| Message ID | 1424267513-15836-4-git-send-email-julien.grall@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 2015-02-18 at 13:51 +0000, Julien Grall wrote: > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > This patch registers hvc0 as the preferred console if no console > has been specified explicitly on the kernel command line. > > The purpose is to allow platform agnostic kernels and boot images > (such as distro installers) to boot in a Xen/ARM domU without the > need to modify the command line by hand. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Reviewed-by: Julien Grall <julien.grall@linaro.org> Acked-by: Ian Campbell <ian.campbell@citrix.com>
On Wed, Feb 18, 2015 at 7:51 AM, Julien Grall <julien.grall@linaro.org> wrote: > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > This patch registers hvc0 as the preferred console if no console > has been specified explicitly on the kernel command line. > > The purpose is to allow platform agnostic kernels and boot images > (such as distro installers) to boot in a Xen/ARM domU without the > need to modify the command line by hand. How does this interact with DT chosen stdout-path? Is there a node for hvc0? Rob > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Reviewed-by: Julien Grall <julien.grall@linaro.org> > --- > arch/arm/xen/enlighten.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c > index 1660432..904bd2d 100644 > --- a/arch/arm/xen/enlighten.c > +++ b/arch/arm/xen/enlighten.c > @@ -24,6 +24,7 @@ > #include <linux/cpuidle.h> > #include <linux/cpufreq.h> > #include <linux/cpu.h> > +#include <linux/console.h> > > #include <linux/mm.h> > > @@ -255,6 +256,9 @@ void __init xen_early_init(void) > xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED; > else > xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED); > + > + if (!console_set_on_cmdline && !xen_initial_domain()) > + add_preferred_console("hvc", 0, NULL); > } > > static int __init xen_guest_init(void) > -- > 2.1.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Wed, 2015-02-18 at 09:50 -0600, Rob Herring wrote: > On Wed, Feb 18, 2015 at 7:51 AM, Julien Grall <julien.grall@linaro.org> wrote: > > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > > This patch registers hvc0 as the preferred console if no console > > has been specified explicitly on the kernel command line. > > > > The purpose is to allow platform agnostic kernels and boot images > > (such as distro installers) to boot in a Xen/ARM domU without the > > need to modify the command line by hand. > > How does this interact with DT chosen stdout-path? I think it shouldn't any more than the existing calls from e.g. the 8250 driver to preferred_console do. > Is there a node for hvc0? Not a direct one, it is inferred from the presence of the general Xen node. I did vaguely consider handling a stdout-path pointing to that -- but it seemed a bit of an abuse. Ian.
On Wed, 18 Feb 2015, Ian Campbell wrote: > On Wed, 2015-02-18 at 09:50 -0600, Rob Herring wrote: > > On Wed, Feb 18, 2015 at 7:51 AM, Julien Grall <julien.grall@linaro.org> wrote: > > > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > > > > This patch registers hvc0 as the preferred console if no console > > > has been specified explicitly on the kernel command line. > > > > > > The purpose is to allow platform agnostic kernels and boot images > > > (such as distro installers) to boot in a Xen/ARM domU without the > > > need to modify the command line by hand. > > > > How does this interact with DT chosen stdout-path? > > I think it shouldn't any more than the existing calls from e.g. the 8250 > driver to preferred_console do. > > > Is there a node for hvc0? > > Not a direct one, it is inferred from the presence of the general Xen > node. Xen PV consoles, including hvc0, as all the other Xen PV devices are advertised on xenstore. > I did vaguely consider handling a stdout-path pointing to that -- > but it seemed a bit of an abuse.
On Thu, 2015-02-26 at 18:22 +0000, Stefano Stabellini wrote: > On Wed, 18 Feb 2015, Ian Campbell wrote: > > On Wed, 2015-02-18 at 09:50 -0600, Rob Herring wrote: > > > On Wed, Feb 18, 2015 at 7:51 AM, Julien Grall <julien.grall@linaro.org> wrote: > > > > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > > > > > > This patch registers hvc0 as the preferred console if no console > > > > has been specified explicitly on the kernel command line. > > > > > > > > The purpose is to allow platform agnostic kernels and boot images > > > > (such as distro installers) to boot in a Xen/ARM domU without the > > > > need to modify the command line by hand. > > > > > > How does this interact with DT chosen stdout-path? > > > > I think it shouldn't any more than the existing calls from e.g. the 8250 > > driver to preferred_console do. > > > > > Is there a node for hvc0? > > > > Not a direct one, it is inferred from the presence of the general Xen > > node. > > Xen PV consoles, including hvc0, as all the other Xen PV devices are > advertised on xenstore. Do we actually use the xenstore node for hvc0? I thought we got it from hvmparams (so the primary it can be used before xenstore is up) > > > > I did vaguely consider handling a stdout-path pointing to that -- > > but it seemed a bit of an abuse. >
On Fri, 27 Feb 2015, Ian Campbell wrote: > On Thu, 2015-02-26 at 18:22 +0000, Stefano Stabellini wrote: > > On Wed, 18 Feb 2015, Ian Campbell wrote: > > > On Wed, 2015-02-18 at 09:50 -0600, Rob Herring wrote: > > > > On Wed, Feb 18, 2015 at 7:51 AM, Julien Grall <julien.grall@linaro.org> wrote: > > > > > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > > > > > > > > This patch registers hvc0 as the preferred console if no console > > > > > has been specified explicitly on the kernel command line. > > > > > > > > > > The purpose is to allow platform agnostic kernels and boot images > > > > > (such as distro installers) to boot in a Xen/ARM domU without the > > > > > need to modify the command line by hand. > > > > > > > > How does this interact with DT chosen stdout-path? > > > > > > I think it shouldn't any more than the existing calls from e.g. the 8250 > > > driver to preferred_console do. > > > > > > > Is there a node for hvc0? > > > > > > Not a direct one, it is inferred from the presence of the general Xen > > > node. > > > > Xen PV consoles, including hvc0, as all the other Xen PV devices are > > advertised on xenstore. > > Do we actually use the xenstore node for hvc0? I thought we got it from > hvmparams (so the primary it can be used before xenstore is up) We always assume that at least one PV console is available and the first one is a bit special because it can be setup before the xenstore driver for early boot messages and debugging purposes. However even the first console is advertised on xenstore.
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 1660432..904bd2d 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -24,6 +24,7 @@ #include <linux/cpuidle.h> #include <linux/cpufreq.h> #include <linux/cpu.h> +#include <linux/console.h> #include <linux/mm.h> @@ -255,6 +256,9 @@ void __init xen_early_init(void) xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED; else xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED); + + if (!console_set_on_cmdline && !xen_initial_domain()) + add_preferred_console("hvc", 0, NULL); } static int __init xen_guest_init(void)