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Namhyung Kimrostedt
Namhyung Kim
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tracing/probes: Move 'symbol' fetch method to kprobes
Move existing functions to trace_kprobe.c and add NULL entries to the uprobes fetch type table. I don't make them static since some generic routines like update/free_XXX_fetch_param() require pointers to the functions. Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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4 files changed

+91
-59
lines changed

4 files changed

+91
-59
lines changed

‎kernel/trace/trace_kprobe.c

Lines changed: 59 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -88,6 +88,51 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
8888
static int kretprobe_dispatcher(struct kretprobe_instance *ri,
8989
struct pt_regs *regs);
9090

91+
/* Memory fetching by symbol */
92+
struct symbol_cache {
93+
char *symbol;
94+
long offset;
95+
unsigned long addr;
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};
97+
98+
unsigned long update_symbol_cache(struct symbol_cache *sc)
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{
100+
sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
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102+
if (sc->addr)
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sc->addr += sc->offset;
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105+
return sc->addr;
106+
}
107+
108+
void free_symbol_cache(struct symbol_cache *sc)
109+
{
110+
kfree(sc->symbol);
111+
kfree(sc);
112+
}
113+
114+
struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
115+
{
116+
struct symbol_cache *sc;
117+
118+
if (!sym || strlen(sym) == 0)
119+
return NULL;
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sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
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if (!sc)
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return NULL;
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125+
sc->symbol = kstrdup(sym, GFP_KERNEL);
126+
if (!sc->symbol) {
127+
kfree(sc);
128+
return NULL;
129+
}
130+
sc->offset = offset;
131+
update_symbol_cache(sc);
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133+
return sc;
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}
135+
91136
/*
92137
* Kprobes-specific fetch functions
93138
*/
@@ -103,6 +148,20 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
103148
#define fetch_stack_string NULL
104149
#define fetch_stack_string_size NULL
105150

151+
#define DEFINE_FETCH_symbol(type) \
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__kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, \
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void *data, void *dest) \
154+
{ \
155+
struct symbol_cache *sc = data; \
156+
if (sc->addr) \
157+
fetch_memory_##type(regs, (void *)sc->addr, dest); \
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else \
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*(type *)dest = 0; \
160+
}
161+
DEFINE_BASIC_FETCH_FUNCS(symbol)
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DEFINE_FETCH_symbol(string)
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DEFINE_FETCH_symbol(string_size)
164+
106165
/* Fetch type information table */
107166
const struct fetch_type kprobes_fetch_type_table[] = {
108167
/* Special types */

‎kernel/trace/trace_probe.c

Lines changed: 0 additions & 59 deletions
Original file line numberDiff line numberDiff line change
@@ -180,65 +180,6 @@ __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
180180
*(u32 *)dest = len;
181181
}
182182

183-
/* Memory fetching by symbol */
184-
struct symbol_cache {
185-
char *symbol;
186-
long offset;
187-
unsigned long addr;
188-
};
189-
190-
static unsigned long update_symbol_cache(struct symbol_cache *sc)
191-
{
192-
sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
193-
194-
if (sc->addr)
195-
sc->addr += sc->offset;
196-
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return sc->addr;
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}
199-
200-
static void free_symbol_cache(struct symbol_cache *sc)
201-
{
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kfree(sc->symbol);
203-
kfree(sc);
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}
205-
206-
static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
207-
{
208-
struct symbol_cache *sc;
209-
210-
if (!sym || strlen(sym) == 0)
211-
return NULL;
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sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
214-
if (!sc)
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return NULL;
216-
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sc->symbol = kstrdup(sym, GFP_KERNEL);
218-
if (!sc->symbol) {
219-
kfree(sc);
220-
return NULL;
221-
}
222-
sc->offset = offset;
223-
update_symbol_cache(sc);
224-
225-
return sc;
226-
}
227-
228-
#define DEFINE_FETCH_symbol(type) \
229-
__kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, \
230-
void *data, void *dest) \
231-
{ \
232-
struct symbol_cache *sc = data; \
233-
if (sc->addr) \
234-
fetch_memory_##type(regs, (void *)sc->addr, dest); \
235-
else \
236-
*(type *)dest = 0; \
237-
}
238-
DEFINE_BASIC_FETCH_FUNCS(symbol)
239-
DEFINE_FETCH_symbol(string)
240-
DEFINE_FETCH_symbol(string_size)
241-
242183
/* Dereference memory access function */
243184
struct deref_fetch_param {
244185
struct fetch_param orig;

‎kernel/trace/trace_probe.h

Lines changed: 24 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -239,6 +239,30 @@ ASSIGN_FETCH_FUNC(bitfield, ftype), \
239239
extern __weak const struct fetch_type kprobes_fetch_type_table[];
240240
extern __weak const struct fetch_type uprobes_fetch_type_table[];
241241

242+
#ifdef CONFIG_KPROBE_EVENT
243+
struct symbol_cache;
244+
unsigned long update_symbol_cache(struct symbol_cache *sc);
245+
void free_symbol_cache(struct symbol_cache *sc);
246+
struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
247+
#else
248+
struct symbol_cache {
249+
};
250+
static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
251+
{
252+
return 0;
253+
}
254+
255+
static inline void __used free_symbol_cache(struct symbol_cache *sc)
256+
{
257+
}
258+
259+
static inline struct symbol_cache * __used
260+
alloc_symbol_cache(const char *sym, long offset)
261+
{
262+
return NULL;
263+
}
264+
#endif /* CONFIG_KPROBE_EVENT */
265+
242266
struct probe_arg {
243267
struct fetch_param fetch;
244268
struct fetch_param fetch_size;

‎kernel/trace/trace_uprobe.c

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -115,6 +115,14 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
115115
#define fetch_stack_string_size NULL
116116

117117

118+
/* uprobes do not support symbol fetch methods */
119+
#define fetch_symbol_u8 NULL
120+
#define fetch_symbol_u16 NULL
121+
#define fetch_symbol_u32 NULL
122+
#define fetch_symbol_u64 NULL
123+
#define fetch_symbol_string NULL
124+
#define fetch_symbol_string_size NULL
125+
118126
/* Fetch type information table */
119127
const struct fetch_type uprobes_fetch_type_table[] = {
120128
/* Special types */

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