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

From: Randy Dunlap <rdunlap@infradead.org>
To: Geert Uytterhoeven <geert+renesas@glider.be>,
	Jonathan Corbet <corbet@lwn.net>,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	Rich Felker <dalias@libc.org>,
	John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Magnus Damm <magnus.damm@gmail.com>
Cc: linux-doc@vger.kernel.org, linux-sh@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] sh: bios: Revive earlyprintk support
Date: Thu, 19 Oct 2023 08:48:32 -0700	[thread overview]
Message-ID: <d0c6044f-11e0-4f00-b7e6-eaf1e72f17a5@infradead.org> (raw)
In-Reply-To: <c40972dfec3dcc6719808d5df388857360262878.1697708489.git.geert+renesas@glider.be>

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