Patchwork [5/6] powerpc: Macros for saving/restore PPR

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Submitter Haren Myneni
Date Oct. 31, 2012, 6:56 a.m.
Message ID <1351666574.32304.18.camel@hbabu-laptop>
Download mbox | patch
Permalink /patch/195752/
State Changes Requested
Delegated to: Benjamin Herrenschmidt
Headers show

Comments

Haren Myneni - Oct. 31, 2012, 6:56 a.m.
[PATCH 5/6] powerpc: Macros for saving/restore PPR

Several macros are defined for saving and restore user defined PPR value.

Signed-off-by: Haren Myneni <haren@us.ibm.com>
---
 arch/powerpc/include/asm/exception-64s.h |   29 +++++++++++++++++++++++++++++
 arch/powerpc/include/asm/ppc_asm.h       |   25 +++++++++++++++++++++++++
 arch/powerpc/include/asm/reg.h           |    1 +
 3 files changed, 55 insertions(+), 0 deletions(-)
Michael Neuling - Nov. 23, 2012, 3:39 a.m.
Haren Myneni <haren@linux.vnet.ibm.com> wrote:

> [PATCH 5/6] powerpc: Macros for saving/restore PPR
> 
> Several macros are defined for saving and restore user defined PPR value.
> 
> Signed-off-by: Haren Myneni <haren@us.ibm.com>
> ---
>  arch/powerpc/include/asm/exception-64s.h |   29 +++++++++++++++++++++++++++++
>  arch/powerpc/include/asm/ppc_asm.h       |   25 +++++++++++++++++++++++++
>  arch/powerpc/include/asm/reg.h           |    1 +
>  3 files changed, 55 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
> index bfd3f1f..880ef7d 100644
> --- a/arch/powerpc/include/asm/exception-64s.h
> +++ b/arch/powerpc/include/asm/exception-64s.h
> @@ -62,6 +62,35 @@
>  #define EXC_HV	H
>  #define EXC_STD
>  
> +/*
> + * PPR save/restore macros used in exceptions_64s.S  
> + * Used for P7 or later processors
> + */
> +#define SAVE_PPR(area, ra, rb)						\
> +BEGIN_FTR_SECTION_NESTED(940)						\
> +	ld	ra,PACACURRENT(r13);					\
> +	ld	rb,area+EX_PPR(r13);	/* Read PPR from paca */	\
> +	std	rb,TASKTHREADPPR(ra);					\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,940)
> +
> +#define RESTORE_PPR_PACA(area, ra)					\
> +BEGIN_FTR_SECTION_NESTED(941)						\
> +	ld	ra,area+EX_PPR(r13);					\
> +	mtspr	SPRN_PPR,ra;						\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,941)
> +

Can you add some documentation here on why we should use the different
versions.

I'm trying to read the next patch and it's not clear to my why some have
HMT_MEDIUM_NO_PPR and other times HMT_MEDIUM and others
HTM_MEDIUM_HAS_PPR.

Looks like HTM_MEDIUM_NO_PPR sets the priority to medium on systems
where we can't save/restore the PPR, hence it can be called earlier in
the exception handler before we have free GPRs.  HTM_MEDIUM_HAS_PPR
saves the priority on systems where it can, and then sets the priority
to medium.

Maybe we should change the names 
  HTM_MEDIUM_NO_PPR  => HTM_MEDIUM_PPR_DISCARD   and
  HTM_MEDIUM_HAS_PPR => HTM_MEDIUM_PPR_SAVE
But now I'm heading into bike shedding territory... plus I think I
suggested the names you have currently, so I'm feeling a bit dumb now
:-)

Mikey

> +#define HMT_MEDIUM_NO_PPR						\
> +BEGIN_FTR_SECTION_NESTED(942)						\
> +	HMT_MEDIUM;							\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,0,942)  /*non P7*/		
> +
> +#define HMT_MEDIUM_HAS_PPR(area, ra)					\
> +BEGIN_FTR_SECTION_NESTED(943)						\
> +	mfspr	ra,SPRN_PPR;						\
> +	std	ra,area+EX_PPR(r13);					\
> +	HMT_MEDIUM;							\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,943) 
> +
>  #define __EXCEPTION_PROLOG_1(area, extra, vec)				\
>  	GET_PACA(r13);							\
>  	std	r9,area+EX_R9(r13);	/* save r9 - r12 */		\


> diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
> index 376e36d..52649cc 100644
> --- a/arch/powerpc/include/asm/ppc_asm.h
> +++ b/arch/powerpc/include/asm/ppc_asm.h
> @@ -389,6 +389,31 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
>  	FTR_SECTION_ELSE_NESTED(848);	\
>  	mtocrf (FXM), RS;		\
>  	ALT_FTR_SECTION_END_NESTED_IFCLR(CPU_FTR_NOEXECUTE, 848)
> +
> +/*
> + * PPR restore macros used in entry_64.S
> + * Used for P7 or later processors
> + */
> +#define HMT_MEDIUM_LOW_HAS_PPR						\
> +BEGIN_FTR_SECTION_NESTED(944)						\
> +	HMT_MEDIUM_LOW;							\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,944)
> +
> +#define SET_DEFAULT_THREAD_PPR(ra, rb)					\
> +BEGIN_FTR_SECTION_NESTED(945)						\
> +	lis	ra,0xc;		/* default ppr=3 */			\
> +	ld	rb,PACACURRENT(r13);					\
> +	sldi	ra,ra,32;	/* 11- 13 bits are used for ppr */	\
> +	std	ra,TASKTHREADPPR(rb);					\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,945)
> +
> +#define RESTORE_PPR(ra, rb)						\
> +BEGIN_FTR_SECTION_NESTED(946)						\
> +	ld	ra,PACACURRENT(r13);					\
> +	ld	rb,TASKTHREADPPR(ra);					\
> +	mtspr	SPRN_PPR,rb;	/* Restore PPR */			\
> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,946)
> +
>  #endif
>  
>  /*
> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
> index d24c141..1723be3 100644
> --- a/arch/powerpc/include/asm/reg.h
> +++ b/arch/powerpc/include/asm/reg.h
> @@ -287,6 +287,7 @@
>  #define SPRN_DBAT6U	0x23C	/* Data BAT 6 Upper Register */
>  #define SPRN_DBAT7L	0x23F	/* Data BAT 7 Lower Register */
>  #define SPRN_DBAT7U	0x23E	/* Data BAT 7 Upper Register */
> +#define SPRN_PPR	0x380	/* SMT Thread status Register */
>  
>  #define SPRN_DEC	0x016		/* Decrement Register */
>  #define SPRN_DER	0x095		/* Debug Enable Regsiter */
> -- 
> 1.7.1
> 
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
Haren Myneni - Nov. 27, 2012, 1:49 a.m.
On 11/22/2012 07:39 PM, Michael Neuling wrote:
> Haren Myneni <haren@linux.vnet.ibm.com> wrote:
> 
>> [PATCH 5/6] powerpc: Macros for saving/restore PPR
>>
>> Several macros are defined for saving and restore user defined PPR value.
>>
>> Signed-off-by: Haren Myneni <haren@us.ibm.com>
>> ---
>>  arch/powerpc/include/asm/exception-64s.h |   29 +++++++++++++++++++++++++++++
>>  arch/powerpc/include/asm/ppc_asm.h       |   25 +++++++++++++++++++++++++
>>  arch/powerpc/include/asm/reg.h           |    1 +
>>  3 files changed, 55 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
>> index bfd3f1f..880ef7d 100644
>> --- a/arch/powerpc/include/asm/exception-64s.h
>> +++ b/arch/powerpc/include/asm/exception-64s.h
>> @@ -62,6 +62,35 @@
>>  #define EXC_HV	H
>>  #define EXC_STD
>>  
>> +/*
>> + * PPR save/restore macros used in exceptions_64s.S  
>> + * Used for P7 or later processors
>> + */
>> +#define SAVE_PPR(area, ra, rb)						\
>> +BEGIN_FTR_SECTION_NESTED(940)						\
>> +	ld	ra,PACACURRENT(r13);					\
>> +	ld	rb,area+EX_PPR(r13);	/* Read PPR from paca */	\
>> +	std	rb,TASKTHREADPPR(ra);					\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,940)
>> +
>> +#define RESTORE_PPR_PACA(area, ra)					\
>> +BEGIN_FTR_SECTION_NESTED(941)						\
>> +	ld	ra,area+EX_PPR(r13);					\
>> +	mtspr	SPRN_PPR,ra;						\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,941)
>> +
> 
> Can you add some documentation here on why we should use the different
> versions.
> 
> I'm trying to read the next patch and it's not clear to my why some have
> HMT_MEDIUM_NO_PPR and other times HMT_MEDIUM and others
> HTM_MEDIUM_HAS_PPR.
> 
> Looks like HTM_MEDIUM_NO_PPR sets the priority to medium on systems
> where we can't save/restore the PPR, hence it can be called earlier in
> the exception handler before we have free GPRs.  HTM_MEDIUM_HAS_PPR
> saves the priority on systems where it can, and then sets the priority
> to medium.
> 
> Maybe we should change the names 
>   HTM_MEDIUM_NO_PPR  => HTM_MEDIUM_PPR_DISCARD   and
>   HTM_MEDIUM_HAS_PPR => HTM_MEDIUM_PPR_SAVE
> But now I'm heading into bike shedding territory... plus I think I
> suggested the names you have currently, so I'm feeling a bit dumb now
> :-)

No problem, We can change these macro names if HTM_MEDIUM_PPR_DISCARD/
HTM_MEDIUM_PPR_SAVE gives better description.

Right, HTM_MEDIUM_NO_PPR is used on systems where we do not save/restore
PPR. So the behaviour is same as before - just increases the priority.
HTM_MEDIUM_HAS_PPR will be executed on systems where CPU_FTR_HAS_PPR is
enabled. I will write some comments around these macros to make it clear.

We can also name them HMT_MEDIUM_CPU_NO_PPR_SAVE and
HMT_MEDIUM_CPU_HAS_PPR_SAVE since we are enabling PPR save/restore using
CPU_FTR macro.

Otherwise I will follow with your suggestions.


Thanks
Haren

> Mikey
> 
>> +#define HMT_MEDIUM_NO_PPR						\
>> +BEGIN_FTR_SECTION_NESTED(942)						\
>> +	HMT_MEDIUM;							\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,0,942)  /*non P7*/		
>> +
>> +#define HMT_MEDIUM_HAS_PPR(area, ra)					\
>> +BEGIN_FTR_SECTION_NESTED(943)						\
>> +	mfspr	ra,SPRN_PPR;						\
>> +	std	ra,area+EX_PPR(r13);					\
>> +	HMT_MEDIUM;							\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,943) 
>> +
>>  #define __EXCEPTION_PROLOG_1(area, extra, vec)				\
>>  	GET_PACA(r13);							\
>>  	std	r9,area+EX_R9(r13);	/* save r9 - r12 */		\
> 
> 
>> diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
>> index 376e36d..52649cc 100644
>> --- a/arch/powerpc/include/asm/ppc_asm.h
>> +++ b/arch/powerpc/include/asm/ppc_asm.h
>> @@ -389,6 +389,31 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
>>  	FTR_SECTION_ELSE_NESTED(848);	\
>>  	mtocrf (FXM), RS;		\
>>  	ALT_FTR_SECTION_END_NESTED_IFCLR(CPU_FTR_NOEXECUTE, 848)
>> +
>> +/*
>> + * PPR restore macros used in entry_64.S
>> + * Used for P7 or later processors
>> + */
>> +#define HMT_MEDIUM_LOW_HAS_PPR						\
>> +BEGIN_FTR_SECTION_NESTED(944)						\
>> +	HMT_MEDIUM_LOW;							\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,944)
>> +
>> +#define SET_DEFAULT_THREAD_PPR(ra, rb)					\
>> +BEGIN_FTR_SECTION_NESTED(945)						\
>> +	lis	ra,0xc;		/* default ppr=3 */			\
>> +	ld	rb,PACACURRENT(r13);					\
>> +	sldi	ra,ra,32;	/* 11- 13 bits are used for ppr */	\
>> +	std	ra,TASKTHREADPPR(rb);					\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,945)
>> +
>> +#define RESTORE_PPR(ra, rb)						\
>> +BEGIN_FTR_SECTION_NESTED(946)						\
>> +	ld	ra,PACACURRENT(r13);					\
>> +	ld	rb,TASKTHREADPPR(ra);					\
>> +	mtspr	SPRN_PPR,rb;	/* Restore PPR */			\
>> +END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,946)
>> +
>>  #endif
>>  
>>  /*
>> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
>> index d24c141..1723be3 100644
>> --- a/arch/powerpc/include/asm/reg.h
>> +++ b/arch/powerpc/include/asm/reg.h
>> @@ -287,6 +287,7 @@
>>  #define SPRN_DBAT6U	0x23C	/* Data BAT 6 Upper Register */
>>  #define SPRN_DBAT7L	0x23F	/* Data BAT 7 Lower Register */
>>  #define SPRN_DBAT7U	0x23E	/* Data BAT 7 Upper Register */
>> +#define SPRN_PPR	0x380	/* SMT Thread status Register */
>>  
>>  #define SPRN_DEC	0x016		/* Decrement Register */
>>  #define SPRN_DER	0x095		/* Debug Enable Regsiter */
>> -- 
>> 1.7.1
>>
>>
>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@lists.ozlabs.org
>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>>
Michael Ellerman - Dec. 11, 2012, 2:41 a.m.
On Mon, 2012-11-26 at 17:49 -0800, Haren Myneni wrote:
> On 11/22/2012 07:39 PM, Michael Neuling wrote:
> > Haren Myneni <haren@linux.vnet.ibm.com> wrote:
> > 
> >> [PATCH 5/6] powerpc: Macros for saving/restore PPR
> > 
> > Maybe we should change the names 
> >   HTM_MEDIUM_NO_PPR  => HTM_MEDIUM_PPR_DISCARD   and
> >   HTM_MEDIUM_HAS_PPR => HTM_MEDIUM_PPR_SAVE
> > But now I'm heading into bike shedding territory... plus I think I
> > suggested the names you have currently, so I'm feeling a bit dumb now
> > :-)
> 
> No problem, We can change these macro names if HTM_MEDIUM_PPR_DISCARD/
> HTM_MEDIUM_PPR_SAVE gives better description.

Yes, those names are better.

Even though they're macros they act as functions, so they should
preferably be named using a verb.

cheers

Patch

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index bfd3f1f..880ef7d 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -62,6 +62,35 @@ 
 #define EXC_HV	H
 #define EXC_STD
 
+/*
+ * PPR save/restore macros used in exceptions_64s.S  
+ * Used for P7 or later processors
+ */
+#define SAVE_PPR(area, ra, rb)						\
+BEGIN_FTR_SECTION_NESTED(940)						\
+	ld	ra,PACACURRENT(r13);					\
+	ld	rb,area+EX_PPR(r13);	/* Read PPR from paca */	\
+	std	rb,TASKTHREADPPR(ra);					\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,940)
+
+#define RESTORE_PPR_PACA(area, ra)					\
+BEGIN_FTR_SECTION_NESTED(941)						\
+	ld	ra,area+EX_PPR(r13);					\
+	mtspr	SPRN_PPR,ra;						\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,941)
+
+#define HMT_MEDIUM_NO_PPR						\
+BEGIN_FTR_SECTION_NESTED(942)						\
+	HMT_MEDIUM;							\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,0,942)  /*non P7*/		
+
+#define HMT_MEDIUM_HAS_PPR(area, ra)					\
+BEGIN_FTR_SECTION_NESTED(943)						\
+	mfspr	ra,SPRN_PPR;						\
+	std	ra,area+EX_PPR(r13);					\
+	HMT_MEDIUM;							\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,943) 
+
 #define __EXCEPTION_PROLOG_1(area, extra, vec)				\
 	GET_PACA(r13);							\
 	std	r9,area+EX_R9(r13);	/* save r9 - r12 */		\
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 376e36d..52649cc 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -389,6 +389,31 @@  END_FTR_SECTION_IFCLR(CPU_FTR_601)
 	FTR_SECTION_ELSE_NESTED(848);	\
 	mtocrf (FXM), RS;		\
 	ALT_FTR_SECTION_END_NESTED_IFCLR(CPU_FTR_NOEXECUTE, 848)
+
+/*
+ * PPR restore macros used in entry_64.S
+ * Used for P7 or later processors
+ */
+#define HMT_MEDIUM_LOW_HAS_PPR						\
+BEGIN_FTR_SECTION_NESTED(944)						\
+	HMT_MEDIUM_LOW;							\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,944)
+
+#define SET_DEFAULT_THREAD_PPR(ra, rb)					\
+BEGIN_FTR_SECTION_NESTED(945)						\
+	lis	ra,0xc;		/* default ppr=3 */			\
+	ld	rb,PACACURRENT(r13);					\
+	sldi	ra,ra,32;	/* 11- 13 bits are used for ppr */	\
+	std	ra,TASKTHREADPPR(rb);					\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,945)
+
+#define RESTORE_PPR(ra, rb)						\
+BEGIN_FTR_SECTION_NESTED(946)						\
+	ld	ra,PACACURRENT(r13);					\
+	ld	rb,TASKTHREADPPR(ra);					\
+	mtspr	SPRN_PPR,rb;	/* Restore PPR */			\
+END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,946)
+
 #endif
 
 /*
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index d24c141..1723be3 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -287,6 +287,7 @@ 
 #define SPRN_DBAT6U	0x23C	/* Data BAT 6 Upper Register */
 #define SPRN_DBAT7L	0x23F	/* Data BAT 7 Lower Register */
 #define SPRN_DBAT7U	0x23E	/* Data BAT 7 Upper Register */
+#define SPRN_PPR	0x380	/* SMT Thread status Register */
 
 #define SPRN_DEC	0x016		/* Decrement Register */
 #define SPRN_DER	0x095		/* Debug Enable Regsiter */