[S390] Standby cpu activation/deactivation.

Add a new interface so that cpus can be put into standby state and
configured state.
Only offline cpus can be put into standby state or configured state.
For that the new percpu sysfs attribute "configure" must be used.
To put a cpu in standby state a "0" must be written to the attribute.
In order to switch it into configured state a "1" must be written to
the attribute.
Only cpus in configured state can be brought online.
In addition this patch introduces a static mapping of physical to
logical cpus. As a result only the sysfs directories of present cpus
will be created. To scan for new cpus the new sysfs attribute "rescan"
must be used.
Writing to /sys/devices/system/cpu/rescan will trigger a rescan of
cpus and will create directories for new cpus.

On IPL only configured cpus will be used. And on reboot/shutdown all
cpus will remain in their current state (configured/standby).

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/include/asm-s390/sclp.h b/include/asm-s390/sclp.h
index cb9faf1ea5cf..b8c7695cd4c8 100644
--- a/include/asm-s390/sclp.h
+++ b/include/asm-s390/sclp.h
@@ -27,7 +27,26 @@ struct sclp_ipl_info {
 	char loadparm[LOADPARM_LEN];
 };
 
-void sclp_readinfo_early(void);
+struct sclp_cpu_entry {
+	u8 address;
+	u8 reserved0[13];
+	u8 type;
+	u8 reserved1;
+} __attribute__((packed));
+
+struct sclp_cpu_info {
+	unsigned int configured;
+	unsigned int standby;
+	unsigned int combined;
+	int has_cpu_type;
+	struct sclp_cpu_entry cpu[255];
+};
+
+int sclp_get_cpu_info(struct sclp_cpu_info *info);
+int sclp_cpu_configure(u8 cpu);
+int sclp_cpu_deconfigure(u8 cpu);
+void sclp_read_info_early(void);
+void sclp_read_cpu_info_early(void);
 void sclp_facilities_detect(void);
 unsigned long long sclp_memory_detect(void);
 int sclp_sdias_blk_count(void);