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Commit 9d07bc84 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc: Properly handshake CPUs going out of boot spin loop 



We need to wait a bit for them to have done their CPU setup
or we might end up with translation and EE on with different
LPCR values between threads

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ad0693ee

arch/powerpc/include/asm/smp.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <asm/percpu.h>



extern int boot_cpuid;

extern int boot_cpu_count;



extern void cpu_die(void);

arch/powerpc/kernel/head_64.S

+13 −5
Original line number Diff line number Diff line
@@ -242,23 +242,31 @@ generic_secondary_common_init: 
	ld	r23,0(r23)

	ld	r23,CPU_SPEC_RESTORE(r23)

	cmpdi	0,r23,0

	beq	4f

	beq	3f

	ld	r23,0(r23)

	mtctr	r23

	bctrl



3:	HMT_LOW

3:	LOAD_REG_ADDR(r3, boot_cpu_count) /* Decrement boot_cpu_count */

	lwarx	r4,0,r3

	subi	r4,r4,1

	stwcx.	r4,0,r3

	bne	3b

	isync



4:	HMT_LOW

	lbz	r23,PACAPROCSTART(r13)	/* Test if this processor should */

					/* start.			 */

#ifndef CONFIG_SMP

	b	3b			/* Never go on non-SMP		 */

	b	4b			/* Never go on non-SMP		 */

#else

	cmpwi	0,r23,0

	beq	3b			/* Loop until told to go	 */

	beq	4b			/* Loop until told to go	 */



	sync				/* order paca.run and cur_cpu_spec */

	isync				/* In case code patching happened */



4:	/* Create a temp kernel stack for use before relocation is on.	*/

	/* Create a temp kernel stack for use before relocation is on.	*/

	ld	r1,PACAEMERGSP(r13)

	subi	r1,r1,STACK_FRAME_OVERHEAD

arch/powerpc/kernel/prom.c

+10 −17
Original line number Diff line number Diff line
@@ -268,13 +268,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, 
					  const char *uname, int depth,

					  void *data)

{

	static int logical_cpuid = 0;

	char *type = of_get_flat_dt_prop(node, "device_type", NULL);

	const u32 *prop;

	const u32 *intserv;

	int i, nthreads;

	unsigned long len;

	int found = 0;

	int found = -1;



	/* We are scanning "cpu" nodes only */

	if (type == NULL || strcmp(type, "cpu") != 0)
@@ -299,11 +298,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node, 
		 * booted proc.

		 */

		if (initial_boot_params && initial_boot_params->version >= 2) {

			if (intserv[i] ==

					initial_boot_params->boot_cpuid_phys) {

				found = 1;

				break;

			}

			if (intserv[i] == initial_boot_params->boot_cpuid_phys)

				found = boot_cpu_count;

		} else {

			/*

			 * Check if it's the boot-cpu, set it's hw index now,
@@ -311,23 +307,20 @@ static int __init early_init_dt_scan_cpus(unsigned long node, 
			 * off secondary threads.

			 */

			if (of_get_flat_dt_prop(node,

					"linux,boot-cpu", NULL) != NULL) {

				found = 1;

				break;

					"linux,boot-cpu", NULL) != NULL)

				found = boot_cpu_count;

		}

		}



#ifdef CONFIG_SMP

		/* logical cpu id is always 0 on UP kernels */

		logical_cpuid++;

		boot_cpu_count++;

#endif

	}



	if (found) {

		DBG("boot cpu: logical %d physical %d\n", logical_cpuid,

	if (found >= 0) {

		DBG("boot cpu: logical %d physical %d\n", found,

			intserv[i]);

		boot_cpuid = logical_cpuid;

		set_hard_smp_processor_id(boot_cpuid, intserv[i]);

		boot_cpuid = found;

		set_hard_smp_processor_id(found, intserv[i]);



		/*

		 * PAPR defines "logical" PVR values for cpus that

arch/powerpc/kernel/setup_32.c

+1 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ extern void bootx_init(unsigned long r4, unsigned long phys); 


int boot_cpuid = -1;

EXPORT_SYMBOL_GPL(boot_cpuid);

int __initdata boot_cpu_count;

int boot_cpuid_phys;



int smp_hw_index[NR_CPUS];

arch/powerpc/kernel/setup_64.c

+12 −1
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ 
#endif



int boot_cpuid = 0;

int __initdata boot_cpu_count;

u64 ppc64_pft_size;



/* Pick defaults since we might want to patch instructions
@@ -233,6 +234,7 @@ void early_setup_secondary(void) 
void smp_release_cpus(void)

{

	unsigned long *ptr;

	int i;



	DBG(" -> smp_release_cpus()\n");
@@ -245,7 +247,16 @@ void smp_release_cpus(void) 
	ptr  = (unsigned long *)((unsigned long)&__secondary_hold_spinloop

			- PHYSICAL_START);

	*ptr = __pa(generic_secondary_smp_init);



	/* And wait a bit for them to catch up */

	for (i = 0; i < 100000; i++) {

		mb();

		HMT_low();

		if (boot_cpu_count == 0)

			break;

		udelay(1);

	}

	DBG("boot_cpu_count = %d\n", boot_cpu_count);



	DBG(" <- smp_release_cpus()\n");

}