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From: Al Viro <viro@zeniv.linux.org.uk>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	kernel-team@meta.com,
	"David S. Miller" <davem@davemloft.net>,
	Andreas Larsson <andreas@gaisler.com>,
	Palmer Dabbelt <palmer@rivosinc.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Marco Elver <elver@google.com>
Subject: [PATCH 4/8] sparc32: add __cmpxchg_u{8,16}() and teach __cmpxchg() to handle those sizes
Date: Tue,  2 Apr 2024 00:28:31 -0400
Message-Id: <20240402042835.11815-4-viro@zeniv.linux.org.uk>
In-Reply-To: <20240402042835.11815-1-viro@zeniv.linux.org.uk>
References: <20240402041138.GF538574@ZenIV>
 <20240402042835.11815-1-viro@zeniv.linux.org.uk>
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trivial now

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sparc/include/asm/cmpxchg_32.h | 7 ++++++-
 arch/sparc/lib/atomic32.c           | 4 ++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/sparc/include/asm/cmpxchg_32.h b/arch/sparc/include/asm/cmpxchg_32.h
index 86254c366477..1324984de36a 100644
--- a/arch/sparc/include/asm/cmpxchg_32.h
+++ b/arch/sparc/include/asm/cmpxchg_32.h
@@ -38,7 +38,8 @@ static __always_inline unsigned long __arch_xchg(unsigned long x, __volatile__ v
 
 /* bug catcher for when unsupported size is used - won't link */
 void __cmpxchg_called_with_bad_pointer(void);
-/* we only need to support cmpxchg of a u32 on sparc */
+u8 __cmpxchg_u8(volatile u8 *m, u8 old, u8 new_);
+u16 __cmpxchg_u16(volatile u16 *m, u16 old, u16 new_);
 u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
 
 /* don't worry...optimizer will get rid of most of this */
@@ -46,6 +47,10 @@ static inline unsigned long
 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
 {
 	switch (size) {
+	case 1:
+		return __cmpxchg_u8((u8 *)ptr, (u8)old, (u8)new_);
+	case 2:
+		return __cmpxchg_u16((u16 *)ptr, (u16)old, (u16)new_);
 	case 4:
 		return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
 	default:
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
index 0d215a772428..8ae880ebf07a 100644
--- a/arch/sparc/lib/atomic32.c
+++ b/arch/sparc/lib/atomic32.c
@@ -173,8 +173,12 @@ EXPORT_SYMBOL(sp32___change_bit);
 		return prev;					\
 	}
 
+CMPXCHG(u8)
+CMPXCHG(u16)
 CMPXCHG(u32)
 CMPXCHG(u64)
+EXPORT_SYMBOL(__cmpxchg_u8);
+EXPORT_SYMBOL(__cmpxchg_u16);
 EXPORT_SYMBOL(__cmpxchg_u32);
 EXPORT_SYMBOL(__cmpxchg_u64);
 
-- 
2.39.2