[PATCH 3/4] Linux Kernel Markers : i386 optimisation

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

This is the i386 optimisation for the Linux Kernel Markers.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- /dev/null
+++ b/include/asm-i386/marker.h
@@ -0,0 +1,54 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. i386 architecture optimisations.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+
+struct __mark_marker_c {
+	const char *name;
+	marker_probe_func **call;
+	const char *format;
+} __attribute__((packed));
+
+struct __mark_marker {
+	struct __mark_marker_c *cmark;
+	volatile char *enable;
+} __attribute__((packed));
+
+#ifdef CONFIG_MARKERS
+#define MARK(name, format, args...) \
+	do { \
+		static marker_probe_func *__mark_call_##name = \
+					__mark_empty_function; \
+		static const struct __mark_marker_c __mark_c_##name \
+			__attribute__((section(".markers.c"))) = \
+			{ #name, &__mark_call_##name, format } ; \
+		char condition; \
+		asm volatile(	".section .markers, \"a\";\n\t" \
+					".long %1, 0f;\n\t" \
+					".previous;\n\t" \
+					".align 2\n\t" \
+					"0:\n\t" \
+					"movb $0,%0;\n\t" \
+				: "=r" (condition) \
+				: "m" (__mark_c_##name)); \
+		__mark_check_format(format, ## args); \
+		if (unlikely(condition)) { \
+			preempt_disable(); \
+			(*__mark_call_##name)(format, ## args); \
+			preempt_enable_no_resched(); \
+		} \
+	} while (0)
+
+/* Offset of the immediate value from the start of the movb instruction, in
+ * bytes. */
+#define MARK_ENABLE_IMMEDIATE_OFFSET 1
+#define MARK_POLYMORPHIC
+
+#endif

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