[PATCH 0/8] generic command line v5

[PATCH 0/8] generic command line v5

[Daniel Walker]

v5 release changes. Generally a rebase from v4.

* Modified OF changes to move the ugly code into the cmdline.h

* Minor compliation update in arm64. Added ifndef __ASSEMBLY__ in
  a few places.

* Worked around arm64 kaslr_early.c.

	This code needs some additional review and consideration. 
	It appears this code is missing the opposite option to nokaslr
	which is kaslr.disabled=1/0 which would allow kaslr to be turn
	back on later in the command line. For example,

	console=ttyS0 nokaslr root=/dev/ram0 nosmp kaslr.disabled=0 loglevel=7
	
	On arm64 in arch/arm64/kernel/idreg-override.c this is parsed correctly
	to turn on kaslr, but the kaslr_early.c is missing this logic.
	Doing this results in kaslr getting disabled with the following message,

	KASLR disabled due to lack of seed

	Even when there is a seed in the device tree.	

	So change to the generic command line would leave built in command
	lines with nokaslr with no option to re-enable kaslr in in the bootloader
	arguments.


Daniel Walker (8):
  CMDLINE: add generic builtin command line
  scripts: insert-sys-cert: add command line insert capability
  scripts: insert-sys-cert: change name to insert-symbol
  CMDLINE: mips: convert to generic builtin command line
  drivers: firmware: efi: libstub: enable generic commandline
  CMDLINE: x86: convert to generic builtin command line
  of: replace command line handling
  CMDLINE: arm64: convert to generic builtin command line

 arch/arm64/Kconfig                            |  33 +--
 arch/arm64/include/asm/setup.h                |   4 +
 arch/arm64/include/uapi/asm/setup.h           |   2 +
 arch/arm64/kernel/idreg-override.c            |   9 +-
 arch/arm64/kernel/pi/kaslr_early.c            |  14 +-
 arch/mips/Kconfig                             |   4 +-
 arch/mips/Kconfig.debug                       |  44 ----
 arch/mips/configs/ar7_defconfig               |   9 +-
 arch/mips/configs/bcm47xx_defconfig           |   8 +-
 arch/mips/configs/bcm63xx_defconfig           |  15 +-
 arch/mips/configs/bmips_be_defconfig          |  11 +-
 arch/mips/configs/bmips_stb_defconfig         |   6 +-
 arch/mips/configs/ci20_defconfig              |   9 +-
 arch/mips/configs/cu1000-neo_defconfig        |  10 +-
 arch/mips/configs/cu1830-neo_defconfig        |  10 +-
 arch/mips/configs/generic_defconfig           |   6 +-
 arch/mips/configs/gpr_defconfig               |  18 +-
 arch/mips/configs/loongson3_defconfig         |  12 +-
 arch/mips/include/asm/setup.h                 |   2 +
 arch/mips/kernel/relocate.c                   |  17 +-
 arch/mips/kernel/setup.c                      |  36 +--
 arch/mips/pic32/pic32mzda/early_console.c     |   2 +-
 arch/mips/pic32/pic32mzda/init.c              |   3 +-
 arch/x86/Kconfig                              |  44 +---
 arch/x86/kernel/setup.c                       |  18 +-
 .../firmware/efi/libstub/efi-stub-helper.c    |  29 +++
 drivers/firmware/efi/libstub/efi-stub.c       |   9 +
 drivers/firmware/efi/libstub/efistub.h        |   1 +
 drivers/firmware/efi/libstub/x86-stub.c       |  13 +-
 drivers/of/fdt.c                              |  22 +-
 include/linux/cmdline.h                       | 137 ++++++++++
 init/Kconfig                                  |  78 ++++++
 lib/Kconfig                                   |   4 +
 lib/Makefile                                  |   3 +
 lib/generic_cmdline.S                         |  53 ++++
 lib/test_cmdline1.c                           | 139 ++++++++++
 scripts/Makefile                              |   2 +-
 .../{insert-sys-cert.c => insert-symbol.c}    | 243 ++++++++++++------
 38 files changed, 724 insertions(+), 355 deletions(-)
 create mode 100644 include/linux/cmdline.h
 create mode 100644 lib/generic_cmdline.S
 create mode 100644 lib/test_cmdline1.c
 rename scripts/{insert-sys-cert.c => insert-symbol.c} (72%)

-- 
2.25.1

[PATCH 7/8] of: replace command line handling

[Daniel Walker]

Rob Herring has complained about this section of code. I removed the
command line handling code to the cmdline.h header. This hopefully makes
it easier for Rob to maintain it (at least he doesn't have to look at it
directly anymore). I would like to add a Kconfig option called
OF_DEPRECATED_CMDLINE which an architecture would set if it uses this code.
This would allow a platform to use the cmdline.h and the added function
directly and remove the Kconfig option. This change would be in a subsequent
patch.

This code was boot tested on powerpc 32bit, powerpc 64bit without
any generic command line conversion.

Cc: xe-linux-external@cisco.com
Signed-off-by: Daniel Walker <danielwa@cisco.com>
---
 drivers/of/fdt.c        | 22 ++--------------------
 include/linux/cmdline.h | 33 ++++++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 21 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 1c573e7a60bc..94e8fa277857 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -27,6 +27,7 @@
 #include <linux/sysfs.h>
 #include <linux/random.h>
 #include <linux/kmemleak.h>
+#include <linux/cmdline.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
@@ -1177,26 +1178,7 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 
 	/* Retrieve command line */
 	p = of_get_flat_dt_prop(node, "bootargs", &l);
-	if (p != NULL && l > 0)
-		strlcpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
-
-	/*
-	 * CONFIG_CMDLINE is meant to be a default in case nothing else
-	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
-	 * is set in which case we override whatever was found earlier.
-	 */
-#ifdef CONFIG_CMDLINE
-#if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
-	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#elif defined(CONFIG_CMDLINE_FORCE)
-	strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#else
-	/* No arguments from boot loader, use kernel's  cmdl*/
-	if (!((char *)cmdline)[0])
-		strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#endif
-#endif /* CONFIG_CMDLINE */
+	of_deprecated_cmdline_update(cmdline, p, l);
 
 	pr_debug("Command line is: %s\n", (char *)cmdline);
 
diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
index a94758a0f257..dc7793265aa3 100644
--- a/include/linux/cmdline.h
+++ b/include/linux/cmdline.h
@@ -103,4 +103,35 @@ __cmdline_add_builtin(
 
 #define cmdline_get_static_builtin(dest) \
 	(CMDLINE_STATIC_PREPEND CMDLINE_STATIC_APPEND)
-#endif
+
+#ifndef CONFIG_GENERIC_CMDLINE
+static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length)
+{
+	if (dt_bootargs != NULL && length > 0)
+		strlcpy(cmdline, dt_bootargs, min(length, COMMAND_LINE_SIZE));
+	/*
+	 * CONFIG_CMDLINE is meant to be a default in case nothing else
+	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
+	 * is set in which case we override whatever was found earlier.
+	 */
+#ifdef CONFIG_CMDLINE
+#if defined(CONFIG_CMDLINE_EXTEND)
+	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
+	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#elif defined(CONFIG_CMDLINE_FORCE)
+	strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#else
+	/* No arguments from boot loader, use kernel's  cmdl*/
+	if (!((char *)cmdline)[0])
+		strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#endif /* CONFIG_CMDLINE_EXTEND */
+#endif /* CONFIG_CMDLINE */
+
+	return true;
+}
+#else
+static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length) { return false; }
+#endif /* CONFIG_GENERIC_CMDLINE */
+
+
+#endif /* _LINUX_CMDLINE_H */
-- 
2.25.1

Re: [PATCH 0/8] generic command line v5

[Sean Anderson]

On 9/28/22 22:32, Daniel Walker wrote:
> v5 release changes. Generally a rebase from v4.
> 
> * Modified OF changes to move the ugly code into the cmdline.h
> 
> * Minor compliation update in arm64. Added ifndef __ASSEMBLY__ in
>   a few places.
> 
> * Worked around arm64 kaslr_early.c.
> 
> 	This code needs some additional review and consideration. 
> 	It appears this code is missing the opposite option to nokaslr
> 	which is kaslr.disabled=1/0 which would allow kaslr to be turn
> 	back on later in the command line. For example,
> 
> 	console=ttyS0 nokaslr root=/dev/ram0 nosmp kaslr.disabled=0 loglevel=7
> 	
> 	On arm64 in arch/arm64/kernel/idreg-override.c this is parsed correctly
> 	to turn on kaslr, but the kaslr_early.c is missing this logic.
> 	Doing this results in kaslr getting disabled with the following message,
> 
> 	KASLR disabled due to lack of seed
> 
> 	Even when there is a seed in the device tree.	
> 
> 	So change to the generic command line would leave built in command
> 	lines with nokaslr with no option to re-enable kaslr in in the bootloader
> 	arguments.
> 
> 
> Daniel Walker (8):
>   CMDLINE: add generic builtin command line
>   scripts: insert-sys-cert: add command line insert capability
>   scripts: insert-sys-cert: change name to insert-symbol
>   CMDLINE: mips: convert to generic builtin command line
>   drivers: firmware: efi: libstub: enable generic commandline
>   CMDLINE: x86: convert to generic builtin command line
>   of: replace command line handling
>   CMDLINE: arm64: convert to generic builtin command line
> 
>  arch/arm64/Kconfig                            |  33 +--
>  arch/arm64/include/asm/setup.h                |   4 +
>  arch/arm64/include/uapi/asm/setup.h           |   2 +
>  arch/arm64/kernel/idreg-override.c            |   9 +-
>  arch/arm64/kernel/pi/kaslr_early.c            |  14 +-
>  arch/mips/Kconfig                             |   4 +-
>  arch/mips/Kconfig.debug                       |  44 ----
>  arch/mips/configs/ar7_defconfig               |   9 +-
>  arch/mips/configs/bcm47xx_defconfig           |   8 +-
>  arch/mips/configs/bcm63xx_defconfig           |  15 +-
>  arch/mips/configs/bmips_be_defconfig          |  11 +-
>  arch/mips/configs/bmips_stb_defconfig         |   6 +-
>  arch/mips/configs/ci20_defconfig              |   9 +-
>  arch/mips/configs/cu1000-neo_defconfig        |  10 +-
>  arch/mips/configs/cu1830-neo_defconfig        |  10 +-
>  arch/mips/configs/generic_defconfig           |   6 +-
>  arch/mips/configs/gpr_defconfig               |  18 +-
>  arch/mips/configs/loongson3_defconfig         |  12 +-
>  arch/mips/include/asm/setup.h                 |   2 +
>  arch/mips/kernel/relocate.c                   |  17 +-
>  arch/mips/kernel/setup.c                      |  36 +--
>  arch/mips/pic32/pic32mzda/early_console.c     |   2 +-
>  arch/mips/pic32/pic32mzda/init.c              |   3 +-
>  arch/x86/Kconfig                              |  44 +---
>  arch/x86/kernel/setup.c                       |  18 +-
>  .../firmware/efi/libstub/efi-stub-helper.c    |  29 +++
>  drivers/firmware/efi/libstub/efi-stub.c       |   9 +
>  drivers/firmware/efi/libstub/efistub.h        |   1 +
>  drivers/firmware/efi/libstub/x86-stub.c       |  13 +-
>  drivers/of/fdt.c                              |  22 +-
>  include/linux/cmdline.h                       | 137 ++++++++++
>  init/Kconfig                                  |  78 ++++++
>  lib/Kconfig                                   |   4 +
>  lib/Makefile                                  |   3 +
>  lib/generic_cmdline.S                         |  53 ++++
>  lib/test_cmdline1.c                           | 139 ++++++++++
>  scripts/Makefile                              |   2 +-
>  .../{insert-sys-cert.c => insert-symbol.c}    | 243 ++++++++++++------
>  38 files changed, 724 insertions(+), 355 deletions(-)
>  create mode 100644 include/linux/cmdline.h
>  create mode 100644 lib/generic_cmdline.S
>  create mode 100644 lib/test_cmdline1.c
>  rename scripts/{insert-sys-cert.c => insert-symbol.c} (72%)
> 

For arm64:

Tested-by: Sean Anderson <sean.anderson@seco.com>

Thanks!

[PATCH 0/8] generic command line v6

[Daniel Walker]

This release is an up-rev of the v5 patches. No additional features have
been added. Some changes were mode to function names and some changes to
Kconfig dependencies. Also updated the config conversion for mips.

There are a number of people who have expressed interest in these
patches either by asking for them to be merge or testing them. If
people are so inclined please continue to request them to be merge
or to ask the status of the next release. It's helpful to motivate me to
release them again and for the maintainers to see the interest
generated.

These patches have been used by Cisco Systems, Inc. on millions of
released products to great effect. Hopefully they can be used by the
entire Linux eco system.

My apologies on the length between releases. I will try to release more
often.


Daniel Walker (8):
  CMDLINE: add generic builtin command line
  scripts: insert-sys-cert: add command line insert capability
  scripts: insert-sys-cert: change name to insert-symbol
  CMDLINE: mips: convert to generic builtin command line
  drivers: firmware: efi: libstub: enable generic commandline
  CMDLINE: x86: convert to generic builtin command line
  of: replace command line handling
  CMDLINE: arm64: convert to generic builtin command line

 arch/arm64/Kconfig                            |  33 +--
 arch/arm64/include/asm/setup.h                |   4 +
 arch/arm64/include/uapi/asm/setup.h           |   2 +
 arch/arm64/kernel/idreg-override.c            |   9 +-
 arch/arm64/kernel/pi/kaslr_early.c            |  14 +-
 arch/mips/Kconfig                             |   4 +-
 arch/mips/Kconfig.debug                       |  44 ----
 arch/mips/configs/ar7_defconfig               |  12 +-
 arch/mips/configs/bcm47xx_defconfig           |  10 +-
 arch/mips/configs/bcm63xx_defconfig           |  21 +-
 arch/mips/configs/bmips_be_defconfig          |  17 +-
 arch/mips/configs/bmips_stb_defconfig         | 139 ++++------
 arch/mips/configs/ci20_defconfig              |   8 +-
 arch/mips/configs/cu1000-neo_defconfig        |  19 +-
 arch/mips/configs/cu1830-neo_defconfig        |  19 +-
 arch/mips/configs/generic_defconfig           |  15 +-
 arch/mips/configs/gpr_defconfig               |  33 +--
 arch/mips/configs/loongson3_defconfig         |  29 +--
 arch/mips/include/asm/setup.h                 |   2 +
 arch/mips/kernel/relocate.c                   |  17 +-
 arch/mips/kernel/setup.c                      |  36 +--
 arch/mips/pic32/pic32mzda/early_console.c     |   2 +-
 arch/mips/pic32/pic32mzda/init.c              |   3 +-
 arch/x86/Kconfig                              |  44 +---
 arch/x86/kernel/setup.c                       |  18 +-
 .../firmware/efi/libstub/efi-stub-helper.c    |  29 +++
 drivers/firmware/efi/libstub/efi-stub.c       |   9 +
 drivers/firmware/efi/libstub/efistub.h        |   1 +
 drivers/firmware/efi/libstub/x86-stub.c       |  14 +-
 drivers/of/fdt.c                              |  22 +-
 include/linux/cmdline.h                       | 137 ++++++++++
 init/Kconfig                                  |  79 ++++++
 lib/Kconfig                                   |   4 +
 lib/Makefile                                  |   3 +
 lib/generic_cmdline.S                         |  53 ++++
 lib/test_cmdline1.c                           | 139 ++++++++++
 scripts/Makefile                              |   2 +-
 .../{insert-sys-cert.c => insert-symbol.c}    | 243 ++++++++++++------
 38 files changed, 807 insertions(+), 482 deletions(-)
 create mode 100644 include/linux/cmdline.h
 create mode 100644 lib/generic_cmdline.S
 create mode 100644 lib/test_cmdline1.c
 rename scripts/{insert-sys-cert.c => insert-symbol.c} (72%)

-- 
2.39.2

[PATCH 7/8] of: replace command line handling

[Daniel Walker]

Rob Herring has complained about this section of code. I removed the
command line handling code to the cmdline.h header. This hopefully makes
it easier for Rob to maintain it (at least he doesn't have to look at it
directly anymore). I would like to add a Kconfig option called
OF_DEPRECATED_CMDLINE which an architecture would set if it uses this code.
This would allow a platform to use the cmdline.h and the added function
directly and remove the Kconfig option. This change would be in a subsequent
patch.

This code was boot tested on powerpc 32bit, powerpc 64bit without
any generic command line conversion.

Cc: xe-linux-external@cisco.com
Signed-off-by: Daniel Walker <danielwa@cisco.com>
---
 drivers/of/fdt.c        | 22 +++-------------------
 include/linux/cmdline.h | 31 +++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index bf502ba8da95..1fc1b17d04dc 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -26,6 +26,7 @@
 #include <linux/serial_core.h>
 #include <linux/sysfs.h>
 #include <linux/random.h>
+#include <linux/cmdline.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
@@ -1183,27 +1184,10 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 
 	/* Retrieve command line */
 	p = of_get_flat_dt_prop(node, "bootargs", &l);
-	if (p != NULL && l > 0)
-		strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
 
 handle_cmdline:
-	/*
-	 * CONFIG_CMDLINE is meant to be a default in case nothing else
-	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
-	 * is set in which case we override whatever was found earlier.
-	 */
-#ifdef CONFIG_CMDLINE
-#if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
-	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#elif defined(CONFIG_CMDLINE_FORCE)
-	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#else
-	/* No arguments from boot loader, use kernel's  cmdl*/
-	if (!((char *)cmdline)[0])
-		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#endif
-#endif /* CONFIG_CMDLINE */
+
+	of_deprecated_cmdline_update(cmdline, p, l);
 
 	pr_debug("Command line is: %s\n", (char *)cmdline);
 
diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
index a94758a0f257..c772afb7340f 100644
--- a/include/linux/cmdline.h
+++ b/include/linux/cmdline.h
@@ -103,4 +103,35 @@ __cmdline_add_builtin(
 
 #define cmdline_get_static_builtin(dest) \
 	(CMDLINE_STATIC_PREPEND CMDLINE_STATIC_APPEND)
+
+#ifndef CONFIG_GENERIC_CMDLINE
+static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length)
+{
+	if (dt_bootargs != NULL && length > 0)
+		strlcpy(cmdline, dt_bootargs, min(length, COMMAND_LINE_SIZE));
+	/*
+	 * CONFIG_CMDLINE is meant to be a default in case nothing else
+	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
+	 * is set in which case we override whatever was found earlier.
+	 */
+
+#ifdef CONFIG_CMDLINE
+#if defined(CONFIG_CMDLINE_EXTEND)
+	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
+	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#elif defined(CONFIG_CMDLINE_FORCE)
+	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#else
+	/* No arguments from boot loader, use kernel's  cmdl*/
+	if (!((char *)cmdline)[0])
+		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #endif
+#endif /* CONFIG_CMDLINE */
+	return true;
+}
+#else
+static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length) { return false; }
+#endif /* CONFIG_GENERIC_CMDLINE */
+
+
+#endif /* _LINUX_CMDLINE_H */
-- 
2.39.2

Re: [PATCH 7/8] of: replace command line handling

[Rob Herring]

On Thu, Nov 09, 2023 at 05:38:11PM -0800, Daniel Walker wrote:
> Rob Herring has complained about this section of code. I removed the
> command line handling code to the cmdline.h header. This hopefully makes
> it easier for Rob to maintain it (at least he doesn't have to look at it
> directly anymore).

Well, my goal is to eliminate drivers/of/, but no.

> I would like to add a Kconfig option called
> OF_DEPRECATED_CMDLINE which an architecture would set if it uses this code.

Which architecture needs this code? Do we wait and see who complains 
their platform broke and then go set this option? In the meantime, new 
platforms started depending on the new behavior and setting the option 
may break them. So we can't have a kconfig option.

> This would allow a platform to use the cmdline.h and the added function
> directly and remove the Kconfig option. This change would be in a subsequent
> patch.

Per platform code handling the cmdline is completely the wrong 
direction. Per arch behavior is bad enough.

Rob

Re: [PATCH 7/8] of: replace command line handling

[Daniel Walker (danielwa)]

On Thu, Nov 16, 2023 at 10:09:36AM -0600, Rob Herring wrote:
> On Thu, Nov 09, 2023 at 05:38:11PM -0800, Daniel Walker wrote:
> > Rob Herring has complained about this section of code. I removed the
> > command line handling code to the cmdline.h header. This hopefully makes
> > it easier for Rob to maintain it (at least he doesn't have to look at it
> > directly anymore).
> 
> Well, my goal is to eliminate drivers/of/, but no.
> 
> > I would like to add a Kconfig option called
> > OF_DEPRECATED_CMDLINE which an architecture would set if it uses this code.
> 
> Which architecture needs this code? Do we wait and see who complains 
> their platform broke and then go set this option? In the meantime, new 
> platforms started depending on the new behavior and setting the option 
> may break them. So we can't have a kconfig option.
 
 I think you misunderstood the comments. The objective is,

 1) Remove the code in drivers/of/
 2) Remove platform specific command line handling

> > This would allow a platform to use the cmdline.h and the added function
> > directly and remove the Kconfig option. This change would be in a subsequent
> > patch.
> 
> Per platform code handling the cmdline is completely the wrong 
> direction. Per arch behavior is bad enough.

This code unifies the handling into generic code outside drivers/of/ .

Daniel

Re: [PATCH 7/8] of: replace command line handling

[Christophe Leroy]

Le 10/11/2023 à 02:38, Daniel Walker a écrit :
> Rob Herring has complained about this section of code. I removed the

This kind of considerations shouldn't appear in the commit message, it 
may appear after the --- so that it gets dropped when applying.

> command line handling code to the cmdline.h header. This hopefully makes
> it easier for Rob to maintain it (at least he doesn't have to look at it
> directly anymore). I would like to add a Kconfig option called
> OF_DEPRECATED_CMDLINE which an architecture would set if it uses this code.

Not sure to understand what you want to do and why that is needed. Why 
can't that work for everyone ? Avoid unnecessary options.

> This would allow a platform to use the cmdline.h and the added function
> directly and remove the Kconfig option. This change would be in a subsequent
> patch.

would or will ? Not sure it is worth mentioning if it won't.

> 
> This code was boot tested on powerpc 32bit, powerpc 64bit without
> any generic command line conversion.
> 
> Cc: xe-linux-external@cisco.com
> Signed-off-by: Daniel Walker <danielwa@cisco.com>
> ---
>   drivers/of/fdt.c        | 22 +++-------------------
>   include/linux/cmdline.h | 31 +++++++++++++++++++++++++++++++
>   2 files changed, 34 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index bf502ba8da95..1fc1b17d04dc 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -26,6 +26,7 @@
>   #include <linux/serial_core.h>
>   #include <linux/sysfs.h>
>   #include <linux/random.h>
> +#include <linux/cmdline.h>
>   
>   #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
>   #include <asm/page.h>
> @@ -1183,27 +1184,10 @@ int __init early_init_dt_scan_chosen(char *cmdline)
>   
>   	/* Retrieve command line */
>   	p = of_get_flat_dt_prop(node, "bootargs", &l);
> -	if (p != NULL && l > 0)
> -		strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
>   
>   handle_cmdline:
> -	/*
> -	 * CONFIG_CMDLINE is meant to be a default in case nothing else
> -	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
> -	 * is set in which case we override whatever was found earlier.
> -	 */
> -#ifdef CONFIG_CMDLINE
> -#if defined(CONFIG_CMDLINE_EXTEND)
> -	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
> -	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> -#elif defined(CONFIG_CMDLINE_FORCE)
> -	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> -#else
> -	/* No arguments from boot loader, use kernel's  cmdl*/
> -	if (!((char *)cmdline)[0])
> -		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> -#endif
> -#endif /* CONFIG_CMDLINE */
> +
> +	of_deprecated_cmdline_update(cmdline, p, l);
>   
>   	pr_debug("Command line is: %s\n", (char *)cmdline);
>   
> diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
> index a94758a0f257..c772afb7340f 100644
> --- a/include/linux/cmdline.h
> +++ b/include/linux/cmdline.h
> @@ -103,4 +103,35 @@ __cmdline_add_builtin(
>   
>   #define cmdline_get_static_builtin(dest) \
>   	(CMDLINE_STATIC_PREPEND CMDLINE_STATIC_APPEND)
> +
> +#ifndef CONFIG_GENERIC_CMDLINE
> +static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length)

Add a comment explaining why it is deprecated.

> +{
> +	if (dt_bootargs != NULL && length > 0)
> +		strlcpy(cmdline, dt_bootargs, min(length, COMMAND_LINE_SIZE));
> +	/*
> +	 * CONFIG_CMDLINE is meant to be a default in case nothing else
> +	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
> +	 * is set in which case we override whatever was found earlier.
> +	 */
> +
> +#ifdef CONFIG_CMDLINE
> +#if defined(CONFIG_CMDLINE_EXTEND)
> +	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
> +	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> +#elif defined(CONFIG_CMDLINE_FORCE)
> +	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
> +#else
> +	/* No arguments from boot loader, use kernel's  cmdl*/
> +	if (!((char *)cmdline)[0])
> +		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
>   #endif
> +#endif /* CONFIG_CMDLINE */
> +	return true;
> +}
> +#else
> +static inline bool of_deprecated_cmdline_update(char *cmdline, const char *dt_bootargs, int length) { return false; }
> +#endif /* CONFIG_GENERIC_CMDLINE */
> +
> +
> +#endif /* _LINUX_CMDLINE_H */