From: Yinghai Lu <yinghai@kernel.org>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jiri Slaby <jslaby@suse.cz>, Rob Herring <robh@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>
Subject: Re: [PATCH v3 -next 11/11] serial: 8250_early: Remove setup_early_serial8250_console()
Date: Thu, 2 Apr 2015 02:15:09 -0700 [thread overview]
Message-ID: <CAE9FiQVKY9KLeBOB0shqTPZZipsmAiU=3_8gzfFhsCW9kxo_uA@mail.gmail.com> (raw)
In-Reply-To: <551CB5DF.1010108@hurleysoftware.com>
[-- Attachment #1: Type: text/plain, Size: 536 bytes --]
On Wed, Apr 1, 2015 at 8:22 PM, Peter Hurley <peter@hurleysoftware.com> wrote:
> The documented behavior of console=ttyS options, to which your
> quote refers, clearly states:
>
> Default is "9600n8".
drivers/tty/serial/8250/8250_early.c:early_serial8250_setup
still have calling to probe_baud, but it is not triggered.
Here is root cause.
The gap between entries in earlycon_table cause
iteration fail to find next entry, so uart8250 handler is
not called proplerly.
attached patch fix the problem.
Thanks
Yinghai
[-- Attachment #2: fix_earlycon_alignment.patch --]
[-- Type: text/x-patch, Size: 4743 bytes --]
Subject: [PATCH] serial: Fix earlycon section iteration
Found when booting with console=uart8250,io,0x3f8
the kernel will revert baud rate to 9600 instead of keeping 115200.
root causes: The gap between entries in earlycon_table cause
iteration fail to find next entry, so uart8250 handler is
not called proplerly.
commit d2fd6810a823 ("tty/serial: convert 8250 to generic earlycon")
add two entries into earlycon_table.
EARLYCON_DECLARE(uart8250, early_serial8250_setup);
EARLYCON_DECLARE(uart, early_serial8250_setup);
and according to System.map, earlycon_uart is before earlycon_uart8250.
ffffffff832049a0 t __earlycon_uart
ffffffff832049c0 t __earlycon_uart8250
And offset between two entries is 0x20.
commit 470ca0de69fe ("serial: earlycon: Enable earlycon without command line param")
setup_earlycon() will loop __earlycon_table with pointer to earlycon_id,
for (match = __earlycon_table; match->name[0]; match++) {
size_t len = strlen(match->name);
if (strncmp(buf, match->name, len))
continue;
but match size (size of struct earlycon_id) is only 0x18. so will point to
wrong place for next match and will get random result.
Make the earlycon_table section have pointer to earlycon_id struct instead.
Fixes: commit 470ca0de69fe ("serial: earlycon: Enable earlycon without command line param")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
drivers/tty/serial/earlycon.c | 13 +++++++------
include/asm-generic/vmlinux.lds.h | 8 ++++----
include/linux/serial_core.h | 8 +++++---
3 files changed, 16 insertions(+), 13 deletions(-)
Index: linux-2.6/include/linux/serial_core.h
===================================================================
--- linux-2.6.orig/include/linux/serial_core.h
+++ linux-2.6/include/linux/serial_core.h
@@ -349,10 +349,12 @@ extern int of_setup_earlycon(unsigned lo
int (*setup)(struct earlycon_device *, const char *));
#define EARLYCON_DECLARE(_name, func) \
- static const struct earlycon_id __earlycon_##_name \
- __used __section(__earlycon_table) \
+ static struct earlycon_id __earlycon_##_name __initdata \
= { .name = __stringify(_name), \
- .setup = func }
+ .setup = func }; \
+ static struct earlycon_id *__p_earlycon_##_name __used \
+ __aligned(sizeof(struct earlycon_id *)) \
+ __section(__earlycon_table) = { &__earlycon_##_name }
#define OF_EARLYCON_DECLARE(name, compat, fn) \
_OF_DECLARE(earlycon, name, compat, fn, void *)
Index: linux-2.6/drivers/tty/serial/earlycon.c
===================================================================
--- linux-2.6.orig/drivers/tty/serial/earlycon.c
+++ linux-2.6/drivers/tty/serial/earlycon.c
@@ -37,9 +37,8 @@ static struct earlycon_device early_cons
.con = &early_con,
};
-extern struct earlycon_id __earlycon_table[];
-static const struct earlycon_id __earlycon_table_sentinel
- __used __section(__earlycon_table_end);
+extern struct earlycon_id *__start_earlycon_table[];
+extern struct earlycon_id *__stop_earlycon_table[];
static const struct of_device_id __earlycon_of_table_sentinel
__used __section(__earlycon_of_table_end);
@@ -103,7 +102,7 @@ static int __init parse_options(struct e
return 0;
}
-static int __init register_earlycon(char *buf, const struct earlycon_id *match)
+static int __init register_earlycon(char *buf, struct earlycon_id *match)
{
int err;
struct uart_port *port = &early_console_dev.port;
@@ -147,7 +146,7 @@ static int __init register_earlycon(char
*/
int __init setup_earlycon(char *buf)
{
- const struct earlycon_id *match;
+ struct earlycon_id **pmatch;
if (!buf || !buf[0])
return -EINVAL;
@@ -155,7 +154,9 @@ int __init setup_earlycon(char *buf)
if (early_con.flags & CON_ENABLED)
return -EALREADY;
- for (match = __earlycon_table; match->name[0]; match++) {
+ for (pmatch = __start_earlycon_table; pmatch < __stop_earlycon_table;
+ pmatch++) {
+ struct earlycon_id *match = *pmatch;
size_t len = strlen(match->name);
if (strncmp(buf, match->name, len))
Index: linux-2.6/include/asm-generic/vmlinux.lds.h
===================================================================
--- linux-2.6.orig/include/asm-generic/vmlinux.lds.h
+++ linux-2.6/include/asm-generic/vmlinux.lds.h
@@ -151,10 +151,10 @@
#endif
#ifdef CONFIG_SERIAL_EARLYCON
-#define EARLYCON_TABLE() . = ALIGN(8); \
- VMLINUX_SYMBOL(__earlycon_table) = .; \
- *(__earlycon_table) \
- *(__earlycon_table_end)
+#define EARLYCON_TABLE() . = ALIGN(8); \
+ VMLINUX_SYMBOL(__start_earlycon_table) = .; \
+ *(__earlycon_table) \
+ VMLINUX_SYMBOL(__stop_earlycon_table) = .;
#else
#define EARLYCON_TABLE()
#endif
next prev parent reply other threads:[~2015-04-02 9:15 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-09 20:27 [PATCH v3 -next 00/11] Extensible console matching & direct earlycon Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 01/11] console: Add extensible console matching Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 02/11] serial: core: Fix kernel doc for uart_console_write() Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 03/11] serial: 8250_early: Remove early_device variable Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 04/11] serial: earlycon: Move ->uartclk initialize Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 05/11] serial: 8250_early: Assume uart already initialized if no baud option Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 06/11] serial: 8250_early: Fix setup() error code Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 07/11] serial: earlycon: Ignore parse_options() " Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 08/11] serial: earlycon: Skip parse_options() if empty string Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 09/11] serial: earlycon: Refactor earlycon registration Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 10/11] serial: earlycon: Enable earlycon without command line param Peter Hurley
2015-03-09 20:27 ` [PATCH v3 -next 11/11] serial: 8250_early: Remove setup_early_serial8250_console() Peter Hurley
2015-04-02 2:04 ` Yinghai Lu
2015-04-02 3:22 ` Peter Hurley
2015-04-02 9:15 ` Yinghai Lu [this message]
2015-04-02 16:31 ` Peter Hurley
2015-04-02 17:23 ` Yinghai Lu
2015-04-02 22:12 ` Yinghai Lu
2015-04-02 22:36 ` Yinghai Lu
2015-04-03 0:02 ` Yinghai Lu
2015-04-03 0:22 ` Yinghai Lu
2015-04-03 2:38 ` Yinghai Lu
2015-04-03 10:37 ` Peter Hurley
2015-04-03 16:57 ` Yinghai Lu
2015-04-03 17:38 ` Peter Hurley
2015-04-03 17:44 ` Yinghai Lu
2015-04-03 18:27 ` Peter Hurley
2015-04-03 19:00 ` Greg Kroah-Hartman
2015-04-03 23:03 ` [PATCH] earlycon: 8250: Fix command line regression Peter Hurley
2015-04-04 0:04 ` [PATCH v2] " Peter Hurley
2015-04-04 2:19 ` Yinghai Lu
2015-04-04 2:29 ` Peter Hurley
2015-04-04 2:50 ` Peter Hurley
2015-04-04 3:00 ` Yinghai Lu
2015-04-04 2:56 ` Yinghai Lu
2015-04-04 3:09 ` Peter Hurley
2015-04-04 3:28 ` Yinghai Lu
2015-04-04 3:09 ` Yinghai Lu
2015-04-04 3:15 ` Peter Hurley
2015-04-04 3:24 ` Yinghai Lu
2015-04-04 3:31 ` Yinghai Lu
2015-04-04 3:32 ` Peter Hurley
2015-04-04 3:37 ` Yinghai Lu
2015-04-04 3:41 ` Peter Hurley
2015-04-04 6:05 ` Yinghai Lu
2015-04-04 14:27 ` [PATCH v3] " Peter Hurley
2015-04-04 16:09 ` Greg Kroah-Hartman
2015-04-04 16:23 ` Peter Hurley
2015-04-04 16:52 ` Greg Kroah-Hartman
2015-04-04 17:08 ` Peter Hurley
2015-04-04 17:19 ` [PATCH v4] " Peter Hurley
2015-04-04 17:24 ` Peter Hurley
2015-04-04 17:41 ` Greg Kroah-Hartman
2015-04-05 7:09 ` Yinghai Lu
2015-04-05 13:06 ` Peter Hurley
2015-04-05 20:14 ` Yinghai Lu
2015-04-05 14:52 ` [PATCH v5] " Peter Hurley
2015-04-05 20:02 ` Yinghai Lu
2015-04-06 14:48 ` [PATCH v6] " Peter Hurley
2015-04-04 0:52 ` [PATCH v3 -next 11/11] serial: 8250_early: Remove setup_early_serial8250_console() Yinghai Lu
2015-04-04 1:16 ` Peter Hurley
2015-04-04 0:58 ` Yinghai Lu
2015-03-26 17:13 ` [PATCH v3 -next 00/11] Extensible console matching & direct earlycon Greg Kroah-Hartman
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