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Message-ID: <4CB35050.7060207@kernel.org>
Date: Mon, 11 Oct 2010 10:58:40 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH -v4] x86: Setup early console as early as possible in x86_start_kernel()
Analyze "console=uart8250,io,0x3f8,115200n8" in i386_start_kernel/x86_64_start_kernel,
and call setup_early_serial8250_console() to init early serial console.
Only can handle io port kind of 8250, because mmio need ioremap.
Use boot_params.hdr.version instead of adding another variable, Suggested by hpa.
Also need to apply this one after x86 memblock patchset.
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/setup.h | 2 ++
arch/x86/kernel/head.c | 26 ++++++++++++++++++++++++++
arch/x86/kernel/head32.c | 2 ++
arch/x86/kernel/head64.c | 13 ++++++++++++-
kernel/printk.c | 4 ++++
5 files changed, 46 insertions(+), 1 deletion(-)
Index: linux-2.6/arch/x86/include/asm/setup.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/setup.h
+++ linux-2.6/arch/x86/include/asm/setup.h
@@ -42,6 +42,8 @@ static inline void visws_early_detect(vo
#endif
extern unsigned long saved_video_mode;
+int setup_early_serial8250_console(char *cmdline);
+void setup_early_console(void);
extern void reserve_standard_io_resources(void);
extern void i386_reserve_resources(void);
Index: linux-2.6/arch/x86/kernel/head.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head.c
+++ linux-2.6/arch/x86/kernel/head.c
@@ -54,3 +54,29 @@ void __init reserve_ebda_region(void)
/* reserve all memory between lowmem and the 1MB mark */
memblock_x86_reserve_range(lowmem, 0x100000, "* BIOS reserved");
}
+
+void __init setup_early_console(void)
+{
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+ char constr[64], *p, *q;
+
+ /* Can not handle mmio type 8250 uart yet, too early */
+ p = strstr(boot_command_line, "console=uart8250,io,");
+ if (!p)
+ p = strstr(boot_command_line, "console=uart,io,");
+ if (!p)
+ return;
+
+ p += 8; /* sizeof "console=" */
+ q = strchr(p, ' ');
+ if ((q - p) >= sizeof(constr))
+ return;
+
+ memset(constr, 0, sizeof(constr));
+ memcpy(constr, p, q - p);
+
+ lockdep_init();
+
+ setup_early_serial8250_console(constr);
+#endif
+}
Index: linux-2.6/arch/x86/kernel/head32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head32.c
+++ linux-2.6/arch/x86/kernel/head32.c
@@ -31,6 +31,8 @@ static void __init i386_default_early_se
void __init i386_start_kernel(void)
{
+ setup_early_console();
+
memblock_init();
#ifdef CONFIG_X86_TRAMPOLINE
Index: linux-2.6/arch/x86/kernel/head64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head64.c
+++ linux-2.6/arch/x86/kernel/head64.c
@@ -74,6 +74,10 @@ void __init x86_64_start_kernel(char * r
/* clear bss before set_intr_gate with early_idt_handler */
clear_bss();
+ /* boot_params is in bss */
+ copy_bootdata(__va(real_mode_data));
+ setup_early_console();
+
/* Make NULL pointers segfault */
zap_identity_mappings();
@@ -97,7 +101,14 @@ void __init x86_64_start_kernel(char * r
void __init x86_64_start_reservations(char *real_mode_data)
{
- copy_bootdata(__va(real_mode_data));
+ /*
+ * hdr.version is always not 0, so check it to see
+ * if boot_params is copied or not.
+ */
+ if (!boot_params.hdr.version) {
+ copy_bootdata(__va(real_mode_data));
+ setup_early_console();
+ }
memblock_init();
Index: linux-2.6/kernel/printk.c
===================================================================
--- linux-2.6.orig/kernel/printk.c
+++ linux-2.6/kernel/printk.c
@@ -1232,6 +1232,10 @@ void register_console(struct console *ne
if (console_drivers && newcon->flags & CON_BOOT) {
/* find the last or real console */
for_each_console(bcon) {
+ /* not again */
+ if (bcon == newcon)
+ return;
+
if (!(bcon->flags & CON_BOOT)) {
printk(KERN_INFO "Too late to register bootconsole %s%d\n",
newcon->name, newcon->index);
--
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