[PATCH openEuler-21.03 v1] arm64: Uninstall cpu park after cpu up

12 Mar 2021

From: Sang Yan <sangyan@huawei.com>

hulk inclusion
category: feature
bugzilla: 48159
CVE: N/A

------------------------------

One cpu in PARK state could not come up in this case:
	CPU 0			    |   CPU 1
	boot_secondary(cpu 1)	    |
	--> write_park_exit(cpu 1)  |
				    |	cpu uping from PARK
				    |	...
	uninstall_cpu_park()	    |
	--> memset to 0 park text   |
				    |	...
				    |	Exception in memory !!
	wait for cpu up		    |

Cpu 1 uping from PARK may trap into exception while cpu 0
clear cpu 1's park text memory.

This uninstall_cpu_park should be after waiting for cpu up.

Signed-off-by: Sang Yan <sangyan@huawei.com>
---
 arch/arm64/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index d7b750a..fb6007d 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -300,15 +300,15 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 		return ret;
 	}
 
-#ifdef CONFIG_ARM64_CPU_PARK
-	uninstall_cpu_park(cpu);
-#endif
 	/*
 	 * CPU was successfully started, wait for it to come online or
 	 * time out.
 	 */
 	wait_for_completion_timeout(&cpu_running,
 				    msecs_to_jiffies(5000));
+#ifdef CONFIG_ARM64_CPU_PARK
+	uninstall_cpu_park(cpu);
+#endif
 	if (cpu_online(cpu))
 		return 0;
 
-- 
2.9.5

    

sangyan＠huawei.com

wangxiongfeng (C)

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