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Diffstat (limited to 'arch/mips/kernel/smp.c')
-rw-r--r--arch/mips/kernel/smp.c51
1 files changed, 27 insertions, 24 deletions
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index af5cd3b8a396..fcacf1aae98a 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -50,7 +50,6 @@ static void smp_tune_scheduling (void)
{
struct cache_desc *cd = &current_cpu_data.scache;
unsigned long cachesize; /* kB */
- unsigned long bandwidth = 350; /* MB/s */
unsigned long cpu_khz;
/*
@@ -121,7 +120,19 @@ struct call_data_struct *call_data;
* or are or have executed.
*
* You must not call this function with disabled interrupts or from a
- * hardware interrupt handler or from a bottom half handler.
+ * hardware interrupt handler or from a bottom half handler:
+ *
+ * CPU A CPU B
+ * Disable interrupts
+ * smp_call_function()
+ * Take call_lock
+ * Send IPIs
+ * Wait for all cpus to acknowledge IPI
+ * CPU A has not responded, spin waiting
+ * for cpu A to respond, holding call_lock
+ * smp_call_function()
+ * Spin waiting for call_lock
+ * Deadlock Deadlock
*/
int smp_call_function (void (*func) (void *info), void *info, int retry,
int wait)
@@ -130,6 +141,11 @@ int smp_call_function (void (*func) (void *info), void *info, int retry,
int i, cpus = num_online_cpus() - 1;
int cpu = smp_processor_id();
+ /*
+ * Can die spectacularly if this CPU isn't yet marked online
+ */
+ BUG_ON(!cpu_online(cpu));
+
if (!cpus)
return 0;
@@ -214,7 +230,6 @@ void __init smp_cpus_done(unsigned int max_cpus)
/* called from main before smp_init() */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
- cpu_data[0].udelay_val = loops_per_jiffy;
init_new_context(current, &init_mm);
current_thread_info()->cpu = 0;
smp_tune_scheduling();
@@ -236,23 +251,28 @@ void __devinit smp_prepare_boot_cpu(void)
}
/*
- * Startup the CPU with this logical number
+ * Called once for each "cpu_possible(cpu)". Needs to spin up the cpu
+ * and keep control until "cpu_online(cpu)" is set. Note: cpu is
+ * physical, not logical.
*/
-static int __init do_boot_cpu(int cpu)
+int __devinit __cpu_up(unsigned int cpu)
{
struct task_struct *idle;
/*
+ * Processor goes to start_secondary(), sets online flag
* The following code is purely to make sure
* Linux can schedule processes on this slave.
*/
idle = fork_idle(cpu);
if (IS_ERR(idle))
- panic("failed fork for CPU %d\n", cpu);
+ panic(KERN_ERR "Fork failed for CPU %d", cpu);
prom_boot_secondary(cpu, idle);
- /* XXXKW timeout */
+ /*
+ * Trust is futile. We should really have timeouts ...
+ */
while (!cpu_isset(cpu, cpu_callin_map))
udelay(100);
@@ -261,23 +281,6 @@ static int __init do_boot_cpu(int cpu)
return 0;
}
-/*
- * Called once for each "cpu_possible(cpu)". Needs to spin up the cpu
- * and keep control until "cpu_online(cpu)" is set. Note: cpu is
- * physical, not logical.
- */
-int __devinit __cpu_up(unsigned int cpu)
-{
- int ret;
-
- /* Processor goes to start_secondary(), sets online flag */
- ret = do_boot_cpu(cpu);
- if (ret < 0)
- return ret;
-
- return 0;
-}
-
/* Not really SMP stuff ... */
int setup_profiling_timer(unsigned int multiplier)
{