[RESEND PATCH v2] netconsole: various improvements
Tony Dinh
mibodhi at gmail.com
Thu Apr 20 05:55:10 CEST 2023
On Wed, Apr 19, 2023 at 6:22 PM Tony Dinh <mibodhi at gmail.com> wrote:
>
> HI Simon,
>
> On Tue, Apr 18, 2023 at 6:46 PM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Tony,
> >
> > On Mon, 3 Apr 2023 at 15:42, Tony Dinh <mibodhi at gmail.com> wrote:
> > >
> > > Use CONFIG_CONSOLE_MUX for netconsole. When netconsole is running,
> > > stdin/stdout/stder must be set to some primary console, in addtion to nc.
> > > For example, stdin=serial,nc. Some recent Linux kernels will not boot with
> > > only nc on the stdout list, ie. stdout=nc. When netconsole exits, remove
> > > nc from the list of devices in stdin/stdout/stderr.
> > >
> > > Signed-off-by: Tony Dinh <mibodhi at gmail.com>
> > > ---
> > >
> > > Changes in v2:
> > > - Select CONFIG_CONSOLE_MUX if CONFIG_NETCONSOLE is enabled
> > > - Add new functions in netconsole driver to support CONSOLE_MUX
> > > - Add new function to encapsulate the process of stopping netconsole
> > > from bootm
> > > - Remove unecessary net_timeout initial value = 1
> > > - Resend to correct missing <stdio_dev.h> include in bootm.c
> > >
> > > boot/bootm.c | 14 +++++++---
> > > drivers/net/Kconfig | 10 +++++++
> > > drivers/net/netconsole.c | 60 ++++++++++++++++++++++++++++++++++++++++
> > > include/stdio_dev.h | 1 +
> > > 4 files changed, 81 insertions(+), 4 deletions(-)
> >
> > This seems OK to me but for a few thoughts below.
> >
> > But can we use this opportunity to move this to driver model? The
> > netconsole driver could be bound in eth_post_bind() and the code in
> > netconsole.c converted to be a driver.
> >
> > I think that would be better than building on an out-of-date driver.
>
> I'd agree that converting to a driver model is the logical next step.
> My motivation is to fix the booting problem for the Linux kernel first
> (I'm having problems booting some kernels without this patch). And
> then in the next go round, I'll convert netconsole to a driver. Most
> of the code in this small patch will be needed whether it is an old
> driver or DM anyway.
>
> >
> > >
> > > diff --git a/boot/bootm.c b/boot/bootm.c
> > > index 2eec60ec7b..1b2542b570 100644
> > > --- a/boot/bootm.c
> > > +++ b/boot/bootm.c
> > > @@ -18,6 +18,7 @@
> > > #include <malloc.h>
> > > #include <mapmem.h>
> > > #include <net.h>
> > > +#include <stdio_dev.h>
> > > #include <asm/cache.h>
> > > #include <asm/global_data.h>
> > > #include <asm/io.h>
> > > @@ -472,11 +473,16 @@ ulong bootm_disable_interrupts(void)
> > > * recover from any failures any more...
> > > */
> > > iflag = disable_interrupts();
> > > -#ifdef CONFIG_NETCONSOLE
> > > - /* Stop the ethernet stack if NetConsole could have left it up */
> > > - eth_halt();
> > > -#endif
> > >
> > > + if (IS_ENABLED(CONFIG_NETCONSOLE)) {
> > > + /*
> > > + * Make sure that the starting kernel message printed out,
> > > + * stop netconsole and the ethernet stack
> > > + */
> > > + printf("\n\nStarting kernel ...\n\n");
> > > + drv_nc_stop();
> > > + eth_halt();
> > > + }
> > > #if defined(CONFIG_CMD_USB)
> > > /*
> > > * turn off USB to prevent the host controller from writing to the
> > > diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> > > index ceadee98a1..0661059dfa 100644
> > > --- a/drivers/net/Kconfig
> > > +++ b/drivers/net/Kconfig
> > > @@ -945,4 +945,14 @@ config MDIO_MUX_MESON_G12A
> > > This driver is used for the MDIO mux found on the Amlogic G12A & compatible
> > > SoCs.
> > >
> > > +config NETCONSOLE
> > > + bool "Enable netconsole"
> > > + select CONSOLE_MUX
> > > + help
> > > + NetConsole requires CONSOLE_MUX, i.e. at least one default console such
> > > + must be specified in addition to nc console. For example, for boards that
> > > + the main console is serial, set each of the envs stdin/stdout/stderr to serial,nc.
> > > + See CONFIG_CONSOLE_MUX and CONFIG_SYS_CONSOLE_IS_IN_ENV help for detailed
> > > + description of usage.
> > > +
> > > endif # NETDEVICES
> > > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> > > index 151bc55e07..bb92d2e130 100644
> > > --- a/drivers/net/netconsole.c
> > > +++ b/drivers/net/netconsole.c
> > > @@ -7,6 +7,7 @@
> > > #include <common.h>
> > > #include <command.h>
> > > #include <env.h>
> > > +#include <iomux.h>
> > > #include <log.h>
> > > #include <stdio_dev.h>
> > > #include <net.h>
> > > @@ -33,6 +34,12 @@ static int output_packet_len;
> > > */
> > > enum proto_t net_loop_last_protocol = BOOTP;
> > >
> > > +/*
> > > + * Net console helpers
> > > + */
> > > +static void usage(void);
> > > +static void remove_nc_from(const int console);
> > > +
> > > static void nc_wait_arp_handler(uchar *pkt, unsigned dest,
> > > struct in_addr sip, unsigned src,
> > > unsigned len)
> > > @@ -111,6 +118,21 @@ static int refresh_settings_from_env(void)
> > > return 0;
> > > }
> > >
> > > +static void remove_nc_from(const int console)
> > > +{
> > > + int ret;
> > > +
> > > + ret = iomux_replace_device(console, "nc", "nulldev");
> > > + if (ret) {
> > > + printf("\n*** Warning: Cannot remove nc from %s Error=%d\n",
> > > + stdio_names[console], ret);
> > > + printf("%s=", stdio_names[console]);
> > > + iomux_printdevs(console);
> > > + usage();
> > > + flush();
> > > + }
> > > +}
> > > +
> > > /**
> > > * Called from net_loop in net/net.c before each packet
> > > */
> > > @@ -241,6 +263,29 @@ static int nc_stdio_start(struct stdio_dev *dev)
> > > return 0;
> > > }
> > >
> > > +void nc_stdio_stop(void)
> > > +{
> > > + if (IS_ENABLED(CONFIG_CONSOLE_MUX)) {
> > > + int ret;
> > > + struct stdio_dev *sdev;
> > > +
> > > + /* Remove nc from each stdio file */
> > > + remove_nc_from(stdin);
> > > + remove_nc_from(stderr);
> > > + remove_nc_from(stdout);
> > > +
> > > + /* Deregister nc device */
> > > + sdev = stdio_get_by_name("nc");
> > > + ret = stdio_deregister_dev(sdev, true);
> > > + if (ret)
> > > + printf("\nWarning: Cannot deregister nc console Error=%d\n", ret);
> > > + } else {
> > > + printf("\n*** Warning: CONFIG_CONSOLE_MUX must be enabled for netconsole\n"
> > > + "to work properly. The nc console will be removed when\n"
> > > + "netconsole driver stops\n");
> > > + }
> > > +}
> > > +
> > > static void nc_stdio_putc(struct stdio_dev *dev, char c)
> > > {
> > > if (output_recursion)
> > > @@ -316,6 +361,16 @@ static int nc_stdio_tstc(struct stdio_dev *dev)
> > > return input_size != 0;
> > > }
> > >
> > > +static void usage(void)
> > > +{
> > > + printf("USAGE:\n"
> > > + "NetConsole requires CONFIG_CONSOLE_MUX. At least one default console\n"
> > > + "must be specified in addition to nc console. For example, for boards\n"
> > > + "that the main console is serial, set the each of envs stdin/stdout/stderr\n"
> > > + "to serial,nc. Some kernel might fail to boot when nc is the only device in\n"
> > > + "stdout list\n");
> >
> > How about creating a doc/ file with info about net console? This is a
> > bit too much text to put in a user message.
>
> Sure.
>
> >
> > > +}
> > > +
> > > int drv_nc_init(void)
> > > {
> > > struct stdio_dev dev;
> > > @@ -335,3 +390,8 @@ int drv_nc_init(void)
> > >
> > > return (rc == 0) ? 1 : rc;
> > > }
> > > +
> > > +void drv_nc_stop(void)
> > > +{
> > > + nc_stdio_stop();
> > > +}
> > > diff --git a/include/stdio_dev.h b/include/stdio_dev.h
> > > index 3105928970..9d2375a67e 100644
> > > --- a/include/stdio_dev.h
> > > +++ b/include/stdio_dev.h
> > > @@ -112,6 +112,7 @@ int drv_keyboard_init(void);
> > > int drv_usbtty_init(void);
> > > int drv_usbacm_init(void);
> > > int drv_nc_init(void);
> > > +void drv_nc_stop(void);
> >
> > Once this is a driver we won't need this.
>
> Yes, but we still need the nc_stdio_stop() to do the cleanup, i.e.
> removing nc from stdin/stdout/stderr and deregistering the nc device.
> Except that it will be a uclass member like .pre_remove()?
>
> It will be a bit of a learning curve for me to do the DM netconsole.
> But I will give it a shot.
In the meantime, can this patch get merged on its own merit as a bug fix?
All the best,
Tony
>
> Thanks,
> Tony
>
> >
> > > int drv_jtag_console_init(void);
> > > int cbmemc_init(void);
> >
> > Regards,
> > Simon
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