+Frank (me)
On 8/5/19 8:53 AM, Daniel Gimpelevich wrote:
> Currently, "bootargs" supplied via the "chosen" node can be used only to
> supply a kernel command line as a whole. No mechanism exists in DT to add
> bootargs to the existing command line instead. This is needed in order to
> avoid having to update the bootloader or default bootloader config when
> upgrading to a DTB and kernel pair that requires bootargs not previously
> needed.
>
> One example use case is that OpenWrt currently supports four ARM devices by
> means of locally applying the previously rejected edition of this patch. So
> far, the patch has been used in production only on ARM, but architecture is
> not a distinction in the design.
>
> On MIPS, Commit 951d223 ("MIPS: Fix CONFIG_CMDLINE handling") currently
> prevents support of such a mechanism, so I am including a workaround, in
> anticipation of upcoming changes.
>
> Signed-off-by: Daniel Gimpelevich <daniel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> Fixes: 951d223 ("MIPS: Fix CONFIG_CMDLINE handling")
> References: https://patchwork.linux-mips.org/patch/17659/
> ---
> arch/mips/kernel/setup.c | 12 ++++++++----
> drivers/of/fdt.c | 9 +++++++--
> 2 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index ab349d2..9ce58f2 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -725,7 +725,10 @@ static void __init arch_mem_init(char **cmdline_p)
> * CONFIG_CMDLINE ourselves below & don't want to duplicate its
> * content because repeating arguments can be problematic.
> */
> - strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE);
> + if (USE_DTB_CMDLINE)
> + strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
> + else
> + strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE);
>
> /* call board setup routine */
> plat_mem_setup();
> @@ -753,9 +756,10 @@ static void __init arch_mem_init(char **cmdline_p)
> #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
> strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
> #else
> - if ((USE_PROM_CMDLINE && arcs_cmdline[0]) ||
> - (USE_DTB_CMDLINE && !boot_command_line[0]))
> + if (USE_PROM_CMDLINE)
> strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
> + else if (!strcmp(boot_command_line, " "))
> + boot_command_line[0] = '\0';
>
> if (EXTEND_WITH_PROM && arcs_cmdline[0]) {
> if (boot_command_line[0])
> @@ -764,7 +768,7 @@ static void __init arch_mem_init(char **cmdline_p)
> }
>
> #if defined(CONFIG_CMDLINE_BOOL)
> - if (builtin_cmdline[0]) {
> + if (builtin_cmdline[0] && strcmp(boot_command_line, builtin_cmdline)) {
> if (boot_command_line[0])
> strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
> strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 9cdf14b..08c25eb 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -1055,8 +1055,13 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>
> /* Retrieve command line */
> p = of_get_flat_dt_prop(node, "bootargs", &l);
> - if (p != NULL && l > 0)
> - strlcpy(data, p, min(l, COMMAND_LINE_SIZE));
> + if (p != NULL && l > 0) {
> + if (!of_get_flat_dt_prop(node, "merge-cmdline", NULL))
> + *(char *)data = '\0';
> + if (*(char *)data)
> + strlcat(data, " ", COMMAND_LINE_SIZE);
> + strlcat(data, p, min(l + strlen(data), COMMAND_LINE_SIZE));
> + }
>
> /*
> * CONFIG_CMDLINE is meant to be a default in case nothing else
>
