s390/smp: initialize cpu_present_mask in setup_arch

In order to be able to setup the cpu to node mappings early it is a
prerequisite to know which cpus are present. Therefore cpus must be
detected much earlier than before.

For sclp based cpu detection this requires yet another early sclp
call, since the system is not ready to use the regular interrupt and
memory allocations.

Reviewed-by: Michael Holzheu <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/sclp.h

···
 	u8 data[0];	/* Subsequent Data passed verbatim to SCLP ET 24 */
 } __packed;
 
-int sclp_get_core_info(struct sclp_core_info *info);
+int _sclp_get_core_info_early(struct sclp_core_info *info);
+int _sclp_get_core_info(struct sclp_core_info *info);
 int sclp_core_configure(u8 core);
 int sclp_core_deconfigure(u8 core);
 int sclp_sdias_blk_count(void);
···
 void sclp_early_detect(void);
 void _sclp_print_early(const char *);
 void sclp_ocf_cpc_name_copy(char *dst);
+
+static inline int sclp_get_core_info(struct sclp_core_info *info, int early)
+{
+	if (early)
+		return _sclp_get_core_info_early(info);
+	return _sclp_get_core_info(info);
+}
 
 #endif /* _ASM_S390_SCLP_H */

arch/s390/include/asm/smp.h

···
 extern void smp_cpu_set_polarization(int cpu, int val);
 extern int smp_cpu_get_polarization(int cpu);
 extern void smp_fill_possible_mask(void);
+extern void smp_detect_cpus(void);
 
 #else /* CONFIG_SMP */
 
···
 static inline int smp_vcpu_scheduled(int cpu) { return 1; }
 static inline void smp_yield_cpu(int cpu) { }
 static inline void smp_fill_possible_mask(void) { }
+static inline void smp_detect_cpus(void) { }
 
 #endif /* CONFIG_SMP */
 

arch/s390/kernel/setup.c

···
 	cpu_detect_mhz_feature();
         cpu_init();
 	numa_setup();
+	smp_detect_cpus();
 
 	/*
 	 * Create kernel page tables and switch to virtual addressing.

arch/s390/kernel/smp.c

···
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include <linux/workqueue.h>
+#include <linux/bootmem.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/mm.h>
···
 	return pcpu_devices[cpu].polarization;
 }
 
-static struct sclp_core_info *smp_get_core_info(void)
+static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 {
 	static int use_sigp_detection;
-	struct sclp_core_info *info;
 	int address;
 
-	info = kzalloc(sizeof(*info), GFP_KERNEL);
-	if (info && (use_sigp_detection || sclp_get_core_info(info))) {
+	if (use_sigp_detection || sclp_get_core_info(info, early)) {
 		use_sigp_detection = 1;
 		for (address = 0;
 		     address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
···
 		}
 		info->combined = info->configured;
 	}
-	return info;
 }
 
 static int smp_add_present_cpu(int cpu);
···
 	return nr;
 }
 
-static void __init smp_detect_cpus(void)
+void __init smp_detect_cpus(void)
 {
 	unsigned int cpu, mtid, c_cpus, s_cpus;
 	struct sclp_core_info *info;
 	u16 address;
 
 	/* Get CPU information */
-	info = smp_get_core_info();
-	if (!info)
-		panic("smp_detect_cpus failed to allocate memory\n");
-
+	info = memblock_virt_alloc(sizeof(*info), 8);
+	smp_get_core_info(info, 1);
 	/* Find boot CPU type */
 	if (sclp.has_core_type) {
 		address = stap();
···
 	get_online_cpus();
 	__smp_rescan_cpus(info, 0);
 	put_online_cpus();
-	kfree(info);
+	memblock_free_early((unsigned long)info, sizeof(*info));
 }
 
 /*
···
 	/* request the 0x1202 external call external interrupt */
 	if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 		panic("Couldn't request external interrupt 0x1202");
-	smp_detect_cpus();
 }
 
 void __init smp_prepare_boot_cpu(void)
···
 	struct sclp_core_info *info;
 	int nr;
 
-	info = smp_get_core_info();
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;
+	smp_get_core_info(info, 0);
 	get_online_cpus();
 	mutex_lock(&smp_cpu_state_mutex);
 	nr = __smp_rescan_cpus(info, 1);

drivers/s390/char/sclp.h

···
 
 typedef unsigned int sclp_cmdw_t;
 
+#define SCLP_CMDW_READ_CPU_INFO		0x00010001
 #define SCLP_CMDW_READ_EVENT_DATA	0x00770005
 #define SCLP_CMDW_WRITE_EVENT_DATA	0x00760005
 #define SCLP_CMDW_WRITE_EVENT_MASK	0x00780005
···
 	sccb_mask_t sclp_receive_mask;
 	sccb_mask_t sclp_send_mask;
 } __attribute__((packed));
+
+struct read_cpu_info_sccb {
+	struct	sccb_header header;
+	u16	nr_configured;
+	u16	offset_configured;
+	u16	nr_standby;
+	u16	offset_standby;
+	u8	reserved[4096 - 16];
+} __attribute__((packed, aligned(PAGE_SIZE)));
+
+static inline void sclp_fill_core_info(struct sclp_core_info *info,
+				       struct read_cpu_info_sccb *sccb)
+{
+	char *page = (char *) sccb;
+
+	memset(info, 0, sizeof(*info));
+	info->configured = sccb->nr_configured;
+	info->standby = sccb->nr_standby;
+	info->combined = sccb->nr_configured + sccb->nr_standby;
+	memcpy(&info->core, page + sccb->offset_configured,
+	       info->combined * sizeof(struct sclp_core_entry));
+}
 
 #define SCLP_HAS_CHP_INFO	(sclp.facilities & 0x8000000000000000ULL)
 #define SCLP_HAS_CHP_RECONFIG	(sclp.facilities & 0x2000000000000000ULL)

drivers/s390/char/sclp_cmd.c

···
  * CPU configuration related functions.
  */
 
-#define SCLP_CMDW_READ_CPU_INFO		0x00010001
 #define SCLP_CMDW_CONFIGURE_CPU		0x00110001
 #define SCLP_CMDW_DECONFIGURE_CPU	0x00100001
 
-struct read_cpu_info_sccb {
-	struct	sccb_header header;
-	u16	nr_configured;
-	u16	offset_configured;
-	u16	nr_standby;
-	u16	offset_standby;
-	u8	reserved[4096 - 16];
-} __attribute__((packed, aligned(PAGE_SIZE)));
-
-static void sclp_fill_core_info(struct sclp_core_info *info,
-				struct read_cpu_info_sccb *sccb)
-{
-	char *page = (char *) sccb;
-
-	memset(info, 0, sizeof(*info));
-	info->configured = sccb->nr_configured;
-	info->standby = sccb->nr_standby;
-	info->combined = sccb->nr_configured + sccb->nr_standby;
-	memcpy(&info->core, page + sccb->offset_configured,
-	       info->combined * sizeof(struct sclp_core_entry));
-}
-
-int sclp_get_core_info(struct sclp_core_info *info)
+int _sclp_get_core_info(struct sclp_core_info *info)
 {
 	int rc;
 	struct read_cpu_info_sccb *sccb;

drivers/s390/char/sclp_early.c

···
 	return sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_MASK, sccb);
 }
 
+static struct sclp_core_info sclp_core_info_early __initdata;
+static int sclp_core_info_early_valid __initdata;
+
+static void __init sclp_init_core_info_early(struct read_cpu_info_sccb *sccb)
+{
+	int rc;
+
+	if (!SCLP_HAS_CPU_INFO)
+		return;
+	memset(sccb, 0, sizeof(*sccb));
+	sccb->header.length = sizeof(*sccb);
+	do {
+		rc = sclp_cmd_sync_early(SCLP_CMDW_READ_CPU_INFO, sccb);
+	} while (rc == -EBUSY);
+	if (rc)
+		return;
+	if (sccb->header.response_code != 0x0010)
+		return;
+	sclp_fill_core_info(&sclp_core_info_early, sccb);
+	sclp_core_info_early_valid = 1;
+}
+
+int __init _sclp_get_core_info_early(struct sclp_core_info *info)
+{
+	if (!sclp_core_info_early_valid)
+		return -EIO;
+	*info = sclp_core_info_early;
+	return 0;
+}
+
 static long __init sclp_hsa_size_init(struct sdias_sccb *sccb)
 {
 	sccb_init_eq_size(sccb);
···
 	void *sccb = &sccb_early;
 
 	sclp_facilities_detect(sccb);
+	sclp_init_core_info_early(sccb);
 	sclp_hsa_size_detect(sccb);
 
 	/* Turn off SCLP event notifications.  Also save remote masks in the