[PATCH 0/6] ARM/arm64: arm_pm_restart removal

[PATCH 0/6] ARM/arm64: arm_pm_restart removal

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Hi Russell, ARM SoC maintainers,

here's the full set of patches that remove arm_pm_restart as discussed
earlier. There's some background on the series in this thread:

	https://lore.kernel.org/linux-arm-kernel/20170130110512.6943-1-thierry.reding@gmail.com/

I also have a set of patches that build on top of this and try to add
something slightly more formal by adding a power/reset framework that
driver can register with. If we can get this series merged, I'll find
some time to refresh those patches and send out for review again.

Thierry

Guenter Roeck (6):
  ARM: prima2: Register with kernel restart handler
  ARM: xen: Register with kernel restart handler
  drivers: firmware: psci: Register with kernel restart handler
  ARM: Register with kernel restart handler
  ARM64: Remove arm_pm_restart()
  ARM: Remove arm_pm_restart()

 arch/arm/include/asm/system_misc.h   |  1 -
 arch/arm/kernel/reboot.c             |  6 +-----
 arch/arm/kernel/setup.c              | 20 ++++++++++++++++++--
 arch/arm/mach-prima2/rstc.c          | 11 +++++++++--
 arch/arm/xen/enlighten.c             | 12 ++++++++++--
 arch/arm64/include/asm/system_misc.h |  2 --
 arch/arm64/kernel/process.c          |  7 +------
 drivers/firmware/psci/psci.c         | 12 ++++++++++--
 8 files changed, 49 insertions(+), 22 deletions(-)

-- 
2.23.0

[PATCH 1/6] ARM: prima2: Register with kernel restart handler

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

Register with kernel restart handler instead of setting arm_pm_restart
directly. By doing this, the prima2 reset handler can be prioritized
among other restart methods available on a particular board.

Select a high priority of 192 since the original code overwrites the
default arm restart handler.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm/mach-prima2/rstc.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-prima2/rstc.c b/arch/arm/mach-prima2/rstc.c
index 9d56606ac87f..825dd5fcc37b 100644
--- a/arch/arm/mach-prima2/rstc.c
+++ b/arch/arm/mach-prima2/rstc.c
@@ -64,11 +64,18 @@ static struct reset_controller_dev sirfsoc_reset_controller = {
 
 #define SIRFSOC_SYS_RST_BIT  BIT(31)
 
-static void sirfsoc_restart(enum reboot_mode mode, const char *cmd)
+static int sirfsoc_restart(struct notifier_block *nb, unsigned long action,
+			   void *data)
 {
 	writel(SIRFSOC_SYS_RST_BIT, sirfsoc_rstc_base);
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block sirfsoc_restart_nb = {
+	.notifier_call  = sirfsoc_restart,
+	.priority       = 192,
+};
+
 static int sirfsoc_rstc_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -79,7 +86,7 @@ static int sirfsoc_rstc_probe(struct platform_device *pdev)
 	}
 
 	sirfsoc_reset_controller.of_node = np;
-	arm_pm_restart = sirfsoc_restart;
+	register_restart_handler(&sirfsoc_restart_nb);
 
 	if (IS_ENABLED(CONFIG_RESET_CONTROLLER))
 		reset_controller_register(&sirfsoc_reset_controller);
-- 
2.23.0

[PATCH 2/6] ARM: xen: Register with kernel restart handler

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

Register with kernel restart handler instead of setting arm_pm_restart
directly.

Select a high priority of 192 to ensure that default restart handlers
are replaced if Xen is running.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm/xen/enlighten.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 1e57692552d9..eb0a0edb9909 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -30,6 +30,7 @@
 #include <linux/cpu.h>
 #include <linux/console.h>
 #include <linux/pvclock_gtod.h>
+#include <linux/reboot.h>
 #include <linux/time64.h>
 #include <linux/timekeeping.h>
 #include <linux/timekeeper_internal.h>
@@ -181,11 +182,18 @@ void xen_reboot(int reason)
 	BUG_ON(rc);
 }
 
-static void xen_restart(enum reboot_mode reboot_mode, const char *cmd)
+static int xen_restart(struct notifier_block *nb, unsigned long action,
+		       void *data)
 {
 	xen_reboot(SHUTDOWN_reboot);
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block xen_restart_nb = {
+	.notifier_call = xen_restart,
+	.priority = 192,
+};
 
 static void xen_power_off(void)
 {
@@ -406,7 +414,7 @@ static int __init xen_pm_init(void)
 		return -ENODEV;
 
 	pm_power_off = xen_power_off;
-	arm_pm_restart = xen_restart;
+	register_restart_handler(&xen_restart_nb);
 	if (!xen_initial_domain()) {
 		struct timespec64 ts;
 		xen_read_wallclock(&ts);
-- 
2.23.0

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Guenter Roeck]

On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> wrote:
> 
> > From: Guenter Roeck <linux@roeck-us.net>
> >
> > Register with kernel restart handler instead of setting arm_pm_restart
> > directly.
> >
> > Select a high priority of 192 to ensure that default restart handlers
> > are replaced if Xen is running.
> >
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> >  arch/arm/xen/enlighten.c | 12 ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> >
> 
> This patch does appear to be useful.
> 
> Is this just being solved in downstream trees at the moment?
> 
> It would be nice if we could relinquish people of this burden and get it
> into Mainline finally.
> 

There must have been half a dozen attempts to send this patch series
upstream. I have tried, and others have tried. Each attempt failed with
someone else objecting for non-technical reasons (such as "we need more
reviews") or no reaction at all, and maintainers just don't pick it up.

So, yes, this patch series can only be found in downstream trees,
and it seems pointless to submit it yet again.

Guenter

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Lee Jones]

On Thu, 03 Jun 2021, Guenter Roeck wrote:

> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> > On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> > wrote:
> > 
> > > From: Guenter Roeck <linux@roeck-us.net>
> > >
> > > Register with kernel restart handler instead of setting arm_pm_restart
> > > directly.
> > >
> > > Select a high priority of 192 to ensure that default restart handlers
> > > are replaced if Xen is running.
> > >
> > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > > Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > > ---
> > >  arch/arm/xen/enlighten.c | 12 ++++++++++--
> > >  1 file changed, 10 insertions(+), 2 deletions(-)
> > >
> > 
> > This patch does appear to be useful.
> > 
> > Is this just being solved in downstream trees at the moment?
> > 
> > It would be nice if we could relinquish people of this burden and get it
> > into Mainline finally.
> > 
> 
> There must have been half a dozen attempts to send this patch series
> upstream. I have tried, and others have tried. Each attempt failed with
> someone else objecting for non-technical reasons (such as "we need more
> reviews") or no reaction at all, and maintainers just don't pick it up.

Looking at the *-by tag list above, I think we have enough quality
reviews to take this forward.

> So, yes, this patch series can only be found in downstream trees,
> and it seems pointless to submit it yet again.

IMHO, it's unfair to burden multiple downstream trees with this purely
due to poor or nervy maintainership.  Functionality as broadly useful
as this should be merged and maintained in Mainline.

OOI, who is blocking?  As I see it, we have 2 of the key maintainers
in the *-by list.  With those on-board, it's difficult to envisage
what the problem is.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Boris Ostrovsky]

On 6/3/21 9:38 AM, Lee Jones wrote:
> On Thu, 03 Jun 2021, Guenter Roeck wrote:
>
>> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
>>> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
>>> wrote:
>>>
>>>> From: Guenter Roeck <linux@roeck-us.net>
>>>>
>>>> Register with kernel restart handler instead of setting arm_pm_restart
>>>> directly.
>>>>
>>>> Select a high priority of 192 to ensure that default restart handlers
>>>> are replaced if Xen is running.
>>>>
>>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>>>> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
>>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>>>> ---
>>>>  arch/arm/xen/enlighten.c | 12 ++++++++++--
>>>>  1 file changed, 10 insertions(+), 2 deletions(-)
>>>>
>>> This patch does appear to be useful.
>>>
>>> Is this just being solved in downstream trees at the moment?
>>>
>>> It would be nice if we could relinquish people of this burden and get it
>>> into Mainline finally.
>>>
>> There must have been half a dozen attempts to send this patch series
>> upstream. I have tried, and others have tried. Each attempt failed with
>> someone else objecting for non-technical reasons (such as "we need more
>> reviews") or no reaction at all, and maintainers just don't pick it up.
> Looking at the *-by tag list above, I think we have enough quality
> reviews to take this forward.
>
>> So, yes, this patch series can only be found in downstream trees,
>> and it seems pointless to submit it yet again.
> IMHO, it's unfair to burden multiple downstream trees with this purely
> due to poor or nervy maintainership.  Functionality as broadly useful
> as this should be merged and maintained in Mainline.
>
> OOI, who is blocking?  As I see it, we have 2 of the key maintainers
> in the *-by list.  With those on-board, it's difficult to envisage
> what the problem is.


Stefano (who is ARM Xen maintainer) left Citrix a while ago. He is at sstabellini@kernel.org (which I added to the CC line).


-boris

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Russell King (Oracle)]

On Thu, Jun 03, 2021 at 09:48:59AM -0400, Boris Ostrovsky wrote:
> On 6/3/21 9:38 AM, Lee Jones wrote:
> > On Thu, 03 Jun 2021, Guenter Roeck wrote:
> >
> >> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> >>> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> >>> wrote:
> >>>
> >>>> From: Guenter Roeck <linux@roeck-us.net>
> >>>>
> >>>> Register with kernel restart handler instead of setting arm_pm_restart
> >>>> directly.
> >>>>
> >>>> Select a high priority of 192 to ensure that default restart handlers
> >>>> are replaced if Xen is running.
> >>>>
> >>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
> >>>> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> >>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> >>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
> >>>> ---
> >>>>  arch/arm/xen/enlighten.c | 12 ++++++++++--
> >>>>  1 file changed, 10 insertions(+), 2 deletions(-)
> >>>>
> >>> This patch does appear to be useful.
> >>>
> >>> Is this just being solved in downstream trees at the moment?
> >>>
> >>> It would be nice if we could relinquish people of this burden and get it
> >>> into Mainline finally.
> >>>
> >> There must have been half a dozen attempts to send this patch series
> >> upstream. I have tried, and others have tried. Each attempt failed with
> >> someone else objecting for non-technical reasons (such as "we need more
> >> reviews") or no reaction at all, and maintainers just don't pick it up.
> > Looking at the *-by tag list above, I think we have enough quality
> > reviews to take this forward.
> >
> >> So, yes, this patch series can only be found in downstream trees,
> >> and it seems pointless to submit it yet again.
> > IMHO, it's unfair to burden multiple downstream trees with this purely
> > due to poor or nervy maintainership.  Functionality as broadly useful
> > as this should be merged and maintained in Mainline.
> >
> > OOI, who is blocking?  As I see it, we have 2 of the key maintainers
> > in the *-by list.  With those on-board, it's difficult to envisage
> > what the problem is.
> 
> 
> Stefano (who is ARM Xen maintainer) left Citrix a while ago. He is at sstabellini@kernel.org (which I added to the CC line).

Stefano already reviewed this patch, which is part of a larger series
that primarily touches 32-bit ARM code, but also touches 64-bit ARM
code as well.

As I said in my previous reply, I don't see that there's any problem
with getting these patches merged had the usual processes been
followed - either ending up in the patch system, or the pull request
being sent to me directly.

Sadly, the pull request was sent to the arm-soc people excluding me,
I happened to notice it and requested to see the patches that were
being asked to be pulled (since I probably couldn't find them)...
and it then took two further weeks before the patches were posted,
which I then missed amongst all the other email.

It's a process failure and unfortunate timing rather than anything
malicious.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Lee Jones]

On Thu, 03 Jun 2021, Russell King (Oracle) wrote:

> On Thu, Jun 03, 2021 at 09:48:59AM -0400, Boris Ostrovsky wrote:
> > On 6/3/21 9:38 AM, Lee Jones wrote:
> > > On Thu, 03 Jun 2021, Guenter Roeck wrote:
> > >
> > >> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> > >>> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> > >>> wrote:
> > >>>
> > >>>> From: Guenter Roeck <linux@roeck-us.net>
> > >>>>
> > >>>> Register with kernel restart handler instead of setting arm_pm_restart
> > >>>> directly.
> > >>>>
> > >>>> Select a high priority of 192 to ensure that default restart handlers
> > >>>> are replaced if Xen is running.
> > >>>>
> > >>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
> > >>>> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > >>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > >>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > >>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
> > >>>> ---
> > >>>>  arch/arm/xen/enlighten.c | 12 ++++++++++--
> > >>>>  1 file changed, 10 insertions(+), 2 deletions(-)
> > >>>>
> > >>> This patch does appear to be useful.
> > >>>
> > >>> Is this just being solved in downstream trees at the moment?
> > >>>
> > >>> It would be nice if we could relinquish people of this burden and get it
> > >>> into Mainline finally.
> > >>>
> > >> There must have been half a dozen attempts to send this patch series
> > >> upstream. I have tried, and others have tried. Each attempt failed with
> > >> someone else objecting for non-technical reasons (such as "we need more
> > >> reviews") or no reaction at all, and maintainers just don't pick it up.
> > > Looking at the *-by tag list above, I think we have enough quality
> > > reviews to take this forward.
> > >
> > >> So, yes, this patch series can only be found in downstream trees,
> > >> and it seems pointless to submit it yet again.
> > > IMHO, it's unfair to burden multiple downstream trees with this purely
> > > due to poor or nervy maintainership.  Functionality as broadly useful
> > > as this should be merged and maintained in Mainline.
> > >
> > > OOI, who is blocking?  As I see it, we have 2 of the key maintainers
> > > in the *-by list.  With those on-board, it's difficult to envisage
> > > what the problem is.
> > 
> > 
> > Stefano (who is ARM Xen maintainer) left Citrix a while ago. He is at sstabellini@kernel.org (which I added to the CC line).
> 
> Stefano already reviewed this patch, which is part of a larger series
> that primarily touches 32-bit ARM code, but also touches 64-bit ARM
> code as well.
> 
> As I said in my previous reply, I don't see that there's any problem
> with getting these patches merged had the usual processes been
> followed - either ending up in the patch system, or the pull request
> being sent to me directly.
> 
> Sadly, the pull request was sent to the arm-soc people excluding me,
> I happened to notice it and requested to see the patches that were
> being asked to be pulled (since I probably couldn't find them)...
> and it then took two further weeks before the patches were posted,
> which I then missed amongst all the other email.
> 
> It's a process failure and unfortunate timing rather than anything
> malicious.

Understood.

Is there anything I can do to help this forward?

I can either collect and re-submit the patches to the MLs if that
makes people's lives any easier.  Or if one of the original submitters
wish to retain responsibility, I have no qualms with that either.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Russell King (Oracle)]

On Thu, Jun 03, 2021 at 03:03:01PM +0100, Lee Jones wrote:
> On Thu, 03 Jun 2021, Russell King (Oracle) wrote:
> 
> > On Thu, Jun 03, 2021 at 09:48:59AM -0400, Boris Ostrovsky wrote:
> > > On 6/3/21 9:38 AM, Lee Jones wrote:
> > > > On Thu, 03 Jun 2021, Guenter Roeck wrote:
> > > >
> > > >> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> > > >>> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> > > >>> wrote:
> > > >>>
> > > >>>> From: Guenter Roeck <linux@roeck-us.net>
> > > >>>>
> > > >>>> Register with kernel restart handler instead of setting arm_pm_restart
> > > >>>> directly.
> > > >>>>
> > > >>>> Select a high priority of 192 to ensure that default restart handlers
> > > >>>> are replaced if Xen is running.
> > > >>>>
> > > >>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > >>>> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > > >>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > >>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > > >>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
> > > >>>> ---
> > > >>>>  arch/arm/xen/enlighten.c | 12 ++++++++++--
> > > >>>>  1 file changed, 10 insertions(+), 2 deletions(-)
> > > >>>>
> > > >>> This patch does appear to be useful.
> > > >>>
> > > >>> Is this just being solved in downstream trees at the moment?
> > > >>>
> > > >>> It would be nice if we could relinquish people of this burden and get it
> > > >>> into Mainline finally.
> > > >>>
> > > >> There must have been half a dozen attempts to send this patch series
> > > >> upstream. I have tried, and others have tried. Each attempt failed with
> > > >> someone else objecting for non-technical reasons (such as "we need more
> > > >> reviews") or no reaction at all, and maintainers just don't pick it up.
> > > > Looking at the *-by tag list above, I think we have enough quality
> > > > reviews to take this forward.
> > > >
> > > >> So, yes, this patch series can only be found in downstream trees,
> > > >> and it seems pointless to submit it yet again.
> > > > IMHO, it's unfair to burden multiple downstream trees with this purely
> > > > due to poor or nervy maintainership.  Functionality as broadly useful
> > > > as this should be merged and maintained in Mainline.
> > > >
> > > > OOI, who is blocking?  As I see it, we have 2 of the key maintainers
> > > > in the *-by list.  With those on-board, it's difficult to envisage
> > > > what the problem is.
> > > 
> > > 
> > > Stefano (who is ARM Xen maintainer) left Citrix a while ago. He is at sstabellini@kernel.org (which I added to the CC line).
> > 
> > Stefano already reviewed this patch, which is part of a larger series
> > that primarily touches 32-bit ARM code, but also touches 64-bit ARM
> > code as well.
> > 
> > As I said in my previous reply, I don't see that there's any problem
> > with getting these patches merged had the usual processes been
> > followed - either ending up in the patch system, or the pull request
> > being sent to me directly.
> > 
> > Sadly, the pull request was sent to the arm-soc people excluding me,
> > I happened to notice it and requested to see the patches that were
> > being asked to be pulled (since I probably couldn't find them)...
> > and it then took two further weeks before the patches were posted,
> > which I then missed amongst all the other email.
> > 
> > It's a process failure and unfortunate timing rather than anything
> > malicious.
> 
> Understood.
> 
> Is there anything I can do to help this forward?
> 
> I can either collect and re-submit the patches to the MLs if that
> makes people's lives any easier.  Or if one of the original submitters
> wish to retain responsibility, I have no qualms with that either.

I think at this point the usual applies - to make sure that they still
apply to current kernels and don't cause any regressions. I would hope
there won't be anything significant to invalidate the reviews already
given. If that's the case, it should just be a matter of someone
putting them in the patch system or send me a pull request.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 4863 bytes --]

On Thu, Jun 03, 2021 at 03:03:01PM +0100, Lee Jones wrote:
> On Thu, 03 Jun 2021, Russell King (Oracle) wrote:
> 
> > On Thu, Jun 03, 2021 at 09:48:59AM -0400, Boris Ostrovsky wrote:
> > > On 6/3/21 9:38 AM, Lee Jones wrote:
> > > > On Thu, 03 Jun 2021, Guenter Roeck wrote:
> > > >
> > > >> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> > > >>> On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> > > >>> wrote:
> > > >>>
> > > >>>> From: Guenter Roeck <linux@roeck-us.net>
> > > >>>>
> > > >>>> Register with kernel restart handler instead of setting arm_pm_restart
> > > >>>> directly.
> > > >>>>
> > > >>>> Select a high priority of 192 to ensure that default restart handlers
> > > >>>> are replaced if Xen is running.
> > > >>>>
> > > >>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > >>>> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > > >>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > >>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > > >>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
> > > >>>> ---
> > > >>>>  arch/arm/xen/enlighten.c | 12 ++++++++++--
> > > >>>>  1 file changed, 10 insertions(+), 2 deletions(-)
> > > >>>>
> > > >>> This patch does appear to be useful.
> > > >>>
> > > >>> Is this just being solved in downstream trees at the moment?
> > > >>>
> > > >>> It would be nice if we could relinquish people of this burden and get it
> > > >>> into Mainline finally.
> > > >>>
> > > >> There must have been half a dozen attempts to send this patch series
> > > >> upstream. I have tried, and others have tried. Each attempt failed with
> > > >> someone else objecting for non-technical reasons (such as "we need more
> > > >> reviews") or no reaction at all, and maintainers just don't pick it up.
> > > > Looking at the *-by tag list above, I think we have enough quality
> > > > reviews to take this forward.
> > > >
> > > >> So, yes, this patch series can only be found in downstream trees,
> > > >> and it seems pointless to submit it yet again.
> > > > IMHO, it's unfair to burden multiple downstream trees with this purely
> > > > due to poor or nervy maintainership.  Functionality as broadly useful
> > > > as this should be merged and maintained in Mainline.
> > > >
> > > > OOI, who is blocking?  As I see it, we have 2 of the key maintainers
> > > > in the *-by list.  With those on-board, it's difficult to envisage
> > > > what the problem is.
> > > 
> > > 
> > > Stefano (who is ARM Xen maintainer) left Citrix a while ago. He is at sstabellini@kernel.org (which I added to the CC line).
> > 
> > Stefano already reviewed this patch, which is part of a larger series
> > that primarily touches 32-bit ARM code, but also touches 64-bit ARM
> > code as well.
> > 
> > As I said in my previous reply, I don't see that there's any problem
> > with getting these patches merged had the usual processes been
> > followed - either ending up in the patch system, or the pull request
> > being sent to me directly.
> > 
> > Sadly, the pull request was sent to the arm-soc people excluding me,
> > I happened to notice it and requested to see the patches that were
> > being asked to be pulled (since I probably couldn't find them)...
> > and it then took two further weeks before the patches were posted,
> > which I then missed amongst all the other email.
> > 
> > It's a process failure and unfortunate timing rather than anything
> > malicious.
> 
> Understood.
> 
> Is there anything I can do to help this forward?
> 
> I can either collect and re-submit the patches to the MLs if that
> makes people's lives any easier.  Or if one of the original submitters
> wish to retain responsibility, I have no qualms with that either.

I had stumbled across these patches from Guenter when I was looking to
solve a reboot/power-off issue on one of the boards that I was working
on. This was supposed to be preparatory work to get rid of the global
function pointers that drivers are simply overwriting, and the goal had
been to add a "system power" framework that would allow drivers to
register a chip structure to provide a bit more "formality" than
overwriting function pointers or registering notifier callbacks.

There ended up not being any interest in such a subsystem, so I wanted
to at least get this prep work in, because it is at least a bit of an
improvement.

I vaguely recall that Arnd or perhaps Olof had mentioned that they'd
pull these patches, but the timing was bad, so they asked me to remind
them after the merge window. By the time we had gotten through the merge
window, I probably had gotten sidetracked and forgot...

Feel free to give this a shot. This series itself is still useful, in my
opinion.

Thierry

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Re: [PATCH 2/6] ARM: xen: Register with kernel restart handler

[Russell King (Oracle)]

On Thu, Jun 03, 2021 at 06:11:24AM -0700, Guenter Roeck wrote:
> On Thu, Jun 03, 2021 at 01:43:36PM +0100, Lee Jones wrote:
> > On Tue, 15 Oct 2019 at 15:52, Thierry Reding <thierry.reding@gmail.com>
> > wrote:
> > 
> > > From: Guenter Roeck <linux@roeck-us.net>
> > >
> > > Register with kernel restart handler instead of setting arm_pm_restart
> > > directly.
> > >
> > > Select a high priority of 192 to ensure that default restart handlers
> > > are replaced if Xen is running.
> > >
> > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > > Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > > ---
> > >  arch/arm/xen/enlighten.c | 12 ++++++++++--
> > >  1 file changed, 10 insertions(+), 2 deletions(-)
> > >
> > 
> > This patch does appear to be useful.
> > 
> > Is this just being solved in downstream trees at the moment?
> > 
> > It would be nice if we could relinquish people of this burden and get it
> > into Mainline finally.
> > 
> 
> There must have been half a dozen attempts to send this patch series
> upstream. I have tried, and others have tried. Each attempt failed with
> someone else objecting for non-technical reasons (such as "we need more
> reviews") or no reaction at all, and maintainers just don't pick it up.
> 
> So, yes, this patch series can only be found in downstream trees,
> and it seems pointless to submit it yet again.

It has plenty of reviews and acks, so that's not the problem. If you
look back at the 2019 attempt:

1) there was a pull request sent on the 2 October 2019 to the arm soc
   guys to merge a series that quite obviously is outside of their
   remit as it touches mostly ARM core code - it should have been
   sent to me but wasn't, not even as a Cc.

2) I raised that issue, and as I could find no trace of the patches,
   I asked for the to be posted - which they were, eventually, two
   weeks later. It looks like I completely missed the patches amongst
   all the other email I don't bother to read anymore though. In any
   case, the pull request by that time would have been completely
   forgotten about.

And that's where it ended - no apparent follow-ups until now.

*Shrug*.

So in summary, I was expected to notice the patches amongst all the
other email, and then remember that there was a pull request that
wasn't even addressed to me...

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

[PATCH 3/6] drivers: firmware: psci: Register with kernel restart handler

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

Register with kernel restart handler instead of setting arm_pm_restart
directly. This enables support for replacing the PSCI restart handler
with a different handler if necessary for a specific board.

Select a priority of 129 to indicate a higher than default priority, but
keep it as low as possible since PSCI reset is known to fail on some
boards.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/firmware/psci/psci.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 84f4ff351c62..a41c6ba043a2 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -250,7 +250,8 @@ static int get_set_conduit_method(struct device_node *np)
 	return 0;
 }
 
-static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
+static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
+			  void *data)
 {
 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
 	    psci_system_reset2_supported) {
@@ -263,8 +264,15 @@ static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 	} else {
 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 	}
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block psci_sys_reset_nb = {
+	.notifier_call = psci_sys_reset,
+	.priority = 129,
+};
+
 static void psci_sys_poweroff(void)
 {
 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
@@ -431,7 +439,7 @@ static void __init psci_0_2_set_functions(void)
 
 	psci_ops.migrate_info_type = psci_migrate_info_type;
 
-	arm_pm_restart = psci_sys_reset;
+	register_restart_handler(&psci_sys_reset_nb);
 
 	pm_power_off = psci_sys_poweroff;
 }
-- 
2.23.0

Re: [PATCH 3/6] drivers: firmware: psci: Register with kernel restart handler

[Stefan Agner]

On 2019-10-15 16:51, Thierry Reding wrote:
> From: Guenter Roeck <linux@roeck-us.net>
> 
> Register with kernel restart handler instead of setting arm_pm_restart
> directly. This enables support for replacing the PSCI restart handler
> with a different handler if necessary for a specific board.
> 
> Select a priority of 129 to indicate a higher than default priority, but
> keep it as low as possible since PSCI reset is known to fail on some
> boards.
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Looks good to me! And helps also in my case, a board which has a broken
PSCI reset capability.

Reviewed-by: Stefan Agner <stefan.agner@toradex.com>

--
Stefan

> ---
>  drivers/firmware/psci/psci.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 84f4ff351c62..a41c6ba043a2 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -250,7 +250,8 @@ static int get_set_conduit_method(struct device_node *np)
>  	return 0;
>  }
>  
> -static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
> +static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
> +			  void *data)
>  {
>  	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
>  	    psci_system_reset2_supported) {
> @@ -263,8 +264,15 @@ static void psci_sys_reset(enum reboot_mode
> reboot_mode, const char *cmd)
>  	} else {
>  		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
>  	}
> +
> +	return NOTIFY_DONE;
>  }
>  
> +static struct notifier_block psci_sys_reset_nb = {
> +	.notifier_call = psci_sys_reset,
> +	.priority = 129,
> +};
> +
>  static void psci_sys_poweroff(void)
>  {
>  	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
> @@ -431,7 +439,7 @@ static void __init psci_0_2_set_functions(void)
>  
>  	psci_ops.migrate_info_type = psci_migrate_info_type;
>  
> -	arm_pm_restart = psci_sys_reset;
> +	register_restart_handler(&psci_sys_reset_nb);
>  
>  	pm_power_off = psci_sys_poweroff;
>  }

[PATCH 4/6] ARM: Register with kernel restart handler

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

By making use of the kernel restart handler, board specific restart
handlers can be prioritized amongst available mechanisms for a particular
board or system.

Select the default priority of 128 to indicate that the restart callback
in the machine description is the default restart mechanism.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm/kernel/setup.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index d0a464e317ea..d403648195de 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1073,6 +1073,20 @@ void __init hyp_mode_check(void)
 #endif
 }
 
+static void (*__arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
+
+static int arm_restart(struct notifier_block *nb, unsigned long action,
+		       void *data)
+{
+	__arm_pm_restart(action, data);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block arm_restart_nb = {
+	.notifier_call = arm_restart,
+	.priority = 128,
+};
+
 void __init setup_arch(char **cmdline_p)
 {
 	const struct machine_desc *mdesc;
@@ -1132,8 +1146,10 @@ void __init setup_arch(char **cmdline_p)
 	paging_init(mdesc);
 	request_standard_resources(mdesc);
 
-	if (mdesc->restart)
-		arm_pm_restart = mdesc->restart;
+	if (mdesc->restart) {
+		__arm_pm_restart = mdesc->restart;
+		register_restart_handler(&arm_restart_nb);
+	}
 
 	unflatten_device_tree();
 
-- 
2.23.0

[PATCH 5/6] ARM64: Remove arm_pm_restart()

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

All users of arm_pm_restart() have been converted to use the kernel
restart handler.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/include/asm/system_misc.h | 2 --
 arch/arm64/kernel/process.c          | 7 +------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h
index 1ab63cfbbaf1..d02c5e5ea015 100644
--- a/arch/arm64/include/asm/system_misc.h
+++ b/arch/arm64/include/asm/system_misc.h
@@ -32,8 +32,6 @@ void hook_debug_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
 struct mm_struct;
 extern void __show_regs(struct pt_regs *);
 
-extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
-
 #endif	/* __ASSEMBLY__ */
 
 #endif	/* __ASM_SYSTEM_MISC_H */
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index a47462def04b..f11d2b261b4e 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -64,8 +64,6 @@ EXPORT_SYMBOL(__stack_chk_guard);
 void (*pm_power_off)(void);
 EXPORT_SYMBOL_GPL(pm_power_off);
 
-void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
-
 static void __cpu_do_idle(void)
 {
 	dsb(sy);
@@ -195,10 +193,7 @@ void machine_restart(char *cmd)
 		efi_reboot(reboot_mode, NULL);
 
 	/* Now call the architecture specific reboot code. */
-	if (arm_pm_restart)
-		arm_pm_restart(reboot_mode, cmd);
-	else
-		do_kernel_restart(cmd);
+	do_kernel_restart(cmd);
 
 	/*
 	 * Whoops - the architecture was unable to reboot.
-- 
2.23.0

[PATCH 6/6] ARM: Remove arm_pm_restart()

[Thierry Reding]

From: Guenter Roeck <linux@roeck-us.net>

All users of arm_pm_restart() have been converted to use the kernel
restart handler.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm/include/asm/system_misc.h | 1 -
 arch/arm/kernel/reboot.c           | 6 +-----
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h
index 66f6a3ae68d2..98b37340376b 100644
--- a/arch/arm/include/asm/system_misc.h
+++ b/arch/arm/include/asm/system_misc.h
@@ -13,7 +13,6 @@
 extern void cpu_init(void);
 
 void soft_restart(unsigned long);
-extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 extern void (*arm_pm_idle)(void);
 
 #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index bb18ed0539f4..1076b26aa699 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -18,7 +18,6 @@ typedef void (*phys_reset_t)(unsigned long, bool);
 /*
  * Function pointers to optional machine specific functions
  */
-void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
@@ -138,10 +137,7 @@ void machine_restart(char *cmd)
 	local_irq_disable();
 	smp_send_stop();
 
-	if (arm_pm_restart)
-		arm_pm_restart(reboot_mode, cmd);
-	else
-		do_kernel_restart(cmd);
+	do_kernel_restart(cmd);
 
 	/* Give a grace period for failure to restart of 1s */
 	mdelay(1000);
-- 
2.23.0