123 строки
3.1 KiB
C
123 строки
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
#ifndef _ASM_POWERPC_PARAVIRT_H
|
|
#define _ASM_POWERPC_PARAVIRT_H
|
|
|
|
#include <linux/jump_label.h>
|
|
#include <asm/smp.h>
|
|
#ifdef CONFIG_PPC64
|
|
#include <asm/paca.h>
|
|
#include <asm/hvcall.h>
|
|
#endif
|
|
|
|
#ifdef CONFIG_PPC_SPLPAR
|
|
#include <linux/smp.h>
|
|
#include <asm/kvm_guest.h>
|
|
#include <asm/cputhreads.h>
|
|
|
|
DECLARE_STATIC_KEY_FALSE(shared_processor);
|
|
|
|
static inline bool is_shared_processor(void)
|
|
{
|
|
return static_branch_unlikely(&shared_processor);
|
|
}
|
|
|
|
/* If bit 0 is set, the cpu has been preempted */
|
|
static inline u32 yield_count_of(int cpu)
|
|
{
|
|
__be32 yield_count = READ_ONCE(lppaca_of(cpu).yield_count);
|
|
return be32_to_cpu(yield_count);
|
|
}
|
|
|
|
/*
|
|
* Spinlock code confers and prods, so don't trace the hcalls because the
|
|
* tracing code takes spinlocks which can cause recursion deadlocks.
|
|
*
|
|
* These calls are made while the lock is not held: the lock slowpath yields if
|
|
* it can not acquire the lock, and unlock slow path might prod if a waiter has
|
|
* yielded). So this may not be a problem for simple spin locks because the
|
|
* tracing does not technically recurse on the lock, but we avoid it anyway.
|
|
*
|
|
* However the queued spin lock contended path is more strictly ordered: the
|
|
* H_CONFER hcall is made after the task has queued itself on the lock, so then
|
|
* recursing on that lock will cause the task to then queue up again behind the
|
|
* first instance (or worse: queued spinlocks use tricks that assume a context
|
|
* never waits on more than one spinlock, so such recursion may cause random
|
|
* corruption in the lock code).
|
|
*/
|
|
static inline void yield_to_preempted(int cpu, u32 yield_count)
|
|
{
|
|
plpar_hcall_norets_notrace(H_CONFER, get_hard_smp_processor_id(cpu), yield_count);
|
|
}
|
|
|
|
static inline void prod_cpu(int cpu)
|
|
{
|
|
plpar_hcall_norets_notrace(H_PROD, get_hard_smp_processor_id(cpu));
|
|
}
|
|
|
|
static inline void yield_to_any(void)
|
|
{
|
|
plpar_hcall_norets_notrace(H_CONFER, -1, 0);
|
|
}
|
|
#else
|
|
static inline bool is_shared_processor(void)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline u32 yield_count_of(int cpu)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
extern void ___bad_yield_to_preempted(void);
|
|
static inline void yield_to_preempted(int cpu, u32 yield_count)
|
|
{
|
|
___bad_yield_to_preempted(); /* This would be a bug */
|
|
}
|
|
|
|
extern void ___bad_yield_to_any(void);
|
|
static inline void yield_to_any(void)
|
|
{
|
|
___bad_yield_to_any(); /* This would be a bug */
|
|
}
|
|
|
|
extern void ___bad_prod_cpu(void);
|
|
static inline void prod_cpu(int cpu)
|
|
{
|
|
___bad_prod_cpu(); /* This would be a bug */
|
|
}
|
|
|
|
#endif
|
|
|
|
#define vcpu_is_preempted vcpu_is_preempted
|
|
static inline bool vcpu_is_preempted(int cpu)
|
|
{
|
|
if (!is_shared_processor())
|
|
return false;
|
|
|
|
#ifdef CONFIG_PPC_SPLPAR
|
|
if (!is_kvm_guest()) {
|
|
int first_cpu = cpu_first_thread_sibling(smp_processor_id());
|
|
|
|
/*
|
|
* Preemption can only happen at core granularity. This CPU
|
|
* is not preempted if one of the CPU of this core is not
|
|
* preempted.
|
|
*/
|
|
if (cpu_first_thread_sibling(cpu) == first_cpu)
|
|
return false;
|
|
}
|
|
#endif
|
|
|
|
if (yield_count_of(cpu) & 1)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
static inline bool pv_is_native_spin_unlock(void)
|
|
{
|
|
return !is_shared_processor();
|
|
}
|
|
|
|
#endif /* _ASM_POWERPC_PARAVIRT_H */
|