From a9af97aa0a12c30178dd7ad9af8887d5b9c4647b Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 13 Jun 2017 23:05:48 +1000 Subject: 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 Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/exceptions-64s.S | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/exceptions-64s.S') 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 @@ -1611,6 +1611,25 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) bl kernel_bad_stack 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 @@ -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 -- cgit v1.2.3-59-g8ed1b