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[PATCH] i386: add smp_call_function_single

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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>
This commit is contained in:
Stephane Eranian 2006-09-25 23:32:32 -07:00 committed by Linus Torvalds
parent 27d26666fc
commit eaa70773e7
1 changed files with 66 additions and 0 deletions
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66
arch/i386/kernel/smp.c
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@ -634,3 +634,69 @@ fastcall void smp_call_function_interrupt(struct pt_regs *regs)
}
}
/*
* this function sends a 'generic call function' IPI to one other CPU
* in the system.
*
* cpu is a standard Linux logical CPU number.
*/
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;
}
EXPORT_SYMBOL(smp_call_function_single);