From 4e287e655e108cbbd6e3e7dcc49d591c8aa5a8a4 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Tue, 6 Jun 2017 23:08:32 +1000
Subject: [PATCH] powerpc: use spin loop primitives in some functions
Git-commit: 4e287e655e108cbbd6e3e7dcc49d591c8aa5a8a4
Patch-mainline: v4.13-rc1
References: bsc#1056912

Use the different spin loop primitives in some simple powerpc
spin loops, including those which will spin as a common case.

This will help to test the spin loop primitives before more
conversions are done.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add some includes of <linux/processor.h>]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 arch/powerpc/include/asm/delay.h | 16 ++++++++++++----
 arch/powerpc/kernel/smp.c        |  4 ++--
 arch/powerpc/kernel/time.c       |  8 +++++---
 arch/powerpc/mm/hash_native_64.c |  5 ++++-
 4 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/delay.h b/arch/powerpc/include/asm/delay.h
index 52e4d54da2a9..3df4417dd9c8 100644
--- a/arch/powerpc/include/asm/delay.h
+++ b/arch/powerpc/include/asm/delay.h
@@ -2,6 +2,7 @@
 #define _ASM_POWERPC_DELAY_H
 #ifdef __KERNEL__
 
+#include <linux/processor.h>
 #include <asm/time.h>
 
 /*
@@ -58,11 +59,18 @@ extern void udelay(unsigned long usecs);
 	typeof(condition) __ret;                                               \
 	unsigned long __loops = tb_ticks_per_usec * timeout;                   \
 	unsigned long __start = get_tbl();                                     \
-	while (!(__ret = (condition)) && (tb_ticks_since(__start) <= __loops)) \
-		if (delay)                                                     \
+                                                                               \
+	if (delay) {                                                           \
+		while (!(__ret = (condition)) &&                               \
+				(tb_ticks_since(__start) <= __loops))          \
 			udelay(delay);                                         \
-		else                                                           \
-			cpu_relax();                                           \
+	} else {                                                               \
+		spin_begin();                                                  \
+		while (!(__ret = (condition)) &&                               \
+				(tb_ticks_since(__start) <= __loops))          \
+			spin_cpu_relax();                                      \
+		spin_end();                                                    \
+	}                                                                      \
 	if (!__ret)                                                            \
 		__ret = (condition);                                           \
 	__ret;		                                                       \
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 418019728efa..a975ddf77200 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -33,6 +33,7 @@
 #include <linux/notifier.h>
 #include <linux/topology.h>
 #include <linux/profile.h>
+#include <linux/processor.h>
 
 #include <asm/ptrace.h>
 #include <linux/atomic.h>
@@ -767,8 +768,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 		smp_ops->give_timebase();
 
 	/* Wait until cpu puts itself in the online & active maps */
-	while (!cpu_online(cpu))
-		cpu_relax();
+	spin_until_cond(cpu_online(cpu));
 
 	return 0;
 }
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 0cc0dad905d5..fe6f3a285455 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -59,10 +59,10 @@
 #include <linux/suspend.h>
 #include <linux/rtc.h>
 #include <linux/sched/cputime.h>
+#include <linux/processor.h>
 #include <asm/trace.h>
 
 #include <asm/io.h>
-#include <asm/processor.h>
 #include <asm/nvram.h>
 #include <asm/cache.h>
 #include <asm/machdep.h>
@@ -442,6 +442,7 @@ void __delay(unsigned long loops)
 	unsigned long start;
 	int diff;
 
+	spin_begin();
 	if (__USE_RTC()) {
 		start = get_rtcl();
 		do {
@@ -449,13 +450,14 @@ void __delay(unsigned long loops)
 			diff = get_rtcl() - start;
 			if (diff < 0)
 				diff += 1000000000;
+			spin_cpu_relax();
 		} while (diff < loops);
 	} else {
 		start = get_tbl();
 		while (get_tbl() - start < loops)
-			HMT_low();
-		HMT_medium();
+			spin_cpu_relax();
 	}
+	spin_end();
 }
 EXPORT_SYMBOL(__delay);
 
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index bdaac28193f7..fbd1acc3b8d9 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -15,6 +15,7 @@
 #include <linux/spinlock.h>
 #include <linux/bitops.h>
 #include <linux/of.h>
+#include <linux/processor.h>
 #include <linux/threads.h>
 #include <linux/smp.h>
 
@@ -184,8 +185,10 @@ static inline void native_lock_hpte(struct hash_pte *hptep)
 	while (1) {
 		if (!test_and_set_bit_lock(HPTE_LOCK_BIT, word))
 			break;
+		spin_begin();
 		while(test_bit(HPTE_LOCK_BIT, word))
-			cpu_relax();
+			spin_cpu_relax();
+		spin_end();
 	}
 }
 
-- 
2.12.0