On 7/9/20 6:53 AM, Michael Ellerman wrote:
Nicholas Piggin <npiggin@xxxxxxxxx> writes:
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/include/asm/paravirt.h | 28 ++++++++
arch/powerpc/include/asm/qspinlock.h | 66 +++++++++++++++++++
arch/powerpc/include/asm/qspinlock_paravirt.h | 7 ++
arch/powerpc/platforms/pseries/Kconfig | 5 ++
arch/powerpc/platforms/pseries/setup.c | 6 +-
include/asm-generic/qspinlock.h | 2 +
Another ack?
I am OK with adding the #ifdef around queued_spin_lock().
Acked-by: Waiman Long <longman@xxxxxxxxxx>
diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h
index 7a8546660a63..f2d51f929cf5 100644
--- a/arch/powerpc/include/asm/paravirt.h
+++ b/arch/powerpc/include/asm/paravirt.h
@@ -45,6 +55,19 @@ 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 */
+}
Why do we do that rather than just not defining yield_to_any() at all
and letting the build fail on that?
There's a condition somewhere that we know will false at compile time
and drop the call before linking?
diff --git a/arch/powerpc/include/asm/qspinlock_paravirt.h b/arch/powerpc/include/asm/qspinlock_paravirt.h
new file mode 100644
index 000000000000..750d1b5e0202
--- /dev/null
+++ b/arch/powerpc/include/asm/qspinlock_paravirt.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_QSPINLOCK_PARAVIRT_H
+#define __ASM_QSPINLOCK_PARAVIRT_H
_ASM_POWERPC_QSPINLOCK_PARAVIRT_H please.
+
+EXPORT_SYMBOL(__pv_queued_spin_unlock);
Why's that in a header? Should that (eventually) go with the generic implementation?
The PV qspinlock implementation is not that generic at the moment. Even
though native qspinlock is used by a number of archs, PV qspinlock is
only currently used in x86. This is certainly an area that needs
improvement.
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 24c18362e5ea..756e727b383f 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -25,9 +25,14 @@ config PPC_PSERIES
select SWIOTLB
default y
+config PARAVIRT_SPINLOCKS
+ bool
+ default n
default n is the default.
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 2db8469e475f..747a203d9453 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -771,8 +771,12 @@ static void __init pSeries_setup_arch(void)
if (firmware_has_feature(FW_FEATURE_LPAR)) {
vpa_init(boot_cpuid);
- if (lppaca_shared_proc(get_lppaca()))
+ if (lppaca_shared_proc(get_lppaca())) {
static_branch_enable(&shared_processor);
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+ pv_spinlocks_init();
+#endif
+ }
We could avoid the ifdef with this I think?
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 434615f1d761..6ec72282888d 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -10,5 +10,9 @@
#include <asm/simple_spinlock.h>
#endif
+#ifndef CONFIG_PARAVIRT_SPINLOCKS
+static inline void pv_spinlocks_init(void) { }
+#endif
+
#endif /* __KERNEL__ */
#endif /* __ASM_SPINLOCK_H */
cheers
We don't really need to do a pv_spinlocks_init() if pv_kick() isn't
supported.
Cheers,
Longman
