* [PATCH] powerpc/book3s64: Always build for power4 or later
@ 2016-10-21 0:01 Michael Ellerman
2016-10-21 3:53 ` Balbir Singh
2016-11-14 12:17 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Michael Ellerman @ 2016-10-21 0:01 UTC (permalink / raw)
To: linuxppc-dev; +Cc: segher, anton
When we're not compiling for a specific CPU, ie. none of the
CONFIG_POWERx_CPU options are set, and CONFIG_GENERIC_CPU *is* set, we
currently don't pass any -mcpu option to the compiler. This means the
compiler builds for a "generic" Power CPU.
But back in 2014 we dropped support for pre power4 CPUs in commit
468a33028edd ("powerpc: Drop support for pre-POWER4 cpus").
Given that, there's no point in building the kernel to run on pre power4
cpus. So update the flags we pass to the compiler when
CONFIG_GENERIC_CPU is set, to specify -mcpu=power4.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 617dece67924..041fda1e2a5d 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -121,6 +121,7 @@ CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 $(MULTIPLEWORD)
ifeq ($(CONFIG_PPC_BOOK3S_64),y)
CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)
+CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power4
else
CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
endif
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/book3s64: Always build for power4 or later
2016-10-21 0:01 [PATCH] powerpc/book3s64: Always build for power4 or later Michael Ellerman
@ 2016-10-21 3:53 ` Balbir Singh
2016-11-14 12:17 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Balbir Singh @ 2016-10-21 3:53 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: anton
On 21/10/16 11:01, Michael Ellerman wrote:
> When we're not compiling for a specific CPU, ie. none of the
> CONFIG_POWERx_CPU options are set, and CONFIG_GENERIC_CPU *is* set, we
> currently don't pass any -mcpu option to the compiler. This means the
> compiler builds for a "generic" Power CPU.
>
> But back in 2014 we dropped support for pre power4 CPUs in commit
> 468a33028edd ("powerpc: Drop support for pre-POWER4 cpus").
>
> Given that, there's no point in building the kernel to run on pre power4
> cpus. So update the flags we pass to the compiler when
> CONFIG_GENERIC_CPU is set, to specify -mcpu=power4.
>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
> arch/powerpc/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 617dece67924..041fda1e2a5d 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -121,6 +121,7 @@ CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 $(MULTIPLEWORD)
>
> ifeq ($(CONFIG_PPC_BOOK3S_64),y)
> CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)
> +CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power4
> else
> CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
> endif
>
Acked-by: Balbir Singh <bsingharora@gmail.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: powerpc/book3s64: Always build for power4 or later
2016-10-21 0:01 [PATCH] powerpc/book3s64: Always build for power4 or later Michael Ellerman
2016-10-21 3:53 ` Balbir Singh
@ 2016-11-14 12:17 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2016-11-14 12:17 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: anton
On Fri, 2016-21-10 at 00:01:51 UTC, Michael Ellerman wrote:
> When we're not compiling for a specific CPU, ie. none of the
> CONFIG_POWERx_CPU options are set, and CONFIG_GENERIC_CPU *is* set, we
> currently don't pass any -mcpu option to the compiler. This means the
> compiler builds for a "generic" Power CPU.
>
> But back in 2014 we dropped support for pre power4 CPUs in commit
> 468a33028edd ("powerpc: Drop support for pre-POWER4 cpus").
>
> Given that, there's no point in building the kernel to run on pre power4
> cpus. So update the flags we pass to the compiler when
> CONFIG_GENERIC_CPU is set, to specify -mcpu=power4.
>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Acked-by: Balbir Singh <bsingharora@gmail.com>
Applied to powerpc next.
https://git.kernel.org/powerpc/c/3a849815a13695ad0e32f6f01c9054
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-10-21 3:53 ` Balbir Singh
2016-11-14 12:17 ` Michael Ellerman
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