diff options
Diffstat (limited to 'arch/x86_64')
| -rw-r--r-- | arch/x86_64/kernel/smp.c | 63 | ||||
| -rw-r--r-- | arch/x86_64/kernel/smpboot.c | 21 |
2 files changed, 75 insertions, 9 deletions
diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c index 6ee74db523030..e5958220d6b8b 100644 --- a/arch/x86_64/kernel/smp.c +++ b/arch/x86_64/kernel/smp.c @@ -293,6 +293,69 @@ void unlock_ipi_call_lock(void) } /* + * this function sends a 'generic call function' IPI to one other CPU + * in the system. + */ +static void __smp_call_function_single (int cpu, void (*func) (void *info), void *info, + int nonatomic, int wait) +{ + struct call_data_struct data; + int cpus = 1; + + data.func = func; + data.info = info; + atomic_set(&data.started, 0); + data.wait = wait; + if (wait) + atomic_set(&data.finished, 0); + + call_data = &data; + wmb(); + /* Send a message to all other CPUs and wait for them to respond */ + send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR); + + /* Wait for response */ + while (atomic_read(&data.started) != cpus) + cpu_relax(); + + if (!wait) + return; + + while (atomic_read(&data.finished) != cpus) + cpu_relax(); +} + +/* + * smp_call_function_single - Run a function on another CPU + * @func: The function to run. This must be fast and non-blocking. + * @info: An arbitrary pointer to pass to the function. + * @nonatomic: Currently unused. + * @wait: If true, wait until function has completed on other CPUs. + * + * Retrurns 0 on success, else a negative status code. + * + * Does not return until the remote CPU is nearly ready to execute <func> + * or is or has executed. + */ + +int smp_call_function_single (int cpu, void (*func) (void *info), void *info, + int nonatomic, int wait) +{ + /* prevent preemption and reschedule on another processor */ + int me = get_cpu(); + if (cpu == me) { + WARN_ON(1); + put_cpu(); + return -EBUSY; + } + spin_lock_bh(&call_lock); + __smp_call_function_single(cpu, func, info, nonatomic, wait); + spin_unlock_bh(&call_lock); + put_cpu(); + return 0; +} + +/* * this function sends a 'generic call function' IPI to all other CPUs * in the system. */ diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c index 6d23354443c03..6e4807d64d461 100644 --- a/arch/x86_64/kernel/smpboot.c +++ b/arch/x86_64/kernel/smpboot.c @@ -211,9 +211,6 @@ static __cpuinit void sync_master(void *arg) { unsigned long flags, i; - if (smp_processor_id() != 0) - return; - go[MASTER] = 0; local_irq_save(flags); @@ -262,7 +259,7 @@ get_delta(long *rt, long *master) return tcenter - best_tm; } -static __cpuinit void sync_tsc(void) +static __cpuinit void sync_tsc(unsigned int master) { int i, done = 0; long delta, adj, adjust_latency = 0; @@ -276,9 +273,17 @@ static __cpuinit void sync_tsc(void) } t[NUM_ROUNDS] __cpuinitdata; #endif + printk(KERN_INFO "CPU %d: Syncing TSC to CPU %u.\n", + smp_processor_id(), master); + go[MASTER] = 1; - smp_call_function(sync_master, NULL, 1, 0); + /* It is dangerous to broadcast IPI as cpus are coming up, + * as they may not be ready to accept them. So since + * we only need to send the ipi to the boot cpu direct + * the message, and avoid the race. + */ + smp_call_function_single(master, sync_master, NULL, 1, 0); while (go[MASTER]) /* wait for master to be ready */ no_cpu_relax(); @@ -322,16 +327,14 @@ static __cpuinit void sync_tsc(void) printk(KERN_INFO "CPU %d: synchronized TSC with CPU %u (last diff %ld cycles, " "maxerr %lu cycles)\n", - smp_processor_id(), boot_cpu_id, delta, rt); + smp_processor_id(), master, delta, rt); } static void __cpuinit tsc_sync_wait(void) { if (notscsync || !cpu_has_tsc) return; - printk(KERN_INFO "CPU %d: Syncing TSC to CPU %u.\n", smp_processor_id(), - boot_cpu_id); - sync_tsc(); + sync_tsc(boot_cpu_id); } static __init int notscsync_setup(char *s) |