[ARM SMP] Fix some sparse warnings in SMP code

[karo-tx-linux.git] / arch / arm / kernel / smp.c

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 826164945747523fa93712d9d0575051b511ccb7..f65750a3d28bf001fa483b207f2b41ffdfeefa75 100644 (file)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -80,19 +80,23 @@ static DEFINE_SPINLOCK(smp_call_function_lock);
 
 int __cpuinit __cpu_up(unsigned int cpu)
 {
-       struct task_struct *idle;
+       struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
+       struct task_struct *idle = ci->idle;
        pgd_t *pgd;
        pmd_t *pmd;
        int ret;
 
        /*
-        * Spawn a new process manually.  Grab a pointer to
-        * its task struct so we can mess with it
+        * Spawn a new process manually, if not already done.
+        * Grab a pointer to its task struct so we can mess with it
         */
-       idle = fork_idle(cpu);
-       if (IS_ERR(idle)) {
-               printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
-               return PTR_ERR(idle);
+       if (!idle) {
+               idle = fork_idle(cpu);
+               if (IS_ERR(idle)) {
+                       printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
+                       return PTR_ERR(idle);
+               }
+               ci->idle = idle;
        }
 
        /*
@@ -138,7 +142,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
                        ret = -EIO;
        }
 
-       secondary_data.stack = 0;
+       secondary_data.stack = NULL;
        secondary_data.pgdir = 0;
 
        *pmd_offset(pgd, PHYS_OFFSET) = __pmd(0);
@@ -155,6 +159,91 @@ int __cpuinit __cpu_up(unsigned int cpu)
        return ret;
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * __cpu_disable runs on the processor to be shutdown.
+ */
+int __cpuexit __cpu_disable(void)
+{
+       unsigned int cpu = smp_processor_id();
+       struct task_struct *p;
+       int ret;
+
+       ret = mach_cpu_disable(cpu);
+       if (ret)
+               return ret;
+
+       /*
+        * Take this CPU offline.  Once we clear this, we can't return,
+        * and we must not schedule until we're ready to give up the cpu.
+        */
+       cpu_clear(cpu, cpu_online_map);
+
+       /*
+        * OK - migrate IRQs away from this CPU
+        */
+       migrate_irqs();
+
+       /*
+        * Flush user cache and TLB mappings, and then remove this CPU
+        * from the vm mask set of all processes.
+        */
+       flush_cache_all();
+       local_flush_tlb_all();
+
+       read_lock(&tasklist_lock);
+       for_each_process(p) {
+               if (p->mm)
+                       cpu_clear(cpu, p->mm->cpu_vm_mask);
+       }
+       read_unlock(&tasklist_lock);
+
+       return 0;
+}
+
+/*
+ * called on the thread which is asking for a CPU to be shutdown -
+ * waits until shutdown has completed, or it is timed out.
+ */
+void __cpuexit __cpu_die(unsigned int cpu)
+{
+       if (!platform_cpu_kill(cpu))
+               printk("CPU%u: unable to kill\n", cpu);
+}
+
+/*
+ * Called from the idle thread for the CPU which has been shutdown.
+ *
+ * Note that we disable IRQs here, but do not re-enable them
+ * before returning to the caller. This is also the behaviour
+ * of the other hotplug-cpu capable cores, so presumably coming
+ * out of idle fixes this.
+ */
+void __cpuexit cpu_die(void)
+{
+       unsigned int cpu = smp_processor_id();
+
+       local_irq_disable();
+       idle_task_exit();
+
+       /*
+        * actual CPU shutdown procedure is at least platform (if not
+        * CPU) specific
+        */
+       platform_cpu_die(cpu);
+
+       /*
+        * Do not return to the idle loop - jump back to the secondary
+        * cpu initialisation.  There's some initialisation which needs
+        * to be repeated to undo the effects of taking the CPU offline.
+        */
+       __asm__("mov    sp, %0\n"
+       "       b       secondary_start_kernel"
+               :
+               : "r" ((void *)current->thread_info + THREAD_SIZE - 8));
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
 /*
  * This is the secondary CPU boot entry.  We're using this CPUs
  * idle thread stack, but a set of temporary page tables.
@@ -236,6 +325,8 @@ void __init smp_prepare_boot_cpu(void)
 {
        unsigned int cpu = smp_processor_id();
 
+       per_cpu(cpu_data, cpu).idle = current;
+
        cpu_set(cpu, cpu_possible_map);
        cpu_set(cpu, cpu_present_map);
        cpu_set(cpu, cpu_online_map);
@@ -268,8 +359,8 @@ static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
  * You must not call this function with disabled interrupts, from a
  * hardware interrupt handler, nor from a bottom half handler.
  */
-int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
-                             int wait, cpumask_t callmap)
+static int smp_call_function_on_cpu(void (*func)(void *info), void *info,
+                                   int retry, int wait, cpumask_t callmap)
 {
        struct smp_call_struct data;
        unsigned long timeout;
@@ -309,8 +400,8 @@ int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
                printk(KERN_CRIT
                       "CPU%u: smp_call_function timeout for %p(%p)\n"
                       "      callmap %lx pending %lx, %swait\n",
-                      smp_processor_id(), func, info, callmap, data.pending,
-                      wait ? "" : "no ");
+                      smp_processor_id(), func, info, *cpus_addr(callmap),
+                      *cpus_addr(data.pending), wait ? "" : "no ");
 
                /*
                 * TRACE