[PATCH 0/2] sh: Revive BIOS earlyprintk support

[PATCH 0/2] sh: Revive BIOS earlyprintk support

[Geert Uytterhoeven]

	Hi all,

SuperH BIOS earlyprintk support was accidently disabled.
This series revives it, and records its existence in the documentation.

This was tested on landisk using "earlyprintk=bios" and
"earlyprintk=bios,keep".

Thanks for your comments!

Geert Uytterhoeven (2):
  sh: bios: Revive earlyprintk support
  Documentation: kernel-parameters: Add earlyprintk=bios on SH

 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 arch/sh/Kconfig.debug                           | 11 +++++++++++
 2 files changed, 14 insertions(+)

-- 
2.34.1

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

[PATCH 1/2] sh: bios: Revive earlyprintk support

[Geert Uytterhoeven]

The SuperH BIOS earlyprintk code is protected by CONFIG_EARLY_PRINTK.
However, when this protection was added, it was missed that SuperH no
longer defines an EARLY_PRINTK config symbol since commit
e76fe57447e88916 ("sh: Remove old early serial console code V2"), so
BIOS earlyprintk can no longer be used.

Fix this by reviving the EARLY_PRINTK config symbol.

Fixes: d0380e6c3c0f6edb ("early_printk: consolidate random copies of identical code")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 arch/sh/Kconfig.debug | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
index c449e7c1b20ff5b5..8bcd6c1431a95be9 100644
--- a/arch/sh/Kconfig.debug
+++ b/arch/sh/Kconfig.debug
@@ -22,6 +22,17 @@ config STACK_DEBUG
 	  every function call and will therefore incur a major
 	  performance hit. Most users should say N.
 
+config EARLY_PRINTK
+	bool "Early printk"
+	depends on SH_STANDARD_BIOS
+	help
+	  Say Y here to redirect kernel printk messages to the serial port
+	  used by the SH-IPL bootloader, starting very early in the boot
+	  process and ending when the kernel's serial console is initialised.
+	  This option is only useful while porting the kernel to a new machine,
+	  when the kernel may crash or hang before the serial console is
+	  initialised.  If unsure, say N.
+
 config 4KSTACKS
 	bool "Use 4Kb for kernel stacks instead of 8Kb"
 	depends on DEBUG_KERNEL && (MMU || BROKEN) && !PAGE_SIZE_64KB
-- 
2.34.1

[PATCH 2/2] Documentation: kernel-parameters: Add earlyprintk=bios on SH

[Geert Uytterhoeven]

Document the use of the "earlyprintk=bios[,keep]" kernel parameter
option on SuperH systems with a SuperH standard BIOS.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 Documentation/admin-guide/kernel-parameters.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 657bb0b54e2fc6cf..8e7f6be051a0e1d3 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1331,6 +1331,7 @@
 			earlyprintk=dbgp[debugController#]
 			earlyprintk=pciserial[,force],bus:device.function[,baudrate]
 			earlyprintk=xdbc[xhciController#]
+			earlyprintk=bios
 
 			earlyprintk is useful when the kernel crashes before
 			the normal console is initialized. It is not enabled by
@@ -1361,6 +1362,8 @@
 
 			The sclp output can only be used on s390.
 
+			The bios output can only be used on SuperH.
+
 			The optional "force" to "pciserial" enables use of a
 			PCI device even when its classcode is not of the
 			UART class.
-- 
2.34.1

Re: [PATCH 0/2] sh: Revive BIOS earlyprintk support

[John Paul Adrian Glaubitz]

Hi Geert!

On Thu, 2023-10-19 at 11:46 +0200, Geert Uytterhoeven wrote:
> SuperH BIOS earlyprintk support was accidently disabled.
> This series revives it, and records its existence in the documentation.
> 
> This was tested on landisk using "earlyprintk=bios" and
> "earlyprintk=bios,keep".
> 
> Thanks for your comments!

Thanks for catching this and fixing this! I will pick this up ASAP!

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH 1/2] sh: bios: Revive earlyprintk support

[Randy Dunlap]

Hi,

On 10/19/23 02:46, Geert Uytterhoeven wrote:
> The SuperH BIOS earlyprintk code is protected by CONFIG_EARLY_PRINTK.
> However, when this protection was added, it was missed that SuperH no
> longer defines an EARLY_PRINTK config symbol since commit
> e76fe57447e88916 ("sh: Remove old early serial console code V2"), so
> BIOS earlyprintk can no longer be used.
> 
> Fix this by reviving the EARLY_PRINTK config symbol.
> 
> Fixes: d0380e6c3c0f6edb ("early_printk: consolidate random copies of identical code")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  arch/sh/Kconfig.debug | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> index c449e7c1b20ff5b5..8bcd6c1431a95be9 100644
> --- a/arch/sh/Kconfig.debug
> +++ b/arch/sh/Kconfig.debug
> @@ -22,6 +22,17 @@ config STACK_DEBUG
>  	  every function call and will therefore incur a major
>  	  performance hit. Most users should say N.
>  
> +config EARLY_PRINTK
> +	bool "Early printk"
> +	depends on SH_STANDARD_BIOS
> +	help
> +	  Say Y here to redirect kernel printk messages to the serial port
> +	  used by the SH-IPL bootloader, starting very early in the boot
> +	  process and ending when the kernel's serial console is initialised.
> +	  This option is only useful while porting the kernel to a new machine,

Can we expect to see new machine ports using arch/sh/ ?

> +	  when the kernel may crash or hang before the serial console is
> +	  initialised.  If unsure, say N.
> +
>  config 4KSTACKS
>  	bool "Use 4Kb for kernel stacks instead of 8Kb"
>  	depends on DEBUG_KERNEL && (MMU || BROKEN) && !PAGE_SIZE_64KB


-- 
~Randy

Re: [PATCH 1/2] sh: bios: Revive earlyprintk support

[John Paul Adrian Glaubitz]

Hello!

On Thu, 2023-10-19 at 08:48 -0700, Randy Dunlap wrote:
> > +config EARLY_PRINTK
> > +	bool "Early printk"
> > +	depends on SH_STANDARD_BIOS
> > +	help
> > +	  Say Y here to redirect kernel printk messages to the serial port
> > +	  used by the SH-IPL bootloader, starting very early in the boot
> > +	  process and ending when the kernel's serial console is initialised.
> > +	  This option is only useful while porting the kernel to a new machine,
> 
> Can we expect to see new machine ports using arch/sh/ ?

There is J-Core which is new open source hardware based on arch/sh.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH 1/2] sh: bios: Revive earlyprintk support

[Randy Dunlap]

On 10/19/23 08:51, John Paul Adrian Glaubitz wrote:
> Hello!
> 
> On Thu, 2023-10-19 at 08:48 -0700, Randy Dunlap wrote:
>>> +config EARLY_PRINTK
>>> +	bool "Early printk"
>>> +	depends on SH_STANDARD_BIOS
>>> +	help
>>> +	  Say Y here to redirect kernel printk messages to the serial port
>>> +	  used by the SH-IPL bootloader, starting very early in the boot
>>> +	  process and ending when the kernel's serial console is initialised.
>>> +	  This option is only useful while porting the kernel to a new machine,
>>
>> Can we expect to see new machine ports using arch/sh/ ?
> 
> There is J-Core which is new open source hardware based on arch/sh.

OK, thanks.

-- 
~Randy

Re: [PATCH 1/2] sh: bios: Revive earlyprintk support

[Geert Uytterhoeven]

Hi Adrian,

On Thu, Oct 19, 2023 at 5:51 PM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On Thu, 2023-10-19 at 08:48 -0700, Randy Dunlap wrote:
> > > +config EARLY_PRINTK
> > > +   bool "Early printk"
> > > +   depends on SH_STANDARD_BIOS
> > > +   help
> > > +     Say Y here to redirect kernel printk messages to the serial port
> > > +     used by the SH-IPL bootloader, starting very early in the boot
> > > +     process and ending when the kernel's serial console is initialised.
> > > +     This option is only useful while porting the kernel to a new machine,
> >
> > Can we expect to see new machine ports using arch/sh/ ?
>
> There is J-Core which is new open source hardware based on arch/sh.

Do J-Core systems use the LinuxSH standard BIOS?
Still, it can be useful while converting existing SH systems to DT.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 1/2] sh: bios: Revive earlyprintk support

[John Paul Adrian Glaubitz]

On Thu, 2023-10-19 at 11:46 +0200, Geert Uytterhoeven wrote:
> The SuperH BIOS earlyprintk code is protected by CONFIG_EARLY_PRINTK.
> However, when this protection was added, it was missed that SuperH no
> longer defines an EARLY_PRINTK config symbol since commit
> e76fe57447e88916 ("sh: Remove old early serial console code V2"), so
> BIOS earlyprintk can no longer be used.
> 
> Fix this by reviving the EARLY_PRINTK config symbol.
> 
> Fixes: d0380e6c3c0f6edb ("early_printk: consolidate random copies of identical code")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  arch/sh/Kconfig.debug | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> index c449e7c1b20ff5b5..8bcd6c1431a95be9 100644
> --- a/arch/sh/Kconfig.debug
> +++ b/arch/sh/Kconfig.debug
> @@ -22,6 +22,17 @@ config STACK_DEBUG
>  	  every function call and will therefore incur a major
>  	  performance hit. Most users should say N.
>  
> +config EARLY_PRINTK
> +	bool "Early printk"
> +	depends on SH_STANDARD_BIOS
> +	help
> +	  Say Y here to redirect kernel printk messages to the serial port
> +	  used by the SH-IPL bootloader, starting very early in the boot
> +	  process and ending when the kernel's serial console is initialised.
> +	  This option is only useful while porting the kernel to a new machine,
> +	  when the kernel may crash or hang before the serial console is
> +	  initialised.  If unsure, say N.
> +
>  config 4KSTACKS
>  	bool "Use 4Kb for kernel stacks instead of 8Kb"
>  	depends on DEBUG_KERNEL && (MMU || BROKEN) && !PAGE_SIZE_64KB

Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH 2/2] Documentation: kernel-parameters: Add earlyprintk=bios on SH

[John Paul Adrian Glaubitz]

On Thu, 2023-10-19 at 11:46 +0200, Geert Uytterhoeven wrote:
> Document the use of the "earlyprintk=bios[,keep]" kernel parameter
> option on SuperH systems with a SuperH standard BIOS.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 657bb0b54e2fc6cf..8e7f6be051a0e1d3 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1331,6 +1331,7 @@
>  			earlyprintk=dbgp[debugController#]
>  			earlyprintk=pciserial[,force],bus:device.function[,baudrate]
>  			earlyprintk=xdbc[xhciController#]
> +			earlyprintk=bios
>  
>  			earlyprintk is useful when the kernel crashes before
>  			the normal console is initialized. It is not enabled by
> @@ -1361,6 +1362,8 @@
>  
>  			The sclp output can only be used on s390.
>  
> +			The bios output can only be used on SuperH.
> +
>  			The optional "force" to "pciserial" enables use of a
>  			PCI device even when its classcode is not of the
>  			UART class.

Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH 0/2] sh: Revive BIOS earlyprintk support

[John Paul Adrian Glaubitz]

On Thu, 2023-10-19 at 11:46 +0200, Geert Uytterhoeven wrote:
> 	Hi all,
> 
> SuperH BIOS earlyprintk support was accidently disabled.
> This series revives it, and records its existence in the documentation.
> 
> This was tested on landisk using "earlyprintk=bios" and
> "earlyprintk=bios,keep".
> 
> Thanks for your comments!
> 
> Geert Uytterhoeven (2):
>   sh: bios: Revive earlyprintk support
>   Documentation: kernel-parameters: Add earlyprintk=bios on SH
> 
>  Documentation/admin-guide/kernel-parameters.txt |  3 +++
>  arch/sh/Kconfig.debug                           | 11 +++++++++++
>  2 files changed, 14 insertions(+)
> 

Series applied for v6.7 to my sh-linux tree in the for-next branch.

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913