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Commit 677d7623 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

[S390] Dont overwrite lowcores on smp_send_stop(). 



Don't perform a sigp store-status-at-address on smp_send_stop().
It will overwrite the lowcores of other cpus and destroys valueable
debug informations.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent ce7e9fae

arch/s390/kernel/smp.c

+7 −49
Original line number Diff line number Diff line
@@ -193,71 +193,29 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, 
}

EXPORT_SYMBOL(smp_call_function_single);



static void do_send_stop(void)

void smp_send_stop(void)

{

	int cpu, rc;



	/* stop all processors */

	for_each_online_cpu(cpu) {

		if (cpu == smp_processor_id())

			continue;

		do {

			rc = signal_processor(cpu, sigp_stop);

		} while (rc == sigp_busy);

	}

}

	/* Disable all interrupts/machine checks */

	__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);



static void do_store_status(void)

{

	int cpu, rc;

	/* write magic number to zero page (absolute 0) */

	lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;



	/* store status of all processors in their lowcores (real 0) */

	/* stop all processors */

	for_each_online_cpu(cpu) {

		if (cpu == smp_processor_id())

			continue;

		do {

			rc = signal_processor_p(

				(__u32)(unsigned long) lowcore_ptr[cpu], cpu,

				sigp_store_status_at_address);

			rc = signal_processor(cpu, sigp_stop);

		} while (rc == sigp_busy);

	}

}



static void do_wait_for_stop(void)

{

	int cpu;



	/* Wait for all other cpus to enter stopped state */

	for_each_online_cpu(cpu) {

		if (cpu == smp_processor_id())

			continue;

		while (!smp_cpu_not_running(cpu))

			cpu_relax();

	}

}



/*

 * this function sends a 'stop' sigp to all other CPUs in the system.

 * it goes straight through.

 */

void smp_send_stop(void)

{

	/* Disable all interrupts/machine checks */

	__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);



	/* write magic number to zero page (absolute 0) */

	lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;



	/* stop other processors. */

	do_send_stop();



	/* wait until other processors are stopped */

	do_wait_for_stop();



	/* store status of other processors. */

	do_store_status();

}



/*

 * Reboot, halt and power_off routines for SMP.

 */