Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933014AbbFILMV (ORCPT ); Tue, 9 Jun 2015 07:12:21 -0400 Received: from mail-lb0-f180.google.com ([209.85.217.180]:35893 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932680AbbFILLy (ORCPT ); Tue, 9 Jun 2015 07:11:54 -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 v11 4/5] x86/earlyprintk: setup earlyprintk as early as possible Date: Tue, 9 Jun 2015 17:11:41 +0600 Message-Id: <1433848301-5296-1-git-send-email-kuleshovmail@gmail.com> X-Mailer: git-send-email 2.4.0.GIT In-Reply-To: <1433848247-3550-1-git-send-email-kuleshovmail@gmail.com> References: <1433848247-3550-1-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: 4818 Lines: 140 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 the 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. It provides earlyprintk only for serial console, because other needs in ioremap which is not initialized yet. Tested it with qemu and real hardware, 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/setup.h | 6 ++++++ arch/x86/kernel/early_printk.c | 33 ++++++++++++++++++++++++++++++--- arch/x86/kernel/head32.c | 3 +++ arch/x86/kernel/head64.c | 5 ++++- 4 files changed, 43 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index 59efd0d..180bda4 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -120,0 +120,0 @@ asmlinkage void __init x86_64_start_reservations(char *real_mode_data); #endif /* __i386__ */ void __init setup_builtin_cmdline(void); +#ifdef CONFIG_EARLY_PRINTK +/* used by arch/x86/kernel/head{32,64}.c */ +extern int __init setup_early_serial_console(void); +#else +static inline int __init setup_early_serial_console(void) { return 0; } +#endif /* CONFIG_EARLY_PRINTK */ #endif /* _SETUP */ #else #define RESERVE_BRK(name,sz) \ diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 89427d8..6442cd2 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -342,19 +342,22 @@ static int __init setup_early_printk(char *buf) keep = (strstr(buf, "keep") != NULL); while (*buf != '\0') { - if (!strncmp(buf, "serial", 6)) { + if (!strncmp(buf, "serial", 6) && + early_serial_console.index == -1) { buf += 6; early_serial_init(buf); early_console_register(&early_serial_console, keep); if (!strncmp(buf, ",ttyS", 5)) buf += 5; } - if (!strncmp(buf, "ttyS", 4)) { + if (!strncmp(buf, "ttyS", 4) && + early_serial_console.index == -1) { early_serial_init(buf + 4); early_console_register(&early_serial_console, keep); } #ifdef CONFIG_PCI - if (!strncmp(buf, "pciserial", 9)) { + if (!strncmp(buf, "pciserial", 9) && + early_serial_console.index == -1) { early_pci_serial_init(buf + 9); early_console_register(&early_serial_console, keep); buf += 9; /* Keep from match the above "serial" */ @@ -385,4 +388,28 @@ static int __init setup_early_printk(char *buf) return 0; } +int __init setup_early_serial_console(void) +{ + 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); +} + early_param("earlyprintk", setup_early_printk); diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index f28d10f..908ee47 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -38,0 +38,0 @@ asmlinkage __visible void __init i386_start_kernel(void) /* Allocate early log buffer */ setup_log_buf(1); + setup_early_serial_console(); + early_printk("Early printk is initialized\n"); + cr4_init_shadow(); sanitize_boot_params(&boot_params); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 53662d2..041be2c 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -176,0 +176,0 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) /* Allocate early log buffer */ setup_log_buf(1); + setup_early_serial_console(); + early_printk("Early printk is initialized\n"); + /* * Load microcode early on BSP. */ -- 2.4.0.GIT -- 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/