[PATCH v6 12/21] tracing: probeevent: Unify fetch_insn processing common part

Masami Hiramatsu
2018-03-17T12:47:08Z

Unify the fetch_insn bottom process (from stage 2: dereference
indirect data) from kprobe and uprobe events, since those are
mostly same.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/trace/trace_kprobe.c | 47 +++++----------------------------
kernel/trace/trace_probe_tmpl.h | 55 ++++++++++++++++++++++++++++++++++++++-
kernel/trace/trace_uprobe.c | 43 +-----------------------------
3 files changed, 63 insertions(+), 82 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7d48ae5f0617..b564d38810b7 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -857,13 +857,18 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
return ret;
}

+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+ return probe_kernel_read(dest, src, size);
+}
+
/* Note that we don't verify it, since the code does not come from user space */
static int
process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
void *base)
{
unsigned long val;
- int ret = 0;

/* 1st stage: get value from context */
switch (code->op) {
@@ -890,45 +895,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
}
code++;

- /* 2nd stage: dereference memory if needed */
- while (code->op == FETCH_OP_DEREF) {
- ret = probe_kernel_read(&val, (void *)val + code->offset,
- sizeof(val));
- if (ret)
- return ret;
- code++;
- }
-
- /* 3rd stage: store value to buffer */
- if (unlikely(!dest)) {
- if (code->op == FETCH_OP_ST_STRING)
- return fetch_store_strlen(val + code->offset);
- else
- return -EILSEQ;
- }
-
- switch (code->op) {
- case FETCH_OP_ST_RAW:
- fetch_store_raw(val, code, dest);
- break;
- case FETCH_OP_ST_MEM:
- probe_kernel_read(dest, (void *)val + code->offset, code->size);
- break;
- case FETCH_OP_ST_STRING:
- ret = fetch_store_string(val + code->offset, dest, base);
- break;
- default:
- return -EILSEQ;
- }
- code++;
-
- /* 4th stage: modify stored value if needed */
- if (code->op == FETCH_OP_MOD_BF) {
- fetch_apply_bitfield(code, dest);
- code++;
- }
-
- return code->op == FETCH_OP_END ? ret : -EILSEQ;
+ return process_fetch_insn_bottom(code, val, dest, base);
}
NOKPROBE_SYMBOL(process_fetch_insn)

diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index d9aebd395a9d..32ae2fc78190 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -49,13 +49,66 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf)
}

/*
- * This must be defined for each callsite.
+ * These functions must be defined for each callsite.
* Return consumed dynamic data size (>= 0), or error (< 0).
* If dest is NULL, don't store result and return required dynamic data size.
*/
static int
process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs,
void *dest, void *base);
+static nokprobe_inline int fetch_store_strlen(unsigned long addr);
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base);
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size);
+
+/* From the 2nd stage, routine is same */
+static nokprobe_inline int
+process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
+ void *dest, void *base)
+{
+ int ret = 0;
+
+ /* 2nd stage: dereference memory if needed */
+ while (code->op == FETCH_OP_DEREF) {
+ ret = probe_mem_read(&val, (void *)val + code->offset,
+ sizeof(val));
+ if (ret)
+ return ret;
+ code++;
+ }
+
+ /* 3rd stage: store value to buffer */
+ if (unlikely(!dest)) {
+ if (code->op == FETCH_OP_ST_STRING)
+ return fetch_store_strlen(val + code->offset);
+ else
+ return -EILSEQ;
+ }
+
+ switch (code->op) {
+ case FETCH_OP_ST_RAW:
+ fetch_store_raw(val, code, dest);
+ break;
+ case FETCH_OP_ST_MEM:
+ probe_mem_read(dest, (void *)val + code->offset, code->size);
+ break;
+ case FETCH_OP_ST_STRING:
+ ret = fetch_store_string(val + code->offset, dest, base);
+ break;
+ default:
+ return -EILSEQ;
+ }
+ code++;
+
+ /* 4th stage: modify stored value if needed */
+ if (code->op == FETCH_OP_MOD_BF) {
+ fetch_apply_bitfield(code, dest);
+ code++;
+ }
+
+ return code->op == FETCH_OP_END ? ret : -EILSEQ;
+}

/* Sum up total data length for dynamic arraies (strings) */
static nokprobe_inline int
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index fafd48310823..64c1fbe087a1 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -111,7 +111,7 @@ static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
* Uprobes-specific fetch functions
*/
static nokprobe_inline int
-probe_user_read(void *dest, void *src, size_t size)
+probe_mem_read(void *dest, void *src, size_t size)
{
void __user *vaddr = (void __force __user *)src;

@@ -172,7 +172,6 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
void *base)
{
unsigned long val;
- int ret = 0;

/* 1st stage: get value from context */
switch (code->op) {
@@ -199,45 +198,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
}
code++;

- /* 2nd stage: dereference memory if needed */
- while (code->op == FETCH_OP_DEREF) {
- ret = probe_user_read(&val, (void *)val + code->offset,
- sizeof(val));
- if (ret)
- return ret;
- code++;
- }
-
- /* 3rd stage: store value to buffer */
- if (unlikely(!dest)) {
- if (code->op == FETCH_OP_ST_STRING)
- return fetch_store_strlen(val + code->offset);
- else
- return -EILSEQ;
- }
-
- switch (code->op) {
- case FETCH_OP_ST_RAW:
- fetch_store_raw(val, code, dest);
- break;
- case FETCH_OP_ST_MEM:
- probe_kernel_read(dest, (void *)val + code->offset, code->size);
- break;
- case FETCH_OP_ST_STRING:
- ret = fetch_store_string(val + code->offset, dest, base);
- break;
- default:
- return -EILSEQ;
- }
- code++;
-
- /* 4th stage: modify stored value if needed */
- if (code->op == FETCH_OP_MOD_BF) {
- fetch_apply_bitfield(code, dest);
- code++;
- }
-
- return code->op == FETCH_OP_END ? ret : -EILSEQ;
+ return process_fetch_insn_bottom(code, val, dest, base);
}
NOKPROBE_SYMBOL(process_fetch_insn)