Move sysfs_devices_system_cpu to the central policy.

Every device has a CPU. This is not device specific.

Allow every domain to read these files/directories.
For unknown reasons, these files are accessed by A LOT
of processes.

Allow ueventd to write to these files. This addresses
the following denials seen on mako:

<5>[    4.935602] type=1400 audit(1383167737.512:4): avc:  denied  { read } for  pid=140 comm="ueventd" name="cpu0" dev="sysfs" ino=3163 scontext=u:r:ueventd:s0 tcontext=u:object_r:sysfs_devices_system_cpu:s0 tclass=dir
<5>[    4.935785] type=1400 audit(1383167737.512:5): avc:  denied  { open } for  pid=140 comm="ueventd" name="cpu0" dev="sysfs" ino=3163 scontext=u:r:ueventd:s0 tcontext=u:object_r:sysfs_devices_system_cpu:s0 tclass=dir
<5>[    4.935937] type=1400 audit(1383167737.512:6): avc:  denied  { search } for  pid=140 comm="ueventd" name="cpu0" dev="sysfs" ino=3163 scontext=u:r:ueventd:s0 tcontext=u:object_r:sysfs_devices_system_cpu:s0 tclass=dir
<5>[    4.936120] type=1400 audit(1383167737.512:7): avc:  denied  { write } for  pid=140 comm="ueventd" name="uevent" dev="sysfs" ino=3164 scontext=u:r:ueventd:s0 tcontext=u:object_r:sysfs_devices_system_cpu:s0 tclass=file
<5>[    4.936303] type=1400 audit(1383167737.512:8): avc:  denied  { open } for  pid=140 comm="ueventd" name="uevent" dev="sysfs" ino=3164 scontext=u:r:ueventd:s0 tcontext=u:object_r:sysfs_devices_system_cpu:s0 tclass=file

Change-Id: I4766dc571762d8fae06aa8c26828c070b80f5936

domain.te

@@ -106,6 +106,7 @@ allow domain sysfs_writable:file rw_file_perms;
 # Read access to pseudo filesystems.
 r_dir_file(domain, proc)
 r_dir_file(domain, sysfs)
+r_dir_file(domain, sysfs_devices_system_cpu)
 r_dir_file(domain, inotify)
 r_dir_file(domain, cgroup)
 

file_contexts

@@ -204,6 +204,7 @@
 /sys/devices/platform/nfc-power/nfc_power -- u:object_r:sysfs_nfc_power_writable:s0
 /sys/class/rfkill/rfkill[0-9]*/state -- u:object_r:sysfs_bluetooth_writable:s0
 /sys/class/rfkill/rfkill[0-9]*/type -- u:object_r:sysfs_bluetooth_writable:s0
+/sys/devices/system/cpu(/.*)?    u:object_r:sysfs_devices_system_cpu:s0
 /sys/power/wake_lock -- u:object_r:sysfs_wake_lock:s0
 /sys/power/wake_unlock -- u:object_r:sysfs_wake_lock:s0
 #############################

ueventd.te

@@ -14,6 +14,7 @@ allow ueventd device:chr_file rw_file_perms;
 allow ueventd sysfs:file rw_file_perms;
 allow ueventd sysfs:file setattr;
 allow ueventd sysfs_type:file { relabelfrom relabelto };
+allow ueventd sysfs_devices_system_cpu:file rw_file_perms;
 allow ueventd tmpfs:chr_file rw_file_perms;
 allow ueventd dev_type:dir create_dir_perms;
 allow ueventd dev_type:lnk_file { create unlink };