[U-Boot] bootm does not work if netconsole is enabled

[U-Boot] bootm does not work if netconsole is enabled

[Michael Walle]

Hi Joe, Hi Tom,

If i have the netconsole enabled i cannot boot linux using the bootm command. 
This bug exists at least in 2013.01.01 and 2013.04-rc2 :/


Here is the output of the serial console of a successful startup:

## Booting kernel from Legacy Image at 00100000 ...
   Image Name:   Linux-3.8.0-rc1-00004-g270c0a0-d
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2799632 Bytes = 2.7 MiB
   Load Address: 00008000
   Entry Point:  00008000
   Verifying Checksum ... OK
## Loading init Ramdisk from Legacy Image at 00800000 ...
   Image Name:   
   Image Type:   ARM Linux RAMDisk Image (uncompressed)
   Data Size:    636966 Bytes = 622 KiB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 00700000
   Booting using the fdt blob at 0x00700000
   Loading Kernel Image ... OK
OK
   Loading Ramdisk to 03aad000, end 03b48826 ... OK
   Loading Device Tree to 03aa8000, end 03aacedd ... OK

Starting kernel ...

[.. more linux kernel output ..]


If the netconsole is enabled, eg. "stdin = stdout = stderr = nc", i see only 
the following output on the netconsole and then nothing more happens:

## Booting kernel from Legacy Image at 00100000 ...
   Image Name:   Linux-3.8.0-rc1-00004-g270c0a0-d
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2799632 Bytes = 2.7 MiB
   Load Address: 00008000
   Entry Point:  00008000
   Verifying Checksum ... OK
## Loading init Ramdisk from Legacy Image at 00800000 ...
   Image Name:   
   Image Type:   ARM Linux RAMDisk Image (uncompressed)
   Data Size:    636966 Bytes = 622 KiB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 00700000
   Booting using the fdt blob at 0x00700000


I've tracked this down to the eth_halt() call in cmd_bootm.c:647. What is the 
purpose of this call? I guess the NIC should be shut down prior to booting 
linux. OTOH, there are still messages printed after this call, and i suppose 
the netconsole tries to bring the network back up. If i remove this call, 
everything works as expected.
Anyway, i can definitely say, that the linux kernel is not starting. Eg. it is 
not only the output that stops working.

FYI, i'm using the mvgbe driver.

Let me know if i can do some more debugging or provide more information. 
Hopefully this will be fixed in 2013.04 :)

-- 
Michael

[U-Boot] bootm does not work if netconsole is enabled

[Joe Hershberger]

Hi Michael,

I just tested this on my Zynq target and it worked.  However, you make
a good point that it is possible for there to be more traces after the
eth_halt call.  I can't imagine the stack would like that in all
situations (since eth_init() will not be called again by netconsole).
I think the solution to this is probably to disable netconsole somehow
before the eth_halt command, so subsequent prints do not try to use
Ethernet again.  However, most of the things you might switch to are
conditional, such as a nulldev or silent.  Any thoughts on how you
would like to see it solved?

Cheers,
-Joe


On Tue, Apr 9, 2013 at 5:21 PM, Michael Walle <michael@walle.cc> wrote:
>
> Hi Joe, Hi Tom,
>
> If i have the netconsole enabled i cannot boot linux using the bootm command.
> This bug exists at least in 2013.01.01 and 2013.04-rc2 :/
>
>
> Here is the output of the serial console of a successful startup:
>
> ## Booting kernel from Legacy Image at 00100000 ...
>    Image Name:   Linux-3.8.0-rc1-00004-g270c0a0-d
>    Image Type:   ARM Linux Kernel Image (uncompressed)
>    Data Size:    2799632 Bytes = 2.7 MiB
>    Load Address: 00008000
>    Entry Point:  00008000
>    Verifying Checksum ... OK
> ## Loading init Ramdisk from Legacy Image at 00800000 ...
>    Image Name:
>    Image Type:   ARM Linux RAMDisk Image (uncompressed)
>    Data Size:    636966 Bytes = 622 KiB
>    Load Address: 00000000
>    Entry Point:  00000000
>    Verifying Checksum ... OK
> ## Flattened Device Tree blob at 00700000
>    Booting using the fdt blob at 0x00700000
>    Loading Kernel Image ... OK
> OK
>    Loading Ramdisk to 03aad000, end 03b48826 ... OK
>    Loading Device Tree to 03aa8000, end 03aacedd ... OK
>
> Starting kernel ...
>
> [.. more linux kernel output ..]
>
>
> If the netconsole is enabled, eg. "stdin = stdout = stderr = nc", i see only
> the following output on the netconsole and then nothing more happens:
>
> ## Booting kernel from Legacy Image at 00100000 ...
>    Image Name:   Linux-3.8.0-rc1-00004-g270c0a0-d
>    Image Type:   ARM Linux Kernel Image (uncompressed)
>    Data Size:    2799632 Bytes = 2.7 MiB
>    Load Address: 00008000
>    Entry Point:  00008000
>    Verifying Checksum ... OK
> ## Loading init Ramdisk from Legacy Image at 00800000 ...
>    Image Name:
>    Image Type:   ARM Linux RAMDisk Image (uncompressed)
>    Data Size:    636966 Bytes = 622 KiB
>    Load Address: 00000000
>    Entry Point:  00000000
>    Verifying Checksum ... OK
> ## Flattened Device Tree blob at 00700000
>    Booting using the fdt blob at 0x00700000
>
>
> I've tracked this down to the eth_halt() call in cmd_bootm.c:647. What is the
> purpose of this call? I guess the NIC should be shut down prior to booting
> linux. OTOH, there are still messages printed after this call, and i suppose
> the netconsole tries to bring the network back up. If i remove this call,
> everything works as expected.
> Anyway, i can definitely say, that the linux kernel is not starting. Eg. it is
> not only the output that stops working.
>
> FYI, i'm using the mvgbe driver.
>
> Let me know if i can do some more debugging or provide more information.
> Hopefully this will be fixed in 2013.04 :)
>
> --
> Michael

[U-Boot] bootm does not work if netconsole is enabled

[Michael Walle]

On Wed, April 10, 2013 03:51, Joe Hershberger wrote:
> Hi Michael,
>
> I just tested this on my Zynq target and it worked.  However, you make
> a good point that it is possible for there to be more traces after the
> eth_halt call.  I can't imagine the stack would like that in all
> situations (since eth_init() will not be called again by netconsole).
> I think the solution to this is probably to disable netconsole somehow
> before the eth_halt command, so subsequent prints do not try to use
> Ethernet again.  However, most of the things you might switch to are
> conditional, such as a nulldev or silent.  Any thoughts on how you
> would like to see it solved?

Hi Joe,

disabling the network console before control is handed over to an
operating system sounds reasonable.

If i understand you correctly, the network will only be halted once the
bootloader starts an operating system. Then what do you think about making
either the nc_send_packet() or nc_putc()/nc_puts() function a noop when
the network is halted?

-- 
michael

[U-Boot] bootm does not work if netconsole is enabled

[Joe Hershberger]

Hi Michael,

On Wed, Apr 10, 2013 at 5:07 AM, Michael Walle <michael@walle.cc> wrote:
> On Wed, April 10, 2013 03:51, Joe Hershberger wrote:
>> Hi Michael,
>>
>> I just tested this on my Zynq target and it worked.  However, you make
>> a good point that it is possible for there to be more traces after the
>> eth_halt call.  I can't imagine the stack would like that in all
>> situations (since eth_init() will not be called again by netconsole).
>> I think the solution to this is probably to disable netconsole somehow
>> before the eth_halt command, so subsequent prints do not try to use
>> Ethernet again.  However, most of the things you might switch to are
>> conditional, such as a nulldev or silent.  Any thoughts on how you
>> would like to see it solved?
>
> Hi Joe,
>
> disabling the network console before control is handed over to an
> operating system sounds reasonable.
>
> If i understand you correctly, the network will only be halted once the
> bootloader starts an operating system. Then what do you think about making
> either the nc_send_packet() or nc_putc()/nc_puts() function a noop when
> the network is halted?

It's not quite that simple since the state does not really reflect the
hardware (I know... that's my fault).  I can try to fix this for next
release, but it is probably too risky to put into the April release.
In the mean time a simple work-around is to use silent or nulldev on
your target and turn off netconsole as part of your boot script
(before you bootm).

Cheers,
-Joe

[U-Boot] bootm does not work if netconsole is enabled

[Michael Walle]

Hi Joe,

Am Mittwoch 10 April 2013, 18:13:57 schrieb Joe Hershberger:
> > If i understand you correctly, the network will only be halted once the
> > bootloader starts an operating system. Then what do you think about
> > making either the nc_send_packet() or nc_putc()/nc_puts() function a
> > noop when the network is halted?
> 
> It's not quite that simple since the state does not really reflect the
> hardware (I know... that's my fault).  I can try to fix this for next
> release, but it is probably too risky to put into the April release.
Agreed. Let me know if i can test something for you.


> In the mean time a simple work-around is to use silent or nulldev on
> your target and turn off netconsole as part of your boot script
> (before you bootm).

I worked around this bug by setting the stdout back to serial just before the 
bootm command.

-- 
michael

[U-Boot] bootm does not work if netconsole is enabled

[Michael Walle]

Am 2013-04-10 18:13, schrieb Joe Hershberger:
> Hi Michael,
>
> On Wed, Apr 10, 2013 at 5:07 AM, Michael Walle <michael@walle.cc> 
> wrote:
>> On Wed, April 10, 2013 03:51, Joe Hershberger wrote:
>>> Hi Michael,
>>>
>>> I just tested this on my Zynq target and it worked.  However, you 
>>> make
>>> a good point that it is possible for there to be more traces after 
>>> the
>>> eth_halt call.  I can't imagine the stack would like that in all
>>> situations (since eth_init() will not be called again by 
>>> netconsole).
>>> I think the solution to this is probably to disable netconsole 
>>> somehow
>>> before the eth_halt command, so subsequent prints do not try to use
>>> Ethernet again.  However, most of the things you might switch to 
>>> are
>>> conditional, such as a nulldev or silent.  Any thoughts on how you
>>> would like to see it solved?
>>
>> Hi Joe,
>>
>> disabling the network console before control is handed over to an
>> operating system sounds reasonable.
>>
>> If i understand you correctly, the network will only be halted once 
>> the
>> bootloader starts an operating system. Then what do you think about 
>> making
>> either the nc_send_packet() or nc_putc()/nc_puts() function a noop 
>> when
>> the network is halted?
>
> It's not quite that simple since the state does not really reflect 
> the
> hardware (I know... that's my fault).  I can try to fix this for next
> release, but it is probably too risky to put into the April release.

Ping :)

-- 
michael

[U-Boot] bootm does not work if netconsole is enabled

[Michael Walle]

Am Mittwoch, 10. April 2013, 18:13:57 schrieb Joe Hershberger:
> > disabling the network console before control is handed over to an
> > operating system sounds reasonable.
> > 
> > If i understand you correctly, the network will only be halted once the
> > bootloader starts an operating system. Then what do you think about
> > making either the nc_send_packet() or nc_putc()/nc_puts() function a
> > noop when the network is halted?
> 
> It's not quite that simple since the state does not really reflect the
> hardware (I know... that's my fault).  I can try to fix this for next
> release, but it is probably too risky to put into the April release.

ping #2 :)

-- 
michael

[U-Boot] [PATCH] Enable serial console only before booting

[Frédéric Leroy]

When netconsole is active, some boards fail to boot.
This patch enables only the serial console before
control is handed by another operating system.

Signed-off-by: Fr?d?ric Leroy <fredo@starox.org>
---

Hello,

I am facing the same problem with LaCie kirkwood boards.
I took a simple approach for fixing this issue.
This works for me ...
Any comments are welcome :)

Fr?d?ric

 common/cmd_bootm.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 15f4599..81e8322 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -62,6 +62,17 @@
 #include <linux/lzo.h>
 #endif /* CONFIG_LZO */
 
+
+#if defined(CONFIG_NETCONSOLE)
+#include <iomux.h>
+void console_set_serial_unconditionally(void)
+{
+	iomux_doenv(stdin, "serial");
+	iomux_doenv(stdout, "serial");
+	iomux_doenv(stderr, "serial");
+}
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifndef CONFIG_SYS_BOOTM_LEN
@@ -577,6 +588,7 @@ static int do_bootm_subcommand(cmd_tbl_t *cmdtp, int flag, int argc,
 			 * Stop the ethernet stack if NetConsole could have
 			 * left it up
 			 */
+			console_set_serial_unconditionally("nc");
 			eth_halt();
 #endif
 			arch_preboot_os();
@@ -645,6 +657,7 @@ int do_bootm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
+	console_set_serial_unconditionally("nc");
 	eth_halt();
 #endif
 
@@ -1849,6 +1862,7 @@ static int do_bootz(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
+	console_set_serial_unconditionally("nc");
 	eth_halt();
 #endif
 
-- 
1.8.1.2

[U-Boot] [PATCH] Enable serial console only before booting

[Frédéric Leroy]

When netconsole is active, some boards fail to boot.
This patch enables only the serial console before
control is handed over to another operating system.

Signed-off-by: Fr?d?ric Leroy <fredo@starox.org>
---

Sorry for the noise, I tend to post faster than my own swadow ...

Changes in v2 :

- remove unused argument from console_set_serial_unconditionally call
- fix platforms where CONFIG_CONSOLE_MUX is not defined

 common/cmd_bootm.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 15f4599..e75c692 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -62,6 +62,18 @@
 #include <linux/lzo.h>
 #endif /* CONFIG_LZO */
 
+#if defined(CONFIG_NETCONSOLE)
+#include <iomux.h>
+void console_set_serial_unconditionally(void)
+{
+#if defined(CONFIG_CONSOLE_MUX)
+	iomux_doenv(stdin, "serial");
+	iomux_doenv(stdout, "serial");
+	iomux_doenv(stderr, "serial");
+#endif
+}
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifndef CONFIG_SYS_BOOTM_LEN
@@ -577,6 +589,7 @@ static int do_bootm_subcommand(cmd_tbl_t *cmdtp, int flag, int argc,
 			 * Stop the ethernet stack if NetConsole could have
 			 * left it up
 			 */
+			console_set_serial_unconditionally();
 			eth_halt();
 #endif
 			arch_preboot_os();
@@ -645,6 +658,7 @@ int do_bootm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
+	console_set_serial_unconditionally();
 	eth_halt();
 #endif
 
@@ -1849,6 +1863,7 @@ static int do_bootz(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
+	console_set_serial_unconditionally();
 	eth_halt();
 #endif
 
-- 
1.8.1.2

[U-Boot] [PATCH] Enable serial console only before booting

[Wolfgang Denk]

Dear Fr?d?ric Leroy,

In message <1373192736-5014-1-git-send-email-fredo@starox.org> you wrote:
> When netconsole is active, some boards fail to boot.
> This patch enables only the serial console before
> control is handed by another operating system.

I really hate adding such fixes without understanding the exact nature
of the problem.

Could you please be so kind and explain in which way booting fails
when netconsole is active?  On what exactly the "some boards" are that
fail that way?  And why this does not appear to be a problem on other
boards? (or is it?)  And thy the "some boards" cannot be fixed in such
a way to behave as the rest of the boards (where it's not a problem) ?

[U-Boot] [PATCH] Enable serial console only before booting

[Tom Rini]

On Sun, Jul 07, 2013 at 12:25:36PM +0200, Fr??d??ric Leroy wrote:

> When netconsole is active, some boards fail to boot.
> This patch enables only the serial console before
> control is handed by another operating system.
> 
> Signed-off-by: Fr??d??ric Leroy <fredo@starox.org>
> ---
> 
> Hello,
> 
> I am facing the same problem with LaCie kirkwood boards.
> I took a simple approach for fixing this issue.
> This works for me ...
> Any comments are welcome :)
> 

Can you please re-base this to mainline and re-post?  Also, can you
expand on the comments in the commit message to explain the problem with
netconsole and thus why this fixes it?

-- 
Tom
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[U-Boot] [PATCH] Fix loading freeze when netconsole is active

[Frédéric Leroy]

Netconsole calls eth_halt() before giving control to another operating
system.
But the state machine of netconsole don't take it into account.
Thus, netconsole calls network functions of an halted network device,
making the whole system freeze.
Rather than modifying the state machine of netconsole, we just unregister
the current network device before booting. It does work because
nc_send_packet() verifies that the current network device is not null.

Signed-off-by: Fr?d?ric Leroy <fredo@starox.org>
---
 common/cmd_bootm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Hello Tom,

I have made a cleaner version of my patch against master.
I didn't touch the netconsole code because I don't fully understand it.

Regards,

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 15f4599..beb25b6 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -577,7 +577,7 @@ static int do_bootm_subcommand(cmd_tbl_t *cmdtp, int flag, int argc,
 			 * Stop the ethernet stack if NetConsole could have
 			 * left it up
 			 */
-			eth_halt();
+			eth_unregister(eth_get_dev());
 #endif
 			arch_preboot_os();
 			boot_fn(BOOTM_STATE_OS_GO, argc, argv, &images);
@@ -645,7 +645,7 @@ int do_bootm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
-	eth_halt();
+	eth_unregister(eth_get_dev());
 #endif
 
 #if defined(CONFIG_CMD_USB)
@@ -1849,7 +1849,7 @@ static int do_bootz(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
-	eth_halt();
+	eth_unregister(eth_get_dev());
 #endif
 
 #if defined(CONFIG_CMD_USB)
-- 
1.8.1.2

[U-Boot] [PATCH v2] Fix loading freeze when netconsole is active

[Frédéric Leroy]

Netconsole calls eth_halt() before giving control to another operating
system.
But the state machine of netconsole don't take it into account.
Thus, netconsole calls network functions of an halted network device,
making the whole system freeze.
Rather than modifying the state machine of netconsole, we just unregister
the current network device before booting. It does work because
nc_send_packet() verifies that the current network device is not null.

Signed-off-by: Fr?d?ric Leroy <fredo@starox.org>
---

Sorry, I was dumb. I don't know why I removed call to eth_halt().
eth_unregister() don't halt the device.

Changes in v2: 
	don't remove the call to eth_halt()
	
 common/cmd_bootm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 15f4599..549a914 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -578,6 +578,7 @@ static int do_bootm_subcommand(cmd_tbl_t *cmdtp, int flag, int argc,
 			 * left it up
 			 */
 			eth_halt();
+			eth_unregister(eth_get_dev());
 #endif
 			arch_preboot_os();
 			boot_fn(BOOTM_STATE_OS_GO, argc, argv, &images);
@@ -646,6 +647,7 @@ int do_bootm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
 	eth_halt();
+	eth_unregister(eth_get_dev());
 #endif
 
 #if defined(CONFIG_CMD_USB)
@@ -1850,6 +1852,7 @@ static int do_bootz(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 #ifdef CONFIG_NETCONSOLE
 	/* Stop the ethernet stack if NetConsole could have left it up */
 	eth_halt();
+	eth_unregister(eth_get_dev());
 #endif
 
 #if defined(CONFIG_CMD_USB)
-- 
1.8.1.2

[U-Boot] [U-Boot, v2] Fix loading freeze when netconsole is active

[Tom Rini]

On Tue, Sep 10, 2013 at 12:02:31PM +0200, Frederic Leroy wrote:

> Netconsole calls eth_halt() before giving control to another operating
> system.
> But the state machine of netconsole don't take it into account.
> Thus, netconsole calls network functions of an halted network device,
> making the whole system freeze.
> Rather than modifying the state machine of netconsole, we just unregister
> the current network device before booting. It does work because
> nc_send_packet() verifies that the current network device is not null.
> 
> Signed-off-by: Fr??d??ric Leroy <fredo@starox.org>

Applied to u-boot/master, thanks!

-- 
Tom
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