why could not ping the interface of firewall

PC---------------(gi0/0/2)FW(gi0/0/1)----------Router
in firewall, the default policy is permit the all packet in security policy, but PC could not ping the interface gi0/0/0 of firewall,
and all the interface add to zones,

security-policy
default action permit
interface gigabitethernet0/0/2
ip address 192.168.1.1 24

in firewall, ping FW's interface need to enable the ping service in the interface view, add the configuration in the gi0/0/2 view
interface gigabitethernet0/0/2
ip address 192.168.1.1 24
service-manager ping permit
and then PC can ping the interface gi0/02
NOTES: The PC ping the interface gi0/0/2 need not permit any in the security-policy.