android_kernel_xiaomi_sm8350/arch/s390/include/asm/smp.h
Gerald Schaefer 59b6978745 [S390] spinlock: check virtual cpu running status
This patch introduces a new function that checks the running status
of a cpu in a hypervisor. This status is not virtualized, so the check
is only correct if running in an LPAR. On acquiring a spinlock, if the
cpu holding the lock is scheduled by the hypervisor, we do a busy wait
on the lock. If it is not scheduled, we yield over to that cpu.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26 22:37:31 +01:00

79 lines
1.8 KiB
C

/*
* Copyright IBM Corp. 1999,2009
* Author(s): Denis Joseph Barrow,
* Martin Schwidefsky <schwidefsky@de.ibm.com>,
* Heiko Carstens <heiko.carstens@de.ibm.com>,
*/
#ifndef __ASM_SMP_H
#define __ASM_SMP_H
#ifdef CONFIG_SMP
#include <asm/system.h>
#include <asm/sigp.h>
extern void machine_restart_smp(char *);
extern void machine_halt_smp(void);
extern void machine_power_off_smp(void);
#define raw_smp_processor_id() (S390_lowcore.cpu_nr)
extern int __cpu_disable (void);
extern void __cpu_die (unsigned int cpu);
extern void cpu_die (void) __attribute__ ((noreturn));
extern int __cpu_up (unsigned int cpu);
extern struct mutex smp_cpu_state_mutex;
extern int smp_cpu_polarization[];
extern void arch_send_call_function_single_ipi(int cpu);
extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
extern void smp_switch_to_ipl_cpu(void (*func)(void *), void *);
extern void smp_switch_to_cpu(void (*)(void *), void *, unsigned long sp,
int from, int to);
extern void smp_restart_cpu(void);
/*
* returns 1 if (virtual) cpu is scheduled
* returns 0 otherwise
*/
static inline int smp_vcpu_scheduled(int cpu)
{
u32 status;
switch (sigp_ps(&status, 0, cpu, sigp_sense_running)) {
case sigp_status_stored:
/* Check for running status */
if (status & 0x400)
return 0;
break;
case sigp_not_operational:
return 0;
default:
break;
}
return 1;
}
#else /* CONFIG_SMP */
static inline void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
{
func(data);
}
#define smp_vcpu_scheduled (1)
#endif /* CONFIG_SMP */
#ifdef CONFIG_HOTPLUG_CPU
extern int smp_rescan_cpus(void);
#else
static inline int smp_rescan_cpus(void) { return 0; }
#endif
#endif /* __ASM_SMP_H */