[PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures

Wilson Felipe Pereira <[email protected]> Thu, 6 Aug 2026 06:14:14 +0000
Newsgroups org.infradead.lists.linux-riscv,org.kernel.vger.linux-arch,org.kernel.vger.linux-s390
Message-ID <[email protected]>
Currently, only s390 has the ability to configure the maximum kernel
command line size via Kconfig (CONFIG_COMMAND_LINE_SIZE). Other
architectures define a hardcoded COMMAND_LINE_SIZE macro in their setup.sh
headers.

In some use cases, such as netboot kernels, rootfs configurations, larger
initramfs setups, require larger sizes. While for embedded workloads, it
can be reduced to save memory.

Move config COMMAND_LINE_SIZE out of arch/s390/Kconfig and into
init/Kconfig under General setup so that all architectures can configure
their maximum command line length. The default values were added to keep
the values unchanged.

Originally-by: Maciej Żenczykowski <[email protected]>
Signed-off-by: Wilson Felipe Pereira <[email protected]>
---
 arch/s390/Kconfig |  8 --------
 init/Kconfig      | 12 ++++++++++++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 84404e6778d50..f5536e042ce29 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -511,14 +511,6 @@ endchoice
 config 64BIT
 	def_bool y
 
-config COMMAND_LINE_SIZE
-	int "Maximum size of kernel command line"
-	default 4096
-	range 896 1048576
-	help
-	  This allows you to specify the maximum length of the kernel command
-	  line.
-
 config SMP
 	def_bool y
 
diff --git a/init/Kconfig b/init/Kconfig
index 10f2013b53216..d42bb55cb2152 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1569,6 +1569,18 @@ config BOOT_CONFIG_EMBED_FILE
 	  This bootconfig will be used if there is no initrd or no other
 	  bootconfig in the initrd.
 
+config COMMAND_LINE_SIZE
+	int "Maximum size of kernel command line"
+	default 4096 if S390 || LOONGARCH || MIPS || UM
+	default 2048 if X86 || ARM64 || POWERPC || SPARC64
+	default 1024 if ARM || PARISC || RISCV
+	default 256 if ALPHA || ARC || M68K || MICROBLAZE || SPARC32 || XTENSA
+	default 512
+	range 256 1048576
+	help
+	  This allows you to specify the maximum length of the kernel command
+	  line.
+
 config CMDLINE_LOG_WRAP_IDEAL_LEN
 	int "Length to try to wrap the cmdline when logged at boot"
 	default 1021
-- 
2.55.0.654.g21b8a5bc05-goog


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