[PATCH] arm64: Remove boot thread synchronisation for spin-table release method
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2014-05-02 15:59:45
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
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> --- arch/arm64/kernel/smp_spin_table.c | 39 +------------------------------------- 1 file changed, 1 insertion(+), 38 deletions(-)
diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
index 7a530d2cc807..0347d38eea29 100644
--- a/arch/arm64/kernel/smp_spin_table.c
+++ b/arch/arm64/kernel/smp_spin_table.c@@ -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, };