x86, setup: Fix earlyprintk=serial,0x3f8,115200

earlyprintk can take and I/O port, so we need to handle this case in
the setup code too, otherwise 0x3f8 will be treated as a baud rate.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C7B05A6.4010801@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/x86/boot/early_serial_console.c b/arch/x86/boot/early_serial_console.c
index 407a8e26f0a7..5df2869c874b 100644
--- a/arch/x86/boot/early_serial_console.c
+++ b/arch/x86/boot/early_serial_console.c
@@ -58,7 +58,19 @@ static void parse_earlyprintk(void)
                 if (arg[pos] == ',')
                         pos++;
 
-                if (!strncmp(arg + pos, "ttyS", 4)) {
+                /*
+                 * make sure we have
+                 *      "serial,0x3f8,115200"
+                 *      "serial,ttyS0,115200"
+                 *      "ttyS0,115200"
+                 */
+                if (pos == 7 && !strncmp(arg + pos, "0x", 2)) {
+                        port = simple_strtoull(arg + pos, &e, 16);
+                        if (port == 0 || arg + pos == e)
+                                port = DEFAULT_SERIAL_PORT;
+                        else
+                                pos = e - arg;
+                } else if (!strncmp(arg + pos, "ttyS", 4)) {
                         static const int bases[] = { 0x3f8, 0x2f8 };
                         int idx = 0;