From: Paul Burton <paul.burton@xxxxxxxx> Our current code to initialize boot_command_line is a mess. Some of this is due to the addition of too many options over the years, and some of this is due to workarounds for early_init_dt_scan_chosen() performing actions specific to options from other architectures that probably shouldn't be in generic code. Clean this up by introducing a new bootcmdline_init() function that simplifies the initialization somewhat. The major changes are: - Because bootcmdline_init() is a function it can return early in the CONFIG_CMDLINE_OVERRIDE case. - We clear boot_command_line rather than inheriting whatever early_init_dt_scan_chosen() may have left us. This means we no longer need to set boot_command_line to a space character in an attempt to prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into boot_command_line without us knowing about it. - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only to obfuscate the code. - The logic is cleaner, clearer & commented. Two minor drawbacks of this approach are: 1) We call of_scan_flat_dt(), which means we scan through the DT again. The overhead is fairly minimal & shouldn't be noticeable. 2) cmdline_scan_chosen() duplicates a small amount of the logic from early_init_dt_scan_chosen(). Alternatives might be to allow the generic FDT code to keep & expose a copy of the arguments taken from the /chosen node's bootargs property, or to introduce a function like early_init_dt_scan_chosen() that retrieves them without modification to handle CONFIG_CMDLINE. Neither of these sounds particularly cleaner though, and this way we at least keep the extra work in arch/mips. Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7784cac697351f0cc0a4bb619594c0c99348c5aa Signed-off-by: Paul Burton <paul.burton@xxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxxx --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -538,11 +538,88 @@ static void __init check_kernel_sections } } -#define USE_PROM_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER) -#define USE_DTB_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB) -#define EXTEND_WITH_PROM IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) -#define BUILTIN_EXTEND_WITH_PROM \ - IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND) +static void __init bootcmdline_append(const char *s, size_t max) +{ + if (!s[0] || !max) + return; + + if (boot_command_line[0]) + strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + + strlcat(boot_command_line, s, max); +} + +static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname, + int depth, void *data) +{ + bool *dt_bootargs = data; + const char *p; + int l; + + if (depth != 1 || !data || + (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0)) + return 0; + + p = of_get_flat_dt_prop(node, "bootargs", &l); + if (p != NULL && l > 0) { + bootcmdline_append(p, min(l, COMMAND_LINE_SIZE)); + *dt_bootargs = true; + } + + return 1; +} + +static void __init bootcmdline_init(char **cmdline_p) +{ + bool dt_bootargs = false; + + /* + * If CMDLINE_OVERRIDE is enabled then initializing the command line is + * trivial - we simply use the built-in command line unconditionally & + * unmodified. + */ + if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) { + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + return; + } + + /* + * If the user specified a built-in command line & + * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is + * prepended to arguments from the bootloader or DT so we'll copy them + * to the start of boot_command_line here. Otherwise, empty + * boot_command_line to undo anything early_init_dt_scan_chosen() did. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + else + boot_command_line[0] = 0; + + /* + * If we're configured to take boot arguments from DT, look for those + * now. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB)) + of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs); + + /* + * If we didn't get any arguments from DT (regardless of whether that's + * because we weren't configured to look for them, or because we looked + * & found none) then we'll take arguments from the bootloader. + * plat_mem_setup() should have filled arcs_cmdline with arguments from + * the bootloader. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs) + bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE); + + /* + * If the user specified a built-in command line & we didn't already + * prepend it, we append it to boot_command_line here. + */ + if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && + !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) + bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE); +} /* * arch_mem_init - initialize memory management subsystem @@ -570,48 +647,12 @@ static void __init arch_mem_init(char ** { extern void plat_mem_setup(void); - /* - * Initialize boot_command_line to an innocuous but non-empty string in - * order to prevent early_init_dt_scan_chosen() from copying - * CONFIG_CMDLINE into it without our knowledge. We handle - * CONFIG_CMDLINE ourselves below & don't want to duplicate its - * content because repeating arguments can be problematic. - */ - strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); - /* call board setup routine */ plat_mem_setup(); memblock_set_bottom_up(true); -#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])) - strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - - if (EXTEND_WITH_PROM && arcs_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - } - -#if defined(CONFIG_CMDLINE_BOOL) - if (builtin_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); - } - - if (BUILTIN_EXTEND_WITH_PROM && arcs_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - } -#endif -#endif + bootcmdline_init(cmdline_p); strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); - *cmdline_p = command_line; parse_early_param();
