mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-04 10:46:53 +07:00
3cded41794
Avoid the pointless function call to pv_lock_ops.vcpu_is_preempted() when a paravirt spinlock enabled kernel is ran on native hardware. Do this by patching out the CALL instruction with "XOR %RAX,%RAX" which has the same effect (0 return value). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: boqun.feng@gmail.com Cc: borntraeger@de.ibm.com Cc: bsingharora@gmail.com Cc: dave@stgolabs.net Cc: jgross@suse.com Cc: kernellwp@gmail.com Cc: konrad.wilk@oracle.com Cc: mpe@ellerman.id.au Cc: paulmck@linux.vnet.ibm.com Cc: paulus@samba.org Cc: pbonzini@redhat.com Cc: rkrcmar@redhat.com Cc: will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
/*
|
|
* Split spinlock implementation out into its own file, so it can be
|
|
* compiled in a FTRACE-compatible way.
|
|
*/
|
|
#include <linux/spinlock.h>
|
|
#include <linux/export.h>
|
|
#include <linux/jump_label.h>
|
|
|
|
#include <asm/paravirt.h>
|
|
|
|
__visible void __native_queued_spin_unlock(struct qspinlock *lock)
|
|
{
|
|
native_queued_spin_unlock(lock);
|
|
}
|
|
PV_CALLEE_SAVE_REGS_THUNK(__native_queued_spin_unlock);
|
|
|
|
bool pv_is_native_spin_unlock(void)
|
|
{
|
|
return pv_lock_ops.queued_spin_unlock.func ==
|
|
__raw_callee_save___native_queued_spin_unlock;
|
|
}
|
|
|
|
__visible bool __native_vcpu_is_preempted(int cpu)
|
|
{
|
|
return false;
|
|
}
|
|
PV_CALLEE_SAVE_REGS_THUNK(__native_vcpu_is_preempted);
|
|
|
|
bool pv_is_native_vcpu_is_preempted(void)
|
|
{
|
|
return pv_lock_ops.vcpu_is_preempted.func ==
|
|
__raw_callee_save___native_vcpu_is_preempted;
|
|
}
|
|
|
|
struct pv_lock_ops pv_lock_ops = {
|
|
#ifdef CONFIG_SMP
|
|
.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
|
|
.queued_spin_unlock = PV_CALLEE_SAVE(__native_queued_spin_unlock),
|
|
.wait = paravirt_nop,
|
|
.kick = paravirt_nop,
|
|
.vcpu_is_preempted = PV_CALLEE_SAVE(__native_vcpu_is_preempted),
|
|
#endif /* SMP */
|
|
};
|
|
EXPORT_SYMBOL(pv_lock_ops);
|
|
|
|
struct static_key paravirt_ticketlocks_enabled = STATIC_KEY_INIT_FALSE;
|
|
EXPORT_SYMBOL(paravirt_ticketlocks_enabled);
|