powerpc/book3s: Add basic infrastructure to handle HMI in Linux.

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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 16 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 6ef2e5c5bc64..d20d69921376 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -514,6 +514,20 @@ 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 d9b88fa7c5a3..5a0e2dc6de5f 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