[PATCH 0/2] ARM: Thumb-2: Fix Kconfig rules to avoid nonworking configs

[PATCH 0/2] ARM: Thumb-2: Fix Kconfig rules to avoid nonworking configs

[Dave Martin]

Some configurations don't make sense with Thumb-2, or don't
currently work and are unlikely to be relevant.

The patches avoid Kconfig from allowing these problematic
combinations, for now.

Dave Martin (2):
  ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6
  ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

 arch/arm/Kconfig |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

[PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6

[Dave Martin]

This makes sense, because Thumb-2 code can't execute on plain
ARMv6 processors.

This will avoid accidentally configuring a broken kernel where the
config otherwise would allow multiple architecture versions to
coexist in the same kernel.

Not adding !CPU_V5 etc., because the chance of anyone trying to
put v5 and v7 in the same kernel is low, and I'm not aware of
any mach which can do this.  These could be added later if it
matters.

Note that the rules may need to be refined if support for the
ARM1156J(F)-S processor is later added to the kernel, since this
processor supports the rare ARMv6T2 extensions, which add support
for Thumb-2 and a few other ARMv7 features.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index db524e7..f9ca7f3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1311,7 +1311,7 @@ config HZ
 
 config THUMB2_KERNEL
 	bool "Compile the kernel in Thumb-2 mode"
-	depends on CPU_V7 && EXPERIMENTAL
+	depends on CPU_V7 && !CPU_V6 && EXPERIMENTAL
 	select AEABI
 	select ARM_ASM_UNIFIED
 	help
-- 
1.7.1

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Dave Martin]

Because the nwfpe support is unlikely to be used on new platforms
and requires CONFIG_OABI_COMPAT, which is not generally used with
ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
kernel.

At present, nwfpe contains assembly code which isn't Thumb-2
compatible, and for now it doesn't appear useful to port this
code.

All ARMv7-A/R platforms necessarily have VFPv3 hardware floating-
point natively, making emulation unnecessary.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index f9ca7f3..7e825c3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1759,7 +1759,7 @@ comment "At least one emulation must be selected"
 
 config FPE_NWFPE
 	bool "NWFPE math emulation"
-	depends on !AEABI || OABI_COMPAT
+	depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
 	---help---
 	  Say Y to include the NWFPE floating point emulator in the kernel.
 	  This is necessary to run most binaries. Linux does not currently
-- 
1.7.1

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Nicolas Pitre]

On Thu, 9 Dec 2010, Dave Martin wrote:

> Because the nwfpe support is unlikely to be used on new platforms
> and requires CONFIG_OABI_COMPAT, which is not generally used with
> ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
> kernel.
> 
> At present, nwfpe contains assembly code which isn't Thumb-2
> compatible, and for now it doesn't appear useful to port this
> code.
> 
> All ARMv7-A/R platforms necessarily have VFPv3 hardware floating-
> point natively, making emulation unnecessary.
> 
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>


> ---
>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f9ca7f3..7e825c3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1759,7 +1759,7 @@ comment "At least one emulation must be selected"
>  
>  config FPE_NWFPE
>  	bool "NWFPE math emulation"
> -	depends on !AEABI || OABI_COMPAT
> +	depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
>  	---help---
>  	  Say Y to include the NWFPE floating point emulator in the kernel.
>  	  This is necessary to run most binaries. Linux does not currently
> -- 
> 1.7.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

[PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6

[Nicolas Pitre]

On Thu, 9 Dec 2010, Dave Martin wrote:

> This makes sense, because Thumb-2 code can't execute on plain
> ARMv6 processors.
> 
> This will avoid accidentally configuring a broken kernel where the
> config otherwise would allow multiple architecture versions to
> coexist in the same kernel.
> 
> Not adding !CPU_V5 etc., because the chance of anyone trying to
> put v5 and v7 in the same kernel is low, and I'm not aware of
> any mach which can do this.  These could be added later if it
> matters.
> 
> Note that the rules may need to be refined if support for the
> ARM1156J(F)-S processor is later added to the kernel, since this
> processor supports the rare ARMv6T2 extensions, which add support
> for Thumb-2 and a few other ARMv7 features.
> 
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>


> ---
>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index db524e7..f9ca7f3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1311,7 +1311,7 @@ config HZ
>  
>  config THUMB2_KERNEL
>  	bool "Compile the kernel in Thumb-2 mode"
> -	depends on CPU_V7 && EXPERIMENTAL
> +	depends on CPU_V7 && !CPU_V6 && EXPERIMENTAL
>  	select AEABI
>  	select ARM_ASM_UNIFIED
>  	help
> -- 
> 1.7.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

[PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6

[Santosh Shilimkar]

> -----Original Message-----
> From: Dave Martin [mailto:dave.martin at linaro.org]
> Sent: Thursday, December 09, 2010 5:30 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: Dave Martin; Santosh Shilimkar; linux-omap at vger.kernel.org
> Subject: [PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend
> on !CPU_V6
>
> This makes sense, because Thumb-2 code can't execute on plain
> ARMv6 processors.
>
> This will avoid accidentally configuring a broken kernel where the
> config otherwise would allow multiple architecture versions to
> coexist in the same kernel.
>
> Not adding !CPU_V5 etc., because the chance of anyone trying to
> put v5 and v7 in the same kernel is low, and I'm not aware of
> any mach which can do this.  These could be added later if it
> matters.
>
> Note that the rules may need to be refined if support for the
> ARM1156J(F)-S processor is later added to the kernel, since this
> processor supports the rare ARMv6T2 extensions, which add support
> for Thumb-2 and a few other ARMv7 features.
>
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
If you like,
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> ---
>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index db524e7..f9ca7f3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1311,7 +1311,7 @@ config HZ
>
>  config THUMB2_KERNEL
>  	bool "Compile the kernel in Thumb-2 mode"
> -	depends on CPU_V7 && EXPERIMENTAL
> +	depends on CPU_V7 && !CPU_V6 && EXPERIMENTAL
>  	select AEABI
>  	select ARM_ASM_UNIFIED
>  	help
> --
> 1.7.1

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Santosh Shilimkar]

> -----Original Message-----
> From: Dave Martin [mailto:dave.martin at linaro.org]
> Sent: Thursday, December 09, 2010 5:30 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: Dave Martin; Santosh Shilimkar; linux-omap at vger.kernel.org
> Subject: [PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend
> on !CONFIG_THUMB2_KERNEL
>
> Because the nwfpe support is unlikely to be used on new platforms
> and requires CONFIG_OABI_COMPAT, which is not generally used with
> ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
> kernel.
>
> At present, nwfpe contains assembly code which isn't Thumb-2
> compatible, and for now it doesn't appear useful to port this
> code.
>
> All ARMv7-A/R platforms necessarily have VFPv3 hardware floating-
> point natively, making emulation unnecessary.
>
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
If you like.
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> ---
>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f9ca7f3..7e825c3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1759,7 +1759,7 @@ comment "At least one emulation must be selected"
>
>  config FPE_NWFPE
>  	bool "NWFPE math emulation"
> -	depends on !AEABI || OABI_COMPAT
> +	depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
>  	---help---
>  	  Say Y to include the NWFPE floating point emulator in the
kernel.
>  	  This is necessary to run most binaries. Linux does not currently
> --
> 1.7.1

[PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6

[Santosh Shilimkar]

> -----Original Message-----
> From: Dave Martin [mailto:dave.martin at linaro.org]
> Sent: Thursday, December 09, 2010 5:30 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: Dave Martin; Santosh Shilimkar; linux-omap at vger.kernel.org
> Subject: [PATCH 1/2] ARM: Thumb-2: Make CONFIG_THUMB2_KERNEL depend
> on !CPU_V6
>
> This makes sense, because Thumb-2 code can't execute on plain
> ARMv6 processors.
>
> This will avoid accidentally configuring a broken kernel where the
> config otherwise would allow multiple architecture versions to
> coexist in the same kernel.
>
> Not adding !CPU_V5 etc., because the chance of anyone trying to
> put v5 and v7 in the same kernel is low, and I'm not aware of
> any mach which can do this.  These could be added later if it
> matters.
>
> Note that the rules may need to be refined if support for the
> ARM1156J(F)-S processor is later added to the kernel, since this
> processor supports the rare ARMv6T2 extensions, which add support
> for Thumb-2 and a few other ARMv7 features.
>
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>`

> ---
>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index db524e7..f9ca7f3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1311,7 +1311,7 @@ config HZ
>
>  config THUMB2_KERNEL
>  	bool "Compile the kernel in Thumb-2 mode"
> -	depends on CPU_V7 && EXPERIMENTAL
> +	depends on CPU_V7 && !CPU_V6 && EXPERIMENTAL
>  	select AEABI
>  	select ARM_ASM_UNIFIED
>  	help
> --
> 1.7.1

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Santosh Shilimkar]

> -----Original Message-----
> From: Dave Martin [mailto:dave.martin at linaro.org]
> Sent: Thursday, December 09, 2010 5:30 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: Dave Martin; Santosh Shilimkar; linux-omap at vger.kernel.org
> Subject: [PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on
> !CONFIG_THUMB2_KERNEL
>
> Because the nwfpe support is unlikely to be used on new platforms
> and requires CONFIG_OABI_COMPAT, which is not generally used with
> ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
> kernel.
>
> At present, nwfpe contains assembly code which isn't Thumb-2
> compatible, and for now it doesn't appear useful to port this
> code.
>
> All ARMv7-A/R platforms necessarily have VFPv3 hardware floating-
> point natively, making emulation unnecessary.
>
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> ---
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>`

>  arch/arm/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f9ca7f3..7e825c3 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1759,7 +1759,7 @@ comment "At least one emulation must be
> selected"
>
>  config FPE_NWFPE
>  	bool "NWFPE math emulation"
> -	depends on !AEABI || OABI_COMPAT
> +	depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
>  	---help---
>  	  Say Y to include the NWFPE floating point emulator in the
> kernel.
>  	  This is necessary to run most binaries. Linux does not
> currently
> --
> 1.7.1

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Russell King - ARM Linux]

On Thu, Dec 09, 2010 at 11:59:42AM +0000, Dave Martin wrote:
> Because the nwfpe support is unlikely to be used on new platforms
> and requires CONFIG_OABI_COMPAT, which is not generally used with
> ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
> kernel.
> 
> At present, nwfpe contains assembly code which isn't Thumb-2
> compatible, and for now it doesn't appear useful to port this
> code.

You might as well make OABI_COMPAT depend on !THUMB2_KERNEL.  OABI
userland is useless without FPA support.

[PATCH 2/2] ARM: Make CONFIG_FPE_NWFPE depend on !CONFIG_THUMB2_KERNEL

[Dave Martin]

On Fri, Feb 4, 2011 at 11:03 AM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Thu, Dec 09, 2010 at 11:59:42AM +0000, Dave Martin wrote:
>> Because the nwfpe support is unlikely to be used on new platforms
>> and requires CONFIG_OABI_COMPAT, which is not generally used with
>> ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
>> kernel.
>>
>> At present, nwfpe contains assembly code which isn't Thumb-2
>> compatible, and for now it doesn't appear useful to port this
>> code.
>
> You might as well make OABI_COMPAT depend on !THUMB2_KERNEL. ?OABI
> userland is useless without FPA support.
>

Sure.  The original patch is already upstream, but I can roll a
supplementary patch for this.

Cheers
---Dave