Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932334AbbELIKW (ORCPT ); Tue, 12 May 2015 04:10:22 -0400 Received: from mail-lb0-f180.google.com ([209.85.217.180]:32829 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932087AbbELIKQ (ORCPT ); Tue, 12 May 2015 04:10:16 -0400 From: Alexander Kuleshov To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Alexander Kuleshov , Andy Shevchenko , LKML , Greg Kroah-Hartman , Borislav Petkov , Mark Rustad , Yinghai Lu Subject: [PATCH v6 3/3] x86/earlyprintk: setup earlyprintk as early as possible Date: Tue, 12 May 2015 14:10:08 +0600 Message-Id: <1431418208-2274-1-git-send-email-kuleshovmail@gmail.com> X-Mailer: git-send-email 2.4.0 In-Reply-To: <1431418137-32320-1-git-send-email-kuleshovmail@gmail.com> References: <1431418137-32320-1-git-send-email-kuleshovmail@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3714 Lines: 109 The early_printk function is usable only after the setup_early_printk will be executed. We pass 'earlyprintk' through the kernel command line, so it will be usable only after the 'parse_early_param' will be executed. This means that we have usable earlyprintk only during early boot, kernel decompression and after call of the 'parse_early_param'. This patchset makes earlyprintk usable before the call of the 'parse_early_param'. This patch makes setup_early_printk visible for head{32,64}.c. So the 'early_printk' function will be usabable after decompression of the kernel and before parse_early_param will be called. It also must be safe if CONFIG_CMDLINE_BOOL and CONFIG_CMDLINE_OVERRIDE are set, because setup_cmdline function will be called before setup_early_printk. Tested it with qemu, so early_printk() is usable and prints to serial console right after setup_early_printk function called. Signed-off-by: Alexander Kuleshov --- arch/x86/include/asm/serial.h | 3 +++ arch/x86/kernel/early_printk.c | 25 +++++++++++++++++++++++++ arch/x86/kernel/head32.c | 5 +++++ arch/x86/kernel/head64.c | 5 +++++ 4 files changed, 38 insertions(+) diff --git a/arch/x86/include/asm/serial.h b/arch/x86/include/asm/serial.h index 8378b8c..198f041 100644 --- a/arch/x86/include/asm/serial.h +++ b/arch/x86/include/asm/serial.h @@ -26,4 +26,7 @@ { .uart = 0, BASE_BAUD, 0x3E8, 4, STD_COMX_FLAGS }, /* ttyS2 */ \ { .uart = 0, BASE_BAUD, 0x2E8, 3, STD_COM4_FLAGS }, /* ttyS3 */ +/* used by arch/x86/kernel/head{32,64}.c */ +int __init setup_early_serial_console(void); + #endif /* _ASM_X86_SERIAL_H */ diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 89427d8..96425c3 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -385,4 +385,29 @@ static int __init setup_early_printk(char *buf) return 0; } +int __init setup_early_serial_console(void) +{ +#ifdef CONFIG_EARLY_PRINTK + char *arg; + + /* + * make sure that we have: + * "serial,0x3f8,115200" + * "serial,ttyS0,115200" + * "ttyS0,115200" + */ + arg = strstr(boot_command_line, "earlyprintk=serial"); + if (!arg) + arg = strstr(boot_command_line, "earlyprintk=ttyS"); + if (!arg) + return -1; + + arg = strstr(boot_command_line, "earlyprintk="); + /* += strlen("earlyprintk"); */ + arg += 12; + + return setup_early_printk(arg); +#endif +} + early_param("earlyprintk", setup_early_printk); diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index 92e8b5f..d325d0c 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -32,6 +32,11 @@ static void __init i386_default_early_setup(void) asmlinkage __visible void __init i386_start_kernel(void) { setup_builtin_cmdline(); + setup_early_serial_console(); + + if (console_loglevel >= CONSOLE_LOGLEVEL_DEBUG) + early_printk("Kernel alive\n"); + cr4_init_shadow(); sanitize_boot_params(&boot_params); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 38da21c..06fcc1b 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -173,6 +173,11 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) copy_bootdata(__va(real_mode_data)); setup_builtin_cmdline(); + setup_early_serial_console(); + + if (console_loglevel >= CONSOLE_LOGLEVEL_DEBUG) + early_printk("Kernel alive\n"); + /* * Load microcode early on BSP. */ -- 2.4.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/