* [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
@ 2016-11-22 9:22 Andrew Donnellan
2016-11-22 10:27 ` Michael Ellerman
2016-12-23 4:20 ` Stewart Smith
0 siblings, 2 replies; 7+ messages in thread
From: Andrew Donnellan @ 2016-11-22 9:22 UTC (permalink / raw)
To: linuxppc-dev; +Cc: stewart, benh
skiboot now supports "fast reboot", a reboot procedure where skiboot
reinitialises hardware and loads a new kernel without re-IPLing the
machine. At present, fast reboot support is still experimental and is not
enabled by default, however it is intended that it will be enabled by
default in a near-future release.
There may be some circumstances where the user wants to force a full IPL
reboot rather than using fast reboot. Add support for the
OPAL_REBOOT_FULL_IPL reboot type, enabled by writing 1 to
/sys/firmware/opal/force_full_ipl_reboot. On versions of skiboot that
implement the OPAL_REBOOT_FULL_IPL reboot type, this will force an IPL. On
versions that do not, print an error message on reboot and proceed with a
regular reboot (which could be a full IPL or a fast reboot).
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
---
Corresponding skiboot patch: http://patchwork.ozlabs.org/patch/697601/
This seemed like a good idea at the time. A sysfs-based flag was the best
option that came to mind; other suggestions are welcome. Is "full IPL" a
reasonable term to use or should I try to think of something a bit less
IBM-ese?
---
arch/powerpc/include/asm/opal-api.h | 1 +
arch/powerpc/include/asm/opal.h | 1 +
arch/powerpc/platforms/powernv/opal.c | 2 ++
arch/powerpc/platforms/powernv/setup.c | 63 +++++++++++++++++++++++++++++++++-
4 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 0e2e57b..4de1f63 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -918,6 +918,7 @@ enum OpalSysCooling {
enum {
OPAL_REBOOT_NORMAL = 0,
OPAL_REBOOT_PLATFORM_ERROR = 1,
+ OPAL_REBOOT_FULL_IPL = 2,
};
/* Argument to OPAL_PCI_TCE_KILL */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index e958b70..a5e4065 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -270,6 +270,7 @@ extern void opal_platform_dump_init(void);
extern void opal_sys_param_init(void);
extern void opal_msglog_init(void);
extern void opal_msglog_sysfs_init(void);
+extern void opal_reboot_sysfs_init(void);
extern int opal_async_comp_init(void);
extern int opal_sensor_init(void);
extern int opal_hmi_handler_init(void);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 6c9a65b..c619d8d 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -750,6 +750,8 @@ static int __init opal_init(void)
opal_sys_param_init();
/* Setup message log sysfs interface. */
opal_msglog_sysfs_init();
+ /* Setup reboot sysfs interface. */
+ opal_reboot_sysfs_init();
}
/* Initialize platform devices: IPMI backend, PRD & flash interface */
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index efe8b6b..d2460fc 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -28,6 +28,7 @@
#include <linux/bug.h>
#include <linux/pci.h>
#include <linux/cpufreq.h>
+#include <linux/sysfs.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
@@ -118,6 +119,53 @@ static void pnv_prepare_going_down(void)
opal_flash_term_callback();
}
+static bool force_full_ipl_reboot = false;
+
+static ssize_t force_full_ipl_reboot_show(struct kobject *k,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", (int) force_full_ipl_reboot);
+}
+
+static ssize_t force_full_ipl_reboot_store(struct kobject *k,
+ struct kobj_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ if (count != 2) /* including trailing NUL */
+ return -EINVAL;
+
+ switch (buf[0]) {
+ case '0':
+ force_full_ipl_reboot = false;
+ return count;
+ case '1':
+ force_full_ipl_reboot = true;
+ return count;
+ default:
+ return -EINVAL;
+ }
+}
+
+static struct kobj_attribute opal_force_full_ipl_reboot_attr =
+ __ATTR(force_full_ipl_reboot, 0644, force_full_ipl_reboot_show,
+ force_full_ipl_reboot_store);
+
+void opal_reboot_sysfs_init(void) {
+ int rc = 0;
+
+ if (!opal_kobj) {
+ pr_warn("setup: opal kobject is not available");
+ return;
+ }
+
+ rc = sysfs_create_file(opal_kobj, &opal_force_full_ipl_reboot_attr.attr);
+ if (rc)
+ pr_err("setup: unable to create sysfs file "
+ "force_full_ipl_reboot (%d)", rc);
+}
+
static void __noreturn pnv_restart(char *cmd)
{
long rc = OPAL_BUSY;
@@ -125,7 +173,20 @@ static void __noreturn pnv_restart(char *cmd)
pnv_prepare_going_down();
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
- rc = opal_cec_reboot();
+ if (force_full_ipl_reboot && opal_check_token(OPAL_CEC_REBOOT2)) {
+ rc = opal_cec_reboot2(OPAL_REBOOT_FULL_IPL,
+ "Full IPL reboot requested");
+
+ if (rc == OPAL_UNSUPPORTED) {
+ pr_err("Firmware doesn't support forcing full "
+ "IPL reboot");
+ force_full_ipl_reboot = false;
+ rc = opal_cec_reboot();
+ }
+ } else {
+ rc = opal_cec_reboot();
+ }
+
if (rc == OPAL_BUSY_EVENT)
opal_poll_events(NULL);
else
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-22 9:22 [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot Andrew Donnellan
@ 2016-11-22 10:27 ` Michael Ellerman
2016-11-23 1:37 ` Andrew Donnellan
2016-12-23 4:20 ` Stewart Smith
1 sibling, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2016-11-22 10:27 UTC (permalink / raw)
To: Andrew Donnellan, linuxppc-dev; +Cc: stewart
Andrew Donnellan <andrew.donnellan@au1.ibm.com> writes:
> skiboot now supports "fast reboot", a reboot procedure where skiboot
> reinitialises hardware and loads a new kernel without re-IPLing the
> machine. At present, fast reboot support is still experimental and is not
> enabled by default, however it is intended that it will be enabled by
> default in a near-future release.
>
> There may be some circumstances where the user wants to force a full IPL
> reboot rather than using fast reboot. Add support for the
> OPAL_REBOOT_FULL_IPL reboot type, enabled by writing 1 to
> /sys/firmware/opal/force_full_ipl_reboot. On versions of skiboot that
> implement the OPAL_REBOOT_FULL_IPL reboot type, this will force an IPL. On
> versions that do not, print an error message on reboot and proceed with a
> regular reboot (which could be a full IPL or a fast reboot).
Hi Andrew,
Can I suggest:
- Fix OPAL
- Fix OPAL
- Fix OPAL
...
Oh OK, it's firmware :D
There's existing logic in kernel/reboot.c to handle a reboot= command
line parameter, which can set the reboot_mode, so my preference would be
that we use that.
Currently we completely ignore the reboot_mode, so there's no backward
compatibility issue.
It looks like the default is REBOOT_COLD, whatever that means. So I
think we could define that on powernv REBOOT_HARD means "do a full IPL".
Or we could use "force", which already exists, though I can't quite see
what that actually means on x86.
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-22 10:27 ` Michael Ellerman
@ 2016-11-23 1:37 ` Andrew Donnellan
2016-11-23 2:33 ` Andrew Donnellan
0 siblings, 1 reply; 7+ messages in thread
From: Andrew Donnellan @ 2016-11-23 1:37 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: stewart
On 22/11/16 21:27, Michael Ellerman wrote:
> Can I suggest:
> - Fix OPAL
> - Fix OPAL
> - Fix OPAL
>
> ...
>
> Oh OK, it's firmware :D
Yep :D
> There's existing logic in kernel/reboot.c to handle a reboot= command
> line parameter, which can set the reboot_mode, so my preference would be
> that we use that.
>
> Currently we completely ignore the reboot_mode, so there's no backward
> compatibility issue.
>
> It looks like the default is REBOOT_COLD, whatever that means. So I
> think we could define that on powernv REBOOT_HARD means "do a full IPL".
Sounds good.
> Or we could use "force", which already exists, though I can't quite see
> what that actually means on x86.
Hmm.
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-23 1:37 ` Andrew Donnellan
@ 2016-11-23 2:33 ` Andrew Donnellan
2016-11-23 3:19 ` Michael Ellerman
0 siblings, 1 reply; 7+ messages in thread
From: Andrew Donnellan @ 2016-11-23 2:33 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: stewart
On 23/11/16 12:37, Andrew Donnellan wrote:
>> There's existing logic in kernel/reboot.c to handle a reboot= command
>> line parameter, which can set the reboot_mode, so my preference would be
>> that we use that.
>>
>> Currently we completely ignore the reboot_mode, so there's no backward
>> compatibility issue.
>>
>> It looks like the default is REBOOT_COLD, whatever that means. So I
>> think we could define that on powernv REBOOT_HARD means "do a full IPL".
>
> Sounds good.
Thinking about this more - you can't change that at runtime. :(
>
>> Or we could use "force", which already exists, though I can't quite see
>> what that actually means on x86.
>
> Hmm.
It looks like that on x86, if reboot_force = 1, we don't call
machine_shutdown() and go straight to __machine_emergency_restart()?
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-23 2:33 ` Andrew Donnellan
@ 2016-11-23 3:19 ` Michael Ellerman
2016-12-23 4:19 ` Stewart Smith
0 siblings, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2016-11-23 3:19 UTC (permalink / raw)
To: Andrew Donnellan, linuxppc-dev; +Cc: stewart
Andrew Donnellan <andrew.donnellan@au1.ibm.com> writes:
> On 23/11/16 12:37, Andrew Donnellan wrote:
>>> There's existing logic in kernel/reboot.c to handle a reboot= command
>>> line parameter, which can set the reboot_mode, so my preference would be
>>> that we use that.
>>>
>>> Currently we completely ignore the reboot_mode, so there's no backward
>>> compatibility issue.
>>>
>>> It looks like the default is REBOOT_COLD, whatever that means. So I
>>> think we could define that on powernv REBOOT_HARD means "do a full IPL".
>>
>> Sounds good.
>
> Thinking about this more - you can't change that at runtime. :(
Yeah. Is that a problem? From my POV this is basically a "my firmware is
broken" workaround, so you're going to want to set it permanently until
you update your firmware.
>>> Or we could use "force", which already exists, though I can't quite see
>>> what that actually means on x86.
>>
>> Hmm.
>
> It looks like that on x86, if reboot_force = 1, we don't call
> machine_shutdown() and go straight to __machine_emergency_restart()?
I think so. But I don't know what that actually means from a user's
point of view.
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-23 3:19 ` Michael Ellerman
@ 2016-12-23 4:19 ` Stewart Smith
0 siblings, 0 replies; 7+ messages in thread
From: Stewart Smith @ 2016-12-23 4:19 UTC (permalink / raw)
To: Michael Ellerman, Andrew Donnellan, linuxppc-dev
Michael Ellerman <mpe@ellerman.id.au> writes:
> Andrew Donnellan <andrew.donnellan@au1.ibm.com> writes:
>
>> On 23/11/16 12:37, Andrew Donnellan wrote:
>>>> There's existing logic in kernel/reboot.c to handle a reboot= command
>>>> line parameter, which can set the reboot_mode, so my preference would be
>>>> that we use that.
>>>>
>>>> Currently we completely ignore the reboot_mode, so there's no backward
>>>> compatibility issue.
>>>>
>>>> It looks like the default is REBOOT_COLD, whatever that means. So I
>>>> think we could define that on powernv REBOOT_HARD means "do a full IPL".
>>>
>>> Sounds good.
>>
>> Thinking about this more - you can't change that at runtime. :(
>
> Yeah. Is that a problem? From my POV this is basically a "my firmware is
> broken" workaround, so you're going to want to set it permanently until
> you update your firmware.
The only real world application I can see wanting to do that is perhaps
HTX - where it chooses what kind of bootme run it wants. So, well, for
certain definitions of "real world".
--
Stewart Smith
OPAL Architect, IBM.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot
2016-11-22 9:22 [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot Andrew Donnellan
2016-11-22 10:27 ` Michael Ellerman
@ 2016-12-23 4:20 ` Stewart Smith
1 sibling, 0 replies; 7+ messages in thread
From: Stewart Smith @ 2016-12-23 4:20 UTC (permalink / raw)
To: Andrew Donnellan, linuxppc-dev
Andrew Donnellan <andrew.donnellan@au1.ibm.com> writes:
> skiboot now supports "fast reboot", a reboot procedure where skiboot
> reinitialises hardware and loads a new kernel without re-IPLing the
> machine. At present, fast reboot support is still experimental and is not
> enabled by default, however it is intended that it will be enabled by
> default in a near-future release.
>
> There may be some circumstances where the user wants to force a full IPL
> reboot rather than using fast reboot. Add support for the
> OPAL_REBOOT_FULL_IPL reboot type, enabled by writing 1 to
> /sys/firmware/opal/force_full_ipl_reboot. On versions of skiboot that
> implement the OPAL_REBOOT_FULL_IPL reboot type, this will force an IPL. On
> versions that do not, print an error message on reboot and proceed with a
> regular reboot (which could be a full IPL or a fast reboot).
>
> Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
>
> ---
>
> Corresponding skiboot patch: http://patchwork.ozlabs.org/patch/697601/
FWIW I've just merged the skiboot patch.
--
Stewart Smith
OPAL Architect, IBM.
^ permalink raw reply [flat|nested] 7+ messages in thread
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2016-11-22 9:22 [PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot Andrew Donnellan
2016-11-22 10:27 ` Michael Ellerman
2016-11-23 1:37 ` Andrew Donnellan
2016-11-23 2:33 ` Andrew Donnellan
2016-11-23 3:19 ` Michael Ellerman
2016-12-23 4:19 ` Stewart Smith
2016-12-23 4:20 ` Stewart Smith
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