Re: [PATCH-RFC 5/7] arm: convert to generic builtin command line

[Rob Herring]

On Tue, Oct 6, 2015 at 10:47 AM, Daniel Walker <danielwa@xxxxxxxxx> wrote:
> This updates the arm 32bit code to use the CONFIG_GENERIC_CMDLINE
> option.
>
> Cc: xe-kernel@xxxxxxxxxxxxxxxxxx
> Cc: Daniel Walker <dwalker@xxxxxxxxxx>
> Signed-off-by: Daniel Walker <danielwa@xxxxxxxxx>
> ---
>  arch/arm/Kconfig              | 38 +-------------------------------------
>  arch/arm/kernel/atags_parse.c | 14 ++++----------
>  arch/arm/kernel/devtree.c     |  2 ++
>  3 files changed, 7 insertions(+), 47 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 72ad724..5a49e36 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -20,6 +20,7 @@ config ARM
>         select GENERIC_ALLOCATOR
>         select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
>         select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> +       select GENERIC_CMDLINE
>         select GENERIC_IDLE_POLL_SETUP
>         select GENERIC_IRQ_PROBE
>         select GENERIC_IRQ_SHOW
> @@ -1949,43 +1950,6 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND
>
>  endchoice
>
> -config CMDLINE
> -       string "Default kernel command string"

Changing to the generic options will break existing configs. At least
any defconfigs should be updated to maintain behavior. Or figure out
how to do it without changing config names.

> -       default ""
> -       help
> -         On some architectures (EBSA110 and CATS), there is currently no way
> -         for the boot loader to pass arguments to the kernel. For these
> -         architectures, you should supply some command-line options at build
> -         time by entering them here. As a minimum, you should specify the
> -         memory size and the root device (e.g., mem=64M root=/dev/nfs).
> -
> -choice
> -       prompt "Kernel command line type" if CMDLINE != ""
> -       default CMDLINE_FROM_BOOTLOADER
> -       depends on ATAGS
> -
> -config CMDLINE_FROM_BOOTLOADER
> -       bool "Use bootloader kernel arguments if available"
> -       help
> -         Uses the command-line options passed by the boot loader. If
> -         the boot loader doesn't provide any, the default kernel command
> -         string provided in CMDLINE will be used.
> -
> -config CMDLINE_EXTEND
> -       bool "Extend bootloader kernel arguments"
> -       help
> -         The command-line arguments provided by the boot loader will be
> -         appended to the default kernel command string.
> -
> -config CMDLINE_FORCE
> -       bool "Always use the default kernel command string"
> -       help
> -         Always use the default kernel command string, even if the boot
> -         loader passes other arguments to the kernel.
> -         This is useful if you cannot or don't want to change the
> -         command-line options your boot loader passes to the kernel.
> -endchoice
> -
>  config XIP_KERNEL
>         bool "Kernel Execute-In-Place from ROM"
>         depends on !ARM_LPAE && !ARCH_MULTIPLATFORM
> diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
> index 68c6ae0..de2193e 100644
> --- a/arch/arm/kernel/atags_parse.c
> +++ b/arch/arm/kernel/atags_parse.c
> @@ -23,6 +23,7 @@
>  #include <linux/root_dev.h>
>  #include <linux/screen_info.h>
>  #include <linux/memblock.h>
> +#include <linux/cmdline.h>
>
>  #include <asm/setup.h>
>  #include <asm/system_info.h>
> @@ -31,7 +32,7 @@
>
>  #include "atags.h"
>
> -static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
> +static char default_command_line[COMMAND_LINE_SIZE] __initdata;

Can't this just be removed?

>
>  #ifndef MEM_SIZE
>  #define MEM_SIZE       (16*1024*1024)
> @@ -125,16 +126,9 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
>
>  static int __init parse_tag_cmdline(const struct tag *tag)
>  {
> -#if defined(CONFIG_CMDLINE_EXTEND)
> -       strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
>         strlcat(default_command_line, tag->u.cmdline.cmdline,
>                 COMMAND_LINE_SIZE);

Just do this here:

cmdline_add_builtin(boot_command_line, tag->u.cmdline.cmdline,
COMMAND_LINE_SIZE);

and remove everything from setup_machine_tags.

Also, I don't think there is any reason to have cmd_line and copy
boot_command_line to it in setup.c.

> -#elif defined(CONFIG_CMDLINE_FORCE)
> -       pr_warn("Ignoring tag cmdline (using the default kernel command line)\n");
> -#else
> -       strlcpy(default_command_line, tag->u.cmdline.cmdline,
> -               COMMAND_LINE_SIZE);
> -#endif
> +
>         return 0;
>  }
>
> @@ -232,7 +226,7 @@ setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr)
>         }
>
>         /* parse_early_param needs a boot_command_line */
> -       strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
> +       cmdline_add_builtin(boot_command_line, from, COMMAND_LINE_SIZE);
>
>         return mdesc;
>  }
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index 11c54de..d0277b5 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -19,6 +19,7 @@
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
>  #include <linux/smp.h>
> +#include <linux/cmdline.h>
>
>  #include <asm/cputype.h>
>  #include <asm/setup.h>
> @@ -242,6 +243,7 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
>                 mdesc->dt_fixup();
>
>         early_init_dt_scan_nodes();
> +       cmdline_add_builtin(boot_command_line, NULL, COMMAND_LINE_SIZE);
>
>         /* Change machine number to match the mdesc we're using */
>         __machine_arch_type = mdesc->nr;
> --
> 2.1.4
>
>
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