[PATCH] i386: add smp_call_function_single
Continiung the series of small patches necessary for the perfmon subsystem, here is a patch that adds support for the smp_call_function_single() function for i386. It exists for almost all other architectures but i386. The perfmon subsystem needs it in one case to free some state on a designated remote CPU. Signed-off-by: Stephane Eranian <eranian@hpl.hp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -634,3 +634,69 @@ fastcall void smp_call_function_interrupt(struct pt_regs *regs)
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}
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}
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/*
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* this function sends a 'generic call function' IPI to one other CPU
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* in the system.
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*
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* cpu is a standard Linux logical CPU number.
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*/
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static void
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__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
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int nonatomic, int wait)
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{
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struct call_data_struct data;
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int cpus = 1;
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data.func = func;
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data.info = info;
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atomic_set(&data.started, 0);
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data.wait = wait;
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if (wait)
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atomic_set(&data.finished, 0);
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call_data = &data;
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wmb();
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/* Send a message to all other CPUs and wait for them to respond */
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send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
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/* Wait for response */
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while (atomic_read(&data.started) != cpus)
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cpu_relax();
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if (!wait)
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return;
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while (atomic_read(&data.finished) != cpus)
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cpu_relax();
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}
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/*
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* smp_call_function_single - Run a function on another CPU
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* @func: The function to run. This must be fast and non-blocking.
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* @info: An arbitrary pointer to pass to the function.
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* @nonatomic: Currently unused.
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* @wait: If true, wait until function has completed on other CPUs.
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*
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* Retrurns 0 on success, else a negative status code.
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*
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* Does not return until the remote CPU is nearly ready to execute <func>
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* or is or has executed.
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*/
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int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
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int nonatomic, int wait)
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{
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/* prevent preemption and reschedule on another processor */
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int me = get_cpu();
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if (cpu == me) {
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WARN_ON(1);
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put_cpu();
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return -EBUSY;
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}
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spin_lock_bh(&call_lock);
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__smp_call_function_single(cpu, func, info, nonatomic, wait);
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spin_unlock_bh(&call_lock);
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put_cpu();
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return 0;
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}
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EXPORT_SYMBOL(smp_call_function_single);
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