From 8256e47cdc8923e9959eb1d7f95d80da538add80 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 18 Oct 2007 23:41:06 -0700 Subject: Linux Kernel Markers The marker activation functions sits in kernel/marker.c. A hash table is used to keep track of the registered probes and armed markers, so the markers within a newly loaded module that should be active can be activated at module load time. marker_query has been removed. marker_get_first, marker_get_next and marker_release should be used as iterators on the markers. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mathieu Desnoyers Acked-by: "Frank Ch. Eigler" Cc: Christoph Hellwig Cc: Rusty Russell Cc: Mike Mason Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/vmlinux.lds.h | 7 +- include/linux/marker.h | 130 ++++++++++++++++++++++++++++++++++++++ include/linux/module.h | 12 ++++ 3 files changed, 148 insertions(+), 1 deletion(-) create mode 100644 include/linux/marker.h (limited to 'include') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 5615440027ec..9f584cc5c5fb 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -12,7 +12,11 @@ /* .data section */ #define DATA_DATA \ *(.data) \ - *(.data.init.refok) + *(.data.init.refok) \ + . = ALIGN(8); \ + VMLINUX_SYMBOL(__start___markers) = .; \ + *(__markers) \ + VMLINUX_SYMBOL(__stop___markers) = .; #define RO_DATA(align) \ . = ALIGN((align)); \ @@ -20,6 +24,7 @@ VMLINUX_SYMBOL(__start_rodata) = .; \ *(.rodata) *(.rodata.*) \ *(__vermagic) /* Kernel version magic */ \ + *(__markers_strings) /* Markers: strings */ \ } \ \ .rodata1 : AT(ADDR(.rodata1) - LOAD_OFFSET) { \ diff --git a/include/linux/marker.h b/include/linux/marker.h new file mode 100644 index 000000000000..8038d89b835d --- /dev/null +++ b/include/linux/marker.h @@ -0,0 +1,130 @@ +#ifndef _LINUX_MARKER_H +#define _LINUX_MARKER_H + +/* + * Code markup for dynamic and static tracing. + * + * See Documentation/marker.txt. + * + * (C) Copyright 2006 Mathieu Desnoyers + * + * This file is released under the GPLv2. + * See the file COPYING for more details. + */ + +#include + +struct module; +struct marker; + +/** + * marker_probe_func - Type of a marker probe function + * @mdata: pointer of type struct marker + * @private_data: caller site private data + * @fmt: format string + * @...: variable argument list + * + * Type of marker probe functions. They receive the mdata and need to parse the + * format string to recover the variable argument list. + */ +typedef void marker_probe_func(const struct marker *mdata, + void *private_data, const char *fmt, ...); + +struct marker { + const char *name; /* Marker name */ + const char *format; /* Marker format string, describing the + * variable argument list. + */ + char state; /* Marker state. */ + marker_probe_func *call;/* Probe handler function pointer */ + void *private; /* Private probe data */ +} __attribute__((aligned(8))); + +#ifdef CONFIG_MARKERS + +/* + * Note : the empty asm volatile with read constraint is used here instead of a + * "used" attribute to fix a gcc 4.1.x bug. + * Make sure the alignment of the structure in the __markers section will + * not add unwanted padding between the beginning of the section and the + * structure. Force alignment to the same alignment as the section start. + */ +#define __trace_mark(name, call_data, format, args...) \ + do { \ + static const char __mstrtab_name_##name[] \ + __attribute__((section("__markers_strings"))) \ + = #name; \ + static const char __mstrtab_format_##name[] \ + __attribute__((section("__markers_strings"))) \ + = format; \ + static struct marker __mark_##name \ + __attribute__((section("__markers"), aligned(8))) = \ + { __mstrtab_name_##name, __mstrtab_format_##name, \ + 0, __mark_empty_function, NULL }; \ + asm volatile("" : : "i" (&__mark_##name)); \ + __mark_check_format(format, ## args); \ + if (unlikely(__mark_##name.state)) { \ + preempt_disable(); \ + (*__mark_##name.call) \ + (&__mark_##name, call_data, \ + format, ## args); \ + preempt_enable(); \ + } \ + } while (0) + +extern void marker_update_probe_range(struct marker *begin, + struct marker *end, struct module *probe_module, int *refcount); +#else /* !CONFIG_MARKERS */ +#define __trace_mark(name, call_data, format, args...) \ + __mark_check_format(format, ## args) +static inline void marker_update_probe_range(struct marker *begin, + struct marker *end, struct module *probe_module, int *refcount) +{ } +#endif /* CONFIG_MARKERS */ + +/** + * trace_mark - Marker + * @name: marker name, not quoted. + * @format: format string + * @args...: variable argument list + * + * Places a marker. + */ +#define trace_mark(name, format, args...) \ + __trace_mark(name, NULL, format, ## args) + +#define MARK_MAX_FORMAT_LEN 1024 + +/** + * MARK_NOARGS - Format string for a marker with no argument. + */ +#define MARK_NOARGS " " + +/* To be used for string format validity checking with gcc */ +static inline void __printf(1, 2) __mark_check_format(const char *fmt, ...) +{ +} + +extern marker_probe_func __mark_empty_function; + +/* + * Connect a probe to a marker. + * private data pointer must be a valid allocated memory address, or NULL. + */ +extern int marker_probe_register(const char *name, const char *format, + marker_probe_func *probe, void *private); + +/* + * Returns the private data given to marker_probe_register. + */ +extern void *marker_probe_unregister(const char *name); +/* + * Unregister a marker by providing the registered private data. + */ +extern void *marker_probe_unregister_private_data(void *private); + +extern int marker_arm(const char *name); +extern int marker_disarm(const char *name); +extern void *marker_get_private_data(const char *name); + +#endif diff --git a/include/linux/module.h b/include/linux/module.h index 642f325e4917..2cbc0b87e329 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -354,6 +355,10 @@ struct module /* The command line arguments (may be mangled). People like keeping pointers to this stuff */ char *args; +#ifdef CONFIG_MARKERS + struct marker *markers; + unsigned int num_markers; +#endif }; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} @@ -457,6 +462,8 @@ int unregister_module_notifier(struct notifier_block * nb); extern void print_modules(void); +extern void module_update_markers(struct module *probe_module, int *refcount); + #else /* !CONFIG_MODULES... */ #define EXPORT_SYMBOL(sym) #define EXPORT_SYMBOL_GPL(sym) @@ -556,6 +563,11 @@ static inline void print_modules(void) { } +static inline void module_update_markers(struct module *probe_module, + int *refcount) +{ +} + #endif /* CONFIG_MODULES */ struct device_driver; -- cgit v1.2.2