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Subject[PATCH 09/17] tracing/probes: Implement 'stack' fetch method for uprobes
Date
From: Namhyung Kim <namhyung.kim@lge.com>

Use separate method to fetch from stack. Move existing functions to
trace_kprobe.c and make them static. Also add new stack fetch
implementation for uprobes.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/trace/trace_kprobe.c | 15 +++++++++++++++
kernel/trace/trace_probe.c | 22 ----------------------
kernel/trace/trace_probe.h | 14 ++++++++++----
kernel/trace/trace_uprobe.c | 41 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 66 insertions(+), 26 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d00ee5ce6ccc..4eaecf9bfd66 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -88,6 +88,21 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
static int kretprobe_dispatcher(struct kretprobe_instance *ri,
struct pt_regs *regs);

+/*
+ * Kprobes-specific fetch functions
+ */
+#define DEFINE_FETCH_stack(type) \
+static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
+ void *offset, void *dest) \
+{ \
+ *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
+ (unsigned int)((unsigned long)offset)); \
+}
+DEFINE_BASIC_FETCH_FUNCS(stack)
+/* No string on the stack entry */
+#define fetch_stack_string NULL
+#define fetch_stack_string_size NULL
+
/* Fetch type information table */
const struct fetch_type kprobes_fetch_type_table[] = {
/* Special types */
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 68b00a214fcc..ddd14a5cb3ee 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -70,16 +70,6 @@ __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,

const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";

-/*
- * Define macro for basic types - we don't need to define s* types, because
- * we have to care only about bitwidth at recording time.
- */
-#define DEFINE_BASIC_FETCH_FUNCS(method) \
-DEFINE_FETCH_##method(u8) \
-DEFINE_FETCH_##method(u16) \
-DEFINE_FETCH_##method(u32) \
-DEFINE_FETCH_##method(u64)
-
#define CHECK_FETCH_FUNCS(method, fn) \
(((FETCH_FUNC_NAME(method, u8) == fn) || \
(FETCH_FUNC_NAME(method, u16) == fn) || \
@@ -102,18 +92,6 @@ DEFINE_BASIC_FETCH_FUNCS(reg)
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL

-#define DEFINE_FETCH_stack(type) \
-__kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
- void *offset, void *dest) \
-{ \
- *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
- (unsigned int)((unsigned long)offset)); \
-}
-DEFINE_BASIC_FETCH_FUNCS(stack)
-/* No string on the stack entry */
-#define fetch_stack_string NULL
-#define fetch_stack_string_size NULL
-
#define DEFINE_FETCH_retval(type) \
__kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
void *dummy, void *dest) \
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 99d3aa1f2d8a..23b2d83ee5fb 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -167,10 +167,6 @@ DECLARE_BASIC_FETCH_FUNCS(reg);
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL

-DECLARE_BASIC_FETCH_FUNCS(stack);
-#define fetch_stack_string NULL
-#define fetch_stack_string_size NULL
-
DECLARE_BASIC_FETCH_FUNCS(retval);
#define fetch_retval_string NULL
#define fetch_retval_string_size NULL
@@ -191,6 +187,16 @@ DECLARE_BASIC_FETCH_FUNCS(bitfield);
#define fetch_bitfield_string NULL
#define fetch_bitfield_string_size NULL

+/*
+ * Define macro for basic types - we don't need to define s* types, because
+ * we have to care only about bitwidth at recording time.
+ */
+#define DEFINE_BASIC_FETCH_FUNCS(method) \
+DEFINE_FETCH_##method(u8) \
+DEFINE_FETCH_##method(u16) \
+DEFINE_FETCH_##method(u32) \
+DEFINE_FETCH_##method(u64)
+
/* Default (unsigned long) fetch type */
#define __DEFAULT_FETCH_TYPE(t) u##t
#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c66ddc744f12..28caa766edf8 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -74,6 +74,47 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
static int uretprobe_dispatcher(struct uprobe_consumer *con,
unsigned long func, struct pt_regs *regs);

+#ifdef CONFIG_STACK_GROWSUP
+static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
+{
+ return addr - (n * sizeof(long));
+}
+#else
+static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
+{
+ return addr + (n * sizeof(long));
+}
+#endif
+
+static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
+{
+ unsigned long ret;
+ unsigned long addr = user_stack_pointer(regs);
+
+ addr = adjust_stack_addr(addr, n);
+
+ if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
+ return 0;
+
+ return ret;
+}
+
+/*
+ * Uprobes-specific fetch functions
+ */
+#define DEFINE_FETCH_stack(type) \
+static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
+ void *offset, void *dest) \
+{ \
+ *(type *)dest = (type)get_user_stack_nth(regs, \
+ ((unsigned long)offset)); \
+}
+DEFINE_BASIC_FETCH_FUNCS(stack)
+/* No string on the stack entry */
+#define fetch_stack_string NULL
+#define fetch_stack_string_size NULL
+
+
/* Fetch type information table */
const struct fetch_type uprobes_fetch_type_table[] = {
/* Special types */
--
1.7.11.7


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