[PATCH v4 02/12] this_cpu_cmpxchg: ARM64: switch this_cpu_cmpxchg to locked, add _local function

[Marcelo Tosatti]

Goal is to have vmstat_shepherd to transfer from
per-CPU counters to global counters remotely. For this, 
an atomic this_cpu_cmpxchg is necessary.

Following the kernel convention for cmpxchg/cmpxchg_local,
change ARM's this_cpu_cmpxchg_ helpers to be atomic,
and add this_cpu_cmpxchg_local_ helpers which are not atomic.

Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

Index: linux-vmstat-remote/arch/arm64/include/asm/percpu.h
===================================================================
--- linux-vmstat-remote.orig/arch/arm64/include/asm/percpu.h
+++ linux-vmstat-remote/arch/arm64/include/asm/percpu.h
@@ -232,13 +232,23 @@ PERCPU_RET_OP(add, add, ldadd)
 	_pcp_protect_return(xchg_relaxed, pcp, val)
 
 #define this_cpu_cmpxchg_1(pcp, o, n)	\
-	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+	_pcp_protect_return(cmpxchg, pcp, o, n)
 #define this_cpu_cmpxchg_2(pcp, o, n)	\
-	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+	_pcp_protect_return(cmpxchg, pcp, o, n)
 #define this_cpu_cmpxchg_4(pcp, o, n)	\
-	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+	_pcp_protect_return(cmpxchg, pcp, o, n)
 #define this_cpu_cmpxchg_8(pcp, o, n)	\
+	_pcp_protect_return(cmpxchg, pcp, o, n)
+
+#define this_cpu_cmpxchg_local_1(pcp, o, n)	\
 	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+#define this_cpu_cmpxchg_local_2(pcp, o, n)	\
+	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+#define this_cpu_cmpxchg_local_4(pcp, o, n)	\
+	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+#define this_cpu_cmpxchg_local_8(pcp, o, n)	\
+	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
+
 
 #ifdef __KVM_NVHE_HYPERVISOR__
 extern unsigned long __hyp_per_cpu_offset(unsigned int cpu);