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-rw-r--r--arch/powerpc/kernel/exceptions-64s.S79
-rw-r--r--arch/powerpc/kernel/idle_book3s.S25
2 files changed, 69 insertions, 35 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index e390fcd04bcb..28f8d7bed6b1 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -178,6 +178,12 @@ BEGIN_FTR_SECTION
* NOTE: We are here with MSR_ME=0 (off), which means we risk a
* checkstop if we get another machine check exception before we do
* rfid with MSR_ME=1.
+ *
+ * This interrupt can wake directly from idle. If that is the case,
+ * the machine check is handled then the idle wakeup code is called
+ * to restore state. In that case, the POWER9 DD1 idle PACA workaround
+ * is not applied in the early machine check code, which will cause
+ * bugs.
*/
mr r11,r1 /* Save r1 */
lhz r10,PACA_IN_MCE(r13)
@@ -306,6 +312,37 @@ EXC_COMMON_BEGIN(machine_check_common)
/* restore original r1. */ \
ld r1,GPR1(r1)
+#ifdef CONFIG_PPC_P7_NAP
+/*
+ * This is an idle wakeup. Low level machine check has already been
+ * done. Queue the event then call the idle code to do the wake up.
+ */
+EXC_COMMON_BEGIN(machine_check_idle_common)
+ bl machine_check_queue_event
+
+ /*
+ * We have not used any non-volatile GPRs here, and as a rule
+ * most exception code including machine check does not.
+ * Therefore PACA_NAPSTATELOST does not need to be set. Idle
+ * wakeup will restore volatile registers.
+ *
+ * Load the original SRR1 into r3 for pnv_powersave_wakeup_mce.
+ *
+ * Then decrement MCE nesting after finishing with the stack.
+ */
+ ld r3,_MSR(r1)
+
+ lhz r11,PACA_IN_MCE(r13)
+ subi r11,r11,1
+ sth r11,PACA_IN_MCE(r13)
+
+ /* Turn off the RI bit because SRR1 is used by idle wakeup code. */
+ /* Recoverability could be improved by reducing the use of SRR1. */
+ li r11,0
+ mtmsrd r11,1
+
+ b pnv_powersave_wakeup_mce
+#endif
/*
* Handle machine check early in real mode. We come here with
* ME=1, MMU (IR=0 and DR=0) off and using MC emergency stack.
@@ -318,6 +355,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
bl machine_check_early
std r3,RESULT(r1) /* Save result */
ld r12,_MSR(r1)
+
#ifdef CONFIG_PPC_P7_NAP
/*
* Check if thread was in power saving mode. We come here when any
@@ -328,43 +366,14 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
*
* Go back to nap/sleep/winkle mode again if (b) is true.
*/
- rlwinm. r11,r12,47-31,30,31 /* Was it in power saving mode? */
- beq 4f /* No, it wasn't */
- /* Thread was in power saving mode. Go back to nap again. */
- cmpwi r11,2
- blt 3f
- /* Supervisor/Hypervisor state loss */
- li r0,1
- stb r0,PACA_NAPSTATELOST(r13)
-3: bl machine_check_queue_event
- MACHINE_CHECK_HANDLER_WINDUP
- GET_PACA(r13)
- ld r1,PACAR1(r13)
- /*
- * Check what idle state this CPU was in and go back to same mode
- * again.
- */
- lbz r3,PACA_THREAD_IDLE_STATE(r13)
- cmpwi r3,PNV_THREAD_NAP
- bgt 10f
- IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP)
- /* No return */
-10:
- cmpwi r3,PNV_THREAD_SLEEP
- bgt 2f
- IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
- /* No return */
-
-2:
- /*
- * Go back to winkle. Please note that this thread was woken up in
- * machine check from winkle and have not restored the per-subcore
- * state.
- */
- IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
- /* No return */
+ BEGIN_FTR_SECTION
+ rlwinm. r11,r12,47-31,30,31
+ beq- 4f
+ BRANCH_TO_COMMON(r10, machine_check_idle_common)
4:
+ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#endif
+
/*
* Check if we are coming from hypervisor userspace. If yes then we
* continue in host kernel in V mode to deliver the MC event.
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index dd8ca7fdf55a..4e5a4fed86c5 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -416,6 +416,31 @@ power9_dd1_recover_paca:
blr
/*
+ * Called from machine check handler for powersave wakeups.
+ * Low level machine check processing has already been done. Now just
+ * go through the wake up path to get everything in order.
+ *
+ * r3 - The original SRR1 value.
+ * Original SRR[01] have been clobbered.
+ * MSR_RI is clear.
+ */
+.global pnv_powersave_wakeup_mce
+pnv_powersave_wakeup_mce:
+ /* Set cr3 for pnv_powersave_wakeup */
+ rlwinm r11,r3,47-31,30,31
+ cmpwi cr3,r11,2
+
+ /*
+ * Now put the original SRR1 with SRR1_WAKEMCE_RESVD as the wake
+ * reason into SRR1, which allows reuse of the system reset wakeup
+ * code without being mistaken for another type of wakeup.
+ */
+ oris r3,r3,SRR1_WAKEMCE_RESVD@h
+ mtspr SPRN_SRR1,r3
+
+ b pnv_powersave_wakeup
+
+/*
* Called from reset vector for powersave wakeups.
* cr3 - set to gt if waking up with partial/complete hypervisor state loss
*/