linux-kernel - [PATCH 27/27] alpha, smpboot: Use generic SMP booting infrastructure

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Date:	Fri, 01 Jun 2012 14:46:30 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	tglx@...utronix.de, peterz@...radead.org,
	paulmck@...ux.vnet.ibm.com
Cc:	rusty@...tcorp.com.au, mingo@...nel.org, yong.zhang0@...il.com,
	akpm@...ux-foundation.org, vatsa@...ux.vnet.ibm.com, rjw@...k.pl,
	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
	srivatsa.bhat@...ux.vnet.ibm.com, nikunj@...ux.vnet.ibm.com,
	Richard Henderson <rth@...ddle.net>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Matt Turner <mattst88@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Mike Frysinger <vapier@...too.org>, linux-alpha@...r.kernel.org
Subject: [PATCH 27/27] alpha, smpboot: Use generic SMP booting infrastructure

Convert alpha to use the generic framework to boot secondary CPUs.

Notes:
1. The secondary cpu was being set in the cpu_online_mask way too early.
Postpone it.

2. The original code was enabling interrupts before calling
wait_boot_cpu_to_stop(). Instead postpone the enabling of interrupts
to after the cpu_online_mask is set.

Cc: Richard Henderson <rth@...ddle.net>
Cc: Ivan Kokshaysky <ink@...assic.park.msu.ru>
Cc: Matt Turner <mattst88@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@...il.com>
Cc: Rusty Russell <rusty@...tcorp.com.au>
Cc: Mike Frysinger <vapier@...too.org>
Cc: linux-alpha@...r.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 arch/alpha/kernel/smp.c |   27 +++++++++++++++------------
 1 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 35ddc02..2547431 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -28,6 +28,7 @@
 #include <linux/profile.h>
 #include <linux/bitops.h>
 #include <linux/cpu.h>
+#include <linux/smpboot.h>
 
 #include <asm/hwrpb.h>
 #include <asm/ptrace.h>
@@ -119,13 +120,17 @@ wait_boot_cpu_to_stop(int cpuid)
 void __cpuinit
 smp_callin(void)
 {
-	int cpuid = hard_smp_processor_id();
+	smpboot_start_secondary(NULL);
+}
+
+void __cpuinit __cpu_pre_starting(void *unused)
+{
+	unsigned int cpuid = hard_smp_processor_id();
 
 	if (cpu_online(cpuid)) {
 		printk("??, cpu 0x%x already present??\n", cpuid);
 		BUG();
 	}
-	set_cpu_online(cpuid, true);
 
 	/* Turn on machine checks.  */
 	wrmces(7);
@@ -145,15 +150,16 @@ smp_callin(void)
 	/* All kernel threads share the same mm context.  */
 	atomic_inc(&init_mm.mm_count);
 	current->active_mm = &init_mm;
+}
 
-	/* inform the notifiers about the new cpu */
-	notify_cpu_starting(cpuid);
-
-	/* Must have completely accurate bogos.  */
-	local_irq_enable();
+void __cpuinit __cpu_pre_online(void *unused)
+{
+	unsigned int cpuid = hard_smp_processor_id();
 
-	/* Wait boot CPU to stop with irq enabled before running
-	   calibrate_delay. */
+	/*
+	 * Wait boot CPU to stop with irq disabled before running
+	 * calibrate_delay.
+	 */
 	wait_boot_cpu_to_stop(cpuid);
 	mb();
 	calibrate_delay();
@@ -165,9 +171,6 @@ smp_callin(void)
 
 	DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
 	      cpuid, current, current->active_mm));
-
-	/* Do nothing.  */
-	cpu_idle();
 }
 
 /* Wait until hwrpb->txrdy is clear for cpu.  Return -1 on timeout.  */

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