diff mbox

[RFC,4/5] arm64: smp: move the pen to a header file

Message ID 1428601031-5366-5-git-send-email-galak@codeaurora.org (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Kumar Gala April 9, 2015, 5:37 p.m. UTC
From: Abhimanyu Kapur <abhimany@codeaurora.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.

Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>
Signed-off-by: Kumar Gala <galak@codeaurora.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(-)

Comments

Arnd Bergmann April 9, 2015, 9:17 p.m. UTC | #1
On Thursday 09 April 2015 12:37:10 Kumar Gala wrote:
> From: Abhimanyu Kapur <abhimany@codeaurora.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.
> 
> Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>
> Signed-off-by: Kumar Gala <galak@codeaurora.org>
> 

I don't believe your SMP implementation can be so broken to require this.
Please fix the code instead to not use a holding pen.

	Arnd
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Mark Rutland April 14, 2015, 3:59 p.m. UTC | #2
On Thu, Apr 09, 2015 at 06:37:10PM +0100, Kumar Gala wrote:
> From: Abhimanyu Kapur <abhimany@codeaurora.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@codeaurora.org>
> Signed-off-by: Kumar Gala <galak@codeaurora.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];
>  
>  /*
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> 
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Kumar Gala April 14, 2015, 7:40 p.m. UTC | #3
> On Apr 14, 2015, at 10:59 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> 
> On Thu, Apr 09, 2015 at 06:37:10PM +0100, Kumar Gala wrote:
>> From: Abhimanyu Kapur <abhimany@codeaurora.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.

Yeah, it appears I can drop this and just set the secondary cores to enter secondary_entry.

- k
Kumar Gala April 14, 2015, 7:41 p.m. UTC | #4
> On Apr 9, 2015, at 4:17 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> 
> On Thursday 09 April 2015 12:37:10 Kumar Gala wrote:
>> From: Abhimanyu Kapur <abhimany@codeaurora.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.
>> 
>> Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>
>> Signed-off-by: Kumar Gala <galak@codeaurora.org>
>> 
> 
> I don't believe your SMP implementation can be so broken to require this.
> Please fix the code instead to not use a holding pen.
> 
> 	Arnd

Yeah, I can drop this.

- k
diff mbox

Patch

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];
 
 /*