[PATCH 0/3] Add HMI handling in Linux host.

[PATCH 0/3] Add HMI handling in Linux host.

[Mahesh J Salgaonkar]

This patch series implements HMI interrupt handling in Linux. First patch
implements basic infrastructure to handle HMI in Linux host. Second patch
invokes opal call to handle hmi in opal firmware and retrieve HMI event
generated by opal. Third patch handles HMI received on cpus in sleep/nap mode.

This patchset have been tested with following scenario:
a. SMT on mode
b. SMT off mode without any guest
c. SMT off + multiple guest
c. SMT off + multiple guest running 'find /' command

Thanks,
-Mahesh.
---

Mahesh Salgaonkar (3):
      powerpc/book3s: Add basic infrastructure to handle HMI in Linux.
      powerpc/powernv: Invoke opal call to handle hmi.
      powerpc/book3s: handle HMIs for cpus in nap mode.


 arch/powerpc/include/asm/exception-64s.h       |    2 
 arch/powerpc/include/asm/hardirq.h             |    1 
 arch/powerpc/include/asm/hw_irq.h              |    1 
 arch/powerpc/include/asm/kvm_asm.h             |    1 
 arch/powerpc/include/asm/machdep.h             |    4 +
 arch/powerpc/include/asm/opal.h                |   49 ++++++
 arch/powerpc/include/asm/paca.h                |    1 
 arch/powerpc/kernel/entry_64.S                 |    5 +
 arch/powerpc/kernel/exceptions-64s.S           |   66 ++++++++
 arch/powerpc/kernel/idle_power7.S              |   32 ++++
 arch/powerpc/kernel/irq.c                      |   14 ++
 arch/powerpc/kernel/traps.c                    |   24 +++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S        |    6 +
 arch/powerpc/platforms/powernv/Makefile        |    2 
 arch/powerpc/platforms/powernv/opal-hmi.c      |  188 ++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/opal-wrappers.S |    1 
 arch/powerpc/platforms/powernv/opal.c          |   43 +++++
 arch/powerpc/platforms/powernv/setup.c         |    2 
 18 files changed, 435 insertions(+), 7 deletions(-)
 create mode 100644 arch/powerpc/platforms/powernv/opal-hmi.c

--
Signature

[PATCH 1/3] powerpc/book3s: Add basic infrastructure to handle HMI in Linux.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

Handle Hypervisor Maintenance Interrupt (HMI) in Linux. This patch implements
basic infrastructure to handle HMI in Linux host. The design is to invoke
opal handle hmi in real mode for recovery and set irq_pending when we hit HMI.
During check_irq_replay pull opal hmi event and print hmi info on console.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/exception-64s.h |    2 +
 arch/powerpc/include/asm/hardirq.h       |    1 
 arch/powerpc/include/asm/hw_irq.h        |    1 
 arch/powerpc/include/asm/kvm_asm.h       |    1 
 arch/powerpc/include/asm/machdep.h       |    4 ++
 arch/powerpc/include/asm/opal.h          |    2 +
 arch/powerpc/kernel/entry_64.S           |    5 ++
 arch/powerpc/kernel/exceptions-64s.S     |   66 +++++++++++++++++++++++++++++-
 arch/powerpc/kernel/irq.c                |   14 ++++++
 arch/powerpc/kernel/traps.c              |   24 +++++++++++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S  |    6 +++
 arch/powerpc/platforms/powernv/opal.c    |   14 ++++++
 arch/powerpc/platforms/powernv/setup.c   |    2 +
 13 files changed, 139 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 8f35cd7..f99ea33 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -425,6 +425,8 @@ label##_relon_hv:						\
 #define SOFTEN_VALUE_0xa00	PACA_IRQ_DBELL
 #define SOFTEN_VALUE_0xe80	PACA_IRQ_DBELL
 #define SOFTEN_VALUE_0xe82	PACA_IRQ_DBELL
+#define SOFTEN_VALUE_0xe60	PACA_IRQ_HMI
+#define SOFTEN_VALUE_0xe62	PACA_IRQ_HMI
 
 #define __SOFTEN_TEST(h, vec)						\
 	lbz	r10,PACASOFTIRQEN(r13);					\
diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h
index 418fb65..1bbb301 100644
--- a/arch/powerpc/include/asm/hardirq.h
+++ b/arch/powerpc/include/asm/hardirq.h
@@ -11,6 +11,7 @@ typedef struct {
 	unsigned int pmu_irqs;
 	unsigned int mce_exceptions;
 	unsigned int spurious_irqs;
+	unsigned int hmi_exceptions;
 #ifdef CONFIG_PPC_DOORBELL
 	unsigned int doorbell_irqs;
 #endif
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 10be1dd..b59ac27 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -25,6 +25,7 @@
 #define PACA_IRQ_EE		0x04
 #define PACA_IRQ_DEC		0x08 /* Or FIT */
 #define PACA_IRQ_EE_EDGE	0x10 /* BookE only */
+#define PACA_IRQ_HMI		0x20
 
 #endif /* CONFIG_PPC64 */
 
diff --git a/arch/powerpc/include/asm/kvm_asm.h b/arch/powerpc/include/asm/kvm_asm.h
index 9601741..ecf7e13 100644
--- a/arch/powerpc/include/asm/kvm_asm.h
+++ b/arch/powerpc/include/asm/kvm_asm.h
@@ -98,6 +98,7 @@
 #define BOOK3S_INTERRUPT_H_DATA_STORAGE	0xe00
 #define BOOK3S_INTERRUPT_H_INST_STORAGE	0xe20
 #define BOOK3S_INTERRUPT_H_EMUL_ASSIST	0xe40
+#define BOOK3S_INTERRUPT_HMI		0xe60
 #define BOOK3S_INTERRUPT_H_DOORBELL	0xe80
 #define BOOK3S_INTERRUPT_PERFMON	0xf00
 #define BOOK3S_INTERRUPT_ALTIVEC	0xf20
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index f92b0b5..06bcf5bd 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -174,6 +174,10 @@ struct machdep_calls {
 	/* Exception handlers */
 	int		(*system_reset_exception)(struct pt_regs *regs);
 	int 		(*machine_check_exception)(struct pt_regs *regs);
+	int		(*handle_hmi_exception)(struct pt_regs *regs);
+
+	/* Early exception handlers called in realmode */
+	int		(*hmi_exception_early)(struct pt_regs *regs);
 
 	/* Called during machine check exception to retrive fixup address. */
 	bool		(*mce_check_early_recovery)(struct pt_regs *regs);
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 0da1dbd..dd1cf8d 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -902,6 +902,8 @@ extern void opal_msglog_init(void);
 
 extern int opal_machine_check(struct pt_regs *regs);
 extern bool opal_mce_check_early_recovery(struct pt_regs *regs);
+extern int opal_hmi_exception_early(struct pt_regs *regs);
+extern int opal_handle_hmi_exception(struct pt_regs *regs);
 
 extern void opal_shutdown(void);
 extern int opal_resync_timebase(void);
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 6528c5e..e9423a8 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -919,6 +919,11 @@ restore_check_irq_replay:
 	addi	r3,r1,STACK_FRAME_OVERHEAD;
  	bl	do_IRQ
 	b	ret_from_except
+1:	cmpwi	cr0,r3,0xe60
+	bne	1f
+	addi	r3,r1,STACK_FRAME_OVERHEAD;
+	bl	handle_hmi_exception
+	b	ret_from_except
 1:	cmpwi	cr0,r3,0x900
 	bne	1f
 	addi	r3,r1,STACK_FRAME_OVERHEAD;
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index a7d36b1..141ce6b 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -339,7 +339,7 @@ emulation_assist_trampoline:
 hv_exception_trampoline:
 	SET_SCRATCH0(r13)
 	EXCEPTION_PROLOG_0(PACA_EXGEN)
-	b	hmi_exception_hv
+	b	hmi_exception_early
 
 	. = 0xe80
 hv_doorbell_trampoline:
@@ -621,8 +621,64 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe22)
 	STD_EXCEPTION_HV_OOL(0xe42, emulation_assist)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe42)
-	STD_EXCEPTION_HV_OOL(0xe62, hmi_exception) /* need to flush cache ? */
+	MASKABLE_EXCEPTION_HV_OOL(0xe62, hmi_exception)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe62)
+
+	.globl hmi_exception_early
+hmi_exception_early:
+	EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0xe60)
+	mr	r10,r1			/* Save r1			*/
+	ld	r1,PACAEMERGSP(r13)	/* Use emergency stack		*/
+	subi	r1,r1,INT_FRAME_SIZE	/* alloc stack frame		*/
+	std	r9,_CCR(r1)		/* save CR in stackframe	*/
+	mfspr	r11,SPRN_HSRR0		/* Save HSRR0 */
+	std	r11,_NIP(r1)		/* save HSRR0 in stackframe	*/
+	mfspr	r12,SPRN_HSRR1		/* Save SRR1 */
+	std	r12,_MSR(r1)		/* save SRR1 in stackframe	*/
+	std	r10,0(r1)		/* make stack chain pointer	*/
+	std	r0,GPR0(r1)		/* save r0 in stackframe	*/
+	std	r10,GPR1(r1)		/* save r1 in stackframe	*/
+	EXCEPTION_PROLOG_COMMON_2(PACA_EXGEN)
+	EXCEPTION_PROLOG_COMMON_3(0xe60)
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	bl	hmi_exception_realmode
+	/* Windup the stack. */
+	/* Clear MSR_RI before setting SRR0 and SRR1. */
+	li	r0,MSR_RI
+	mfmsr	r9			/* get MSR value */
+	andc	r9,r9,r0
+	mtmsrd	r9,1			/* Clear MSR_RI */
+	/* Move original HSRR0 and HSRR1 into the respective regs */
+	ld	r9,_MSR(r1)
+	mtspr	SPRN_HSRR1,r9
+	ld	r3,_NIP(r1)
+	mtspr	SPRN_HSRR0,r3
+	ld	r9,_CTR(r1)
+	mtctr	r9
+	ld	r9,_XER(r1)
+	mtxer	r9
+	ld	r9,_LINK(r1)
+	mtlr	r9
+	REST_GPR(0, r1)
+	REST_8GPRS(2, r1)
+	REST_GPR(10, r1)
+	ld	r11,_CCR(r1)
+	mtcr	r11
+	REST_GPR(11, r1)
+	REST_2GPRS(12, r1)
+	/* restore original r1. */
+	ld	r1,GPR1(r1)
+
+	/*
+	 * Go to virtual mode and pull the HMI event information from
+	 * firmware.
+	 */
+	.globl hmi_exception_after_realmode
+hmi_exception_after_realmode:
+	SET_SCRATCH0(r13)
+	EXCEPTION_PROLOG_0(PACA_EXGEN)
+	b	hmi_exception_hv
+
 	MASKABLE_EXCEPTION_HV_OOL(0xe82, h_doorbell)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe82)
 
@@ -643,6 +699,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
  * - 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.
+ * - If it was a HMI we return immediately since we handled it in realmode
+ *   and it won't refire.
  * - else we hard disable and return.
  * This is called with r10 containing the value to OR to the paca field.
  */
@@ -660,6 +718,8 @@ masked_##_H##interrupt:					\
 	b	2f;					\
 1:	cmpwi	r10,PACA_IRQ_DBELL;			\
 	beq	2f;					\
+	cmpwi	r10,PACA_IRQ_HMI;			\
+	beq	2f;					\
 	mfspr	r10,SPRN_##_H##SRR1;			\
 	rldicl	r10,r10,48,1; /* clear MSR_EE */	\
 	rotldi	r10,r10,16;				\
@@ -799,7 +859,7 @@ kvmppc_skip_Hinterrupt:
 	STD_EXCEPTION_COMMON(0xd00, single_step, single_step_exception)
 	STD_EXCEPTION_COMMON(0xe00, trap_0e, unknown_exception)
 	STD_EXCEPTION_COMMON(0xe40, emulation_assist, emulation_assist_interrupt)
-	STD_EXCEPTION_COMMON(0xe60, hmi_exception, unknown_exception)
+	STD_EXCEPTION_COMMON_ASYNC(0xe60, hmi_exception, handle_hmi_exception)
 #ifdef CONFIG_PPC_DOORBELL
 	STD_EXCEPTION_COMMON_ASYNC(0xe80, h_doorbell, doorbell_exception)
 #else
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 248ee7e..4c5891d 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -189,6 +189,11 @@ notrace unsigned int __check_irq_replay(void)
 	}
 #endif /* CONFIG_PPC_BOOK3E */
 
+	/* Check if an hypervisor Maintenance interrupt happened */
+	local_paca->irq_happened &= ~PACA_IRQ_HMI;
+	if (happened & PACA_IRQ_HMI)
+		return 0xe60;
+
 	/* There should be nothing left ! */
 	BUG_ON(local_paca->irq_happened != 0);
 
@@ -377,6 +382,14 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
 	seq_printf(p, "  Machine check exceptions\n");
 
+	if (cpu_has_feature(CPU_FTR_HVMODE)) {
+		seq_printf(p, "%*s: ", prec, "HMI");
+		for_each_online_cpu(j)
+			seq_printf(p, "%10u ",
+					per_cpu(irq_stat, j).hmi_exceptions);
+		seq_printf(p, "  Hypervisor Maintenance Interrupts\n");
+	}
+
 #ifdef CONFIG_PPC_DOORBELL
 	if (cpu_has_feature(CPU_FTR_DBELL)) {
 		seq_printf(p, "%*s: ", prec, "DBL");
@@ -400,6 +413,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 	sum += per_cpu(irq_stat, cpu).mce_exceptions;
 	sum += per_cpu(irq_stat, cpu).spurious_irqs;
 	sum += per_cpu(irq_stat, cpu).timer_irqs_others;
+	sum += per_cpu(irq_stat, cpu).hmi_exceptions;
 #ifdef CONFIG_PPC_DOORBELL
 	sum += per_cpu(irq_stat, cpu).doorbell_irqs;
 #endif
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 239f1cd..0ace286 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -302,6 +302,16 @@ long machine_check_early(struct pt_regs *regs)
 	return handled;
 }
 
+long hmi_exception_realmode(struct pt_regs *regs)
+{
+	__get_cpu_var(irq_stat).hmi_exceptions++;
+
+	if (ppc_md.hmi_exception_early)
+		ppc_md.hmi_exception_early(regs);
+
+	return 0;
+}
+
 #endif
 
 /*
@@ -738,6 +748,20 @@ void SMIException(struct pt_regs *regs)
 	die("System Management Interrupt", regs, SIGABRT);
 }
 
+void handle_hmi_exception(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs;
+
+	old_regs = set_irq_regs(regs);
+	irq_enter();
+
+	if (ppc_md.handle_hmi_exception)
+		ppc_md.handle_hmi_exception(regs);
+
+	irq_exit();
+	set_irq_regs(old_regs);
+}
+
 void unknown_exception(struct pt_regs *regs)
 {
 	enum ctx_state prev_state = exception_enter();
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 868347e..0de9309 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -159,6 +159,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 	cmpwi	r12, BOOK3S_INTERRUPT_EXTERNAL
 BEGIN_FTR_SECTION
 	beq	11f
+	cmpwi	cr2, r12, BOOK3S_INTERRUPT_HMI
+	beq	cr2, 14f			/* HMI check */
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
 	/* RFI into the highmem handler, or branch to interrupt handler */
@@ -179,6 +181,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
 13:	b	machine_check_fwnmi
 
+14:	mtspr	SPRN_HSRR0, r8
+	mtspr	SPRN_HSRR1, r7
+	b	hmi_exception_after_realmode
+
 kvmppc_primary_no_guest:
 	/* We handle this much like a ceded vcpu */
 	/* set our bit in napping_threads */
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 1999756..af4c5ac 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -513,6 +513,20 @@ int opal_machine_check(struct pt_regs *regs)
 	return 0;
 }
 
+/* Early hmi handler called in real mode. */
+int opal_hmi_exception_early(struct pt_regs *regs)
+{
+	/* TODO: Call opal hmi handler. */
+	return 0;
+}
+
+/* HMI exception handler called in virtual mode during check_irq_replay. */
+int opal_handle_hmi_exception(struct pt_regs *regs)
+{
+	/* TODO: Retrive and print HMI event from OPAL. */
+	return 0;
+}
+
 static uint64_t find_recovery_address(uint64_t nip)
 {
 	int i;
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index d9b88fa..5a0e2dc 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -264,6 +264,8 @@ static void __init pnv_setup_machdep_opal(void)
 	ppc_md.halt = pnv_halt;
 	ppc_md.machine_check_exception = opal_machine_check;
 	ppc_md.mce_check_early_recovery = opal_mce_check_early_recovery;
+	ppc_md.hmi_exception_early = opal_hmi_exception_early;
+	ppc_md.handle_hmi_exception = opal_handle_hmi_exception;
 }
 
 #ifdef CONFIG_PPC_POWERNV_RTAS

[PATCH 2/3] powerpc/powernv: Invoke opal call to handle hmi.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

When we hit the HMI in Linux, invoke opal call to handle/recover from HMI
errors in real mode and then in virtual mode during check_irq_replay()
invoke opal_poll_events()/opal_do_notifier() to retrieve HMI event from
OPAL and act accordingly.

Now that we are ready to handle HMI interrupt directly in linux, remove
the HMI interrupt registration with firmware.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/opal.h                |   47 ++++++
 arch/powerpc/include/asm/paca.h                |    1 
 arch/powerpc/platforms/powernv/Makefile        |    2 
 arch/powerpc/platforms/powernv/opal-hmi.c      |  188 ++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/opal-wrappers.S |    1 
 arch/powerpc/platforms/powernv/opal.c          |   35 ++++
 6 files changed, 267 insertions(+), 7 deletions(-)
 create mode 100644 arch/powerpc/platforms/powernv/opal-hmi.c

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index dd1cf8d..b81b99e 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -147,6 +147,7 @@ struct opal_sg_list {
 #define OPAL_SET_PARAM				90
 #define OPAL_DUMP_RESEND			91
 #define OPAL_DUMP_INFO2				94
+#define OPAL_HANDLE_HMI				98
 
 #ifndef __ASSEMBLY__
 
@@ -240,6 +241,7 @@ enum OpalMessageType {
 	OPAL_MSG_MEM_ERR,
 	OPAL_MSG_EPOW,
 	OPAL_MSG_SHUTDOWN,
+	OPAL_MSG_HMI_EVT,
 	OPAL_MSG_TYPE_MAX,
 };
 
@@ -502,6 +504,50 @@ struct OpalMemoryErrorData {
 	} u;
 };
 
+/* HMI interrupt event */
+enum OpalHMI_Version {
+	OpalHMIEvt_V1 = 1,
+};
+
+enum OpalHMI_Severity {
+	OpalHMI_SEV_NO_ERROR = 0,
+	OpalHMI_SEV_WARNING = 1,
+	OpalHMI_SEV_ERROR_SYNC = 2,
+	OpalHMI_SEV_FATAL = 3,
+};
+
+enum OpalHMI_Disposition {
+	OpalHMI_DISPOSITION_RECOVERED = 0,
+	OpalHMI_DISPOSITION_NOT_RECOVERED = 1,
+};
+
+enum OpalHMI_ErrType {
+	OpalHMI_ERROR_MALFUNC_ALERT	= 0,
+	OpalHMI_ERROR_PROC_RECOV_DONE,
+	OpalHMI_ERROR_PROC_RECOV_DONE_AGAIN,
+	OpalHMI_ERROR_PROC_RECOV_MASKED,
+	OpalHMI_ERROR_TFAC,
+	OpalHMI_ERROR_TFMR_PARITY,
+	OpalHMI_ERROR_HA_OVERFLOW_WARN,
+	OpalHMI_ERROR_XSCOM_FAIL,
+	OpalHMI_ERROR_XSCOM_DONE,
+	OpalHMI_ERROR_SCOM_FIR,
+	OpalHMI_ERROR_DEBUG_TRIG_FIR,
+	OpalHMI_ERROR_HYP_RESOURCE,
+};
+
+struct OpalHMIEvent {
+	uint8_t		version;	/* 0x00 */
+	uint8_t		severity;	/* 0x01 */
+	uint8_t		type;		/* 0x02 */
+	uint8_t		disposition;	/* 0x03 */
+	uint8_t		reserved_1[4];	/* 0x04 */
+
+	__be64		hmer;
+	/* TFMR register. Valid only for TFAC and TFMR_PARITY error type. */
+	__be64		tfmr;
+};
+
 enum {
 	OPAL_P7IOC_DIAG_TYPE_NONE	= 0,
 	OPAL_P7IOC_DIAG_TYPE_RGC	= 1,
@@ -860,6 +906,7 @@ int64_t opal_get_param(uint64_t token, uint32_t param_id, uint64_t buffer,
 int64_t opal_set_param(uint64_t token, uint32_t param_id, uint64_t buffer,
 		uint64_t length);
 int64_t opal_sensor_read(uint32_t sensor_hndl, int token, __be32 *sensor_data);
+int64_t opal_handle_hmi(void);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index bb0bd25..dd799a3 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -171,6 +171,7 @@ struct paca_struct {
 	 * and already using emergency stack.
 	 */
 	u16 in_mce;
+	u8 hmi_event_available;		 /* HMI event is available */
 #endif
 
 	/* Stuff for accurate time accounting */
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 4ad227d..495fed0 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,7 +1,7 @@
 obj-y			+= setup.o opal-wrappers.o opal.o opal-async.o
 obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
-obj-y			+= opal-msglog.o
+obj-y			+= opal-msglog.o opal-hmi.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/opal-hmi.c b/arch/powerpc/platforms/powernv/opal-hmi.c
new file mode 100644
index 0000000..97ac8dc
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-hmi.c
@@ -0,0 +1,188 @@
+/*
+ * OPAL hypervisor Maintenance interrupt handling support in PowreNV.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 IBM Corporation
+ * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include <asm/opal.h>
+#include <asm/cputable.h>
+
+static int opal_hmi_handler_nb_init;
+struct OpalHmiEvtNode {
+	struct list_head list;
+	struct OpalHMIEvent hmi_evt;
+};
+static LIST_HEAD(opal_hmi_evt_list);
+static DEFINE_SPINLOCK(opal_hmi_evt_lock);
+
+static void print_hmi_event_info(struct OpalHMIEvent *hmi_evt)
+{
+	const char *level, *sevstr, *error_info;
+	static const char *hmi_error_types[] = {
+		"Malfunction Alert",
+		"Processor Recovery done",
+		"Processor recovery occurred again",
+		"Processor recovery occurred for masked error",
+		"Timer facility experienced an error",
+		"TFMR SPR is corrupted",
+		"UPS (Uniterrupted Power System) Overflow indication",
+		"An XSCOM operation failure",
+		"An XSCOM operation completed",
+		"SCOM has set a reserved FIR bit to cause recovery",
+		"Debug trigger has set a reserved FIR bit to cause recovery",
+		"A hypervisor resource error occurred"
+	};
+
+	/* Print things out */
+	if (hmi_evt->version != OpalHMIEvt_V1) {
+		pr_err("HMI Interrupt, Unknown event version %d !\n",
+			hmi_evt->version);
+		return;
+	}
+	switch (hmi_evt->severity) {
+	case OpalHMI_SEV_NO_ERROR:
+		level = KERN_INFO;
+		sevstr = "Harmless";
+		break;
+	case OpalHMI_SEV_WARNING:
+		level = KERN_WARNING;
+		sevstr = "";
+		break;
+	case OpalHMI_SEV_ERROR_SYNC:
+		level = KERN_ERR;
+		sevstr = "Severe";
+		break;
+	case OpalHMI_SEV_FATAL:
+	default:
+		level = KERN_ERR;
+		sevstr = "Fatal";
+		break;
+	}
+
+	printk("%s%s Hypervisor Maintenance interrupt [%s]\n",
+		level, sevstr,
+		hmi_evt->disposition == OpalHMI_DISPOSITION_RECOVERED ?
+		"Recovered" : "Not recovered");
+	error_info = hmi_evt->type < ARRAY_SIZE(hmi_error_types) ?
+			hmi_error_types[hmi_evt->type]
+			: "Unknown";
+	printk("%s Error detail: %s\n", level, error_info);
+	printk("%s	HMER: %016llx\n", level, be64_to_cpu(hmi_evt->hmer));
+	if ((hmi_evt->type == OpalHMI_ERROR_TFAC) ||
+		(hmi_evt->type == OpalHMI_ERROR_TFMR_PARITY))
+		printk("%s	TFMR: %016llx\n", level,
+						be64_to_cpu(hmi_evt->tfmr));
+}
+
+static void hmi_event_handler(struct work_struct *work)
+{
+	unsigned long flags;
+	struct OpalHMIEvent *hmi_evt;
+	struct OpalHmiEvtNode *msg_node;
+	uint8_t disposition;
+
+	spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+	while (!list_empty(&opal_hmi_evt_list)) {
+		msg_node = list_entry(opal_hmi_evt_list.next,
+					   struct OpalHmiEvtNode, list);
+		list_del(&msg_node->list);
+		spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+
+		hmi_evt = (struct OpalHMIEvent *) &msg_node->hmi_evt;
+		print_hmi_event_info(hmi_evt);
+		disposition = hmi_evt->disposition;
+		kfree(msg_node);
+
+		/*
+		 * Check if HMI event has been recovered or not. If not
+		 * then we can't continue, invoke panic.
+		 */
+		if (disposition != OpalHMI_DISPOSITION_RECOVERED)
+			panic("Unrecoverable HMI exception");
+
+		spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+	}
+	spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+}
+
+static DECLARE_WORK(hmi_event_work, hmi_event_handler);
+/*
+ * opal_handle_hmi_event - notifier handler that queues up HMI events
+ * to be preocessed later.
+ */
+static int opal_handle_hmi_event(struct notifier_block *nb,
+			  unsigned long msg_type, void *msg)
+{
+	unsigned long flags;
+	struct OpalHMIEvent *hmi_evt;
+	struct opal_msg *hmi_msg = msg;
+	struct OpalHmiEvtNode *msg_node;
+
+	/* Sanity Checks */
+	if (msg_type != OPAL_MSG_HMI_EVT)
+		return 0;
+
+	/* HMI event info starts from param[0] */
+	hmi_evt = (struct OpalHMIEvent *)&hmi_msg->params[0];
+
+	/* Delay the logging of HMI events to workqueue. */
+	msg_node = kzalloc(sizeof(*msg_node), GFP_ATOMIC);
+	if (!msg_node) {
+		pr_err("HMI: out of memory, Opal message event not handled\n");
+		return -ENOMEM;
+	}
+	memcpy(&msg_node->hmi_evt, hmi_evt, sizeof(struct OpalHMIEvent));
+
+	spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+	list_add(&msg_node->list, &opal_hmi_evt_list);
+	spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+
+	schedule_work(&hmi_event_work);
+	return 0;
+}
+
+static struct notifier_block opal_hmi_handler_nb = {
+	.notifier_call	= opal_handle_hmi_event,
+	.next		= NULL,
+	.priority	= 0,
+};
+
+static int __init opal_hmi_handler_init(void)
+{
+	int ret;
+
+	if (!opal_hmi_handler_nb_init) {
+		ret = opal_message_notifier_register(
+				OPAL_MSG_HMI_EVT, &opal_hmi_handler_nb);
+		if (ret) {
+			pr_err("%s: Can't register OPAL event notifier (%d)\n",
+			       __func__, ret);
+			return ret;
+		}
+		opal_hmi_handler_nb_init = 1;
+	}
+	return 0;
+}
+subsys_initcall(opal_hmi_handler_init);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 4abbff2..8d98745 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -146,3 +146,4 @@ OPAL_CALL(opal_sync_host_reboot,		OPAL_SYNC_HOST_REBOOT);
 OPAL_CALL(opal_sensor_read,			OPAL_SENSOR_READ);
 OPAL_CALL(opal_get_param,			OPAL_GET_PARAM);
 OPAL_CALL(opal_set_param,			OPAL_SET_PARAM);
+OPAL_CALL(opal_handle_hmi,			OPAL_HANDLE_HMI);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index af4c5ac..05b24dc 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -192,9 +192,6 @@ static int __init opal_register_exception_handlers(void)
 	 * fwnmi area at 0x7000 to provide the glue space to OPAL
 	 */
 	glue = 0x7000;
-	opal_register_exception_handler(OPAL_HYPERVISOR_MAINTENANCE_HANDLER,
-					0, glue);
-	glue += 128;
 	opal_register_exception_handler(OPAL_SOFTPATCH_HANDLER, 0, glue);
 #endif
 
@@ -516,15 +513,41 @@ int opal_machine_check(struct pt_regs *regs)
 /* Early hmi handler called in real mode. */
 int opal_hmi_exception_early(struct pt_regs *regs)
 {
-	/* TODO: Call opal hmi handler. */
+	s64 rc;
+
+	/*
+	 * call opal hmi handler. Pass paca address as token.
+	 * The return value OPAL_SUCCESS is an indication that there is
+	 * an HMI event generated waiting to pull by Linux.
+	 */
+	rc = opal_handle_hmi();
+	if (rc == OPAL_SUCCESS) {
+		local_paca->hmi_event_available = 1;
+		return 1;
+	}
 	return 0;
 }
 
 /* HMI exception handler called in virtual mode during check_irq_replay. */
 int opal_handle_hmi_exception(struct pt_regs *regs)
 {
-	/* TODO: Retrive and print HMI event from OPAL. */
-	return 0;
+	s64 rc;
+	__be64 evt = 0;
+
+	/*
+	 * Check if HMI event is available.
+	 * if Yes, then call opal_poll_events to pull opal messages and
+	 * process them.
+	 */
+	if (!local_paca->hmi_event_available)
+		return 0;
+
+	local_paca->hmi_event_available = 0;
+	rc = opal_poll_events(&evt);
+	if (rc == OPAL_SUCCESS && evt)
+		opal_do_notifier(be64_to_cpu(evt));
+
+	return 1;
 }
 
 static uint64_t find_recovery_address(uint64_t nip)

[PATCH 3/3] powerpc/book3s: handle HMIs for cpus in nap mode.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

HMIs are thread specific and can come while thread is in sleep/nap mode.
Hence with SMT=off mode we can receive HMIs on sleeping threads. For
interrupt received in nap mode, cpu wakes up at system reset vector, clears
the interrupt and go back to nap mode again. But HMIs are sticky and they
keep happening until we clear reason bits from HMER. Hence add a special
check for HMI in reset vector (through power7_wakeup_* functions) and
invoke opal call to handle HMI.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/idle_power7.S |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S
index 5cf3d36..06305f6 100644
--- a/arch/powerpc/kernel/idle_power7.S
+++ b/arch/powerpc/kernel/idle_power7.S
@@ -135,10 +135,36 @@ _GLOBAL(power7_sleep)
 	b	power7_powersave_common
 	/* No return */
 
+#define CHECK_HMI_INTERRUPT						\
+	mfspr	r0,SPRN_SRR1;						\
+BEGIN_FTR_SECTION_NESTED(66);						\
+	rlwinm	r0,r0,45-31,0xf;  /* extract wake reason field (P8) */	\
+FTR_SECTION_ELSE_NESTED(66);						\
+	rlwinm	r0,r0,45-31,0xe;  /* P7 wake reason field is 3 bits */	\
+ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
+	cmpwi	r0,0xa;			/* Hypervisor maintenance ? */	\
+	bne	20f;							\
+	/* Invoke opal call to handle hmi */				\
+	ld	r2,PACATOC(r13);					\
+	ld	r1,PACAR1(r13);						\
+	std	r3,ORIG_GPR3(r1);	/* Save original r3 */		\
+	li	r0,OPAL_HANDLE_HMI;					\
+	LOAD_REG_ADDR(r11,opal);					\
+	ld	r12,8(r11);						\
+	ld	r2,0(r11);						\
+	mtctr	r12;							\
+	bctrl;								\
+	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
+20:	nop;
+
+
 _GLOBAL(power7_wakeup_tb_loss)
 	ld	r2,PACATOC(r13);
 	ld	r1,PACAR1(r13)
 
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 	/* Time base re-sync */
 	li	r0,OPAL_RESYNC_TIMEBASE
 	LOAD_REG_ADDR(r11,opal);
@@ -163,6 +189,9 @@ _GLOBAL(power7_wakeup_tb_loss)
 
 _GLOBAL(power7_wakeup_loss)
 	ld	r1,PACAR1(r13)
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 	REST_NVGPRS(r1)
 	REST_GPR(2, r1)
 	ld	r3,_CCR(r1)
@@ -178,6 +207,9 @@ _GLOBAL(power7_wakeup_noloss)
 	lbz	r0,PACA_NAPSTATELOST(r13)
 	cmpwi	r0,0
 	bne	power7_wakeup_loss
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 	ld	r1,PACAR1(r13)
 	ld	r4,_MSR(r1)
 	ld	r5,_NIP(r1)