powerpc: Add code to handle soft-disabled doorbells on server
This patch adds the logic to properly handle doorbells that come in when
interrupts have been soft disabled and to replay them when interrupts
are re-enabled:
- masked_##_H##interrupt is modified to leave interrupts enabled when a
doorbell has come in since doorbells are edge sensitive and as such
won't be automatically re-raised.
- __check_irq_replay now tests if a doorbell happened on book3s, and
returns either 0xe80 or 0xa00 depending on whether we are the
hypervisor or not.
- restore_check_irq_replay now tests for the two possible server
doorbell vector numbers to replay.
- __replay_interrupt also adds tests for the two server doorbell vector
numbers, and is modified to use a compare instruction rather than an
andi. on the single bit difference between 0x500 and 0x900.
The last two use a CPU feature section to avoid needlessly testing
against the hypervisor vector if it is not the hypervisor, and vice
versa.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 176bf99..32fc04f 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -528,10 +528,12 @@
KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xf40)
/*
- * An interrupt came in while soft-disabled. We set paca->irq_happened,
- * then, if it was a decrementer interrupt, we bump the dec to max and
- * and return, else we hard disable and return. This is called with
- * r10 containing the value to OR to the paca field.
+ * An interrupt came in while soft-disabled. We set paca->irq_happened, then:
+ * - If it was a decrementer interrupt, we bump the dec to max and and return.
+ * - If it was a doorbell we return immediately since doorbells are edge
+ * triggered and won't automatically refire.
+ * - else we hard disable and return.
+ * This is called with r10 containing the value to OR to the paca field.
*/
#define MASKED_INTERRUPT(_H) \
masked_##_H##interrupt: \
@@ -539,13 +541,15 @@
lbz r11,PACAIRQHAPPENED(r13); \
or r11,r11,r10; \
stb r11,PACAIRQHAPPENED(r13); \
- andi. r10,r10,PACA_IRQ_DEC; \
- beq 1f; \
+ cmpwi r10,PACA_IRQ_DEC; \
+ bne 1f; \
lis r10,0x7fff; \
ori r10,r10,0xffff; \
mtspr SPRN_DEC,r10; \
b 2f; \
-1: mfspr r10,SPRN_##_H##SRR1; \
+1: cmpwi r10,PACA_IRQ_DBELL; \
+ beq 2f; \
+ mfspr r10,SPRN_##_H##SRR1; \
rldicl r10,r10,48,1; /* clear MSR_EE */ \
rotldi r10,r10,16; \
mtspr SPRN_##_H##SRR1,r10; \
@@ -562,8 +566,8 @@
/*
* Called from arch_local_irq_enable when an interrupt needs
- * to be resent. r3 contains 0x500 or 0x900 to indicate which
- * kind of interrupt. MSR:EE is already off. We generate a
+ * to be resent. r3 contains 0x500, 0x900, 0xa00 or 0xe80 to indicate
+ * which kind of interrupt. MSR:EE is already off. We generate a
* stackframe like if a real interrupt had happened.
*
* Note: While MSR:EE is off, we need to make sure that _MSR
@@ -579,9 +583,18 @@
mflr r11
mfcr r9
ori r12,r12,MSR_EE
- andi. r3,r3,0x0800
- bne decrementer_common
- b hardware_interrupt_common
+ cmpwi r3,0x900
+ beq decrementer_common
+ cmpwi r3,0x500
+ beq hardware_interrupt_common
+BEGIN_FTR_SECTION
+ cmpwi r3,0xe80
+ beq h_doorbell_common
+FTR_SECTION_ELSE
+ cmpwi r3,0xa00
+ beq doorbell_super_common
+ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
+ blr
#ifdef CONFIG_PPC_PSERIES
/*