* [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE
@ 2026-08-06 6:05 Wilson Felipe Pereira
2026-08-06 6:05 ` [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures Wilson Felipe Pereira
2026-08-06 6:05 ` Wilson Felipe Pereira
0 siblings, 2 replies; 7+ 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, Paul Walmsley, Palmer Dabbelt,
Albert Ou, Alexandre Ghiti, linux-riscv
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
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures
2026-08-06 6:05 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
@ 2026-08-06 6:05 ` Wilson Felipe Pereira
2026-08-06 6:05 ` Wilson Felipe Pereira
1 sibling, 0 replies; 7+ 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,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, linux-s390
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
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
2026-08-06 6:05 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
@ 2026-08-06 6:05 ` Wilson Felipe Pereira
2026-08-06 6:05 ` Wilson Felipe Pereira
1 sibling, 0 replies; 7+ 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
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
@ 2026-08-06 6:05 ` Wilson Felipe Pereira
0 siblings, 0 replies; 7+ 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
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 7+ 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 ` Wilson Felipe Pereira
0 siblings, 1 reply; 7+ 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
^ permalink raw reply [flat|nested] 7+ 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 ` Wilson Felipe Pereira
0 siblings, 0 replies; 7+ 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
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
@ 2026-08-06 6:14 ` Wilson Felipe Pereira
0 siblings, 0 replies; 7+ 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
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
2026-08-06 6:14 ` Wilson Felipe Pereira
(?)
@ 2026-08-06 6:25 ` sashiko-bot
-1 siblings, 0 replies; 7+ messages in thread
From: sashiko-bot @ 2026-08-06 6:25 UTC (permalink / raw)
To: Wilson Felipe Pereira
Cc: Alexander Gordeev, linux-s390, Heiko Carstens, Vasily Gorbik
Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] RISC-V default command line size is silently truncated from 2048 to 1024 bytes.
- [High] Exposing COMMAND_LINE_SIZE to Kconfig allows deterministic stack exhaustion in the ARM boot decompressor.
- [High] Configurable COMMAND_LINE_SIZE causes stack exhaustion during early boot on m68k Atari.
--
--- Patch [2]: [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures ---
commit 86e4b8b798d614166a3d212659ea7796c8a7ee99
Author: Wilson Felipe Pereira <wfelipe@google.com>
arch: use CONFIG_COMMAND_LINE_SIZE across all architectures
This commit updates every architecture's setup.h to define COMMAND_LINE_SIZE
using CONFIG_COMMAND_LINE_SIZE for the kernel. The historical hardcoded
defaults are retained in user-space API headers by wrapping the definition
in an #ifdef __KERNEL__ guard.
> 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
[Severity: High]
Does exposing COMMAND_LINE_SIZE to Kconfig allow deterministic stack exhaustion
in the ARM boot decompressor?
The ARM boot decompressor uses a fixed 4KB stack (.L_user_stack in
arch/arm/boot/compressed/head.S), and merge_fdt_bootargs() allocates:
arch/arm/boot/compressed/atags_to_fdt.c:merge_fdt_bootargs() {
...
char cmdline[COMMAND_LINE_SIZE];
...
}
If a user configures CONFIG_COMMAND_LINE_SIZE to a value larger than ~3KB,
will this stack allocation deterministically crash on boot?
[ ... ]
> 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
[Severity: High]
Can a configurable COMMAND_LINE_SIZE cause stack exhaustion during early boot
on m68k Atari?
atari_switches_setup() allocates an array locally on the limited kernel stack:
arch/m68k/atari/config.c:atari_switches_setup() {
...
char switches[COMMAND_LINE_SIZE];
...
}
Will tying this to an unbound Kconfig option introduce deterministic stack
exhaustion on boot for m68k Atari kernels?
[ ... ]
> 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
[Severity: High]
Is the RISC-V default command line size silently truncated from 2048 to 1024
bytes?
The Kconfig default in init/Kconfig erroneously groups RISC-V with ARM and
PARISC (1024):
init/Kconfig:
default 1024 if ARM || PARISC || RISCV
By replacing the kernel definition with CONFIG_COMMAND_LINE_SIZE here, does
this create a dangerous discrepancy where userspace headers claim the limit
is 2048, while the kernel internally enforces 1024 and truncates existing
boot configurations?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260806061429.474992-1-wfelipe@google.com?part=2
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-08-06 6:25 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-06 6:05 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
2026-08-06 6:05 ` [PATCH 1/3] init/Kconfig: generalize config COMMAND_LINE_SIZE to all architectures Wilson Felipe Pereira
2026-08-06 6:05 ` [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across " Wilson Felipe Pereira
2026-08-06 6:05 ` Wilson Felipe Pereira
-- strict thread matches above, loose matches on Subject: below --
2026-08-06 6:14 [PATCH 0/3] init/Kconfig: generalize config COMMAND_LINE_SIZE Wilson Felipe Pereira
2026-08-06 6:14 ` [PATCH 2/3] arch: use CONFIG_COMMAND_LINE_SIZE across all architectures Wilson Felipe Pereira
2026-08-06 6:14 ` Wilson Felipe Pereira
2026-08-06 6:25 ` sashiko-bot
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.