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

Mathieu Desnoyers
2006-12-21T00:00:50Z

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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