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

2 files changed, 10 insertions, 13 deletions

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index b57e28f1edc2..aba3c5ce1559 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -923,6 +923,7 @@ void __init setup_arch(char **cmdline_p)
 	cpu_detect_mhz_feature();
         cpu_init();
 	numa_setup();
+	smp_detect_cpus();
 
 	/*
 	 * Create kernel page tables and switch to virtual addressing.
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 66ffc2350f24..5d53ab646b3f 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -19,6 +19,7 @@
 #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>
@@ -655,14 +656,12 @@ int smp_cpu_get_polarization(int cpu)
 	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);
@@ -676,7 +675,6 @@ static struct sclp_core_info *smp_get_core_info(void)
 		}
 		info->combined = info->configured;
 	}
-	return info;
 }
 
 static int smp_add_present_cpu(int cpu);
@@ -717,17 +715,15 @@ static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 	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();
@@ -763,7 +759,7 @@ static void __init smp_detect_cpus(void)
 	get_online_cpus();
 	__smp_rescan_cpus(info, 0);
 	put_online_cpus();
-	kfree(info);
+	memblock_free_early((unsigned long)info, sizeof(*info));
 }
 
 /*
@@ -900,7 +896,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	/* 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)
@@ -1111,9 +1106,10 @@ int __ref smp_rescan_cpus(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);