4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vijay Kumar <vijay.ac.kumar@xxxxxxxxxx>
[ Upstream commit 7dd4fcf5b70694dc961eb6b954673e4fc9730dbd ]
On panic, all other CPUs are stopped except the one which had
hit panic. To keep console alive, we need to migrate hvcons irq
to panicked CPU.
Signed-off-by: Vijay Kumar <vijay.ac.kumar@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/include/asm/setup.h | 5 ++++-
arch/sparc/kernel/smp_64.c | 6 +++++-
drivers/tty/serial/sunhv.c | 6 ++++++
3 files changed, 15 insertions(+), 2 deletions(-)
--- a/arch/sparc/include/asm/setup.h
+++ b/arch/sparc/include/asm/setup.h
@@ -59,8 +59,11 @@ extern atomic_t dcpage_flushes;
extern atomic_t dcpage_flushes_xcall;
extern int sysctl_tsb_ratio;
-#endif
+#ifdef CONFIG_SERIAL_SUNHV
+void sunhv_migrate_hvcons_irq(int cpu);
+#endif
+#endif
void sun_do_break(void);
extern int stop_a_enabled;
extern int scons_pwroff;
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1465,8 +1465,12 @@ void smp_send_stop(void)
int cpu;
if (tlb_type == hypervisor) {
+ int this_cpu = smp_processor_id();
+#ifdef CONFIG_SERIAL_SUNHV
+ sunhv_migrate_hvcons_irq(this_cpu);
+#endif
for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
+ if (cpu == this_cpu)
continue;
#ifdef CONFIG_SUN_LDOMS
if (ldom_domaining_enabled) {
--- a/drivers/tty/serial/sunhv.c
+++ b/drivers/tty/serial/sunhv.c
@@ -398,6 +398,12 @@ static struct uart_driver sunhv_reg = {
static struct uart_port *sunhv_port;
+void sunhv_migrate_hvcons_irq(int cpu)
+{
+ /* Migrate hvcons irq to param cpu */
+ irq_force_affinity(sunhv_port->irq, cpumask_of(cpu));
+}
+
/* Copy 's' into the con_write_page, decoding "\n" into
* "\r\n" along the way. We have to return two lengths
* because the caller needs to know how much to advance