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arm64: Remove boot thread synchronisation for spin-table release method 

The synchronisation with the boot thread already happens in __cpu_up()
via wait_for_completion_timeout(). In addition, __cpu_up() calls are
protected by the cpu_add_remove_lock mutex and already serialised.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas 2014-04-04 11:49:05 +01:00
parent a41dc0e841
commit 6400111399
1 changed files with 1 additions and 38 deletions
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39
arch/arm64/kernel/smp_spin_table.c
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@ -30,7 +30,6 @@ extern void secondary_holding_pen(void);
volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
static phys_addr_t cpu_release_addr[NR_CPUS];
static DEFINE_RAW_SPINLOCK(boot_lock);
/*
* Write secondary_holding_pen_release in a way that is guaranteed to be
@ -94,14 +93,6 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu)
static int smp_spin_table_cpu_boot(unsigned int cpu)
{
unsigned long timeout;
/*
* Set synchronisation state between this boot processor
* and the secondary one
*/
raw_spin_lock(&boot_lock);
/*
* Update the pen release flag.
*/
@ -112,34 +103,7 @@ static int smp_spin_table_cpu_boot(unsigned int cpu)
*/
sev();
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
if (secondary_holding_pen_release == INVALID_HWID)
break;
udelay(10);
}
/*
* Now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
raw_spin_unlock(&boot_lock);
return secondary_holding_pen_release != INVALID_HWID ? -ENOSYS : 0;
}
static void smp_spin_table_cpu_postboot(void)
{
/*
* Let the primary processor know we're out of the pen.
*/
write_pen_release(INVALID_HWID);
/*
* Synchronise with the boot thread.
*/
raw_spin_lock(&boot_lock);
raw_spin_unlock(&boot_lock);
return 0;
}
const struct cpu_operations smp_spin_table_ops = {
@ -147,5 +111,4 @@ const struct cpu_operations smp_spin_table_ops = {
.cpu_init = smp_spin_table_cpu_init,
.cpu_prepare = smp_spin_table_cpu_prepare,
.cpu_boot = smp_spin_table_cpu_boot,
.cpu_postboot = smp_spin_table_cpu_postboot,
};