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SubjectRe: [PATCH v3] powerpc: Support CMDLINE_EXTEND
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Le 02/08/2019 à 00:50, Chris Packham a écrit :
> Bring powerpc in line with other architectures that support extending or
> overriding the bootloader provided command line.
>
> The current behaviour is most like CMDLINE_FROM_BOOTLOADER where the
> bootloader command line is preferred but the kernel config can provide a
> fallback so CMDLINE_FROM_BOOTLOADER is the default. CMDLINE_EXTEND can
> be used to append the CMDLINE from the kernel config to the one provided
> by the bootloader.
>
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>

Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>

> ---
> Changes in v3:
> - don't use BUG_ON in prom_strlcat
> - rearrange things to eliminate prom_strlcpy
>
> Changes in v2:
> - incorporate ideas from Christope's patch https://patchwork.ozlabs.org/patch/1074126/
> - support CMDLINE_FORCE
>
> arch/powerpc/Kconfig | 20 +++++++++++++++++-
> arch/powerpc/kernel/prom_init.c | 36 ++++++++++++++++++++++-----------
> 2 files changed, 43 insertions(+), 13 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 77f6ebf97113..d413fe1b4058 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -852,15 +852,33 @@ config CMDLINE
> some command-line options at build time by entering them here. In
> most cases you will need to specify the root device here.
>
> +choice
> + prompt "Kernel command line type" if CMDLINE != ""
> + default CMDLINE_FROM_BOOTLOADER
> +
> +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"
> - depends on CMDLINE_BOOL
> 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 EXTRA_TARGETS
> string "Additional default image types"
> help
> diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
> index 514707ef6779..1c7010cc6ec9 100644
> --- a/arch/powerpc/kernel/prom_init.c
> +++ b/arch/powerpc/kernel/prom_init.c
> @@ -298,16 +298,24 @@ static char __init *prom_strstr(const char *s1, const char *s2)
> return NULL;
> }
>
> -static size_t __init prom_strlcpy(char *dest, const char *src, size_t size)
> -{
> - size_t ret = prom_strlen(src);
> +static size_t __init prom_strlcat(char *dest, const char *src, size_t count)
> +{
> + size_t dsize = prom_strlen(dest);
> + size_t len = prom_strlen(src);
> + size_t res = dsize + len;
> +
> + /* This would be a bug */
> + if (dsize >= count)
> + return count;
> +
> + dest += dsize;
> + count -= dsize;
> + if (len >= count)
> + len = count-1;
> + memcpy(dest, src, len);
> + dest[len] = 0;
> + return res;
>
> - if (size) {
> - size_t len = (ret >= size) ? size - 1 : ret;
> - memcpy(dest, src, len);
> - dest[len] = '\0';
> - }
> - return ret;
> }
>
> #ifdef CONFIG_PPC_PSERIES
> @@ -759,10 +767,14 @@ static void __init early_cmdline_parse(void)
>
> prom_cmd_line[0] = 0;
> p = prom_cmd_line;
> - if ((long)prom.chosen > 0)
> +
> + if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && (long)prom.chosen > 0)
> l = prom_getprop(prom.chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
> - if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && (l <= 0 || p[0] == '\0')) /* dbl check */
> - prom_strlcpy(prom_cmd_line, CONFIG_CMDLINE, sizeof(prom_cmd_line));
> +
> + if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || l <= 0 || p[0] == '\0')
> + prom_strlcat(prom_cmd_line, " " CONFIG_CMDLINE,
> + sizeof(prom_cmd_line));
> +
> prom_printf("command line: %s\n", prom_cmd_line);
>
> #ifdef CONFIG_PPC64
>

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