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From:   Geert Uytterhoeven <geert+renesas@glider.be>
To:     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,
        Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 1/2] sh: bios: Revive earlyprintk support
Date:   Thu, 19 Oct 2023 11:46:43 +0200
Message-Id: <c40972dfec3dcc6719808d5df388857360262878.1697708489.git.geert+renesas@glider.be>
In-Reply-To: <cover.1697708489.git.geert+renesas@glider.be>
References: <cover.1697708489.git.geert+renesas@glider.be>
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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