linux-kernel - [PATCH 2/2] x86/earlyprintk: setup earlyprintk as possible

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Message-Id: <1428404578-17480-1-git-send-email-kuleshovmail@gmail.com>
Date:	Tue,  7 Apr 2015 17:02:58 +0600
From:	Alexander Kuleshov <kuleshovmail@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Alexander Kuleshov <kuleshovmail@...il.com>
Subject: [PATCH 2/2] x86/earlyprintk: setup earlyprintk as possible

As setup_early_printk passed to the early_param, it will be usable only after
'parse_early_param' function will be called from the 'setup_arch'. So we have
earlyprintk during early boot and decompression. Next point after decompression
of the kernel where we can use early_printk is after call of the
'parse_early_param'.

This patch removes 'earlyprintk' from the early_param and setup it right after
boot data copying. So 'early_printk' function will be usabable after
decompression of kernel and before parse_early_param will be called.

Kernel with this patch was tested with qemu-i386. early_printk function works
after early_printk initialization.

Signed-off-by: Alexander Kuleshov <kuleshovmail@...il.com>
---
 arch/x86/kernel/head32.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 2911ef3..dd0aadc 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -34,6 +34,9 @@ asmlinkage __visible void __init i386_start_kernel(void)
 	cr4_init_shadow();
 	sanitize_boot_params(&boot_params);

+	/* setup earlyprintk as early as possible */
+	setup_early_printk(boot_command_line);
+
 	/* Call the subarch specific early setup function */
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_INTEL_MID:
-- 
2.3.3.611.g09038fc.dirty

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