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From:   "wuqiang.matt" <wuqiang.matt@bytedance.com>
To:     vgupta@kernel.org, bcain@quicinc.com, jonas@southpole.se,
        stefan.kristiansson@saunalahti.fi, shorne@gmail.com,
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Cc:     linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org, mattwu@163.com,
        linux@roeck-us.ne, "wuqiang.matt" <wuqiang.matt@bytedance.com>
Subject: [PATCH v2 2/4] locking/atomic: arc: arch_cmpxchg[64]_local undefined
Date:   Sat,  4 Nov 2023 17:16:13 +0800
Message-Id: <20231104091615.4884-3-wuqiang.matt@bytedance.com>
In-Reply-To: <20231104091615.4884-1-wuqiang.matt@bytedance.com>
References: <20231104091615.4884-1-wuqiang.matt@bytedance.com>
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For architectures that support native cmpxchg, we'd like to
implement arch_cmpxchg[64]_local with the native variants of
supported data size. If not, the generci_cmpxchg[64]_local
will be used.

Signed-off-by: wuqiang.matt <wuqiang.matt@bytedance.com>
---
 arch/arc/include/asm/cmpxchg.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index bf46514f6f12..91429f2350df 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -80,6 +80,34 @@
 
 #endif
 
+/*
+ * always make arch_cmpxchg[64]_local available, native cmpxchg
+ * will be used if available, then generic_cmpxchg[64]_local
+ */
+#include <asm-generic/cmpxchg-local.h>
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+				      unsigned long old,
+				      unsigned long new, int size)
+{
+	switch (size) {
+#ifdef CONFIG_ARC_HAS_LLSC
+	case 4:
+		return __cmpxchg_32((int32_t *)ptr, old, new);
+#endif
+	default:
+		return __generic_cmpxchg_local(ptr, old, new, size);
+	}
+
+	return old;
+}
+#define arch_cmpxchg_local(ptr, o, n) ({				\
+	(__typeof__(*ptr))__cmpxchg_local((ptr),			\
+					(unsigned long)(o),		\
+					(unsigned long)(n),		\
+					sizeof(*(ptr)));		\
+})
+#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
+
 /*
  * xchg
  */
-- 
2.40.1