4 files changed, 49 insertions, 23 deletions

diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index e05278087ffa..4d3355da0e26 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -11,6 +11,8 @@
                         Joel Schopp <jschopp@austin.ibm.com>
                 ia64/x86_64:
                         Ashok Raj <ashok.raj@intel.com>
+                s390:
+                        Heiko Carstens <heiko.carstens@de.ibm.com>
 
 Authors: Ashok Raj <ashok.raj@intel.com>
 Lots of feedback: Nathan Lynch <nathanl@austin.ibm.com>,
@@ -44,11 +46,9 @@ maxcpus=n    Restrict boot time cpus to n. Say if you have 4 cpus, using
              maxcpus=2 will only boot 2. You can choose to bring the
              other cpus later online, read FAQ's for more info.
 
-additional_cpus*=n      Use this to limit hotpluggable cpus. This option sets
-                        cpu_possible_map = cpu_present_map + additional_cpus
-
-(*) Option valid only for following architectures
-- x86_64, ia64
+additional_cpus=n       [x86_64, s390 only] use this to limit hotpluggable cpus.
+                          This option sets
+                        cpu_possible_map = cpu_present_map + additional_cpus
 
 ia64 and x86_64 use the number of disabled local apics in ACPI tables MADT
 to determine the number of potentially hot-pluggable cpus. The implementation
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index de8784267473..24f62f16c0e5 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -600,6 +600,7 @@ setup_arch(char **cmdline_p)
         init_mm.brk = (unsigned long) &_end;
 
         parse_cmdline_early(cmdline_p);
+        parse_early_param();
 
         setup_memory();
         setup_resources();
@@ -607,6 +608,7 @@ setup_arch(char **cmdline_p)
 
         cpu_init();
         __cpu_logical_map[0] = S390_lowcore.cpu_data.cpu_addr;
+        smp_setup_cpu_possible_map();
 
         /*
          * Create kernel page tables and switch to virtual addressing.
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0d1ad5dbe2b1..53291e94ac7b 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -1,8 +1,7 @@
 /*
  *  arch/s390/kernel/smp.c
  *
- *  S390 version
- *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Copyright (C) IBM Corp. 1999,2006
  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
  *               Heiko Carstens (heiko.carstens@de.ibm.com)
@@ -41,8 +40,6 @@
 #include <asm/cpcmd.h>
 #include <asm/tlbflush.h>
 
-/* prototypes */
-
 extern volatile int __cpu_logical_map[];
 
 /*
@@ -51,13 +48,11 @@ extern volatile int __cpu_logical_map[];
 
 struct _lowcore *lowcore_ptr[NR_CPUS];
 
-cpumask_t cpu_online_map;
-cpumask_t cpu_possible_map = CPU_MASK_ALL;
+cpumask_t cpu_online_map = CPU_MASK_NONE;
+cpumask_t cpu_possible_map = CPU_MASK_NONE;
 
 static struct task_struct *current_set[NR_CPUS];
 
-EXPORT_SYMBOL(cpu_online_map);
-
 /*
  * Reboot, halt and power_off routines for SMP.
  */
@@ -490,10 +485,10 @@ void smp_ctl_clear_bit(int cr, int bit) {
  * Lets check how many CPUs we have.
  */
 
-void
-__init smp_check_cpus(unsigned int max_cpus)
+static unsigned int
+__init smp_count_cpus(void)
 {
-        int cpu, num_cpus;
+        unsigned int cpu, num_cpus;
         __u16 boot_cpu_addr;
 
         /*
@@ -503,19 +498,20 @@ __init smp_check_cpus(unsigned int max_cpus)
         boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;
         current_thread_info()->cpu = 0;
         num_cpus = 1;
-        for (cpu = 0; cpu <= 65535 && num_cpus < max_cpus; cpu++) {
+        for (cpu = 0; cpu <= 65535; cpu++) {
                 if ((__u16) cpu == boot_cpu_addr)
                         continue;
-                __cpu_logical_map[num_cpus] = (__u16) cpu;
-                if (signal_processor(num_cpus, sigp_sense) ==
+                __cpu_logical_map[1] = (__u16) cpu;
+                if (signal_processor(1, sigp_sense) ==
                     sigp_not_operational)
                         continue;
-                cpu_set(num_cpus, cpu_present_map);
                 num_cpus++;
         }
 
         printk("Detected %d CPU's\n",(int) num_cpus);
         printk("Boot cpu address %2X\n", boot_cpu_addr);
+
+        return num_cpus;
 }
 
 /*
@@ -676,6 +672,32 @@ __cpu_up(unsigned int cpu)
         return 0;
 }
 
+static unsigned int __initdata additional_cpus;
+
+void __init smp_setup_cpu_possible_map(void)
+{
+        unsigned int pcpus, cpu;
+
+        pcpus = smp_count_cpus() + additional_cpus;
+
+        if (pcpus > NR_CPUS)
+                pcpus = NR_CPUS;
+
+        for (cpu = 0; cpu < pcpus; cpu++)
+                cpu_set(cpu, cpu_possible_map);
+
+        cpu_present_map = cpu_possible_map;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static int __init setup_additional_cpus(char *s)
+{
+        additional_cpus = simple_strtoul(s, NULL, 0);
+        return 0;
+}
+early_param("additional_cpus", setup_additional_cpus);
+
 int
 __cpu_disable(void)
 {
@@ -744,6 +766,8 @@ cpu_die(void)
         for(;;);
 }
 
+#endif /* CONFIG_HOTPLUG_CPU */
+
 /*
  *      Cycle through the processors and setup structures.
  */
@@ -757,7 +781,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
         /* request the 0x1201 emergency signal external interrupt */
         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
                 panic("Couldn't request external interrupt 0x1201");
-        smp_check_cpus(max_cpus);
         memset(lowcore_ptr,0,sizeof(lowcore_ptr));  
         /*
          *  Initialize prefix pages and stacks for all possible cpus
@@ -806,14 +829,12 @@ void __devinit smp_prepare_boot_cpu(void)
         BUG_ON(smp_processor_id() != 0);
 
         cpu_set(0, cpu_online_map);
-        cpu_set(0, cpu_present_map);
         S390_lowcore.percpu_offset = __per_cpu_offset[0];
         current_set[0] = current;
 }
 
 void smp_cpus_done(unsigned int max_cpus)
 {
-        cpu_present_map = cpu_possible_map;
 }
 
 /*
@@ -845,6 +866,7 @@ static int __init topology_init(void)
 
 subsys_initcall(topology_init);
 
+EXPORT_SYMBOL(cpu_online_map);
 EXPORT_SYMBOL(cpu_possible_map);
 EXPORT_SYMBOL(lowcore_ptr);
 EXPORT_SYMBOL(smp_ctl_set_bit);
diff --git a/include/asm-s390/smp.h b/include/asm-s390/smp.h
index 9c6e9c300eb9..444dae5912e6 100644
--- a/include/asm-s390/smp.h
+++ b/include/asm-s390/smp.h
@@ -31,6 +31,7 @@ typedef struct
         __u16      cpu;
 } sigp_info;
 
+extern void smp_setup_cpu_possible_map(void);
 extern int smp_call_function_on(void (*func) (void *info), void *info,
                                 int nonatomic, int wait, int cpu);
 #define NO_PROC_ID              0xFF            /* No processor magic marker */
@@ -104,6 +105,7 @@ smp_call_function_on(void (*func) (void *info), void *info,
 #define smp_cpu_not_running(cpu)        1
 #define smp_get_cpu(cpu) ({ 0; })
 #define smp_put_cpu(cpu) ({ 0; })
+#define smp_setup_cpu_possible_map()
 #endif
 
 #endif