* FAILED: patch "[PATCH] powerpc/powernv: Fix save/restore of SPRG3 on entry/exit from" failed to apply to 4.14-stable tree
@ 2018-07-22 16:33 gregkh
2018-07-23 5:30 ` [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop Gautham R. Shenoy
0 siblings, 1 reply; 7+ messages in thread
From: gregkh @ 2018-07-22 16:33 UTC (permalink / raw)
To: ego, fweimer, mpe; +Cc: stable
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From b03897cf318dfc47de33a7ecbc7655584266f034 Mon Sep 17 00:00:00 2001
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
Date: Wed, 18 Jul 2018 14:03:16 +0530
Subject: [PATCH] powerpc/powernv: Fix save/restore of SPRG3 on entry/exit from
stop (idle)
On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
SPRN_USPRG3 are used as userspace VDSO write and read registers
respectively.
SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
restored. As a result, any read from SPRN_USPRG3 returns zero on an
exit from stop4 (Power9 only) and above.
Thus in this situation, on POWER9, any call from sched_getcpu() always
returns zero, as on powerpc, we call __kernel_getcpu() which relies
upon SPRN_USPRG3 to report the CPU and NUMA node information.
Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
with the sprg_vdso value that is cached in PACA.
Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs for stop4 cpuidle")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index e734f6e45abc..689306118b48 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -144,7 +144,9 @@ power9_restore_additional_sprs:
mtspr SPRN_MMCR1, r4
ld r3, STOP_MMCR2(r13)
+ ld r4, PACA_SPRG_VDSO(r13)
mtspr SPRN_MMCR2, r3
+ mtspr SPRN_SPRG3, r4
blr
/*
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
2018-07-22 16:33 FAILED: patch "[PATCH] powerpc/powernv: Fix save/restore of SPRG3 on entry/exit from" failed to apply to 4.14-stable tree gregkh
@ 2018-07-23 5:30 ` Gautham R. Shenoy
2018-07-23 6:16 ` Greg KH
0 siblings, 1 reply; 7+ messages in thread
From: Gautham R. Shenoy @ 2018-07-23 5:30 UTC (permalink / raw)
To: stable; +Cc: Michael Ellerman, Gautham R. Shenoy
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
[ Upstream commit b03897cf318dfc47de33a7ecbc7655584266f034 ]
On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
SPRN_USPRG3 are used as userspace VDSO write and read registers
respectively.
SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
restored. As a result, any read from SPRN_USPRG3 returns zero on an
exit from stop4 and above.
Thus in this situation, on POWER9, any call from sched_getcpu() always
returns zero, as on powerpc, we call __kernel_getcpu() which relies
upon SPRN_USPRG3 to report the CPU and NUMA node information.
Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
with the sprg_vdso value that is cached in PACA.
Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs
for stop4 cpuidle")
Reported-by: Florian Weimer <fweimer@redhat.com>
Cc: <stable@vger.kernel.org> # 4.14
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/kernel/idle_book3s.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 1125c9b..8959057 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -140,6 +140,8 @@ power9_restore_additional_sprs:
ld r4, STOP_MMCR2(r13)
mtspr SPRN_MMCR1, r3
mtspr SPRN_MMCR2, r4
+ ld r4, PACA_SPRG_VDSO(r13)
+ mtspr SPRN_SPRG3, r4
blr
/*
--
1.9.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
2018-07-23 5:30 ` [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop Gautham R. Shenoy
@ 2018-07-23 6:16 ` Greg KH
2018-07-23 7:53 ` Greg KH
0 siblings, 1 reply; 7+ messages in thread
From: Greg KH @ 2018-07-23 6:16 UTC (permalink / raw)
To: Gautham R. Shenoy; +Cc: stable, Michael Ellerman
On Mon, Jul 23, 2018 at 11:00:55AM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> [ Upstream commit b03897cf318dfc47de33a7ecbc7655584266f034 ]
>
> On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
> SPRN_USPRG3 are used as userspace VDSO write and read registers
> respectively.
>
> SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
> restored. As a result, any read from SPRN_USPRG3 returns zero on an
> exit from stop4 and above.
>
> Thus in this situation, on POWER9, any call from sched_getcpu() always
> returns zero, as on powerpc, we call __kernel_getcpu() which relies
> upon SPRN_USPRG3 to report the CPU and NUMA node information.
>
> Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
> with the sprg_vdso value that is cached in PACA.
>
> Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs
> for stop4 cpuidle")
>
> Reported-by: Florian Weimer <fweimer@redhat.com>
> Cc: <stable@vger.kernel.org> # 4.14
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
> arch/powerpc/kernel/idle_book3s.S | 2 ++
> 1 file changed, 2 insertions(+)
What stable tree(s) do you want this applied to?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
2018-07-23 6:16 ` Greg KH
@ 2018-07-23 7:53 ` Greg KH
2018-07-23 12:13 ` Gautham R Shenoy
0 siblings, 1 reply; 7+ messages in thread
From: Greg KH @ 2018-07-23 7:53 UTC (permalink / raw)
To: Gautham R. Shenoy; +Cc: stable, Michael Ellerman
On Mon, Jul 23, 2018 at 08:16:28AM +0200, Greg KH wrote:
> On Mon, Jul 23, 2018 at 11:00:55AM +0530, Gautham R. Shenoy wrote:
> > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> >
> > [ Upstream commit b03897cf318dfc47de33a7ecbc7655584266f034 ]
> >
> > On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
> > SPRN_USPRG3 are used as userspace VDSO write and read registers
> > respectively.
> >
> > SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
> > restored. As a result, any read from SPRN_USPRG3 returns zero on an
> > exit from stop4 and above.
> >
> > Thus in this situation, on POWER9, any call from sched_getcpu() always
> > returns zero, as on powerpc, we call __kernel_getcpu() which relies
> > upon SPRN_USPRG3 to report the CPU and NUMA node information.
> >
> > Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
> > with the sprg_vdso value that is cached in PACA.
> >
> > Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs
> > for stop4 cpuidle")
> >
> > Reported-by: Florian Weimer <fweimer@redhat.com>
> > Cc: <stable@vger.kernel.org> # 4.14
> > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> > Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> > ---
> > arch/powerpc/kernel/idle_book3s.S | 2 ++
> > 1 file changed, 2 insertions(+)
>
> What stable tree(s) do you want this applied to?
I've now guessed that it is 4.14.y. If that's not the case, please let
me know.
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
2018-07-23 7:53 ` Greg KH
@ 2018-07-23 12:13 ` Gautham R Shenoy
0 siblings, 0 replies; 7+ messages in thread
From: Gautham R Shenoy @ 2018-07-23 12:13 UTC (permalink / raw)
To: Greg KH; +Cc: Gautham R. Shenoy, stable, Michael Ellerman
Hello Greg,
On Mon, Jul 23, 2018 at 09:53:50AM +0200, Greg KH wrote:
> On Mon, Jul 23, 2018 at 08:16:28AM +0200, Greg KH wrote:
> > On Mon, Jul 23, 2018 at 11:00:55AM +0530, Gautham R. Shenoy wrote:
> > > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> > >
> > > [ Upstream commit b03897cf318dfc47de33a7ecbc7655584266f034 ]
> > >
> > > On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
> > > SPRN_USPRG3 are used as userspace VDSO write and read registers
> > > respectively.
> > >
> > > SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
> > > restored. As a result, any read from SPRN_USPRG3 returns zero on an
> > > exit from stop4 and above.
> > >
> > > Thus in this situation, on POWER9, any call from sched_getcpu() always
> > > returns zero, as on powerpc, we call __kernel_getcpu() which relies
> > > upon SPRN_USPRG3 to report the CPU and NUMA node information.
> > >
> > > Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
> > > with the sprg_vdso value that is cached in PACA.
> > >
> > > Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs
> > > for stop4 cpuidle")
> > >
> > > Reported-by: Florian Weimer <fweimer@redhat.com>
> > > Cc: <stable@vger.kernel.org> # 4.14
> > > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> > > Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
> > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> > > ---
> > > arch/powerpc/kernel/idle_book3s.S | 2 ++
> > > 1 file changed, 2 insertions(+)
> >
> > What stable tree(s) do you want this applied to?
>
> I've now guessed that it is 4.14.y. If that's not the case, please let
> me know.
Yes, this backport is for 4.14.y. The upstream commit cleanly applies
on 4.15.18 and 4.16.18.
>
> greg k-h
>
--
Thanks and Regards
gautham.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
2018-07-17 11:27 Gautham R. Shenoy
@ 2018-07-17 11:47 ` Gautham R Shenoy
0 siblings, 0 replies; 7+ messages in thread
From: Gautham R Shenoy @ 2018-07-17 11:47 UTC (permalink / raw)
To: Gautham R. Shenoy
Cc: Michael Ellerman, Benjamin Herrenschmidt, Michael Neuling,
Vaidyanathan Srinivasan, linuxppc-dev, linux-kernel,
Florian Weimer, Oleg Nesterov
On Tue, Jul 17, 2018 at 04:57:29PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> On 64-bit Servers, SPRN_SPRG3 and its userspace read-only mirror
> SPRN_USPRG3 are used as userspace VDSO write and read registers
> respectively.
>
> SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
> restored. As a result, any read from SPRN_USPRG3 returns zero on an
> exit from stop4 and above.
>
> Thus in this situation, any call from sched_getcpu() always returns
This happens only on POWER9.
> zero, as on powerpc, we call __kernel_getcpu() which relies upon
> SPRN_USPRG3 to report the CPU and NUMA node information.
>
> Fix this by saving the SPRN_SPRG3 before entering a deep stop state,
> and restoring it back on wakeup from the stop state.
>
I forgot to add that this fixes commit e1c1cfed5432 ("powerpc/powernv:
Save/Restore additional SPRs for stop4 cpuidle").
@mpe, do you want me to send fresh patch with these updates ?
> Reported-by: Florian Weimer <fweimer@redhat.com>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/cpuidle.h | 1 +
> arch/powerpc/kernel/asm-offsets.c | 1 +
> arch/powerpc/kernel/idle_book3s.S | 5 +++++
> 3 files changed, 7 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
> index e210a83..03fa904 100644
> --- a/arch/powerpc/include/asm/cpuidle.h
> +++ b/arch/powerpc/include/asm/cpuidle.h
> @@ -77,6 +77,7 @@ struct stop_sprs {
> u64 mmcr1;
> u64 mmcr2;
> u64 mmcra;
> + u64 sprg3;
> };
>
> extern u32 pnv_fastsleep_workaround_at_entry[];
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 89cf155..a35ebfc 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -776,6 +776,7 @@ int main(void)
> STOP_SPR(STOP_MMCR1, mmcr1);
> STOP_SPR(STOP_MMCR2, mmcr2);
> STOP_SPR(STOP_MMCRA, mmcra);
> + STOP_SPR(STOP_SPRG3, sprg3);
> #endif
>
> DEFINE(PPC_DBELL_SERVER, PPC_DBELL_SERVER);
> diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
> index d85d551..5069d42 100644
> --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -120,6 +120,9 @@ power9_save_additional_sprs:
> mfspr r4, SPRN_MMCR2
> std r3, STOP_MMCR1(r13)
> std r4, STOP_MMCR2(r13)
> +
> + mfspr r3, SPRN_SPRG3
> + std r3, STOP_SPRG3(r13)
> blr
>
> power9_restore_additional_sprs:
> @@ -144,7 +147,9 @@ power9_restore_additional_sprs:
> mtspr SPRN_MMCR1, r4
>
> ld r3, STOP_MMCR2(r13)
> + ld r4, STOP_SPRG3(r13)
> mtspr SPRN_MMCR2, r3
> + mtspr SPRN_SPRG3, r4
> blr
>
> /*
> --
> 1.9.4
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
@ 2018-07-17 11:27 Gautham R. Shenoy
2018-07-17 11:47 ` Gautham R Shenoy
0 siblings, 1 reply; 7+ messages in thread
From: Gautham R. Shenoy @ 2018-07-17 11:27 UTC (permalink / raw)
To: Michael Ellerman, Benjamin Herrenschmidt, Michael Neuling,
Vaidyanathan Srinivasan
Cc: linuxppc-dev, linux-kernel, Florian Weimer, Gautham R. Shenoy,
Oleg Nesterov
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
On 64-bit Servers, SPRN_SPRG3 and its userspace read-only mirror
SPRN_USPRG3 are used as userspace VDSO write and read registers
respectively.
SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
restored. As a result, any read from SPRN_USPRG3 returns zero on an
exit from stop4 and above.
Thus in this situation, any call from sched_getcpu() always returns
zero, as on powerpc, we call __kernel_getcpu() which relies upon
SPRN_USPRG3 to report the CPU and NUMA node information.
Fix this by saving the SPRN_SPRG3 before entering a deep stop state,
and restoring it back on wakeup from the stop state.
Reported-by: Florian Weimer <fweimer@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/cpuidle.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/idle_book3s.S | 5 +++++
3 files changed, 7 insertions(+)
diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
index e210a83..03fa904 100644
--- a/arch/powerpc/include/asm/cpuidle.h
+++ b/arch/powerpc/include/asm/cpuidle.h
@@ -77,6 +77,7 @@ struct stop_sprs {
u64 mmcr1;
u64 mmcr2;
u64 mmcra;
+ u64 sprg3;
};
extern u32 pnv_fastsleep_workaround_at_entry[];
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 89cf155..a35ebfc 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -776,6 +776,7 @@ int main(void)
STOP_SPR(STOP_MMCR1, mmcr1);
STOP_SPR(STOP_MMCR2, mmcr2);
STOP_SPR(STOP_MMCRA, mmcra);
+ STOP_SPR(STOP_SPRG3, sprg3);
#endif
DEFINE(PPC_DBELL_SERVER, PPC_DBELL_SERVER);
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index d85d551..5069d42 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -120,6 +120,9 @@ power9_save_additional_sprs:
mfspr r4, SPRN_MMCR2
std r3, STOP_MMCR1(r13)
std r4, STOP_MMCR2(r13)
+
+ mfspr r3, SPRN_SPRG3
+ std r3, STOP_SPRG3(r13)
blr
power9_restore_additional_sprs:
@@ -144,7 +147,9 @@ power9_restore_additional_sprs:
mtspr SPRN_MMCR1, r4
ld r3, STOP_MMCR2(r13)
+ ld r4, STOP_SPRG3(r13)
mtspr SPRN_MMCR2, r3
+ mtspr SPRN_SPRG3, r4
blr
/*
--
1.9.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-07-23 13:14 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-07-22 16:33 FAILED: patch "[PATCH] powerpc/powernv: Fix save/restore of SPRG3 on entry/exit from" failed to apply to 4.14-stable tree gregkh
2018-07-23 5:30 ` [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop Gautham R. Shenoy
2018-07-23 6:16 ` Greg KH
2018-07-23 7:53 ` Greg KH
2018-07-23 12:13 ` Gautham R Shenoy
-- strict thread matches above, loose matches on Subject: below --
2018-07-17 11:27 Gautham R. Shenoy
2018-07-17 11:47 ` Gautham R Shenoy
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