Re: [PATCH] sparc32: refactor smp boot

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

On 02/15/2013 08:49 PM, Sam Ravnborg wrote:
> From 1bf0fa77f722275cf7c7be0fbb80e4399f60c734 Mon Sep 17 00:00:00 2001
> From: Sam Ravnborg <sam@ravnborg.org>
> Date: Fri, 15 Feb 2013 15:52:06 +0100
> Subject: [PATCH] sparc32: refactor smp boot
> 
> Introduce a common smp_callin() function to call
> from trampoline_32.S.
> Add platform specific functions to handle the
> platform details.
> 
> This is in preparation for a patch that will
> unify the smp boot stuff for all architectures.
> sparc32 was significantly different to warrant
> this patch in preparation.
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Acked-by: David S. Miller <davem@davemloft.net>
> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
> ---
> 
> Hi David.
> 
> I have had this patch lingering for a long time now.
> Can you please apply it to sparc.
> 
> Then it has hopefully hit mainline before Srivatsa re-visits
> the smpboot stuff.
>

Hey Sam,

Thanks a lot for following up with this! I really appreciate
your work on making it easier to convert sparc to a common
smpboot infrastructure. Thank you!

Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

Regards,
Srivatsa S. Bhat
 
> 	Sam
> 
> 
>  arch/sparc/kernel/kernel.h        |   12 +++++
>  arch/sparc/kernel/leon_smp.c      |   33 ++++----------
>  arch/sparc/kernel/smp_32.c        |   86 +++++++++++++++++++++++++++++++++++++
>  arch/sparc/kernel/sun4d_smp.c     |   29 ++++---------
>  arch/sparc/kernel/sun4m_smp.c     |   33 ++++----------
>  arch/sparc/kernel/trampoline_32.S |   17 +++----
>  6 files changed, 132 insertions(+), 78 deletions(-)
> 
> diff --git a/arch/sparc/kernel/kernel.h b/arch/sparc/kernel/kernel.h
> index 291bb5d..a702d9a 100644
> --- a/arch/sparc/kernel/kernel.h
> +++ b/arch/sparc/kernel/kernel.h
> @@ -48,6 +48,10 @@ extern void sun4m_init_IRQ(void);
>  extern void sun4m_unmask_profile_irq(void);
>  extern void sun4m_clear_profile_irq(int cpu);
> 
> +/* sun4m_smp.c */
> +void sun4m_cpu_pre_starting(void *arg);
> +void sun4m_cpu_pre_online(void *arg);
> +
>  /* sun4d_irq.c */
>  extern spinlock_t sun4d_imsk_lock;
> 
> @@ -60,6 +64,14 @@ extern int show_sun4d_interrupts(struct seq_file *, void *);
>  extern void sun4d_distribute_irqs(void);
>  extern void sun4d_free_irq(unsigned int irq, void *dev_id);
> 
> +/* sun4d_smp.c */
> +void sun4d_cpu_pre_starting(void *arg);
> +void sun4d_cpu_pre_online(void *arg);
> +
> +/* leon_smp.c */
> +void leon_cpu_pre_starting(void *arg);
> +void leon_cpu_pre_online(void *arg);
> +
>  /* head_32.S */
>  extern unsigned int t_nmi[];
>  extern unsigned int linux_trap_ipi15_sun4d[];
> diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
> index 0f3fb6d..9b40c9c 100644
> --- a/arch/sparc/kernel/leon_smp.c
> +++ b/arch/sparc/kernel/leon_smp.c
> @@ -69,31 +69,19 @@ static inline unsigned long do_swap(volatile unsigned long *ptr,
>  	return val;
>  }
> 
> -void __cpuinit leon_callin(void)
> +void __cpuinit leon_cpu_pre_starting(void *arg)
>  {
> -	int cpuid = hard_smp_processor_id();
> -
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
>  	leon_configure_cache_smp();
> +}
> 
> -	notify_cpu_starting(cpuid);
> -
> -	/* Get our local ticker going. */
> -	register_percpu_ce(cpuid);
> -
> -	calibrate_delay();
> -	smp_store_cpu_info(cpuid);
> -
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
> +void __cpuinit leon_cpu_pre_online(void *arg)
> +{
> +	int cpuid = hard_smp_processor_id();
> 
> -	/*
> -	 * Unblock the master CPU _only_ when the scheduler state
> -	 * of all secondary CPUs will be up-to-date, so after
> -	 * the SMP initialization the master will be just allowed
> -	 * to call the scheduler code.
> -	 * Allow master to continue.
> +	/* Allow master to continue. The master will then give us the
> +	 * go-ahead by setting the smp_commenced_mask and will wait without
> +	 * timeouts until our setup is completed fully (signified by
> +	 * our bit being set in the cpu_online_mask).
>  	 */
>  	do_swap(&cpu_callin_map[cpuid], 1);
> 
> @@ -110,9 +98,6 @@ void __cpuinit leon_callin(void)
> 
>  	while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
>  		mb();
> -
> -	local_irq_enable();
> -	set_cpu_online(cpuid, true);
>  }
> 
>  /*
> diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
> index 79db45e..9e7e6d7 100644
> --- a/arch/sparc/kernel/smp_32.c
> +++ b/arch/sparc/kernel/smp_32.c
> @@ -20,6 +20,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/cache.h>
>  #include <linux/delay.h>
> +#include <linux/cpu.h>
> 
>  #include <asm/ptrace.h>
>  #include <linux/atomic.h>
> @@ -32,8 +33,10 @@
>  #include <asm/cacheflush.h>
>  #include <asm/tlbflush.h>
>  #include <asm/cpudata.h>
> +#include <asm/timer.h>
>  #include <asm/leon.h>
> 
> +#include "kernel.h"
>  #include "irq.h"
> 
>  volatile unsigned long cpu_callin_map[NR_CPUS] __cpuinitdata = {0,};
> @@ -294,6 +297,89 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
>  	return ret;
>  }
> 
> +void __cpuinit arch_cpu_pre_starting(void *arg)
> +{
> +	local_ops->cache_all();
> +	local_ops->tlb_all();
> +
> +	switch(sparc_cpu_model) {
> +	case sun4m:
> +		sun4m_cpu_pre_starting(arg);
> +		break;
> +	case sun4d:
> +		sun4d_cpu_pre_starting(arg);
> +		break;
> +	case sparc_leon:
> +		leon_cpu_pre_starting(arg);
> +		break;
> +	default:
> +		BUG();
> +	}
> +}
> +
> +void __cpuinit arch_cpu_pre_online(void *arg)
> +{
> +	unsigned int cpuid = hard_smp_processor_id();
> +
> +	register_percpu_ce(cpuid);
> +
> +	calibrate_delay();
> +	smp_store_cpu_info(cpuid);
> +
> +	local_ops->cache_all();
> +	local_ops->tlb_all();
> +
> +	switch(sparc_cpu_model) {
> +	case sun4m:
> +		sun4m_cpu_pre_online(arg);
> +		break;
> +	case sun4d:
> +		sun4d_cpu_pre_online(arg);
> +		break;
> +	case sparc_leon:
> +		leon_cpu_pre_online(arg);
> +		break;
> +	default:
> +		BUG();
> +	}
> +}
> +
> +void __cpuinit sparc_start_secondary(void *arg)
> +{
> +	unsigned int cpu;
> +
> +	/*
> +	 * SMP booting is extremely fragile in some architectures. So run
> +	 * the cpu initialization code first before anything else.
> +	 */
> +	arch_cpu_pre_starting(arg);
> +
> +	preempt_disable();
> +	cpu = smp_processor_id();
> +
> +	/* Invoke the CPU_STARTING notifier callbacks */
> +	notify_cpu_starting(cpu);
> +
> +	arch_cpu_pre_online(arg);
> +
> +	/* Set the CPU in the cpu_online_mask */
> +	set_cpu_online(cpu, true);
> +
> +	/* Enable local interrupts now */
> +	local_irq_enable();
> +
> +	wmb();
> +	cpu_idle();
> +
> +	/* We should never reach here! */
> +	BUG();
> +}
> +
> +void __cpuinit smp_callin(void)
> +{
> +	sparc_start_secondary(NULL);
> +}
> +
>  void smp_bogo(struct seq_file *m)
>  {
>  	int i;
> diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
> index ddaea31..c9eb82f 100644
> --- a/arch/sparc/kernel/sun4d_smp.c
> +++ b/arch/sparc/kernel/sun4d_smp.c
> @@ -50,10 +50,9 @@ static inline void show_leds(int cpuid)
>  			      "i" (ASI_M_CTL));
>  }
> 
> -void __cpuinit smp4d_callin(void)
> +void __cpuinit sun4d_cpu_pre_starting(void *arg)
>  {
>  	int cpuid = hard_smp_processor_id();
> -	unsigned long flags;
> 
>  	/* Show we are alive */
>  	cpu_leds[cpuid] = 0x6;
> @@ -61,26 +60,20 @@ void __cpuinit smp4d_callin(void)
> 
>  	/* Enable level15 interrupt, disable level14 interrupt for now */
>  	cc_set_imsk((cc_get_imsk() & ~0x8000) | 0x4000);
> +}
> 
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
> +void __cpuinit sun4d_cpu_pre_online(void *arg)
> +{
> +	unsigned long flags;
> +	int cpuid;
> 
> -	notify_cpu_starting(cpuid);
> -	/*
> -	 * Unblock the master CPU _only_ when the scheduler state
> +	cpuid = hard_smp_processor_id();
> +
> +	/* Unblock the master CPU _only_ when the scheduler state
>  	 * of all secondary CPUs will be up-to-date, so after
>  	 * the SMP initialization the master will be just allowed
>  	 * to call the scheduler code.
>  	 */
> -	/* Get our local ticker going. */
> -	register_percpu_ce(cpuid);
> -
> -	calibrate_delay();
> -	smp_store_cpu_info(cpuid);
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
> -
> -	/* Allow master to continue. */
>  	sun4d_swap((unsigned long *)&cpu_callin_map[cpuid], 1);
>  	local_ops->cache_all();
>  	local_ops->tlb_all();
> @@ -106,16 +99,12 @@ void __cpuinit smp4d_callin(void)
>  	local_ops->cache_all();
>  	local_ops->tlb_all();
> 
> -	local_irq_enable();	/* We don't allow PIL 14 yet */
> -
>  	while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
>  		barrier();
> 
>  	spin_lock_irqsave(&sun4d_imsk_lock, flags);
>  	cc_set_imsk(cc_get_imsk() & ~0x4000); /* Allow PIL 14 as well */
>  	spin_unlock_irqrestore(&sun4d_imsk_lock, flags);
> -	set_cpu_online(cpuid, true);
> -
>  }
> 
>  /*
> diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
> index 128af73..8a65f15 100644
> --- a/arch/sparc/kernel/sun4m_smp.c
> +++ b/arch/sparc/kernel/sun4m_smp.c
> @@ -34,30 +34,19 @@ swap_ulong(volatile unsigned long *ptr, unsigned long val)
>  	return val;
>  }
> 
> -void __cpuinit smp4m_callin(void)
> +void __cpuinit sun4m_cpu_pre_starting(void *arg)
>  {
> -	int cpuid = hard_smp_processor_id();
> -
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
> -
> -	notify_cpu_starting(cpuid);
> -
> -	register_percpu_ce(cpuid);
> -
> -	calibrate_delay();
> -	smp_store_cpu_info(cpuid);
> +}
> 
> -	local_ops->cache_all();
> -	local_ops->tlb_all();
> +void __cpuinit sun4m_cpu_pre_online(void *arg)
> +{
> +	int cpuid = hard_smp_processor_id();
> 
> -	/*
> -	 * Unblock the master CPU _only_ when the scheduler state
> -	 * of all secondary CPUs will be up-to-date, so after
> -	 * the SMP initialization the master will be just allowed
> -	 * to call the scheduler code.
> +	/* Allow master to continue. The master will then give us the
> +	 * go-ahead by setting the smp_commenced_mask and will wait without
> +	 * timeouts until our setup is completed fully (signified by
> +	 * our bit being set in the cpu_online_mask).
>  	 */
> -	/* Allow master to continue. */
>  	swap_ulong(&cpu_callin_map[cpuid], 1);
> 
>  	/* XXX: What's up with all the flushes? */
> @@ -75,10 +64,6 @@ void __cpuinit smp4m_callin(void)
> 
>  	while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
>  		mb();
> -
> -	local_irq_enable();
> -
> -	set_cpu_online(cpuid, true);
>  }
> 
>  /*
> diff --git a/arch/sparc/kernel/trampoline_32.S b/arch/sparc/kernel/trampoline_32.S
> index af27aca..6cdb08c 100644
> --- a/arch/sparc/kernel/trampoline_32.S
> +++ b/arch/sparc/kernel/trampoline_32.S
> @@ -79,18 +79,15 @@ cpu3_startup:
>  	 nop
> 
>  	/* Start this processor. */
> -	call	smp4m_callin
> +	call	smp_callin
>  	 nop
> 
> -	b,a	smp_do_cpu_idle
> +	b,a	smp_panic
> 
>  	.text
>  	.align	4
> 
> -smp_do_cpu_idle:
> -	call	cpu_idle
> -	 mov	0, %o0
> -
> +smp_panic:
>  	call	cpu_panic
>  	 nop
> 
> @@ -144,10 +141,10 @@ sun4d_cpu_startup:
>  	 nop
> 
>  	/* Start this processor. */
> -	call	smp4d_callin
> +	call	smp_callin
>  	 nop
> 
> -	b,a	smp_do_cpu_idle
> +	b,a	smp_panic
> 
>  	__CPUINIT
>  	.align	4
> @@ -201,7 +198,7 @@ leon_smp_cpu_startup:
>  	 nop
> 
>  	/* Start this processor. */
> -	call	leon_callin
> +	call	smp_callin
>  	 nop
> 
> -	b,a	smp_do_cpu_idle
> +	b,a	smp_panic
>