[PATCH v2 2/4] sparc64: Migrate hvcons irq to panicked cpu

From: Vijay Kumar
Date: Fri Nov 11 2016 - 13:13:54 EST


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>
---
arch/sparc/include/asm/setup.h | 1 +
arch/sparc/kernel/smp_64.c | 6 +++++-
drivers/tty/serial/sunhv.c | 6 ++++++
3 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/arch/sparc/include/asm/setup.h b/arch/sparc/include/asm/setup.h
index 29d64b1..41691a5 100644
--- a/arch/sparc/include/asm/setup.h
+++ b/arch/sparc/include/asm/setup.h
@@ -61,6 +61,7 @@ extern atomic_t dcpage_flushes_xcall;
extern int sysctl_tsb_ratio;
#endif

+void sunhv_migrate_hvcons_irq(int cpu);
void sun_do_break(void);
extern int stop_a_enabled;
extern int scons_pwroff;
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 14138ad..52dc4b7 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1444,8 +1444,12 @@ void smp_send_stop(void)
int cpu;

if (tlb_type == hypervisor) {
+ int this_cpu = smp_processor_id();
+
+ sunhv_migrate_hvcons_irq(this_cpu);
+
for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
+ if (cpu == this_cpu)
continue;

set_cpu_online(cpu, false);
diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c
index 4e603d0..59828d8 100644
--- 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
--
1.7.1