[PATCH 6/7] earlyprintk,vga,kdb: Fix \b and \r for earlyprintk=vga with kdb

From: Jason Wessel
Date: Tue May 18 2010 - 21:41:54 EST


Allow kdb to work properly with with earlyprintk=vga by interpreting
the backspace and carriage return output characters. These
interpretation of these characters is used for simple line editing
provided in the kdb shell.

CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: H. Peter Anvin <hpa@xxxxxxxxx>
CC: x86@xxxxxxxxxx
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
arch/x86/kernel/early_printk.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index b9c830c..fa99bae 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -41,6 +41,14 @@ static void early_vga_write(struct console *con, const char *str, unsigned n)
writew(0x720, VGABASE + 2*(max_xpos*j + i));
current_ypos = max_ypos-1;
}
+#ifdef CONFIG_KGDB_KDB
+ if (c == '\b') {
+ if (current_xpos > 0)
+ current_xpos--;
+ } else if (c == '\r') {
+ current_xpos = 0;
+ } else
+#endif
if (c == '\n') {
current_xpos = 0;
current_ypos++;
--
1.6.3.3

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