Hello,
On Tue, 21 Jan 2014, Heiko Carstens wrote:
> On Tue, Jan 21, 2014 at 12:22:52PM +0100, Heiko Carstens wrote:
> > On Tue, Jan 21, 2014 at 04:57:39AM -0500, Mike Frysinger wrote:
> > > hmm, doesn't seem to work for me. don't get a crash, just a "virtual machine
> > > is placed in CP mode due to a SIGP initial C". whatever that means :).
> >
> > Ah, that probably happened because the kernel failed to mount the
> > root file system and killed all CPUs before printing a nice error message.
>
> Ok, that's not correct. Just bisected it down to:
>
> commit 14556b33f2a5d6a3bc75cd33b709452a31555b25
> Author: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
> Date: Sat Apr 13 13:03:54 2013 +0200
>
> s390/css: introduce cio_register_early_subchannels
>
> Use cio_register_early_subchannels to register early subchannels
> which are already in use. Call this function before we do the
> actual subchannel scanning loop. This helps us to get rid of some
> more special cases regarding the console subchannel.
>
> Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
>
> For some non-obvious reason this kills 31 bit with your config under z/VM.
>
The patch to address this is scheduled for upstream inclusion. Thanks to
both of you for reporting/debugging this!
Regards,
Sebastian
>From 6aa85cf65ac1016a75cd94ef4c70c8ad6d109d60 Mon Sep 17 00:00:00 2001
From: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Date: Mon, 27 Jan 2014 13:26:10 +0100
Subject: [PATCH] s390/cio: fix driver callback initialization for ccw consoles
ccw consoles are in use before they can be properly registered with
the driver core. For devices which are in use by a device driver we
rely on the ccw_device's pointer to the driver callbacks to be valid.
For ccw consoles this pointer is NULL until they are registered later
during boot and we dereferenced this pointer. This worked by
chance on 64 bit builds (cdev->drv was NULL but the optional callback
cdev->drv->path_event was also NULL by coincidence) and was unnoticed
until we received reports about boot failures on 31 bit systems.
Fix it by initializing the driver pointer for ccw consoles.
Cc: <stable@xxxxxxxxxxxxxxx> # 3.10+
Reported-by: Mike Frysinger <vapier@xxxxxxxxxx>
Reported-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/ccwdev.h | 2 +-
drivers/s390/char/con3215.c | 2 +-
drivers/s390/char/con3270.c | 6 +-----
drivers/s390/char/raw3270.c | 10 +++++++++-
drivers/s390/char/raw3270.h | 2 +-
drivers/s390/cio/device.c | 3 ++-
6 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/s390/include/asm/ccwdev.h b/arch/s390/include/asm/ccwdev.h
index f201af8..31b5ca8 100644
--- a/arch/s390/include/asm/ccwdev.h
+++ b/arch/s390/include/asm/ccwdev.h
@@ -219,7 +219,7 @@ extern void ccw_device_get_id(struct ccw_device *, struct ccw_dev_id *);
#define to_ccwdev(n) container_of(n, struct ccw_device, dev)
#define to_ccwdrv(n) container_of(n, struct ccw_driver, driver)
-extern struct ccw_device *ccw_device_probe_console(void);
+extern struct ccw_device *ccw_device_probe_console(struct ccw_driver *);
extern void ccw_device_wait_idle(struct ccw_device *);
extern int ccw_device_force_console(struct ccw_device *);
diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index eb5d227..bb86494 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -922,7 +922,7 @@ static int __init con3215_init(void)
raw3215_freelist = req;
}
- cdev = ccw_device_probe_console();
+ cdev = ccw_device_probe_console(&raw3215_ccw_driver);
if (IS_ERR(cdev))
return -ENODEV;
diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c
index 699fd3e..bb6b0df 100644
--- a/drivers/s390/char/con3270.c
+++ b/drivers/s390/char/con3270.c
@@ -576,7 +576,6 @@ static struct console con3270 = {
static int __init
con3270_init(void)
{
- struct ccw_device *cdev;
struct raw3270 *rp;
void *cbuf;
int i;
@@ -591,10 +590,7 @@ con3270_init(void)
cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
}
- cdev = ccw_device_probe_console();
- if (IS_ERR(cdev))
- return -ENODEV;
- rp = raw3270_setup_console(cdev);
+ rp = raw3270_setup_console();
if (IS_ERR(rp))
return PTR_ERR(rp);
diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index 2cdec21..de2c048 100644
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -776,16 +776,24 @@ raw3270_setup_device(struct ccw_device *cdev, struct raw3270 *rp, char *ascebc)
}
#ifdef CONFIG_TN3270_CONSOLE
+/* Tentative definition - see below for actual definition. */
+static struct ccw_driver raw3270_ccw_driver;
+
/*
* Setup 3270 device configured as console.
*/
-struct raw3270 __init *raw3270_setup_console(struct ccw_device *cdev)
+struct raw3270 __init *raw3270_setup_console(void)
{
+ struct ccw_device *cdev;
unsigned long flags;
struct raw3270 *rp;
char *ascebc;
int rc;
+ cdev = ccw_device_probe_console(&raw3270_ccw_driver);
+ if (IS_ERR(cdev))
+ return ERR_CAST(cdev);
+
rp = kzalloc(sizeof(struct raw3270), GFP_KERNEL | GFP_DMA);
ascebc = kzalloc(256, GFP_KERNEL);
rc = raw3270_setup_device(cdev, rp, ascebc);
diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h
index 7b73ff8..359276a 100644
--- a/drivers/s390/char/raw3270.h
+++ b/drivers/s390/char/raw3270.h
@@ -190,7 +190,7 @@ raw3270_put_view(struct raw3270_view *view)
wake_up(&raw3270_wait_queue);
}
-struct raw3270 *raw3270_setup_console(struct ccw_device *cdev);
+struct raw3270 *raw3270_setup_console(void);
void raw3270_wait_cons_dev(struct raw3270 *);
/* Notifier for device addition/removal */
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index e9d7835..4283dd3 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1609,7 +1609,7 @@ out_unlock:
return rc;
}
-struct ccw_device *ccw_device_probe_console(void)
+struct ccw_device *ccw_device_probe_console(struct ccw_driver *drv)
{
struct io_subchannel_private *io_priv;
struct ccw_device *cdev;
@@ -1631,6 +1631,7 @@ struct ccw_device *ccw_device_probe_console(void)
kfree(io_priv);
return cdev;
}
+ cdev->drv = drv;
set_io_private(sch, io_priv);
ret = ccw_device_console_enable(cdev, sch);
if (ret) {
--
1.8.3.1
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