* [RFC/PATCH] powernv: Handle wakeup from stop due to SRESET
@ 2016-11-21 18:37 Gautham R. Shenoy
2016-11-22 17:36 ` [PATCH v2] powernv: Handle wakeup from idle " Gautham R. Shenoy
0 siblings, 1 reply; 3+ messages in thread
From: Gautham R. Shenoy @ 2016-11-21 18:37 UTC (permalink / raw)
To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
Michael Neuling, Vaidyanathan Srinivasan, Shreyas B. Prabhu
Cc: linuxppc-dev@lists.ozlabs.org>,
linux-kernel@vger.kernel.org>,
skiboot, Gautham R. Shenoy
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
The existing code doesn't handle the case when CPU which was in a
hardware-idle state (nap,sleep,winkle on POWER8 and various stop
states on POWER9) gets woken up due to a System Reset interrupt.
This patch checks if the CPU was woken up due to System Reset, in
which case, after restoring the required hardware state, it jumps to
the system reset handler.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
---
arch/powerpc/kernel/idle_book3s.S | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 72dac0b..0098879 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -353,6 +353,18 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \
20: nop;
+#define CHECK_SRESET_INTERRUPT \
+BEGIN_FTR_SECTION_NESTED(67); \
+ mfspr r0,SPRN_SRR1; \
+ rlwinm r0,r0,45-31,0xf; /* Extract wake reason field (P8,9) */ \
+ cmpwi r0,0x4; /* System Reset ? */ \
+ bne 21f; \
+ b system_reset_common; \
+ b .; /* We shouldn't return here */ \
+FTR_SECTION_ELSE_NESTED(67); \
+ nop ; \
+ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 67); \
+21: nop;
/*
* r3 - requested stop state
@@ -644,6 +656,7 @@ _GLOBAL(pnv_wakeup_loss)
ld r1,PACAR1(r13)
BEGIN_FTR_SECTION
CHECK_HMI_INTERRUPT
+ CHECK_SRESET_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
REST_NVGPRS(r1)
REST_GPR(2, r1)
@@ -666,6 +679,7 @@ _GLOBAL(pnv_wakeup_noloss)
bne pnv_wakeup_loss
BEGIN_FTR_SECTION
CHECK_HMI_INTERRUPT
+ CHECK_SRESET_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
ld r1,PACAR1(r13)
ld r6,_CCR(r1)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH v2] powernv: Handle wakeup from idle due to SRESET
2016-11-21 18:37 [RFC/PATCH] powernv: Handle wakeup from stop due to SRESET Gautham R. Shenoy
@ 2016-11-22 17:36 ` Gautham R. Shenoy
2016-11-22 21:18 ` Paul Mackerras
0 siblings, 1 reply; 3+ messages in thread
From: Gautham R. Shenoy @ 2016-11-22 17:36 UTC (permalink / raw)
To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
Michael Neuling, Vaidyanathan Srinivasan, Shreyas B. Prabhu
Cc: linuxppc-dev, linux-kernel, Gautham R. Shenoy
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
The existing code doesn't handle the case when CPU which was in a
hardware-idle state (nap,sleep,winkle on POWER8 and various stop
states on POWER9) gets woken up due to a System Reset interrupt.
This patch checks if the CPU was woken up due to System Reset, in
which case, after restoring the required hardware state, it jumps to
the system reset handler.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
---
v1 -> v2: Set r9,r11,r12 to CR,SRR0,SRR1 values
before jumping to system_reset_common as expected by
EXCEPTION_PROLOG_COMMON
arch/powerpc/kernel/idle_book3s.S | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 72dac0b..06afe0e 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -353,6 +353,22 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \
20: nop;
+#define CHECK_SRESET_INTERRUPT \
+BEGIN_FTR_SECTION_NESTED(67); \
+ mfspr r0,SPRN_SRR1; \
+ rlwinm r0,r0,45-31,0xf; /* Extract wake reason field (P8,9) */ \
+ cmpwi r0,0x4; /* System Reset ? */ \
+ bne 21f; \
+ ld r1,PACAR1(r13); \
+ ld r9,_CCR(r1); \
+ ld r11,_NIP(r1); \
+ mfspr r12, SPRN_SRR1; \
+ b system_reset_common ; \
+ b .; /* We shouldn't return here */ \
+FTR_SECTION_ELSE_NESTED(67); \
+ nop ; \
+ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 67); \
+21: nop;
/*
* r3 - requested stop state
@@ -644,6 +660,7 @@ _GLOBAL(pnv_wakeup_loss)
ld r1,PACAR1(r13)
BEGIN_FTR_SECTION
CHECK_HMI_INTERRUPT
+ CHECK_SRESET_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
REST_NVGPRS(r1)
REST_GPR(2, r1)
@@ -666,6 +683,7 @@ _GLOBAL(pnv_wakeup_noloss)
bne pnv_wakeup_loss
BEGIN_FTR_SECTION
CHECK_HMI_INTERRUPT
+ CHECK_SRESET_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
ld r1,PACAR1(r13)
ld r6,_CCR(r1)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] powernv: Handle wakeup from idle due to SRESET
2016-11-22 17:36 ` [PATCH v2] powernv: Handle wakeup from idle " Gautham R. Shenoy
@ 2016-11-22 21:18 ` Paul Mackerras
0 siblings, 0 replies; 3+ messages in thread
From: Paul Mackerras @ 2016-11-22 21:18 UTC (permalink / raw)
To: Gautham R. Shenoy
Cc: Michael Ellerman, Benjamin Herrenschmidt, Michael Neuling,
Vaidyanathan Srinivasan, Shreyas B. Prabhu, linuxppc-dev,
linux-kernel
On Tue, Nov 22, 2016 at 11:06:32PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> The existing code doesn't handle the case when CPU which was in a
> hardware-idle state (nap,sleep,winkle on POWER8 and various stop
> states on POWER9) gets woken up due to a System Reset interrupt.
>
> This patch checks if the CPU was woken up due to System Reset, in
> which case, after restoring the required hardware state, it jumps to
> the system reset handler.
>
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> v1 -> v2: Set r9,r11,r12 to CR,SRR0,SRR1 values
> before jumping to system_reset_common as expected by
> EXCEPTION_PROLOG_COMMON
>
> arch/powerpc/kernel/idle_book3s.S | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
> index 72dac0b..06afe0e 100644
> --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -353,6 +353,22 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
> ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \
> 20: nop;
>
> +#define CHECK_SRESET_INTERRUPT \
> +BEGIN_FTR_SECTION_NESTED(67); \
> + mfspr r0,SPRN_SRR1; \
> + rlwinm r0,r0,45-31,0xf; /* Extract wake reason field (P8,9) */ \
> + cmpwi r0,0x4; /* System Reset ? */ \
> + bne 21f; \
> + ld r1,PACAR1(r13); \
> + ld r9,_CCR(r1); \
> + ld r11,_NIP(r1); \
> + mfspr r12, SPRN_SRR1; \
> + b system_reset_common ; \
> + b .; /* We shouldn't return here */ \
> +FTR_SECTION_ELSE_NESTED(67); \
> + nop ; \
> +ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 67); \
What's the point of the else section?
Paul.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-11-21 18:37 [RFC/PATCH] powernv: Handle wakeup from stop due to SRESET Gautham R. Shenoy
2016-11-22 17:36 ` [PATCH v2] powernv: Handle wakeup from idle " Gautham R. Shenoy
2016-11-22 21:18 ` Paul Mackerras
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