Commit 9b6695a8 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

[MIPS] SMP: Fix initialization order bug. 


    
A recent change requires cpu_possible_map to be initialized before
smp_sched_init() but most MIPS platforms were initializing their
processors in the prom_prepare_cpus callback of smp_prepare_cpus.  The
simple fix of calling prom_prepare_cpus from one of the earlier SMP
initialization hooks doesn't work well either since IPIs may require
init_IRQ() to have completed, so bit the bullet and split
prom_prepare_cpus into two initialization functions, plat_smp_setup
which is called early from setup_arch and plat_prepare_cpus called where
prom_prepare_cpus used to be called.
    
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 3e6cb2d3

arch/mips/kernel/setup.c

+3 −0
Original line number Diff line number Diff line
@@ -540,6 +540,9 @@ void __init setup_arch(char **cmdline_p) 
	sparse_init();

	paging_init();

	resource_init();

#ifdef CONFIG_SMP

	plat_smp_setup();

#endif

}



int __init fpu_disable(char *s)

arch/mips/kernel/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -236,7 +236,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus) 
	init_new_context(current, &init_mm);

	current_thread_info()->cpu = 0;

	smp_tune_scheduling();

	prom_prepare_cpus(max_cpus);

	plat_prepare_cpus(max_cpus);

}



/* preload SMP state for boot cpu */

arch/mips/kernel/smp_mt.c

+7 −6
Original line number Diff line number Diff line
@@ -143,7 +143,7 @@ static struct irqaction irq_call = { 
 * Make sure all CPU's are in a sensible state before we boot any of the

 * secondarys

 */

void prom_prepare_cpus(unsigned int max_cpus)

void plat_smp_setup(void)

{

	unsigned long val;

	int i, num;
@@ -179,12 +179,10 @@ void prom_prepare_cpus(unsigned int max_cpus) 
				write_vpe_c0_vpeconf0(tmp);



				/* Record this as available CPU */

				if (i < max_cpus) {

				cpu_set(i, phys_cpu_present_map);

				__cpu_number_map[i]	= ++num;

				__cpu_logical_map[num]	= i;

			}

			}



			/* disable multi-threading with TC's */

			write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);
@@ -241,7 +239,10 @@ void prom_prepare_cpus(unsigned int max_cpus) 
		set_vi_handler (MIPS_CPU_IPI_RESCHED_IRQ, ipi_resched_dispatch);

		set_vi_handler (MIPS_CPU_IPI_CALL_IRQ, ipi_call_dispatch);

	}

}



void __init plat_prepare_cpus(unsigned int max_cpus)

{

	cpu_ipi_resched_irq = MIPSCPU_INT_BASE + MIPS_CPU_IPI_RESCHED_IRQ;

	cpu_ipi_call_irq = MIPSCPU_INT_BASE + MIPS_CPU_IPI_CALL_IRQ;

arch/mips/pmc-sierra/yosemite/smp.c

+6 −18
Original line number Diff line number Diff line
@@ -50,37 +50,25 @@ void __init prom_grab_secondary(void) 
 * We don't want to start the secondary CPU yet nor do we have a nice probing

 * feature in PMON so we just assume presence of the secondary core.

 */

static char maxcpus_string[] __initdata =

	KERN_WARNING "max_cpus set to 0; using 1 instead\n";



void __init prom_prepare_cpus(unsigned int max_cpus)

void __init plat_smp_setup(void)

{

	int enabled = 0, i;



	if (max_cpus == 0) {

		printk(maxcpus_string);

		max_cpus = 1;

	}

	int i;



	cpus_clear(phys_cpu_present_map);



	for (i = 0; i < 2; i++) {

		if (i == max_cpus)

			break;



		/*

		 * The boot CPU

		 */

		cpu_set(i, phys_cpu_present_map);

		__cpu_number_map[i]	= i;

		__cpu_logical_map[i]	= i;

		enabled++;

	}

}



void __init plat_prepare_cpus(unsigned int max_cpus)

{

	/*

	 * Be paranoid.  Enable the IPI only if we're really about to go SMP.

	 */

	if (enabled > 1)

	if (cpus_weight(cpu_possible_map))

		set_c0_status(STATUSF_IP5);

}

arch/mips/sgi-ip27/ip27-smp.c

+6 −1
Original line number Diff line number Diff line
@@ -140,7 +140,7 @@ static __init void intr_clear_all(nasid_t nasid) 
		REMOTE_HUB_CLR_INTR(nasid, i);

}



void __init prom_prepare_cpus(unsigned int max_cpus)

void __init plat_smp_setup(void)

{

	cnodeid_t	cnode;
@@ -161,6 +161,11 @@ void __init prom_prepare_cpus(unsigned int max_cpus) 
	alloc_cpupda(0, 0);

}



void __init plat_prepare_cpus(unsigned int max_cpus)

{

	/* We already did everything necessary earlier */

}



/*

 * Launch a slave into smp_bootstrap().  It doesn't take an argument, and we

 * set sp to the kernel stack of the newly created idle process, gp to the proc

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