From: Heiko Carstens <hca@linux.ibm.com>
Date: Wed, 4 Dec 2024 11:31:01 +0000 (+0100)
Subject: s390/preempt: Remove special pre MARCH_HAS_Z196_FEATURES implementation
X-Git-Tag: io_uring-6.14-20240131~23^2~36
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=5eee66c5bf6034c84a67fdbf224110f5288d9195;p=linux-block.git

s390/preempt: Remove special pre MARCH_HAS_Z196_FEATURES implementation

Remove the preempt count implementation for pre MARCH_HAS_Z196_FEATURES
builds. If the kernel is compiled with PREEMPT=n, which is the default for
all distributions, this has close to zero impact in the generated code.

Therefore remove the alternative implementation to keep things simple.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---

diff --git a/arch/s390/include/asm/preempt.h b/arch/s390/include/asm/preempt.h
index 3e3f21385db9..e100dd32f766 100644
--- a/arch/s390/include/asm/preempt.h
+++ b/arch/s390/include/asm/preempt.h
@@ -8,8 +8,6 @@
 #include <asm/cmpxchg.h>
 #include <asm/march.h>
 
-#ifdef MARCH_HAS_Z196_FEATURES
-
 /* We use the MSB mostly because its available */
 #define PREEMPT_NEED_RESCHED	0x80000000
 
@@ -101,56 +99,6 @@ static __always_inline bool should_resched(int preempt_offset)
 			preempt_offset);
 }
 
-#else /* MARCH_HAS_Z196_FEATURES */
-
-#define PREEMPT_ENABLED	(0)
-
-static __always_inline int preempt_count(void)
-{
-	return READ_ONCE(get_lowcore()->preempt_count);
-}
-
-static __always_inline void preempt_count_set(int pc)
-{
-	get_lowcore()->preempt_count = pc;
-}
-
-static __always_inline void set_preempt_need_resched(void)
-{
-}
-
-static __always_inline void clear_preempt_need_resched(void)
-{
-}
-
-static __always_inline bool test_preempt_need_resched(void)
-{
-	return false;
-}
-
-static __always_inline void __preempt_count_add(int val)
-{
-	get_lowcore()->preempt_count += val;
-}
-
-static __always_inline void __preempt_count_sub(int val)
-{
-	get_lowcore()->preempt_count -= val;
-}
-
-static __always_inline bool __preempt_count_dec_and_test(void)
-{
-	return !--get_lowcore()->preempt_count && tif_need_resched();
-}
-
-static __always_inline bool should_resched(int preempt_offset)
-{
-	return unlikely(preempt_count() == preempt_offset &&
-			tif_need_resched());
-}
-
-#endif /* MARCH_HAS_Z196_FEATURES */
-
 #define init_task_preempt_count(p)	do { } while (0)
 /* Deferred to CPU bringup time */
 #define init_idle_preempt_count(p, cpu)	do { } while (0)