e2823..235ff04 100644
> --- a/arch/arm64/include/asm/smp_plat.h
> +++ b/arch/arm64/include/asm/smp_plat.h
> @@ -34,10 +34,12 @@ static inline u32 mpidr_hash_size(void)
>  	return 1 << mpidr_hash.bits;
>  }
>  
> +extern void secondary_holding_pen(void);
>  /*
>   * Logical CPU mapping.
>   */
>  extern u64 __cpu_logical_map[NR_CPUS];
>  #define cpu_logical_map(cpu)    __cpu_logical_map[cpu]
> +extern volatile unsigned long secondary_holding_pen_release;
>  
>  #endif /* __ASM_SMP_PLAT_H */
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 328b8ce..4ce1f23 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -61,6 +61,7 @@
>   * where to place its SVC stack
>   */
>  struct secondary_data secondary_data;
> +volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
>  
>  enum ipi_msg_type {
>  	IPI_RESCHEDULE,
> diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
> index b41a8b4..be833b9 100644
> --- a/arch/arm64/kernel/smp_spin_table.c
> +++ b/arch/arm64/kernel/smp_spin_table.c
> @@ -28,9 +28,6 @@
>  #include <asm/io.h>
>  #include <asm/smp_plat.h>
>  
> -extern void secondary_holding_pen(void);
> -volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
> -
>  static phys_addr_t cpu_release_addr[NR_CPUS];
>  
>  /*
> -- 
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
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