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hw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces

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This patch adds an ftrace plugin to detect and profile memory access over kernel
variables. It uses HW Breakpoint interfaces to 'watch memory addresses.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
K.Prasad
2009-06-01 23:46:40 +05:30
committed by Frederic Weisbecker
parent 432039933a
commit 0722db015c
5 changed files with 623 additions and 0 deletions
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23
kernel/trace/trace.h
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@ -15,6 +15,10 @@
#include <linux/trace_seq.h>
#include <linux/ftrace_event.h>
#ifdef CONFIG_KSYM_TRACER
#include <asm/hw_breakpoint.h>
#endif
enum trace_type {
__TRACE_FIRST_TYPE = 0,
@ -40,6 +44,7 @@ enum trace_type {
TRACE_KMEM_FREE,
TRACE_POWER,
TRACE_BLK,
TRACE_KSYM,
__TRACE_LAST_TYPE,
};
@ -207,6 +212,21 @@ struct syscall_trace_exit {
unsigned long ret;
};
#define KSYM_SELFTEST_ENTRY "ksym_selftest_dummy"
extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr);
struct trace_ksym {
struct trace_entry ent;
struct hw_breakpoint *ksym_hbp;
unsigned long ksym_addr;
unsigned long ip;
#ifdef CONFIG_PROFILE_KSYM_TRACER
unsigned long counter;
#endif
struct hlist_node ksym_hlist;
char ksym_name[KSYM_NAME_LEN];
char p_name[TASK_COMM_LEN];
};
/*
* trace_flag_type is an enumeration that holds different
@ -323,6 +343,7 @@ extern void __ftrace_bad_type(void);
TRACE_SYSCALL_ENTER); \
IF_ASSIGN(var, ent, struct syscall_trace_exit, \
TRACE_SYSCALL_EXIT); \
IF_ASSIGN(var, ent, struct trace_ksym, TRACE_KSYM); \
__ftrace_bad_type(); \
} while (0)
@ -540,6 +561,8 @@ extern int trace_selftest_startup_branch(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_hw_branches(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_ksym(struct tracer *trace,
struct trace_array *tr);
#endif /* CONFIG_FTRACE_STARTUP_TEST */
extern void *head_page(struct trace_array_cpu *data);