* [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
2026-08-06 6:05 Wilson Felipe Pereira
@ 2026-08-06 6:05 ` Wilson Felipe Pereira
0 siblings, 0 replies; 6+ messages in thread
From: Wilson Felipe Pereira @ 2026-08-06 6:05 UTC (permalink / raw)
To: Arnd Bergmann, Andrew Morton
Cc: Yosry Ahmed, Wilson Felipe Pereira, Maciej Żenczykowski,
Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
linux-riscv, linux-arch
Now that CONFIG_COMMAND_LINE_SIZE is available in init/Kconfig for all
architectures, update every architecture's setup.h header to define
COMMAND_LINE_SIZE as CONFIG_COMMAND_LINE_SIZE.
For user-space API (uapi) headers, wrap the definition in an
`#ifdef __KERNEL__` guard and retain the historical hardcoded default in
the `#else` block. When user-space headers are installed via
`make headers_install`, unifdef strips out the kernel section, ensuring
same value as before for user-space applications including `<asm/setup.h>`.
Originally-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Wilson Felipe Pereira <wfelipe@google.com>
---
arch/alpha/include/uapi/asm/setup.h | 4 ++++
arch/arc/include/asm/setup.h | 2 +-
arch/arm/include/uapi/asm/setup.h | 6 +++++-
arch/arm64/include/uapi/asm/setup.h | 4 ++++
arch/loongarch/include/uapi/asm/setup.h | 4 ++++
arch/m68k/include/uapi/asm/setup.h | 6 +++++-
arch/microblaze/include/uapi/asm/setup.h | 4 ++++
arch/mips/include/uapi/asm/setup.h | 4 ++++
arch/parisc/include/uapi/asm/setup.h | 4 ++++
arch/powerpc/include/uapi/asm/setup.h | 4 ++++
arch/riscv/include/uapi/asm/setup.h | 4 ++++
arch/sparc/include/uapi/asm/setup.h | 10 +++++++---
arch/um/include/asm/setup.h | 2 +-
arch/x86/include/asm/setup.h | 2 +-
arch/xtensa/include/uapi/asm/setup.h | 4 ++++
include/uapi/asm-generic/setup.h | 4 ++++
16 files changed, 60 insertions(+), 8 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/setup.h b/arch/alpha/include/uapi/asm/setup.h
index f881ea5947cbc..169f743ef7658 100644
--- a/arch/alpha/include/uapi/asm/setup.h
+++ b/arch/alpha/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _UAPI__ALPHA_SETUP_H
#define _UAPI__ALPHA_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI__ALPHA_SETUP_H */
diff --git a/arch/arc/include/asm/setup.h b/arch/arc/include/asm/setup.h
index 1c6db599e1fcc..60e158d58cec7 100644
--- a/arch/arc/include/asm/setup.h
+++ b/arch/arc/include/asm/setup.h
@@ -9,7 +9,7 @@
#include <linux/types.h>
#include <uapi/asm/setup.h>
-#define COMMAND_LINE_SIZE 256
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
/*
* Data structure to map a ID to string
diff --git a/arch/arm/include/uapi/asm/setup.h b/arch/arm/include/uapi/asm/setup.h
index 8e50e034fec73..4aa93558af1e7 100644
--- a/arch/arm/include/uapi/asm/setup.h
+++ b/arch/arm/include/uapi/asm/setup.h
@@ -17,7 +17,11 @@
#include <linux/types.h>
-#define COMMAND_LINE_SIZE 1024
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
+#define COMMAND_LINE_SIZE 1024
+#endif
/* The list ends with an ATAG_NONE node. */
#define ATAG_NONE 0x00000000
diff --git a/arch/arm64/include/uapi/asm/setup.h b/arch/arm64/include/uapi/asm/setup.h
index 5d703888f3511..2236890175a5a 100644
--- a/arch/arm64/include/uapi/asm/setup.h
+++ b/arch/arm64/include/uapi/asm/setup.h
@@ -22,6 +22,10 @@
#include <linux/types.h>
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif
diff --git a/arch/loongarch/include/uapi/asm/setup.h b/arch/loongarch/include/uapi/asm/setup.h
index d46363ce3e024..03c7bfa1e5d9f 100644
--- a/arch/loongarch/include/uapi/asm/setup.h
+++ b/arch/loongarch/include/uapi/asm/setup.h
@@ -3,6 +3,10 @@
#ifndef _UAPI_ASM_LOONGARCH_SETUP_H
#define _UAPI_ASM_LOONGARCH_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 4096
+#endif
#endif /* _UAPI_ASM_LOONGARCH_SETUP_H */
diff --git a/arch/m68k/include/uapi/asm/setup.h b/arch/m68k/include/uapi/asm/setup.h
index 25fe26d5597cc..2d5b24a5345f9 100644
--- a/arch/m68k/include/uapi/asm/setup.h
+++ b/arch/m68k/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _UAPI_M68K_SETUP_H
#define _UAPI_M68K_SETUP_H
-#define COMMAND_LINE_SIZE 256
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
+#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI_M68K_SETUP_H */
diff --git a/arch/microblaze/include/uapi/asm/setup.h b/arch/microblaze/include/uapi/asm/setup.h
index 16c56807f86a2..e4b253064c7d9 100644
--- a/arch/microblaze/include/uapi/asm/setup.h
+++ b/arch/microblaze/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _UAPI_ASM_MICROBLAZE_SETUP_H
#define _UAPI_ASM_MICROBLAZE_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI_ASM_MICROBLAZE_SETUP_H */
diff --git a/arch/mips/include/uapi/asm/setup.h b/arch/mips/include/uapi/asm/setup.h
index 7d48c433b0c27..8d6c474835aec 100644
--- a/arch/mips/include/uapi/asm/setup.h
+++ b/arch/mips/include/uapi/asm/setup.h
@@ -2,7 +2,11 @@
#ifndef _UAPI_MIPS_SETUP_H
#define _UAPI_MIPS_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 4096
+#endif
#endif /* _UAPI_MIPS_SETUP_H */
diff --git a/arch/parisc/include/uapi/asm/setup.h b/arch/parisc/include/uapi/asm/setup.h
index 78b2f4ec7d652..cfa77e84205dc 100644
--- a/arch/parisc/include/uapi/asm/setup.h
+++ b/arch/parisc/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _PARISC_SETUP_H
#define _PARISC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 1024
+#endif
#endif /* _PARISC_SETUP_H */
diff --git a/arch/powerpc/include/uapi/asm/setup.h b/arch/powerpc/include/uapi/asm/setup.h
index c54940b09d065..daa15ac4e94c6 100644
--- a/arch/powerpc/include/uapi/asm/setup.h
+++ b/arch/powerpc/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _UAPI_ASM_POWERPC_SETUP_H
#define _UAPI_ASM_POWERPC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif /* _UAPI_ASM_POWERPC_SETUP_H */
diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
index eb4f0209c6960..a6c1f4b0987e3 100644
--- a/arch/riscv/include/uapi/asm/setup.h
+++ b/arch/riscv/include/uapi/asm/setup.h
@@ -3,6 +3,10 @@
#ifndef _UAPI_ASM_RISCV_SETUP_H
#define _UAPI_ASM_RISCV_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif /* _UAPI_ASM_RISCV_SETUP_H */
diff --git a/arch/sparc/include/uapi/asm/setup.h b/arch/sparc/include/uapi/asm/setup.h
index 3c208a4dd4640..7054f5249a3a6 100644
--- a/arch/sparc/include/uapi/asm/setup.h
+++ b/arch/sparc/include/uapi/asm/setup.h
@@ -6,10 +6,14 @@
#ifndef _UAPI_SPARC_SETUP_H
#define _UAPI_SPARC_SETUP_H
-#if defined(__sparc__) && defined(__arch64__)
-# define COMMAND_LINE_SIZE 2048
+#ifdef __KERNEL__
+# define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#else
-# define COMMAND_LINE_SIZE 256
+# if defined(__sparc__) && defined(__arch64__)
+# define COMMAND_LINE_SIZE 2048
+# else
+# define COMMAND_LINE_SIZE 256
+# endif
#endif
diff --git a/arch/um/include/asm/setup.h b/arch/um/include/asm/setup.h
index 80ada899f2542..bc83dc4d467d3 100644
--- a/arch/um/include/asm/setup.h
+++ b/arch/um/include/asm/setup.h
@@ -6,6 +6,6 @@
* command line, so this choice is ok.
*/
-#define COMMAND_LINE_SIZE 4096
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#endif /* SETUP_H_INCLUDED */
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 914eb32581c73..b73caf64f2199 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -4,7 +4,7 @@
#include <uapi/asm/setup.h>
-#define COMMAND_LINE_SIZE 2048
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#include <linux/linkage.h>
#include <asm/page_types.h>
diff --git a/arch/xtensa/include/uapi/asm/setup.h b/arch/xtensa/include/uapi/asm/setup.h
index 5356a5fd4d173..dcf33a403527a 100644
--- a/arch/xtensa/include/uapi/asm/setup.h
+++ b/arch/xtensa/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _XTENSA_SETUP_H
#define _XTENSA_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif
diff --git a/include/uapi/asm-generic/setup.h b/include/uapi/asm-generic/setup.h
index 88ac5100df359..b8d06e6d56bd7 100644
--- a/include/uapi/asm-generic/setup.h
+++ b/include/uapi/asm-generic/setup.h
@@ -2,6 +2,10 @@
#ifndef __ASM_GENERIC_SETUP_H
#define __ASM_GENERIC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 512
+#endif
#endif /* __ASM_GENERIC_SETUP_H */
--
2.55.0.654.g21b8a5bc05-goog
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE
@ 2026-08-06 6:14 Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures Wilson Felipe Pereira
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Wilson Felipe Pereira @ 2026-08-06 6:14 UTC (permalink / raw)
To: Arnd Bergmann, Andrew Morton
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-arch, linux-riscv,
linux-s390, Wilson Felipe Pereira
[Note: Resending the full series to ensure all patches are delivered with a
unified recipient and CC list across all mailing lists.]
This patch series promotes COMMAND_LINE_SIZE from arch/s390/Kconfig to
init/Kconfig to be generally available to other architectures.
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.
Since COMMAND_LINE_SIZE can be larger, it also makes sense to allow
INIT_ENV_ARG_LIMIT to be configured.
Wilson Felipe Pereira (3):
init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures
arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
init/Kconfig: make config INIT_ENV_ARG_LIMIT user-configurable
arch/alpha/include/uapi/asm/setup.h | 4 ++++
arch/arc/include/asm/setup.h | 2 +-
arch/arm/include/uapi/asm/setup.h | 6 +++++-
arch/arm64/include/uapi/asm/setup.h | 4 ++++
arch/loongarch/include/uapi/asm/setup.h | 4 ++++
arch/m68k/include/uapi/asm/setup.h | 6 +++++-
arch/microblaze/include/uapi/asm/setup.h | 4 ++++
arch/mips/include/uapi/asm/setup.h | 4 ++++
arch/parisc/include/uapi/asm/setup.h | 4 ++++
arch/powerpc/include/uapi/asm/setup.h | 4 ++++
arch/riscv/include/uapi/asm/setup.h | 4 ++++
arch/s390/Kconfig | 8 --------
arch/sparc/include/uapi/asm/setup.h | 10 +++++++---
arch/um/include/asm/setup.h | 2 +-
arch/x86/include/asm/setup.h | 2 +-
arch/xtensa/include/uapi/asm/setup.h | 4 ++++
include/uapi/asm-generic/setup.h | 4 ++++
init/Kconfig | 15 ++++++++++++++-
18 files changed, 74 insertions(+), 17 deletions(-)
--
2.55.0.654.g21b8a5bc05-goog
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures
2026-08-06 6:14 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
@ 2026-08-06 6:14 ` Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across " Wilson Felipe Pereira
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Wilson Felipe Pereira @ 2026-08-06 6:14 UTC (permalink / raw)
To: Arnd Bergmann, Andrew Morton
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-arch, linux-riscv,
linux-s390, Wilson Felipe Pereira, Maciej Żenczykowski
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 <maze@google.com>
Signed-off-by: Wilson Felipe Pereira <wfelipe@google.com>
---
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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^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
2026-08-06 6:14 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures Wilson Felipe Pereira
@ 2026-08-06 6:14 ` Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 3/3] init/Kconfig: make config INIT_ENV_ARG_LIMIT user-configurable Wilson Felipe Pereira
2026-08-06 22:57 ` [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: Wilson Felipe Pereira @ 2026-08-06 6:14 UTC (permalink / raw)
To: Arnd Bergmann, Andrew Morton
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-arch, linux-riscv,
linux-s390, Wilson Felipe Pereira, Maciej Żenczykowski
Now that CONFIG_COMMAND_LINE_SIZE is available in init/Kconfig for all
architectures, update every architecture's setup.h header to define
COMMAND_LINE_SIZE as CONFIG_COMMAND_LINE_SIZE.
For user-space API (uapi) headers, wrap the definition in an
`#ifdef __KERNEL__` guard and retain the historical hardcoded default in
the `#else` block. When user-space headers are installed via
`make headers_install`, unifdef strips out the kernel section, ensuring
same value as before for user-space applications including `<asm/setup.h>`.
Originally-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Wilson Felipe Pereira <wfelipe@google.com>
---
arch/alpha/include/uapi/asm/setup.h | 4 ++++
arch/arc/include/asm/setup.h | 2 +-
arch/arm/include/uapi/asm/setup.h | 6 +++++-
arch/arm64/include/uapi/asm/setup.h | 4 ++++
arch/loongarch/include/uapi/asm/setup.h | 4 ++++
arch/m68k/include/uapi/asm/setup.h | 6 +++++-
arch/microblaze/include/uapi/asm/setup.h | 4 ++++
arch/mips/include/uapi/asm/setup.h | 4 ++++
arch/parisc/include/uapi/asm/setup.h | 4 ++++
arch/powerpc/include/uapi/asm/setup.h | 4 ++++
arch/riscv/include/uapi/asm/setup.h | 4 ++++
arch/sparc/include/uapi/asm/setup.h | 10 +++++++---
arch/um/include/asm/setup.h | 2 +-
arch/x86/include/asm/setup.h | 2 +-
arch/xtensa/include/uapi/asm/setup.h | 4 ++++
include/uapi/asm-generic/setup.h | 4 ++++
16 files changed, 60 insertions(+), 8 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/setup.h b/arch/alpha/include/uapi/asm/setup.h
index f881ea5947cbc..169f743ef7658 100644
--- a/arch/alpha/include/uapi/asm/setup.h
+++ b/arch/alpha/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _UAPI__ALPHA_SETUP_H
#define _UAPI__ALPHA_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI__ALPHA_SETUP_H */
diff --git a/arch/arc/include/asm/setup.h b/arch/arc/include/asm/setup.h
index 1c6db599e1fcc..60e158d58cec7 100644
--- a/arch/arc/include/asm/setup.h
+++ b/arch/arc/include/asm/setup.h
@@ -9,7 +9,7 @@
#include <linux/types.h>
#include <uapi/asm/setup.h>
-#define COMMAND_LINE_SIZE 256
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
/*
* Data structure to map a ID to string
diff --git a/arch/arm/include/uapi/asm/setup.h b/arch/arm/include/uapi/asm/setup.h
index 8e50e034fec73..4aa93558af1e7 100644
--- a/arch/arm/include/uapi/asm/setup.h
+++ b/arch/arm/include/uapi/asm/setup.h
@@ -17,7 +17,11 @@
#include <linux/types.h>
-#define COMMAND_LINE_SIZE 1024
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
+#define COMMAND_LINE_SIZE 1024
+#endif
/* The list ends with an ATAG_NONE node. */
#define ATAG_NONE 0x00000000
diff --git a/arch/arm64/include/uapi/asm/setup.h b/arch/arm64/include/uapi/asm/setup.h
index 5d703888f3511..2236890175a5a 100644
--- a/arch/arm64/include/uapi/asm/setup.h
+++ b/arch/arm64/include/uapi/asm/setup.h
@@ -22,6 +22,10 @@
#include <linux/types.h>
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif
diff --git a/arch/loongarch/include/uapi/asm/setup.h b/arch/loongarch/include/uapi/asm/setup.h
index d46363ce3e024..03c7bfa1e5d9f 100644
--- a/arch/loongarch/include/uapi/asm/setup.h
+++ b/arch/loongarch/include/uapi/asm/setup.h
@@ -3,6 +3,10 @@
#ifndef _UAPI_ASM_LOONGARCH_SETUP_H
#define _UAPI_ASM_LOONGARCH_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 4096
+#endif
#endif /* _UAPI_ASM_LOONGARCH_SETUP_H */
diff --git a/arch/m68k/include/uapi/asm/setup.h b/arch/m68k/include/uapi/asm/setup.h
index 25fe26d5597cc..2d5b24a5345f9 100644
--- a/arch/m68k/include/uapi/asm/setup.h
+++ b/arch/m68k/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _UAPI_M68K_SETUP_H
#define _UAPI_M68K_SETUP_H
-#define COMMAND_LINE_SIZE 256
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
+#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI_M68K_SETUP_H */
diff --git a/arch/microblaze/include/uapi/asm/setup.h b/arch/microblaze/include/uapi/asm/setup.h
index 16c56807f86a2..e4b253064c7d9 100644
--- a/arch/microblaze/include/uapi/asm/setup.h
+++ b/arch/microblaze/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _UAPI_ASM_MICROBLAZE_SETUP_H
#define _UAPI_ASM_MICROBLAZE_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif /* _UAPI_ASM_MICROBLAZE_SETUP_H */
diff --git a/arch/mips/include/uapi/asm/setup.h b/arch/mips/include/uapi/asm/setup.h
index 7d48c433b0c27..8d6c474835aec 100644
--- a/arch/mips/include/uapi/asm/setup.h
+++ b/arch/mips/include/uapi/asm/setup.h
@@ -2,7 +2,11 @@
#ifndef _UAPI_MIPS_SETUP_H
#define _UAPI_MIPS_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 4096
+#endif
#endif /* _UAPI_MIPS_SETUP_H */
diff --git a/arch/parisc/include/uapi/asm/setup.h b/arch/parisc/include/uapi/asm/setup.h
index 78b2f4ec7d652..cfa77e84205dc 100644
--- a/arch/parisc/include/uapi/asm/setup.h
+++ b/arch/parisc/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _PARISC_SETUP_H
#define _PARISC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 1024
+#endif
#endif /* _PARISC_SETUP_H */
diff --git a/arch/powerpc/include/uapi/asm/setup.h b/arch/powerpc/include/uapi/asm/setup.h
index c54940b09d065..daa15ac4e94c6 100644
--- a/arch/powerpc/include/uapi/asm/setup.h
+++ b/arch/powerpc/include/uapi/asm/setup.h
@@ -2,6 +2,10 @@
#ifndef _UAPI_ASM_POWERPC_SETUP_H
#define _UAPI_ASM_POWERPC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif /* _UAPI_ASM_POWERPC_SETUP_H */
diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
index eb4f0209c6960..a6c1f4b0987e3 100644
--- a/arch/riscv/include/uapi/asm/setup.h
+++ b/arch/riscv/include/uapi/asm/setup.h
@@ -3,6 +3,10 @@
#ifndef _UAPI_ASM_RISCV_SETUP_H
#define _UAPI_ASM_RISCV_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 2048
+#endif
#endif /* _UAPI_ASM_RISCV_SETUP_H */
diff --git a/arch/sparc/include/uapi/asm/setup.h b/arch/sparc/include/uapi/asm/setup.h
index 3c208a4dd4640..7054f5249a3a6 100644
--- a/arch/sparc/include/uapi/asm/setup.h
+++ b/arch/sparc/include/uapi/asm/setup.h
@@ -6,10 +6,14 @@
#ifndef _UAPI_SPARC_SETUP_H
#define _UAPI_SPARC_SETUP_H
-#if defined(__sparc__) && defined(__arch64__)
-# define COMMAND_LINE_SIZE 2048
+#ifdef __KERNEL__
+# define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#else
-# define COMMAND_LINE_SIZE 256
+# if defined(__sparc__) && defined(__arch64__)
+# define COMMAND_LINE_SIZE 2048
+# else
+# define COMMAND_LINE_SIZE 256
+# endif
#endif
diff --git a/arch/um/include/asm/setup.h b/arch/um/include/asm/setup.h
index 80ada899f2542..bc83dc4d467d3 100644
--- a/arch/um/include/asm/setup.h
+++ b/arch/um/include/asm/setup.h
@@ -6,6 +6,6 @@
* command line, so this choice is ok.
*/
-#define COMMAND_LINE_SIZE 4096
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#endif /* SETUP_H_INCLUDED */
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 914eb32581c73..b73caf64f2199 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -4,7 +4,7 @@
#include <uapi/asm/setup.h>
-#define COMMAND_LINE_SIZE 2048
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
#include <linux/linkage.h>
#include <asm/page_types.h>
diff --git a/arch/xtensa/include/uapi/asm/setup.h b/arch/xtensa/include/uapi/asm/setup.h
index 5356a5fd4d173..dcf33a403527a 100644
--- a/arch/xtensa/include/uapi/asm/setup.h
+++ b/arch/xtensa/include/uapi/asm/setup.h
@@ -12,6 +12,10 @@
#ifndef _XTENSA_SETUP_H
#define _XTENSA_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 256
+#endif
#endif
diff --git a/include/uapi/asm-generic/setup.h b/include/uapi/asm-generic/setup.h
index 88ac5100df359..b8d06e6d56bd7 100644
--- a/include/uapi/asm-generic/setup.h
+++ b/include/uapi/asm-generic/setup.h
@@ -2,6 +2,10 @@
#ifndef __ASM_GENERIC_SETUP_H
#define __ASM_GENERIC_SETUP_H
+#ifdef __KERNEL__
+#define COMMAND_LINE_SIZE CONFIG_COMMAND_LINE_SIZE
+#else
#define COMMAND_LINE_SIZE 512
+#endif
#endif /* __ASM_GENERIC_SETUP_H */
--
2.55.0.654.g21b8a5bc05-goog
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/3] init/Kconfig: make config INIT_ENV_ARG_LIMIT user-configurable
2026-08-06 6:14 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across " Wilson Felipe Pereira
@ 2026-08-06 6:14 ` Wilson Felipe Pereira
2026-08-06 22:57 ` [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: Wilson Felipe Pereira @ 2026-08-06 6:14 UTC (permalink / raw)
To: Arnd Bergmann, Andrew Morton
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-arch, linux-riscv,
linux-s390, Wilson Felipe Pereira, Maciej Żenczykowski
INIT_ENV_ARG_LIMIT is defined without a prompt string (`int`), making it
a hidden Kconfig symbol that defaults to 32 (or 128 for UML) and cannot
be configured in `make menuconfig`.
Now that CONFIG_COMMAND_LINE_SIZE is configurable across all architectures,
users who select larger kernel command lines (e.g., 4096 bytes) may pass
more than 32 command-line arguments or environment variables (`foo=bar`) to
`/sbin/init`. If INIT_ENV_ARG_LIMIT remains hardcoded at 32, any argument
after the 32nd is silently dropped when the kernel executes init.
Add a prompt string ("Maximum number of kernel command line arguments") and
a `range 32 4096` to `config INIT_ENV_ARG_LIMIT` so that users can
configure their init argument and environment variable limit when needed,
while preserving the existing default of 32 for standard builds.
Originally-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Wilson Felipe Pereira <wfelipe@google.com>
---
init/Kconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index d42bb55cb2152..28c0f1fb00ebb 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -231,9 +231,10 @@ config BROKEN_ON_SMP
default y
config INIT_ENV_ARG_LIMIT
- int
+ int "Maximum number of kernel command line arguments"
default 32 if !UML
default 128 if UML
+ range 32 4096
help
Maximum of each of the number of arguments and environment
variables passed to init from the kernel command line.
--
2.55.0.654.g21b8a5bc05-goog
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE
2026-08-06 6:14 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
` (2 preceding siblings ...)
2026-08-06 6:14 ` [PATCH 3/3] init/Kconfig: make config INIT_ENV_ARG_LIMIT user-configurable Wilson Felipe Pereira
@ 2026-08-06 22:57 ` Andrew Morton
3 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2026-08-06 22:57 UTC (permalink / raw)
To: Wilson Felipe Pereira
Cc: Arnd Bergmann, Paul Walmsley, Palmer Dabbelt, Albert Ou,
Alexandre Ghiti, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-arch, linux-riscv,
linux-s390
On Thu, 6 Aug 2026 06:14:13 +0000 Wilson Felipe Pereira <wfelipe@google.com> wrote:
> This patch series promotes COMMAND_LINE_SIZE from arch/s390/Kconfig to
> init/Kconfig to be generally available to other architectures.
>
> 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.
>
> Since COMMAND_LINE_SIZE can be larger, it also makes sense to allow
> INIT_ENV_ARG_LIMIT to be configured.
Thanks.
AI review pointed at a few possible issues - I eyeballed a couple and
they appear significant.
https://sashiko.dev/#/patchset/20260806061429.474992-1-wfelipe@google.com
> Originally-by: Maciej Żenczykowski <maze@google.com>
fyi, it's minor, but Originally-by: isn't actually a thing. It's
mentioned in the -tip documentation, nothing else endorses it.
I have no issue with it but formally these patches should also have
Maciej's Signed-off-by:
Please let's target 7.3-rc1 for these changes - I'm deep into
stem-the-flood mode for this -rc cycle.
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-08-06 22:58 UTC | newest]
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2026-08-06 6:14 ` [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across " Wilson Felipe Pereira
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