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authorNicholas Piggin <npiggin@gmail.com>2017-06-13 23:05:48 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2017-06-19 19:46:27 +1000
commita9af97aa0a12c30178dd7ad9af8887d5b9c4647b (patch)
tree463875705ded254aebad36ee4347c5eeba5b0846 /arch/powerpc/kernel/exceptions-64s.S
parent771d4304d07f080b6ce751e12f3579cb012a1b22 (diff)
powerpc/64s: msgclr when handling doorbell exceptions from system reset
msgsnd doorbell exceptions are cleared when the doorbell interrupt is taken. However if a doorbell exception causes a system reset interrupt wake from power saving state, the message is not cleared. Processing the doorbell from the system reset interrupt requires msgclr to avoid taking the exception again. Testing this plus the previous wakup direct patch gives: original wakeup direct msgclr Different threads, same core: 315k/s 264k/s 345k/s Different cores: 235k/s 242k/s 242k/s Net speedup is +10% for same core, and +3% for different core. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
-rw-r--r--arch/powerpc/kernel/exceptions-64s.S23
1 files changed, 21 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2f700a15bfa3..1752beefee69 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1612,6 +1612,25 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
b 1b
/*
+ * When doorbell is triggered from system reset wakeup, the message is
+ * not cleared, so it would fire again when EE is enabled.
+ *
+ * When coming from local_irq_enable, there may be the same problem if
+ * we were hard disabled.
+ *
+ * Execute msgclr to clear pending exceptions before handling it.
+ */
+h_doorbell_common_msgclr:
+ LOAD_REG_IMMEDIATE(r3, PPC_DBELL_MSGTYPE << (63-36))
+ PPC_MSGCLR(3)
+ b h_doorbell_common
+
+doorbell_super_common_msgclr:
+ LOAD_REG_IMMEDIATE(r3, PPC_DBELL_MSGTYPE << (63-36))
+ PPC_MSGCLRP(3)
+ b doorbell_super_common
+
+/*
* Called from arch_local_irq_enable when an interrupt needs
* to be resent. r3 contains 0x500, 0x900, 0xa00 or 0xe80 to indicate
* which kind of interrupt. MSR:EE is already off. We generate a
@@ -1636,13 +1655,13 @@ _GLOBAL(__replay_interrupt)
beq hardware_interrupt_common
BEGIN_FTR_SECTION
cmpwi r3,0xe80
- beq h_doorbell_common
+ beq h_doorbell_common_msgclr
cmpwi r3,0xea0
beq h_virt_irq_common
cmpwi r3,0xe60
beq hmi_exception_common
FTR_SECTION_ELSE
cmpwi r3,0xa00
- beq doorbell_super_common
+ beq doorbell_super_common_msgclr
ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
blr