From: James Morse <james.morse@xxxxxxx>
Hibernate relies on cpu hotplug to prevent secondary cores executing
the kernel text while it is being restored.
Add a call to cpus_are_stuck_in_kernel() to determine if there are
CPUs not counted by 'num_online_cpus()', and prevent hibernate in this
case.
Fixes: 82869ac57b5 ("arm64: kernel: Add support for hibernate/suspend-to-disk")
Signed-off-by: James Morse <james.morse at arm.com>
---
arch/arm64/kernel/hibernate.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index f8df75d..21ab5df 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -33,6 +33,7 @@
#include <asm/pgtable.h>
#include <asm/pgtable-hwdef.h>
#include <asm/sections.h>
+#include <asm/smp.h>
#include <asm/suspend.h>
#include <asm/virt.h>
@@ -236,6 +237,11 @@ int swsusp_arch_suspend(void)
unsigned long flags;
struct sleep_stack_data state;
+ if (cpus_are_stuck_in_kernel()) {
+ pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n");
+ return -EBUSY;
+ }
+
local_dbg_save(flags);
if (__cpu_suspend_enter(&state)) {
--
2.5.0
