[PATCH 0/4] powerpc/e500: rework compiler flags

[PATCH 0/4] powerpc/e500: rework compiler flags

[Scott Wood]

This replaces the reverted "powerpc/e500: Update compilation flags with
core specific options" with a more multiplatform friendly approach
(on 64-bit) and hopefully without breaking anything this time. :-)

This patchset touches parts of code that are also touched by
http://patchwork.ozlabs.org/patch/261248/, so that patch is a
prerequisite.

Scott Wood (4):
  powerpc: Convert some mftb/mftbu into mfspr
  powerpc/85xx: Remove -Wa,-me500
  powerpc/booke64: Use appropriate -mcpu
  powerpc/e500: Set -mcpu flag for 32-bit e500

 arch/powerpc/Makefile                     | 18 +++++++++++++++++-
 arch/powerpc/boot/ppc_asm.h               |  3 +++
 arch/powerpc/boot/util.S                  | 10 +++++-----
 arch/powerpc/include/asm/ppc_asm.h        |  4 ++--
 arch/powerpc/include/asm/reg.h            | 15 ++++++++++-----
 arch/powerpc/include/asm/timex.h          |  4 ++--
 arch/powerpc/kernel/vdso32/gettimeofday.S |  6 +++---
 arch/powerpc/platforms/85xx/smp.c         |  6 ++++--
 arch/powerpc/platforms/Kconfig.cputype    | 13 +++++++++++++
 9 files changed, 59 insertions(+), 20 deletions(-)

-- 
1.8.1.2

[PATCH 1/4] powerpc: Convert some mftb/mftbu into mfspr

[Scott Wood]

Some CPUs (such as e500v1/v2) don't implement mftb and will take a
trap.  mfspr should work on everything that has a timebase, and is the
preferred instruction according to ISA v2.06.

Currently we get away with mftb on 85xx because the assembler converts
it to mfspr due to -Wa,-me500.  However, that flag has other effects
that are undesireable for certain targets (e.g.  lwsync is converted to
sync), and is hostile to multiplatform kernels.  Thus we would like to
stop setting it for all e500-family builds.

mftb/mftbu instances which are in 85xx code or common code are
converted.  Instances which will never run on 85xx are left alone.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/boot/ppc_asm.h               |  3 +++
 arch/powerpc/boot/util.S                  | 10 +++++-----
 arch/powerpc/include/asm/ppc_asm.h        |  4 ++--
 arch/powerpc/include/asm/reg.h            | 15 ++++++++++-----
 arch/powerpc/include/asm/timex.h          |  4 ++--
 arch/powerpc/kernel/vdso32/gettimeofday.S |  6 +++---
 arch/powerpc/platforms/85xx/smp.c         |  6 ++++--
 7 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/boot/ppc_asm.h b/arch/powerpc/boot/ppc_asm.h
index 1c2c281..eb0e98b 100644
--- a/arch/powerpc/boot/ppc_asm.h
+++ b/arch/powerpc/boot/ppc_asm.h
@@ -59,4 +59,7 @@
 #define	r30	30
 #define	r31	31
 
+#define SPRN_TBRL	268
+#define SPRN_TBRU	269
+
 #endif /* _PPC64_PPC_ASM_H */
diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S
index 427ddfc..5143228 100644
--- a/arch/powerpc/boot/util.S
+++ b/arch/powerpc/boot/util.S
@@ -71,18 +71,18 @@ udelay:
 	add	r4,r4,r5
 	addi	r4,r4,-1
 	divw	r4,r4,r5	/* BUS ticks */
-1:	mftbu	r5
-	mftb	r6
-	mftbu	r7
+1:	mfspr	r5, SPRN_TBRU
+	mfspr	r6, SPRN_TBRL
+	mfspr	r7, SPRN_TBRU
 	cmpw	0,r5,r7
 	bne	1b		/* Get [synced] base time */
 	addc	r9,r6,r4	/* Compute end time */
 	addze	r8,r5
-2:	mftbu	r5
+2:	mfspr	r5, SPRN_TBRU
 	cmpw	0,r5,r8
 	blt	2b
 	bgt	3f
-	mftb	r6
+	mfspr	r6, SPRN_TBRL
 	cmpw	0,r6,r9
 	blt	2b
 3:	blr
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 8fdd3da..5995457 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -433,13 +433,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
 
 #if defined(CONFIG_PPC_CELL) || defined(CONFIG_PPC_FSL_BOOK3E)
 #define MFTB(dest)			\
-90:	mftb  dest;			\
+90:	mfspr dest, SPRN_TBRL;		\
 BEGIN_FTR_SECTION_NESTED(96);		\
 	cmpwi dest,0;			\
 	beq-  90b;			\
 END_FTR_SECTION_NESTED(CPU_FTR_CELL_TB_BUG, CPU_FTR_CELL_TB_BUG, 96)
 #else
-#define MFTB(dest)			mftb dest
+#define MFTB(dest)			mfspr dest, SPRN_TBRL
 #endif
 
 #ifndef CONFIG_SMP
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 55b0307..64264bf 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1120,7 +1120,7 @@
 #if defined(CONFIG_PPC_CELL) || defined(CONFIG_PPC_FSL_BOOK3E)
 #define mftb()		({unsigned long rval;				\
 			asm volatile(					\
-				"90:	mftb %0;\n"			\
+				"90:	mfspr %0, %2;\n"		\
 				"97:	cmpwi %0,0;\n"			\
 				"	beq- 90b;\n"			\
 				"99:\n"					\
@@ -1134,18 +1134,23 @@
 				"	.llong 0\n"			\
 				"	.llong 0\n"			\
 				".previous"				\
-			: "=r" (rval) : "i" (CPU_FTR_CELL_TB_BUG)); rval;})
+			: "=r" (rval) \
+			: "i" (CPU_FTR_CELL_TB_BUG), "i" (SPRN_TBRL)); \
+			rval;})
 #else
 #define mftb()		({unsigned long rval;	\
-			asm volatile("mftb %0" : "=r" (rval)); rval;})
+			asm volatile("mfspr %0, %1" : \
+				     "=r" (rval) : "i" (SPRN_TBRL)); rval;})
 #endif /* !CONFIG_PPC_CELL */
 
 #else /* __powerpc64__ */
 
 #define mftbl()		({unsigned long rval;	\
-			asm volatile("mftbl %0" : "=r" (rval)); rval;})
+			asm volatile("mfspr %0, %1" : "=r" (rval) : \
+				"i" (SPRN_TBRL)); rval;})
 #define mftbu()		({unsigned long rval;	\
-			asm volatile("mftbu %0" : "=r" (rval)); rval;})
+			asm volatile("mfspr %0, %1" : "=r" (rval) : \
+				"i" (SPRN_TBRU)); rval;})
 #endif /* !__powerpc64__ */
 
 #define mttbl(v)	asm volatile("mttbl %0":: "r"(v))
diff --git a/arch/powerpc/include/asm/timex.h b/arch/powerpc/include/asm/timex.h
index c55e14f..18908ca 100644
--- a/arch/powerpc/include/asm/timex.h
+++ b/arch/powerpc/include/asm/timex.h
@@ -29,7 +29,7 @@ static inline cycles_t get_cycles(void)
 	ret = 0;
 
 	__asm__ __volatile__(
-		"97:	mftb %0\n"
+		"97:	mfspr %0, %2\n"
 		"99:\n"
 		".section __ftr_fixup,\"a\"\n"
 		".align 2\n"
@@ -41,7 +41,7 @@ static inline cycles_t get_cycles(void)
 		"	.long 0\n"
 		"	.long 0\n"
 		".previous"
-		: "=r" (ret) : "i" (CPU_FTR_601));
+		: "=r" (ret) : "i" (CPU_FTR_601), "i" (SPRN_TBRL));
 	return ret;
 #endif
 }
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 27e2f62..6b1f2a6 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -232,9 +232,9 @@ __do_get_tspec:
 	lwz	r6,(CFG_TB_ORIG_STAMP+4)(r9)
 
 	/* Get a stable TB value */
-2:	mftbu	r3
-	mftbl	r4
-	mftbu	r0
+2:	mfspr	r3, SPRN_TBRU
+	mfspr	r4, SPRN_TBRL
+	mfspr	r0, SPRN_TBRU
 	cmplw	cr0,r3,r0
 	bne-	2b
 
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index ea7e629..281b7f0 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -83,11 +83,13 @@ static void mpc85xx_give_timebase(void)
 	{
 		u64 prev;
 
-		asm volatile("mftb %0" : "=r" (timebase));
+		asm volatile("mfspr %0, %1" : "=r" (timebase) :
+			     "i" (SPRN_TBRL));
 
 		do {
 			prev = timebase;
-			asm volatile("mftb %0" : "=r" (timebase));
+			asm volatile("mfspr %0, %1" : "=r" (timebase) :
+				     "i" (SPRN_TBRL));
 		} while (prev != timebase);
 	}
 #else
-- 
1.8.1.2

[PATCH 2/4] powerpc/85xx: Remove -Wa,-me500

[Scott Wood]

This caused lwsync to be converted to sync on 64-bit (on 32-bit lwsync
is generated at runtime, and so wasn't affected).  Not using lwsync
caused a significant slowdown on certain workloads.

Setting this flag for any e500-enabled build is also not friendly to
multiplatform kernels.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/Makefile | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 967fd23..6930c93 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -139,7 +139,6 @@ endif
 
 cpu-as-$(CONFIG_4xx)		+= -Wa,-m405
 cpu-as-$(CONFIG_ALTIVEC)	+= -Wa,-maltivec
-cpu-as-$(CONFIG_E500)		+= -Wa,-me500
 cpu-as-$(CONFIG_E200)		+= -Wa,-me200
 
 KBUILD_AFLAGS += $(cpu-as-y)
-- 
1.8.1.2

[PATCH 3/4] powerpc/booke64: Use appropriate -mcpu

[Scott Wood]

By default use -mcpu=powerpc64 rather than -mtune=power7

Add options for e5500/e6500, with fallbacks for older compilers.

Hide the POWER cpu options in booke configs.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/Makefile                  |  9 +++++++++
 arch/powerpc/platforms/Kconfig.cputype | 13 +++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 6930c93..32dfd5d 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -88,13 +88,22 @@ CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mcmodel=medium,-mminimal-toc)
 CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mno-pointers-to-nested-functions)
 CFLAGS-$(CONFIG_PPC32)	:= -ffixed-r2 -mmultiple
 
+ifeq ($(CONFIG_PPC_BOOK3S_64),y)
 CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)
+else
+CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
+endif
+
 CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
 CFLAGS-$(CONFIG_POWER4_CPU) += $(call cc-option,-mcpu=power4)
 CFLAGS-$(CONFIG_POWER5_CPU) += $(call cc-option,-mcpu=power5)
 CFLAGS-$(CONFIG_POWER6_CPU) += $(call cc-option,-mcpu=power6)
 CFLAGS-$(CONFIG_POWER7_CPU) += $(call cc-option,-mcpu=power7)
 
+E5500_CPU := $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
+CFLAGS-$(CONFIG_E5500_CPU) += $(E5500_CPU)
+CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
+
 CFLAGS-$(CONFIG_TUNE_CELL) += $(call cc-option,-mtune=cell)
 
 KBUILD_CPPFLAGS	+= -Iarch/$(ARCH)
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 47d9a03..6704e2e 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -96,18 +96,31 @@ config GENERIC_CPU
 
 config CELL_CPU
 	bool "Cell Broadband Engine"
+	depends on PPC_BOOK3S_64
 
 config POWER4_CPU
 	bool "POWER4"
+	depends on PPC_BOOK3S_64
 
 config POWER5_CPU
 	bool "POWER5"
+	depends on PPC_BOOK3S_64
 
 config POWER6_CPU
 	bool "POWER6"
+	depends on PPC_BOOK3S_64
 
 config POWER7_CPU
 	bool "POWER7"
+	depends on PPC_BOOK3S_64
+
+config E5500_CPU
+	bool "Freescale e5500"
+	depends on E500
+
+config E6500_CPU
+	bool "Freescale e6500"
+	depends on E500
 
 endchoice
 
-- 
1.8.1.2

Re: [PATCH 3/4] powerpc/booke64: Use appropriate -mcpu

[Rojhalat Ibrahim]

Just out of curiosity: What's the difference (if any) between -mcpu=e500mc64 
and -mcpu=e5500? AFAIK -mcpu=e500mc64 is supported by gcc since at least 
version 4.6 whereas -mcpu=e5500 is only supported since gcc 4.8. But is there 
actually any difference?

   Rojhalat


On Tuesday 20 August 2013 21:12:41 Scott Wood wrote:
> By default use -mcpu=powerpc64 rather than -mtune=power7
> 
> Add options for e5500/e6500, with fallbacks for older compilers.
> 
> Hide the POWER cpu options in booke configs.
> 
> Signed-off-by: Scott Wood <scottwood@freescale.com>
> ---
>  arch/powerpc/Makefile                  |  9 +++++++++
>  arch/powerpc/platforms/Kconfig.cputype | 13 +++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 6930c93..32dfd5d 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -88,13 +88,22 @@ CFLAGS-$(CONFIG_PPC64)	+= $(call
> cc-option,-mcmodel=medium,-mminimal-toc) CFLAGS-$(CONFIG_PPC64)	+= $(call
> cc-option,-mno-pointers-to-nested-functions) CFLAGS-$(CONFIG_PPC32)	:=
> -ffixed-r2 -mmultiple
> 
> +ifeq ($(CONFIG_PPC_BOOK3S_64),y)
>  CFLAGS-$(CONFIG_GENERIC_CPU) += $(call
> cc-option,-mtune=power7,-mtune=power4) +else
> +CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
> +endif
> +
>  CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
>  CFLAGS-$(CONFIG_POWER4_CPU) += $(call cc-option,-mcpu=power4)
>  CFLAGS-$(CONFIG_POWER5_CPU) += $(call cc-option,-mcpu=power5)
>  CFLAGS-$(CONFIG_POWER6_CPU) += $(call cc-option,-mcpu=power6)
>  CFLAGS-$(CONFIG_POWER7_CPU) += $(call cc-option,-mcpu=power7)
> 
> +E5500_CPU := $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
> +CFLAGS-$(CONFIG_E5500_CPU) += $(E5500_CPU)
> +CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
> +
>  CFLAGS-$(CONFIG_TUNE_CELL) += $(call cc-option,-mtune=cell)
> 
>  KBUILD_CPPFLAGS	+= -Iarch/$(ARCH)
> diff --git a/arch/powerpc/platforms/Kconfig.cputype
> b/arch/powerpc/platforms/Kconfig.cputype index 47d9a03..6704e2e 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -96,18 +96,31 @@ config GENERIC_CPU
> 
>  config CELL_CPU
>  	bool "Cell Broadband Engine"
> +	depends on PPC_BOOK3S_64
> 
>  config POWER4_CPU
>  	bool "POWER4"
> +	depends on PPC_BOOK3S_64
> 
>  config POWER5_CPU
>  	bool "POWER5"
> +	depends on PPC_BOOK3S_64
> 
>  config POWER6_CPU
>  	bool "POWER6"
> +	depends on PPC_BOOK3S_64
> 
>  config POWER7_CPU
>  	bool "POWER7"
> +	depends on PPC_BOOK3S_64
> +
> +config E5500_CPU
> +	bool "Freescale e5500"
> +	depends on E500
> +
> +config E6500_CPU
> +	bool "Freescale e6500"
> +	depends on E500
> 
>  endchoice

Re: [PATCH 3/4] powerpc/booke64: Use appropriate -mcpu

[Scott Wood]

On Thu, 2013-08-22 at 15:56 +0200, Rojhalat Ibrahim wrote:
> Just out of curiosity: What's the difference (if any) between -mcpu=e500mc64 
> and -mcpu=e5500? AFAIK -mcpu=e500mc64 is supported by gcc since at least 
> version 4.6 whereas -mcpu=e5500 is only supported since gcc 4.8. But is there 
> actually any difference?

I had asked our compiler person that before sending...  the answer
wasn't very clear, but when I asked whether there was any benefit for
the kernel specifying e5500 (requiring an extra fallback check) he said
"probably not".  Eventually they'll probably just become aliases for the
same thing.  Currently they do have separate .md files though, so
they're not identical.

-Scott

[PATCH 4/4] powerpc/e500: Set -mcpu flag for 32-bit e500

[Scott Wood]

Unlike 64-bit, we don't currently support multiplatform between e500
and non-e500, so the -mcpu is not configurable at this time.

-msoft-float is specified when testing for -mcpu=8540 because otherwise
some older toolchains will fail with "error: E500 and FPRs not
supported".

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 32dfd5d..51cfb78 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -104,6 +104,14 @@ E5500_CPU := $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
 CFLAGS-$(CONFIG_E5500_CPU) += $(E5500_CPU)
 CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
 
+ifeq ($(CONFIG_PPC32),y)
+ifeq ($(CONFIG_PPC_E500MC),y)
+CFLAGS-y += $(call cc-option,-mcpu=e500mc,-mcpu=powerpc)
+else
+CFLAGS-$(CONFIG_E500) += $(call cc-option,-mcpu=8540 -msoft-float,-mcpu=powerpc)
+endif
+endif
+
 CFLAGS-$(CONFIG_TUNE_CELL) += $(call cc-option,-mtune=cell)
 
 KBUILD_CPPFLAGS	+= -Iarch/$(ARCH)
-- 
1.8.1.2