s390x: SCLP feature checking
Availability of SIE is announced via a feature bit in a SCLP info CPU
entry. Let's add a framework that allows us to easily check for such
facilities.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
diff --git a/lib/s390x/io.c b/lib/s390x/io.c
index 6a1da63..ef9f59e 100644
--- a/lib/s390x/io.c
+++ b/lib/s390x/io.c
@@ -35,6 +35,7 @@
setup_args_progname(ipl_args);
setup_facilities();
sclp_read_info();
+ sclp_facilities_setup();
sclp_console_setup();
sclp_memory_setup();
smp_setup();
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index 12916f5..06819a6 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -25,6 +25,7 @@
static uint64_t ram_size;
char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static ReadInfo *read_info;
+struct sclp_facilities sclp_facilities;
char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
static volatile bool sclp_busy;
@@ -128,6 +129,30 @@
return (CPUEntry *)(_read_info + read_info->offset_cpu);
}
+void sclp_facilities_setup(void)
+{
+ unsigned short cpu0_addr = stap();
+ CPUEntry *cpu;
+ int i;
+
+ assert(read_info);
+
+ cpu = sclp_get_cpu_entries();
+ for (i = 0; i < read_info->entries_cpu; i++, cpu++) {
+ /*
+ * The logic for only reading the facilities from the
+ * boot cpu comes from the kernel. I haven't yet found
+ * documentation that explains why this is necessary
+ * but I figure there's a reason behind doing it this
+ * way.
+ */
+ if (cpu->address == cpu0_addr) {
+ sclp_facilities.has_sief2 = cpu->feat_sief2;
+ break;
+ }
+ }
+}
+
/* Perform service call. Return 0 on success, non-zero otherwise. */
int sclp_service_call(unsigned int command, void *sccb)
{
diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
index f005bd0..c3128b9 100644
--- a/lib/s390x/sclp.h
+++ b/lib/s390x/sclp.h
@@ -92,12 +92,22 @@
typedef struct CPUEntry {
uint8_t address;
uint8_t reserved0;
- uint8_t features[SCCB_CPU_FEATURE_LEN];
+ uint8_t : 4;
+ uint8_t feat_sief2 : 1;
+ uint8_t : 3;
+ uint8_t features_res2 [SCCB_CPU_FEATURE_LEN - 1];
uint8_t reserved2[6];
uint8_t type;
uint8_t reserved1;
} __attribute__((packed)) CPUEntry;
+extern struct sclp_facilities sclp_facilities;
+
+struct sclp_facilities {
+ uint64_t has_sief2 : 1;
+ uint64_t : 63;
+};
+
typedef struct ReadInfo {
SCCBHeader h;
uint16_t rnmax;
@@ -271,6 +281,7 @@
void sclp_read_info(void);
int sclp_get_cpu_num(void);
CPUEntry *sclp_get_cpu_entries(void);
+void sclp_facilities_setup(void);
int sclp_service_call(unsigned int command, void *sccb);
void sclp_memory_setup(void);
uint64_t get_ram_size(void);
