powerpc/spinlocks: Refactor SHARED_PROCESSOR

Determining if a processor is in shared processor mode is not a constant
so don't hide it behind a #define.

Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190813031314.1828-2-cmr@informatik.wtf

diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index a47f827..e9c60fb 100644 (file)
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -101,15 +101,27 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
 
 #if defined(CONFIG_PPC_SPLPAR)
 /* We only yield to the hypervisor if we are in shared processor mode */
-#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
 extern void __spin_yield(arch_spinlock_t *lock);
 extern void __rw_yield(arch_rwlock_t *lock);
 #else /* SPLPAR */
 #define __spin_yield(x)        barrier()
 #define __rw_yield(x)  barrier()
-#define SHARED_PROCESSOR       0
 #endif
 
+static inline bool is_shared_processor(void)
+{
+/*
+ * LPPACA is only available on Pseries so guard anything LPPACA related to
+ * allow other platforms (which include this common header) to compile.
+ */
+#ifdef CONFIG_PPC_PSERIES
+       return (IS_ENABLED(CONFIG_PPC_SPLPAR) &&
+               lppaca_shared_proc(local_paca->lppaca_ptr));
+#else
+       return false;
+#endif
+}
+
 static inline void arch_spin_lock(arch_spinlock_t *lock)
 {
        while (1) {
@@ -117,7 +129,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
                        break;
                do {
                        HMT_low();
-                       if (SHARED_PROCESSOR)
+                       if (is_shared_processor())
                                __spin_yield(lock);
                } while (unlikely(lock->slock != 0));
                HMT_medium();
@@ -136,7 +148,7 @@ void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
                local_irq_restore(flags);
                do {
                        HMT_low();
-                       if (SHARED_PROCESSOR)
+                       if (is_shared_processor())
                                __spin_yield(lock);
                } while (unlikely(lock->slock != 0));
                HMT_medium();
@@ -226,7 +238,7 @@ static inline void arch_read_lock(arch_rwlock_t *rw)
                        break;
                do {
                        HMT_low();
-                       if (SHARED_PROCESSOR)
+                       if (is_shared_processor())
                                __rw_yield(rw);
                } while (unlikely(rw->lock < 0));
                HMT_medium();
@@ -240,7 +252,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw)
                        break;
                do {
                        HMT_low();
-                       if (SHARED_PROCESSOR)
+                       if (is_shared_processor())
                                __rw_yield(rw);
                } while (unlikely(rw->lock != 0));
                HMT_medium();