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-rw-r--r--arch/x86/include/asm/percpu.h158
1 files changed, 157 insertions, 1 deletions
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index f899e01a8ac9..8ee45167e817 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -230,6 +230,125 @@ do { \
})
/*
+ * Add return operation
+ */
+#define percpu_add_return_op(var, val) \
+({ \
+ typeof(var) paro_ret__ = val; \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm("xaddb %0, "__percpu_arg(1) \
+ : "+q" (paro_ret__), "+m" (var) \
+ : : "memory"); \
+ break; \
+ case 2: \
+ asm("xaddw %0, "__percpu_arg(1) \
+ : "+r" (paro_ret__), "+m" (var) \
+ : : "memory"); \
+ break; \
+ case 4: \
+ asm("xaddl %0, "__percpu_arg(1) \
+ : "+r" (paro_ret__), "+m" (var) \
+ : : "memory"); \
+ break; \
+ case 8: \
+ asm("xaddq %0, "__percpu_arg(1) \
+ : "+re" (paro_ret__), "+m" (var) \
+ : : "memory"); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+ paro_ret__ += val; \
+ paro_ret__; \
+})
+
+/*
+ * xchg is implemented using cmpxchg without a lock prefix. xchg is
+ * expensive due to the implied lock prefix. The processor cannot prefetch
+ * cachelines if xchg is used.
+ */
+#define percpu_xchg_op(var, nval) \
+({ \
+ typeof(var) pxo_ret__; \
+ typeof(var) pxo_new__ = (nval); \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm("\n1:mov "__percpu_arg(1)",%%al" \
+ "\n\tcmpxchgb %2, "__percpu_arg(1) \
+ "\n\tjnz 1b" \
+ : "=a" (pxo_ret__), "+m" (var) \
+ : "q" (pxo_new__) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm("\n1:mov "__percpu_arg(1)",%%ax" \
+ "\n\tcmpxchgw %2, "__percpu_arg(1) \
+ "\n\tjnz 1b" \
+ : "=a" (pxo_ret__), "+m" (var) \
+ : "r" (pxo_new__) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm("\n1:mov "__percpu_arg(1)",%%eax" \
+ "\n\tcmpxchgl %2, "__percpu_arg(1) \
+ "\n\tjnz 1b" \
+ : "=a" (pxo_ret__), "+m" (var) \
+ : "r" (pxo_new__) \
+ : "memory"); \
+ break; \
+ case 8: \
+ asm("\n1:mov "__percpu_arg(1)",%%rax" \
+ "\n\tcmpxchgq %2, "__percpu_arg(1) \
+ "\n\tjnz 1b" \
+ : "=a" (pxo_ret__), "+m" (var) \
+ : "r" (pxo_new__) \
+ : "memory"); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+ pxo_ret__; \
+})
+
+/*
+ * cmpxchg has no such implied lock semantics as a result it is much
+ * more efficient for cpu local operations.
+ */
+#define percpu_cmpxchg_op(var, oval, nval) \
+({ \
+ typeof(var) pco_ret__; \
+ typeof(var) pco_old__ = (oval); \
+ typeof(var) pco_new__ = (nval); \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm("cmpxchgb %2, "__percpu_arg(1) \
+ : "=a" (pco_ret__), "+m" (var) \
+ : "q" (pco_new__), "0" (pco_old__) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm("cmpxchgw %2, "__percpu_arg(1) \
+ : "=a" (pco_ret__), "+m" (var) \
+ : "r" (pco_new__), "0" (pco_old__) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm("cmpxchgl %2, "__percpu_arg(1) \
+ : "=a" (pco_ret__), "+m" (var) \
+ : "r" (pco_new__), "0" (pco_old__) \
+ : "memory"); \
+ break; \
+ case 8: \
+ asm("cmpxchgq %2, "__percpu_arg(1) \
+ : "=a" (pco_ret__), "+m" (var) \
+ : "r" (pco_new__), "0" (pco_old__) \
+ : "memory"); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+ pco_ret__; \
+})
+
+/*
* percpu_read() makes gcc load the percpu variable every time it is
* accessed while percpu_read_stable() allows the value to be cached.
* percpu_read_stable() is more efficient and can be used if its value
@@ -267,6 +386,12 @@ do { \
#define __this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
#define __this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
#define __this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
+/*
+ * Generic fallback operations for __this_cpu_xchg_[1-4] are okay and much
+ * faster than an xchg with forced lock semantics.
+ */
+#define __this_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval)
+#define __this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
#define this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
#define this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
@@ -286,6 +411,11 @@ do { \
#define this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
#define this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
#define this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
+#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(pcp, nval)
+#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(pcp, nval)
+#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(pcp, nval)
+#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval)
+#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
#define irqsafe_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
#define irqsafe_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
@@ -299,6 +429,31 @@ do { \
#define irqsafe_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
#define irqsafe_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
#define irqsafe_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
+#define irqsafe_cpu_xchg_1(pcp, nval) percpu_xchg_op(pcp, nval)
+#define irqsafe_cpu_xchg_2(pcp, nval) percpu_xchg_op(pcp, nval)
+#define irqsafe_cpu_xchg_4(pcp, nval) percpu_xchg_op(pcp, nval)
+#define irqsafe_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval)
+#define irqsafe_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+
+#ifndef CONFIG_M386
+#define __this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
+#define __this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
+#define __this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
+#define __this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define __this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define __this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+
+#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
+#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
+#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
+#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+
+#define irqsafe_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define irqsafe_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define irqsafe_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#endif /* !CONFIG_M386 */
/*
* Per cpu atomic 64 bit operations are only available under 64 bit.
@@ -311,6 +466,7 @@ do { \
#define __this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define __this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define __this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
+#define __this_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val)
#define this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
#define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
@@ -318,12 +474,12 @@ do { \
#define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
+#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val)
#define irqsafe_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
#define irqsafe_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define irqsafe_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define irqsafe_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
-
#endif
/* This is not atomic against other CPUs -- CPU preemption needs to be off */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 18:07:31 +0000