s390: add SMT support

The multi-threading facility is introduced with the z13 processor family.
This patch adds code to detect the multi-threading facility. With the
facility enabled each core will surface multiple hardware threads to the
system. Each hardware threads looks like a normal CPU to the operating
system with all its registers and properties.

The SCLP interface reports the SMT topology indirectly via the maximum
thread id. Each reported CPU in the result of a read-scp-information
is a core representing a number of hardware threads.

To reflect the reduced CPU capacity if two hardware threads run on a
single core the MT utilization counter set is used to normalize the
raw cputime obtained by the CPU timer deltas. This scaled cputime is
reported via the taskstats interface. The normal /proc/stat numbers
are based on the raw cputime and are not affected by the normalization.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h
index b6f8066..edb453c 100644
--- a/arch/s390/include/asm/sclp.h
+++ b/arch/s390/include/asm/sclp.h
@@ -27,7 +27,7 @@ struct sclp_ipl_info {
 };
 
 struct sclp_cpu_entry {
-	u8 address;
+	u8 core_id;
 	u8 reserved0[2];
 	u8 : 3;
 	u8 siif : 1;
@@ -51,6 +51,9 @@ int sclp_cpu_deconfigure(u8 cpu);
 unsigned long long sclp_get_rnmax(void);
 unsigned long long sclp_get_rzm(void);
 unsigned int sclp_get_max_cpu(void);
+unsigned int sclp_get_mtid(u8 cpu_type);
+unsigned int sclp_get_mtid_max(void);
+unsigned int sclp_get_mtid_prev(void);
 int sclp_sdias_blk_count(void);
 int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);
 int sclp_chp_configure(struct chp_id chpid);