From: Gerd Hoffmann Date: Tue, 8 May 2007 07:26:49 +0000 (-0700) Subject: Fixes and cleanups for earlyprintk aka boot console X-Git-Tag: v2.6.22-rc1~728 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69331af79cf29e26d1231152a172a1a10c2df511;p=linux-2.6 Fixes and cleanups for earlyprintk aka boot console The console subsystem already has an idea of a boot console, using the CON_BOOT flag. The implementation has some flaws though. The major problem is that presence of a boot console makes register_console() ignore any other console devices (unless explicitly specified on the kernel command line). This patch fixes the console selection code to *not* consider a boot console a full-featured one, so the first non-boot console registering will become the default console instead. This way the unregister call for the boot console in the register_console() function actually triggers and the handover from the boot console to the real console device works smoothly. Added a printk for the handover, so you know which console device the output goes to when the boot console stops printing messages. The disable_early_printk() call is obsolete with that patch, explicitly disabling the early console isn't needed any more as it works automagically with that patch. I've walked through the tree, dropped all disable_early_printk() instances found below arch/ and tagged the consoles with CON_BOOT if needed. The code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf). Changes to last version: Rediffed against -rc3, adapted to mips cleanups by Ralf, fixed "udbg-immortal" cmd line arg on powerpc. Signed-off-by: Gerd Hoffmann Acked-by: Paul Mundt Acked-by: Ralf Baechle Cc: Andi Kleen Cc: Alan Cox Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Jeremy Fitzhardinge Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index d352c2b05f..915f26345c 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -744,15 +744,6 @@ setup_arch(char **cmdline_p) paging_init(); } -void __init -disable_early_printk(void) -{ - if (alpha_using_srm && srmcons_output) { - unregister_srm_console(); - srmcons_output = 0; - } -} - static char sys_unknown[] = "Unknown"; static char systype_names[][16] = { "0", diff --git a/arch/alpha/kernel/srmcons.c b/arch/alpha/kernel/srmcons.c index 85a821aace..930cedc8be 100644 --- a/arch/alpha/kernel/srmcons.c +++ b/arch/alpha/kernel/srmcons.c @@ -300,7 +300,7 @@ static struct console srmcons = { .write = srm_console_write, .device = srm_console_device, .setup = srm_console_setup, - .flags = CON_PRINTBUFFER, + .flags = CON_PRINTBUFFER | CON_BOOT, .index = -1, }; diff --git a/arch/mips/kernel/early_printk.c b/arch/mips/kernel/early_printk.c index 304efdc568..4fa54b230c 100644 --- a/arch/mips/kernel/early_printk.c +++ b/arch/mips/kernel/early_printk.c @@ -33,8 +33,3 @@ void __init setup_early_printk(void) { register_console(&early_console); } - -void __init disable_early_printk(void) -{ - unregister_console(&early_console); -} diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c index 7e0971868f..147a2d83de 100644 --- a/arch/powerpc/kernel/udbg.c +++ b/arch/powerpc/kernel/udbg.c @@ -142,29 +142,22 @@ static void udbg_console_write(struct console *con, const char *s, static struct console udbg_console = { .name = "udbg", .write = udbg_console_write, - .flags = CON_PRINTBUFFER | CON_ENABLED, + .flags = CON_PRINTBUFFER | CON_ENABLED | CON_BOOT, .index = -1, }; static int early_console_initialized; -void __init disable_early_printk(void) -{ - if (!early_console_initialized) - return; - if (strstr(boot_command_line, "udbg-immortal")) { - printk(KERN_INFO "early console immortal !\n"); - return; - } - unregister_console(&udbg_console); - early_console_initialized = 0; -} - /* called by setup_system */ void register_early_udbg_console(void) { if (early_console_initialized) return; + + if (strstr(boot_command_line, "udbg-immortal")) { + printk(KERN_INFO "early console immortal !\n"); + udbg_console.flags &= ~CON_BOOT; + } early_console_initialized = 1; register_console(&udbg_console); } diff --git a/arch/sh/kernel/early_printk.c b/arch/sh/kernel/early_printk.c index 9048c0326d..9833493d88 100644 --- a/arch/sh/kernel/early_printk.c +++ b/arch/sh/kernel/early_printk.c @@ -192,20 +192,14 @@ int __init setup_early_printk(char *buf) } #endif - if (likely(early_console)) + if (likely(early_console)) { + if (keep_early) + early_console->flags &= ~CON_BOOT; + else + early_console->flags |= CON_BOOT; register_console(early_console); + } return 0; } early_param("earlyprintk", setup_early_printk); - -void __init disable_early_printk(void) -{ - if (!early_console_initialized || !early_console) - return; - if (!keep_early) { - printk("disabling early console\n"); - unregister_console(early_console); - } else - printk("keeping early console\n"); -} diff --git a/arch/sh64/kernel/early_printk.c b/arch/sh64/kernel/early_printk.c index 8c8a76e180..4f91311236 100644 --- a/arch/sh64/kernel/early_printk.c +++ b/arch/sh64/kernel/early_printk.c @@ -79,7 +79,7 @@ static struct console sh_console = { .name = "scifcon", .write = sh_console_write, .setup = sh_console_setup, - .flags = CON_PRINTBUFFER, + .flags = CON_PRINTBUFFER | CON_BOOT, .index = -1, }; @@ -97,9 +97,3 @@ void __init enable_early_printk(void) register_console(&sh_console); } - -void disable_early_printk(void) -{ - unregister_console(&sh_console); -} - diff --git a/arch/x86_64/kernel/early_printk.c b/arch/x86_64/kernel/early_printk.c index 92213d2b7c..56eaa25978 100644 --- a/arch/x86_64/kernel/early_printk.c +++ b/arch/x86_64/kernel/early_printk.c @@ -243,22 +243,12 @@ static int __init setup_early_printk(char *buf) early_console = &simnow_console; keep_early = 1; } + + if (keep_early) + early_console->flags &= ~CON_BOOT; + else + early_console->flags |= CON_BOOT; register_console(early_console); return 0; } - early_param("earlyprintk", setup_early_printk); - -void __init disable_early_printk(void) -{ - if (!early_console_initialized || !early_console) - return; - if (!keep_early) { - printk("disabling early console\n"); - unregister_console(early_console); - early_console_initialized = 0; - } else { - printk("keeping early console\n"); - } -} - diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 389da364e6..730cbd209a 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -141,8 +141,6 @@ static DECLARE_MUTEX(allocated_ptys_lock); static int ptmx_open(struct inode *, struct file *); #endif -extern void disable_early_printk(void); - static void initialize_tty_struct(struct tty_struct *tty); static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); @@ -3897,9 +3895,6 @@ void __init console_init(void) * set up the console device so that later boot sequences can * inform about problems etc.. */ -#ifdef CONFIG_EARLY_PRINTK - disable_early_printk(); -#endif call = __con_initcall_start; while (call < __con_initcall_end) { (*call)(); diff --git a/kernel/printk.c b/kernel/printk.c index 4b47e59248..c4c5a29a7b 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -931,8 +931,16 @@ void register_console(struct console *console) { int i; unsigned long flags; + struct console *bootconsole = NULL; - if (preferred_console < 0) + if (console_drivers) { + if (console->flags & CON_BOOT) + return; + if (console_drivers->flags & CON_BOOT) + bootconsole = console_drivers; + } + + if (preferred_console < 0 || bootconsole || !console_drivers) preferred_console = selected_console; /* @@ -978,8 +986,11 @@ void register_console(struct console *console) if (!(console->flags & CON_ENABLED)) return; - if (console_drivers && (console_drivers->flags & CON_BOOT)) { - unregister_console(console_drivers); + if (bootconsole) { + printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n", + bootconsole->name, bootconsole->index, + console->name, console->index); + unregister_console(bootconsole); console->flags &= ~CON_PRINTBUFFER; } @@ -1030,16 +1041,11 @@ int unregister_console(struct console *console) } } - /* If last console is removed, we re-enable picking the first - * one that gets registered. Without that, pmac early boot console - * would prevent fbcon from taking over. - * + /* * If this isn't the last console and it has CON_CONSDEV set, we * need to set it on the next preferred console. */ - if (console_drivers == NULL) - preferred_console = selected_console; - else if (console->flags & CON_CONSDEV) + if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; release_console_sem();