With CONFIG_SYSTEMD_OF_WATCHDOG, the device tree bootargs fixup puts systemd.watchdog_device= into global.linux.bootargs.dyn.watchdog only to read it back right away via linux_bootargs_get(). This has side effects beyond the fixup:
- The variable is created whenever the fixup runs, so also for of_dump -F, oftree -s or of_diff after a boot attempt has enabled the watchdog, and stays around afterwards. - Its mere existence makes linux_bootargs_get() ignore the legacy bootargs environment variable, which is only used when no global.linux.bootargs.* variables exist. Return the option from watchdog_build_bootargs() and append it to the bootargs in of_write_bootargs() instead. Note this moves the option to the end of the command line, while it was previously sorted among the global.linux.bootargs.* variables. Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Sascha Hauer <[email protected]> --- Documentation/user/booting-linux.rst | 2 ++ common/Kconfig | 6 +++--- common/oftree.c | 41 ++++++++++++++++++++---------------- 3 files changed, 28 insertions(+), 21 deletions(-) diff --git a/Documentation/user/booting-linux.rst b/Documentation/user/booting-linux.rst index 0fbdc52c68..158aa8b313 100644 --- a/Documentation/user/booting-linux.rst +++ b/Documentation/user/booting-linux.rst @@ -124,6 +124,8 @@ interleaved with externally provided command-line arguments: * ``systemd.machine_id=`` controlled by :ref:`global.bootm.provide_machine_id <magicvar_global_bootm_provide_machine_id>` * ``systemd.hostname=`` controlled by :ref:`global.bootm.provide_hostname <magicvar_global_bootm_provide_hostname>` * ``barebox.security.policy=`` controlled by :ref:`global.bootm.provide_policy <magicvar_global_bootm_provide_policy>` + * ``systemd.watchdog_device=`` controlled by ``CONFIG_SYSTEMD_OF_WATCHDOG``, + only when booting with a device tree Creating root= options for the Kernel ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/common/Kconfig b/common/Kconfig index 9adecfd2e4..da4cc8a5c9 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -1443,9 +1443,9 @@ config SYSTEMD_OF_WATCHDOG bool "inform devicetree-enabled kernel of used watchdog" depends on WATCHDOG && OFTREE && FLEXIBLE_BOOTARGS help - Sets the linux.bootargs.dyn.watchdog global variable with a value of - systemd.watchdog_device=/dev/WDOG if barebox succeeded in enabling - the watchdog WDOG prior to boot. WDOG is the alias of the watchdog + Appends systemd.watchdog_device=/dev/WDOG to the Kernel command line + in the device tree if barebox succeeded in enabling the watchdog + WDOG prior to boot. WDOG is the alias of the watchdog in the kernel device tree. If the kernel is booted without a device tree or with one that lacks aliases, nothing is added. diff --git a/common/oftree.c b/common/oftree.c index 7aaed70e40..5f9b2e50cb 100644 --- a/common/oftree.c +++ b/common/oftree.c @@ -160,22 +160,18 @@ static int of_fixup_bootargs_reset_source(struct device_node *root, return of_property_write_string(chosen, "reset-source-device", np->full_name); } -static void watchdog_build_bootargs(struct watchdog *watchdog, struct device_node *root) +static char *watchdog_build_bootargs(struct watchdog *watchdog, struct device_node *root) { int alias_id; - char *buf; if (!watchdog) - return; + return NULL; alias_id = watchdog_get_alias_id_from(watchdog, root); if (alias_id < 0) - return; - - buf = xasprintf("systemd.watchdog_device=/dev/watchdog%d", alias_id); + return NULL; - globalvar_add_simple("linux.bootargs.dyn.watchdog", buf); - free(buf); + return xasprintf("systemd.watchdog_device=/dev/watchdog%d", alias_id); } static int bootargs_append = 0; @@ -183,31 +179,40 @@ BAREBOX_MAGICVAR(global.linux.bootargs_append, "append to original oftree bootar static int of_write_bootargs(struct device_node *node) { - const char *str; + const char *str, *oldstr; + char *watchdog = NULL; char *buf = NULL; int ret; if (IS_ENABLED(CONFIG_SYSTEMD_OF_WATCHDOG)) - watchdog_build_bootargs(boot_get_enabled_watchdog(), of_get_parent(node)); + watchdog = watchdog_build_bootargs(boot_get_enabled_watchdog(), + of_get_parent(node)); - str = linux_bootargs_get(); - if (!str) - return 0; + str = skip_spaces(linux_bootargs_get() ?: ""); + + if (watchdog) { + if (*str) + str = buf = xasprintf("%s %s", str, watchdog); + else + str = watchdog; + } - str = skip_spaces(str); if (strlen(str) == 0) return 0; if (bootargs_append) { - const char *oldstr; - ret = of_property_read_string(node, "bootargs", &oldstr); - if (!ret) - str = buf = xasprintf("%s %s", oldstr, str); + if (!ret) { + char *tmp = xasprintf("%s %s", oldstr, str); + + free(buf); + str = buf = tmp; + } } ret = of_property_write_string(node, "bootargs", str); free(buf); + free(watchdog); return ret; } -- 2.47.3
